Most origami replicas come with the brake calipers seized onto their pins. This creates problems with braking, poor adjustability, brake pad wear and can warp a brake disc. To correct this problem, remove the brake calipers from the bike, and grease the pins with copper grease and refit, sometimes some filing of the caliper itself is required to let the calipers float freely. Once reconstructed when the brake is applied the caliper shouldnt move, if the caliper moves its not floating and will be problematic.
Brake Pic
2. Fuel tank Heat Problems.
There have been several reports of the exhaust heating up enough to melt the fuel tank pouring petrol on the engine, which you can expect is a bad thing, to stop this happening purchase some aluminium foil and line the bottom of the tank.
Tank Pic
I have personally lined my tank and it is strongly advised as is a common problem.
3. Fairing Heat Problems.
As the exhaust header is very close to the bottom of the fairing the exhaust will melt thru the fairing, as with the tank line the bottom of the fairing with aluminium tape. The seat fairing can be lined aswell if that starts heating up.
Fairing Pic
4. Align Clutch.
Most replica origami clutches come unadjusted, we have seen several with the clutches with their clutch springs set to completely different lengths. Remove the clutch bell and adjust the clutch so each spring is of a similar length, after 30 mins running, remove the clutch again and check that the pads are wearing evenly, adjust if not.
Clutch Pic
5. Cut Origami Bar Ends.
To allow more movement of the bars and to be able to straighten the bars up, remove the bars, cut off excess bar, pop the plastic cap out and refit in the cut bars.
Bars Pic
6. Rebuild the Origamis Coolant Cap.
We have found that most origami minimotos come with the coolant cap built incorrectly, and because of the coolant system isnt pressurised and when the coolant heats up, will spray coolant out. To solve this rebuild the cap. Reassemble the components in the following order ( see pic ) and then the system should be pressurised and therefore allow the coolant to get hotter without blowing.
Coolant cap Pic
7. Coolant : Dont use the coolant supplied with the bike as when this spills on the track it can create an extremely slippy surface that cant be cleaned, use distilled water with food colouring or anti freeze to show the coolant level. This has no eefect on the cooling by the way.
8. Coolant Level : Fill the coolant level to about 1/4 of the coolant tank as this will allow for expansion
9. Bake Clutch To extend the life of the standard clutch it can be baked, ( info coming later )
10. Adjust rear mudguard.
The rear mudguard as standard is far too close to the tyre and will catch , usually throwing the mudguard off, to fix this remove the rear mudguard and slightly bend the mount tabs upwards and refit, the mudguard should be 1 cm away from the tyre. Fit and locktight bolts behind the mudguard mounting tabs to hold the bolts firmly.
Mudguard Pic
11. Padding : Add draught excluder under tank to stop the tank bouncing on the hard metal frame, which stops fuel foaming and better flow.
12. Bolts : Tighten and locktight all bolts
13. Tighten chain : Adjust the rear wheel spacers to increase or decrease chain tension, check the manual for the specs
14. Brakes : Adjust the front brakes so both brakes activate at the same time, check after 10 minutes of riding that both discs are at a similar temperature ( be careful ! ) if not adjust
15. Coolant bottleSome Origami Reps are supplied with the coolant bottle attached to the wrong side of the mounting tab, if your fairing visor doesnt fit correctly move the bottle to the opposite side of the tab.
16. Tiewrap Brake cable.
The rear mudguard as standard is far too close to the tyre and will catch , usually throwing the mudguard off, to fix this remove the rear mudguard and slightly bend the mount tabs upwards and refit, the mudguard should be 1 cm away from the tyre. Fit and locktight bolts behind the mudguard mounting tabs to hold the bolts firmly.
Tiewrap Pic
17. Footpeg bar.
This isnt shown in the picture, but due to the lower frame and peg supports being weak, to strengthen the pegs, a threaded bar can be passed from peg to peg and bolted in place, this will stop the frame cracking or snapping
Footpeg Pic
18. Bounce the bike : When the coolant or water is added there usually are several airlocks in the system. The easiest way of getting rid of all these is to run the bike so its warmed up, then bounce the bike on its back tyre with the bike vertical, and do this several times, then the coolant might need topping up, but the air locks will be gone and should stop oveheating
19. Radiator Mod.
Add a strip of metal from the top fairing mount to the bottom of the origami replicas radiator to stop it vibrating and causing the top mounts to weep
Radiator Pic 1
Radiator Pic 2
UPDRADES
1. 74t Sprocket.
For smaller tracks fit a 74 tooth sprocket, this will increase acceleration dramatically
Sprocket Pic
2. Kevlar Clutches.
Probably the best upgrade for your origami replica ! A kevlar clutch lasts about 20 times longer than the standard one and seems to offer better grip. Upgrading to a kevlar is very simple and is recommended
Kevlar Pic
3. Quick Response Throttle : A nice upgrade, to a polini quick response throttle, offers faster response to the bike, specially when cornering and braking and accelerating out of the corners
4. 17.5 del orta carb Adding a 17.5 phva Del Orto carb to these bikes gives the bike an extra 2 bhp supposedly, this will be testing on some bikes shortly and a report written here on the fitting and adjusting and if its worth the upgrade cost
Carburation and Spark Plugs or more precisely reading spark plugs I’ll cover in the same topic, as the key to carburetion/jetting is being able to read a plug correctly, plus there’s some other ‘stuff’ we need to know about plugs to understand how your engine is running/performing.
Spark Plugs:
Issues of spark plug size aside, the main considerations of the spark plug is heat range. The heat range of a ‘plug’ is identified by a number within the Spark Plug product code. Manufacturers have their own unique code which can be cross referenced to other manufacturers codes. The cross referencing is not an exact match, just the nearest equivalent.
A Spark Plug has to be maintained at a sufficient temperature to burn away deposits (oil and Carbon) which means typical operating range has to be between 370 and 600 degrees Celsius. The temperature of the plug varies according to the loadings the engine is being subjected to. Heat escapes from the plug via the insulator nose to the threads and onto the cylinder head. The length of that ’heat path’ determines how quickly the heat is drawn away from the plug and therefore the heat range of the plug! The engine puts heat into the plug! A hot plug does not make the engine run hotter and a cold plug does not make the engine run cooler. The heat range is there only to maintain the plug at its optimum operating range. A higher number plug indicates a plug designed to deal with higher engine temperatures.
The Spark plug ignites the charge at roughly 20 degrees BTDC. Its not an explosion it’s a burning process. A lean mixture burns slowly and a rich mixture burns slowly. The burning process reaches its peak at about the time the piston reaches TDC and is completed within 2mm ATDC, or at least if the ignition timing and jetting is set correctly, it does!
The spark plug can reveal not only the mixture setting and ignition timing but also if the correct heat range plug is being used, not to mention detonation which we wont really get into here.
The correct heat range of the plug can be read within a few minutes of running and the tell tale signs of a too cold plug are (i) melted or rounded by erosion centre electrode (ii) ground electrode with similar appearance and (iii) a porous or grainy appearance of the insulator material. If the overheating size is confined to only the centre electrode then detonation will be the cause.
Correct ignition timing is indicated by evidence of fuel deposits extending to within a whisker of the tip of the centre electrode. 1mm of scorched centre electrode is a sign of too much ignition advance.
Mixture settings here’s where it gets a bit more complicated because there are several theories or ways of reading mixture strength off a spark plug. Most people are familiar with the “mocha brown” or “light tan” or “biscuit colour” method. As mentioned above the brown colour left on the insulator material is caused by burnt oil in the fuel. Using this method is fine for general purpose mixture readings but it has problems associated with it. For starters it isn’t a good idea to try and gauge mixture strength from an old or previously used plug as previous readings distort the present reading. Secondly it takes a lot longer than a single Minimoto practice to reach plug discoloration on a new plug and therefore if the mixture was set way too weak you might not finish practice without a lean mixture associated problem occurring first and Thirdly you need to perform a “plug chop” at wide open throttle after a longer period of time than a Minimoto practice allows. Idling back and forth from the ’pit lane’ is gonna distort readings. Before I get to carried away with this ‘techie stuff’ people, including me, have been doing it this way for years and rarely encountered a problem but strictly speaking its not best practice. Importers generally give jetting advise which includes a margin for error. Mixture needs to be increased in colder weather so the jetting they suggest will take this into account. If you don’t want to get too deeply involved in this ‘techie’ stuff heed their advise and read no further, you wont go far wrong. Actual lap times on ‘Proddys’ wont vary with jetting, so long as its in the right ‘ball park’ anyway, so don’t waste time and money swapping from an 80 to a 79 jet in the hope of losing tenths of a second. Just be aware that if you were to set your mixture at optimum on a hot humid day in July, you would be advised to put a bigger jet in come October!
Another and much quicker way to obtain mixture readings off a plug is at the base of the insulator material buried deep in the plug behind the threads. This method requires the use of a magnifier and good light. If the plug is getting hot enough it wont leave any brown colouring on the insulator at least in the early stages of use but if the fuel air ratio is sufficient it will leave a black “soot” ring deep in the plug where the insulator material meets the shell. The plug is much cooler in this region and therefore if sufficient mixture is available some of it will remain as soot as the temperatures aren’t sufficient enough to burn soot too. If even 1mm of soot is evident mixture is sufficient to be safe but foe best performance the jetting should be leaned off to the point if leaving just a tiny whisker of soot. Air cooled engines benefit from slightly richer jetting than water cooled. I would say though that this method is probably more suited to people doing ‘Supers’
Spark plug
The carburettor is designed to meter the amount of fuel drawn into the engine. When the throttle is opened air rushes through the carburettor drawing fuel from the float bowl with it. It is worth noting that the float in the bowl controls the level of fuel within the bowl and that if the level were to high it would cause an engine to run rich and conversely if too low, to run lean. On a Proddy/4.2 with a Dellorto 14mm carb the process is simple in that the fuel only has one avenue (the main jet) from which to draw the fuel into the air path rushing through the main body of the carb. This air rushing through causes a vacuum in the carburettor bore which allows the normal atmospheric pressure in the bowl to push fuel up through the jet (or needle) into the air stream. This is the basic theory behind how a ‘carb’ works. Its also worth noting that the Jet number relates to the flow characteristics of the jet and is not number which relates to its size, although the size plays a large part
There’s not much to be said about the Dellorto 14mm carb used on Proddys, one jet controls all Throttle positions. It is worthwhile ensuring the slide clears the carburettor bore when the throttle is fully opened, if it doesn’t adjust the cable and idle screw to get it as close to fully open as you can. I like to see as much of that 14mm as possible. Usually that means having the idle screw fully, or near fully out, and controlling the idle with the handlebar cable adjustment. Ideally you want some degree of play in the twist grip so that turning the handle bars doesn’t cause the stretched cable to open the throttle unintentionally, you’ve just gotta play around with the adjustment and find the best compromise if necessary. Ideally the carb should also be level/ parallel to the floor. Some degree of angle is usually found and is not a major concern but it does affect the level of the fuel in the float bowl in relation to the Jet which can lean off the mixture if angles are too severe.
[color=blue]Dellorto 14/14 Carb! Idle adjustment screw is slap bang in the middle and has a taper on the end to raise or lower the plastic throttle slide. I found the best set up is to have the screw almost fully out or so that it just skims the plastic slide and adjust idle speed at the handle bar. I'm not saying this will work for everyone but that was the only way I could ensure the slide cleared the whole bore of the carb. Strictly speaking you should have a small amount of playat the twist grip so that turning the handle bars doesnt cause the cable to open the throttle.
Ensuring the slide opens fully is a requirement of any ‘carb’ and an often overlooked basic. On an Adjustable carb with different metering circuits various jets are in operation according to the throttle position, all of which overlap each other
The Pilot circuit controls idle through to ¼ throttle opening and is adjustable both by the screw and the jet in which the screw locates. Different carbs have a different methods, on a carb with the pilot screw located at the rear of the carb turning the screw out allows more air in. On a carb with the pilot screw at the front (closest to the engine) turning the screw out allows more petrol in. Generally the rear screw requires 1 ½ turns out from fully closed.
The Slide Valve controls 1/8 through to ½ throttle opening. The amount of the “cut away” varies, the more “cut away” there is, the leaner the mixture. The slide valve should be marked to give an indication of the amount of “cut away” .as various options are available
The Jet Needle and Needle Jet affects carburetion between ¼ through ¾ throttle positions. The thickness of the needle controls the amount of fuel able to flow. The needle also has clips slotted into one of a number of grooves depending on how lean or rich the mixture setting required. The bottom groove is rich, the top groove is lean. The ‘needle jet’ is where the ‘jet needle’ locates into and control 1/8 through to ¾ throttle position and works in conjunction with the ‘jet needle’ Most of the adjustment to this metering circuit is achieved by adjustment of the clip position on the ‘jet needle’
The Main Jet operates from ¾ through full throttle position. Once the ‘jet needle’ clears the ‘needle jet’ the ‘main jet’ comes into operation and fuel flow is controlled by the size or flow ability of the main jet. To get a richer mixture is a matter of increasing the jet size used.
The Choke Circuit is used simply to start cold engines to compensate for the fuel stuck to the cylinder walls as a result of condensation in the engine.
Dellorto 21mm PHBG Carb! The idle screw is again slap bang in the middle. The gold coloured screw to the left is the Pilot Screw and controls carburation by increasing the amount of air. 1 1/2 turns out from closed is generally considered best practice. Any more and the pilot jet needs to be smaller.The Choke is the black nob on the top.
Top view of the 21mm together with the Slide and Jet Needle attached. The Jet Needle locates in the Needle Jet which can be seen coloured gold at the bottom of the hole in the main body of the Carb. You cannot see in the pictures but the Jet Needle is adjustabl by means of clips on the end which control its position within the slide. Raise it for richer, lower it for leaner, the needle has a taper and controls the amount of fuel allowed to flow according to its height.
The above shows the underside of the 21mm carb which contains the Floats on either side of the Main Jet and Pilot Jet underneath.
14.7 grams of air to 1 gram of fuel is the optimum fuel /air ratio but an engine doesn’t run at that for long due to the incomplete vaporization of fuel at lower engine speeds.
Carburettor setting is all about THROTTLE POSITION, not engine speed! Bear the above metering circuits to throttle position(s) in mind when setting up carbs. One way to set up a carb is to place some tape on the throttle with a series of intermittent marks thereon and then assess how the engine is running and perhaps spark plug readings in conjunction with those marks.
Atmospheric conditions ultimately determines the jet setting an engine requires. Barometric Pressure, Humidity and Temperature all determine the Air Density available on any given day, Altitude also plays a part as there is less air available the higher you go, not generally a consideration here in the UK except to say that tracks like Racelands and Bayford Meadows are at sea level and an upping in jet size should be considered as there is good quantities of air at tracks like that.
Relative Air Density (RAD) Tuning a carb taking RAD into account requires a base settings to be established. If you established RAD to be 97% on a given day and you observed the correct procedure for reading your spark plug and it was a satisfactory reading and the bike ran to your liking you could consider this to be a‘Base Setting’ A change in RAD also affects the pressure exerted on the fuel in the float bowl. A decrease in RAD will, in itself, lean off the mixture to some degree due to the decreased pressure in the float bowl but it also means that there is less air available to mix with the fuel and this richens the mixture. You cannot just change to a smaller/larger jet the minute you see a 2% change in RAD, its requires more of a change than that, more like 12-15%. You would be unlikely to see a change of that size during summer, it would more likely be the sort of variation you would see between a reading taken on a Hot July day and a cold January day. The Jetting you start with in March is however unlikely to be appropriate on a sticky August day so keep an eye on it, Having said that it would be safe to run rhe same jet in August as was used earlier in the year, but probably not the other way round!
You also need to bear in mind the nature of the track. Tracks with long straights requiring sustained wide open throttle (WOT) encourage higher engine temperatures than tight twisty tracks with short bursts of WOT.
Weather Station Available From Argos. This one cost about 60 quid. You can see the temperature, humidity and Barometric air pressure in my house.
The pipe used varies on different bikes and this has a large bearing on the jetting required, indeed two apparently identical bikes can require different jetting which could be down to the level of fuel in the float bowl or the ignition timing which varies slightly from bike to bike. Rider weight also needs to be considered, heavier riders need larger jet sizes.
Procedure for minimoto Wheel Balancing
Courtesy of (Street and Track)
Instructions for minimoto wheel balancing.
Tool List and Parts
1. Tape Weights-- self-adhering lead strips measuring 12in L X 1/2in W. One-ounce divisions are scored and marked along their length. Available through most motorcycle dealers after market catalogs.
2. Contact Cleaner--PJ1 Super Cleaner (recommended) or similar. Available at most motorcycle dealers.
3.Duct Tape-- A range of colors is available through motorcycle race suppliers or well-stocked automotive stores. Otherwise you’re stuck with common Grey.
4. Metal Cutters/ Tin Snips-- Available at most hardware stores.
5. WD40 Lubricant or similar--Available at most hardware stores.
6. Combination Bubble Level Straight Edge or Square-- Available at most hardware stores.
7. Yellow Grease Pencil. -- Available at most hardware stores.
8. Metric Sockets 6mm-14mm, Metric Hex Key set, Phillips Head Screw Driver
Medium taper.
9. Fine Flat File or Fine Grit Emery Cloth (Preferred)-- Available at most hardware
Or Paint stores.
10. Clean rags, Paper Towels etc. You know where to get them.
11. Two Steel Precision V-Blocks. -- Available at most large hardware outlets.
(If you have a Wheel Balancing Stand or Steel V-Blocks, Skip 12. a, b, c) .12. An alternative to Steel V-Blocks is Hardwood V-Blocks, these you can buy
Or make (They must be Precisely Squared and Matched) not as accurate as
Steel V-Blocks. If neither is obtainable, you may use the forks in one of three ways as a
Stand. (Least Recommended)
Forks as Wheel Balancing Stand.
12a.
Remove the Fender, Brake Calipers, Fork legs and any Fork Obstructions. Invert the Fork legs and clamp them into a Soft Jaw Vise. Firmly and equidistantly apart the length of the Axle. Square the Unit and level the axle.
12b.
Remove bodywork, Drain All Fluids, Invert the Bike. Remove the fender, Brake Calipers and any Fork Obstructions. Level the Axle. Clamp Handlebars to the work surface to prevent the Forks from moving.
12c.
Raise Front end off of the work surface using wood blocks. Remove the Fender, Brake Calipers and any Fork Obstructions. Clamp or Tie the Upper Triple Clamp to the frame to prevent the Forks from moving. Level the Axle. (Using the Forks as a Wheel Balancing Stand may require removal of the Rear Wheel Drive Sprocket).
13. Grease- Motul lc 300 (recommended) For greasing the Axle prior to reinstallation.
14 10mm Dia-16in long Precision spindle -- Required for Professional Wheel Balancing Stands. (Motorcycle Spindles are not this small). Available through most Machinists
Supply catalogs. It is not required for use with the V-Blocks but is recommended, If unobtainable use the Wheel Axle as a spindle. (Not as accurate but will
Work). If You Have A Spindle you can take your tire mounted wheel to any motorcycle service dept that uses a Static Wheel Balancer with Tape Weights and have them balance the wheel for you.
Balancing The Wheels
. Remove the wheels from the bike. If you have a Dual Disc front, remove one of
The discs. Remove the Rear wheel disc. (The Disc removal is to gain access to the inner wheel in order to install the Balance Weights.) After you have balanced the wheel and reinstalled the disc you must recheck the balance and may have to adjust the Balance Weight for the disc. (Not necessary on a Single Disc front) It is a tedious process but worth it!
Place each V-Block on an elevated surface, (If they are not tall enough for Tire to Work Surface Clearance when the wheel is mounted). The V-Blocks must be Square, Level and spaced far enough apart to support the Wheel Spindle/ Axle assembly while maintaining clearance for the wheel to rotate freely.
Be sure to install the Valve Caps that you intend to use. The type you choose metal or plastic must remain the same after the Balancing. Otherwise you will have to rebalance. If you don’t have caps and balance the wheels you will have to rebalance when you install them. If you don’t have caps I recommend getting them. (Metal with O-rings is best).
Start with either Wheel and it’s Corresponding Axle. Thoroughly clean both the wheel and Axle. Inspect for wear, burrs and damage (Replace either if required) Burrs can be removed with the Emery cloth or file. Recline and coat the Axle with the WD40.
Support the wheel with the Axle/ Spindle on the V-Blocks so that it can spin freely
Balancing the wheels
.
Spin the wheel lightly, and mark the wheel at the top on the sidewall with the Grease Pencil when it stops. With your mark at the top spin the wheel again and repeat several times. If the wheel stops in various positions, it is well balanced.
If the wheel always stops in the same position, with your mark at the top, the wheel is out of balance with your mark being the lightest point.
Cut and Press fit a Balance Weight to the flat surface of the inner rim (Press hard for the Balance Weight to Contour to the shape of the rim.)
Temporarily attach the Balance Weight to the wheel at your Mark by pulling back the Adhesive Backing Cover at the corners. (Do not remove the Entire cover). Starting with your mark at the top Rotate the wheel a1/4 turn. If the wheel stops in this position the correct balance weight is being used.
If the Mark rises add more weight (If the weight becomes too large Divide the Corrective Balance Weight to Both sides of the wheel at your Mark to limit lateral dynamic imbalance).
If the Mark descends remove weight. Repeat these steps until the wheel remains at rest after being rotated a1/4 turn.
Rotate the wheel another 1/4 turn and then another 1/4 turn to see if the wheel is correctly balanced. Repeat the entire procedure as many times as necessary to achieve correct wheel balance.
Make sure the wheel is Absolutely Clean then install the balance weight by removing the entire adhesive backing cover and Pressing firmly to its marked position on the rim. Secure the Weight with the Duct Tape. (It acts as safety wire for the weight as its sponge adhesive backing deteriorates.) On precision balances you have to adjust the Balance Weight for the (Weight of the Duct Tape.) This is the common Wheel Balancing Procedure as practiced by all of the Motorcycle Factory Race teams and Privateers.
Balance your wheels anytime you change or alter the Tires, Inner tubes, Wheels, or Sprockets.
Since the introduction of the Chinese Copy of Blata's Origami B1, there have been numerouse accounts of overheating and boiling up problems reported with the said bike. The bike uses a liquid cooled 39cc 2 stroke petrol engine with an out put of aprox 7 horse power making it the most powerfull minibike to have come from china so far. Following on the trend from china the workmanship has much to be desierd, the frame welds are poor, the screws and bolts are of low grade material and nothing seems to line up corectly. All this considard, the price of the bike in comparison, and in my opinion is well worth it.
The overheating problem became evident almost straight away, most people where lucky to get 5 minuets ride time out of the bike, seemingley the lighter the rider the less likley the bike would overheat, several instances of youngsters riding the B1 Rep dislpayed a longer ride time.
Armed with this knowage i went about to rectify this problem on my own B1 Rep. I had my radiator checked for leaks by Northants Auto Rads bocouse when my bike overheated i noticed the rad leaking, However the report from NAR did suprise me, the radiator did not leak! and there where no other problems with, i.e. no blockage ect. i also checked the water pump was working corectly and that there wher no other blocks to the water system.
Satisfied that the system was clear i began to look at how the water was circulated through the cooling system. it seemed evident to me that the radiator was not being used to its full potential as water seemed to only flow through aprox 60% of it. My answer to this was to introduce an additional pice of pipe to redirect some of the water to the other side of the radiator thus useing more of the radiator and keeping the motor cooler.
Below are instructions on how to modify your B1 Rep cooling system.
Things you will need for this mod are:
An electric drill and bits, a tap and die set, a pice of water hose aprox 12in long, 2 nipples with a 6mm thread to one end and a 4mm internal bore, 2 hose clips for the said hose.
Remove all plastic fairing and seat units and remove the petrol tank. Remove the water header tank situated between the handlebars. Drain out any water that may be in the cooling system.
Remove the TOP water pipe, this is the pipe that conects the HEAD of the engine to the TOP LEFT of the radiator, it has the bleed screw assembaly located in the middle of the pipe.
Remove the existing bleed screw and rubber O ring from the housing, you now need to drill out and re tap the housing to a 6mm thread. Once you have a new thread you can replace the rubber O ring and then attach the nipple into the newly threded housing sealing it with a bit of sillicone sealer.
Next you need to drill a 6mm hole in the front of the expansion tank. Make this hole as close to the top (bottom of the Tank cap) as you can, but make sure you can get a nut on the inside of the tank. You can not put the hole on the side of the tank as the hadlebars get in the way. I used a clear pipe so that i could see the water pumping through the pipe, this gives me a visual check that the water pump is working. You can add a touch of FOOD colouring to the water to make it easyer to see, But NEVER ADD COOLANT ! it is very slipery and damages the surface of the track if spilt.
Place the secound nipple on the tank and secure with a 6mm nut on the inside of the tank. You can now add the pipe, connect it to each nipple and secure with the pipe clips. You may find that the pipe at the expansion tank may kink slightly when you re-fit the front fairing, dont panic, as long as water passes through the the pipe it will work fine.
This is roughly what your bike should look like when you have finished the mod (obviously there is still no tank and seat unit on the bike in this pic). You can now refill the system with DISTILLED water. This you may find a bit easyer now as ther is less chance you will get an air lock, and if you do it will be alot easyer to clear. Top the expansion tank up to around 3/4 full and then lift the front of the bike right up as far as you can without spilling any water, give the bike a little shake and then let it back down, chack the water level and top it up to about 1/4 full.
Leave the expansion tank cap off and start your bike, check the new pipe for leaks. If all is ok then look inside the expansion tank at the new pipe nipple and rev the bike, you should see a spurt of water when the bike hits revs of about 8000. If you need to rev the engine higher than this then add a touch more water to the system.
Testing
We did 2 test's on the moded bike.
first test: We ran the bike outside at intermitant intervals (5 mins riding and 5 mins on the stand on tickover) for 30 mins It DID NOT over heat!!!
Second Test: We ran the bike Indoors in race conditions for around 15 to 20 mins with a 2 min break inbetween. It DID NOT over heat !!!!!
Since the testing we have run the bike in race conditions several times and for long periods with no sign of overheating, we conclude t at this modification is a true fix for this problem.
FRONT MUDGUARD MOD
This is a simple modification that will improve the overall look of your B1R and help with the airflow to the radiator.
The front mudguard on your B1R comes already fitted by the means of two screws in each side of the unit, you will notice that it sits quite high over the front wheel.
Remove the mudguard and trim each side of the unit so that you only have the TOP fixing hole left. Then replace the unit onto the bike and position the securing hole to the BOTTOM most point. This will lower the mudguard by aprox 3/4 of an inch.
you will now see that the unit sits allot closer to the front wheel and you now have more room for air flow over the front mudguard.
A simple but efective modification that is cheap and east to do.
Courtesy of Northants Mini Moto
911 Rep
911 SET UP GUIDE
Petrol Tank and Fuel line
Where the outlet screws into the tank isn’t great quality, unscrew the outlet and apply either hot glue or araldite around the threads, screw back in and apply more glue around the outer section to reinforce it.
There is no filter on these until the fuel hits the carb (small strainer in the side of the carb body) so flush out the tank well before starting the bike. On Mk1 reps there is no spring around the fuel line to protect it from the exhaust (its very close) but on Mk2’s the required spring is there, although the fuel line may be a bit short and make tank removal awkward, best to put a new length of pipe on. The spring clip that comes supplied is hopeless and will need replacing with a better one.
Check to see if there are rubber blocks between your frame and tank, Mk2’s have said rubber blocks. If you don’t have them buy some foam tape from B&Q and stick it to the top side of the frame, in fact stick it anywhere the tank touches as the vibrations will soon wear through the tank. A rubber tap washer (again from B&Q) underneath the front tank mounting bolt will help and prevent it from coming loose.
The filler neck of the tank can wear and make the cap loose fitting, if this happens smooth some chemical metal around the inner lip of the tank (only a thin film) to fix it.
Radiator and Cooling System
The bracket that the radiator mounts to isn’t the best, and touches the rad when tightened up. Vibration will eventually make the bracket wear through the radiator and leak. To prevent this remove the rad and glue a piece of old inner tube or foam tape to the bracket itself. If yours is already leaking don’t worry, the radiator is copper and can be soldered up.
To fill the system with water remove the radiator bleed screw (top left on a mk1) or remove the breather hose (top left on a mk2) and fill the bottle, blow on the neck of the header tank to force the liquid into the rest of the system, keep filling the tank up and blowing into it until liquid comes out of the bleed screw (that you’ve already taken out) rotating the back wheel so the pump circulates water will help to remove any unwanted air.
The header tank cap is pretty poor quality but is a different thread to the original polini part, its best to swap both tank and cap (part no 143.330.003 Coolant Bottle/Cap 911 & 911GP2) which will cost you £6-£7 but well worth it.
Bodywork
The fairing is held together with nuts and bolts which are a pain to remove, especially when you’re rushing around in the pits trying to make the next session. Replace these with original polini quick fastners (part no 143.305.023 Nutserts 5 mm qty-8 £8.95)
A good idea is to remove the black front cowling which the forks popke through as it lessens the chore of removing the bodywork.
The stock bodywork is very brittle and will snap easily if you’re unlucky, standard polini parts are quite cheap and a lot stronger.
Brakes
The twin front brake on these bikes is very powerful, but if badly set up can have no feel to it whatsoever. Replacing the platic brake levers with metal ones may help.
First, slacken your front brake cables so that both operating arms on the calipers drop back to their rest fully, then adjust the play in the cable out so that they are equal, put the bike on its stand and get someone to push down on the rear to lift the front wheel, loosen the locknut and allen bolt to wind the pad away from the disc, then adjust the knurled knob to bring the inner pad as close to the disc as possible WITHOUT binding. I adjust it up till it binds then back off just enough to clear, do this on both calipers first, all the while keep spinning the wheel to ensure its free. once your happy that the inner pad is set right adjust up the allen bolt until the outer pad touches the disc and locks the wheel...then back off enough so its clear - DO THIS ONE CALIPER AT A TIME! When your happy its right lock up the locknut and repeat on the other calliper, you should find the brakes will be very sharp and enough to put you over the handlebars.
The rear brake is floating and is adjusted via the allen screw and locknut. Check the mounting bracket as mine was bent and pushed the calliper out of alignment.
Clutch and Chain
The standard clutch is very similar to a 3 shoe cag clutch and is non adjustable so no use whatsoever, bin it. Replace it with your choice of Polini or Bizeta 2 shoe adjustable clutch. You’ll also need to swap the drum and pinion, make sure you get the one for rear wheel driven pump models. These will work well with the polini yellow springs set to bite at 6500-7000rpm, or 7500rpm if you want a bigger hit when it engages. Getting your shoes relined with Kevlar (ask Vaughan)
The standard chain isn’t very strong, replace it with Bizeta, its £15.00 a metre, one metre will be ample.
Mk1’s come with a 6 tooth pinion installed but Mk2’s come with an 8 tooth, for better acceleration swap it for a 6.
Exhaust
The exhaust silencer, which looks nasty with the downturned pipe, is held on with 3 screw, these do work loose and should be loctited in place, the mounting bracket isn’t too clever, remove and refit it to be sure. You can swap the silencer for the polini part but this will need to be welded onto the existing system (Part no 143.285.004 Exhaust Muffler – 911 Racing Carbon Fibre - £22.90 or 143.285.005 Exhaust Muffler 6.2hp 910 Steel - £14.50)
Replacing the mounting bolts with proper polini rubber mounts is a good idea to cut vibrations (part no 214.0104 Exhaust Rubber Support Mounting Bolt – M6 - £4.00)
also, swapping to the full Polini race exhaust should give you an extra 2bhp
Frame etc
If you have a Mk1 the subframe is held together with rivets which aren’t that strong, especially if you’re fond of pies, replace these with 5mm bolts and nyloc nuts. The Mk2 has this done already.
The stock rubber footpegs aren’t very strong and may vibrate loose, loctite them on when they they do break replace them with polini ones (part n
Be very careful when tightening up the fork clamps, the bolts screw straight into aluminium.
Engine
Some units can be very tight from the factory and can stall when combined with the awful standard clutch, careful running in is recommended if you have this problem.
On Mk1 bikes the woodruff keys may be made from chocolate, swap these for good quality ones from Polini
Tighten your cylinder head bolts – mine were loose
There has been a problem on one of the bikes with a very sloppy fitting flywheel, the problem was that when the but is all the way tight its still not up against the flywheel, put a washer on after the flywheel, before the but to cure this. Mk2’s may already have this done.
heres some pics of the mod to the rear water pump drive....a little blurry, but show the basics....all done with chemical metal.....(quicksteel) just remove your rear wheel, take your rear sprocket off, leaving the waterpump pulley attached to it.....use some acetone or thinners to fully degrease your rear wheel hub and pulley, especially on the areas you can see the wheel has been ground for the pulley to clear, then press a small amount of quicksteel onto the ground areas and rebolt your sprocket. Once on mould the chemical metal to the pulley neatly, allow it to harden (bout 5 mins) then remove your sprocket from the wheel and pulley, this will leave the pulley mounted to the wheel, just push more chemical metal around to completely fill the area, from both sides, and voila one wheel with pulley attached, and its very strong!!! simple to use normal alloy sprockets...
Front Forks - Banshee and GRC forks are both 28 mm. GRC GP forks are 1/2" shorter in length
water pump belt - pinion driven belt from GRC or Polini is much larger than banshee
Handlebars - Thickness matchesGRC bars are 3/4" shorter than banshee
Brake pads - same as GRC
Brake Caliper - seem to match up to the GRC's
Brake disk - holes match to grc's Banshee 3.09 thick / GRC 2.95 thickGRC dia 122mm / Banshee dia 120mm
Carb - can be a replacement with Delorto 15, 17.5, or 18
Manifold - matches polini part # 143.270.010
Brake Caliper bolts - GRC bolts have tighter threads
Triple trees - match GRC gp
Triple tree through bolt - Match GRC gp
Coolant bottle - do not match
Foot peg brackets - ride angle will be slightly different spacing is 2mm less on GRC brackets
Foot pegs - match
Water pump - match Bi-Zeta part # 212.012.001
Brake caliper support bracket - match GRC
Front brake cables - match GRC
Rear brake cable - Does not match. Banshee cable much longer than GRC
Brake levers - match
Pull starter complete - same as polini
Ratchet plate - same as polini
Ignition coil - same as polini
Read block - same as polini
Head - same as polini
Top end - same as polini
UNDER CONSTRUCTION
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