brucey

I've just aquired the above bike to use for local club trials. (I also have just finished building a Cub for pre 65 stuff) For a 2000 bike it is pretty good condition but needs water pump seals (judging my the mayo in the gearbox) and fork seals. I have the following questions: Fork Seals: I have removed the fork legs and seal cartridges. I drained the oil by removing the bolt at the bottom (about 350ml oil came out of each leg). I have tried removing the big nuts(with the damper adjusters in) at the top of the stancions, but they don't come out (they just click). I understand I put 300ml of 5 wt oil in, but am not sure how to do this and bleed the air. As I weigh over 100kg, I would like to add say 10mm spacers to the spring preload. How do I do this? I have 1lt fully sythetic 7.5 wt fork oil in the shed. Would this be o.k. considering my weight? Before I stripped the fork legs, I tried altering the adjusters on the top of each leg but they seem to make little or no difference to the dampening (in either direction) are they broken? I know the adjusters turn because I made new stainless tops! Water Pump Seals: I have ordered a shaft and seal kit from John Shirt. I have removed the small cover (to expose the impellor) but it looks like I need to remove the RH engine Cover to access the seal and shaft. Is this assumption correct? Any advice would be appreciated. Bruce.

Thanks for the response guys, I purchased another B6HS and a B5HS to try today. If it works, I'll let you know! Bruce

Hi all, Having managed to oil up NGK B6HS at a rate of roughly 1 per trial, would it do any harm trying a slightly hotter NGK B5HS? I won't be riding the bike on the road! Does anyone else use these in their Cub? Bruce.

I just got my spare Cub frame from the attic to fit some strengthening plates. Before I do, is there a recognised way to steepen the steering head angle and is this a worthwhile mod? Cutting the head casting looks a bit dodgy but extending the top tube and/or shortening the down tube looks possible. Although I wouldn't have a clue by how much! I know I've got it up for sale but I find it hard to resist building things in the shed and feel another project comming on!

Hi Charlie, I remembered what I did to lengthen my clutch arm. The standard Cub arm is twisted so it goes from vertical at the pivot end to horizontal at the cable end. I cut mine at the twist, flattened and slotted it out. I then made another (longer) cable end of the arm and slotted that too. I pushed the slotted pieces together and silver soldered them. Hey presto, an extended, webbed clutch arm. Alans mod effectively moves the cable entry point further towards the back of the engine case. I won't say how as that's his IPR, but it isn't difficult to work out! Hope this helps, Bruce.

Gordon, Thanks for your vote of confidence. I tested the bike with the cover off and there was no slip when starting cold and hot! Things are looking up so I've replaced the cover and put 100cc of ATF in. I stengthened the arm when I extended it by adding a small web on both sides. This seems to work well. Thanks to everyone for taking the time to help me. I now plan to enter my first pre67 trial in Horsmonden this Sunday! Bruce.

Windlestone, I really must type faster. Thanks for that, it seems like I've done it right! Bruce.

Charlie, I did wonder what the coefficient of friction was on the ally pressure plate compared with the standard steel one. I'm still a little unclear on how to 'clock' the pressure plate. I have done the following: Adjusted push rod clearance as Gordons instructions. Adjusted pressure spring nuts until the top of the head is approx 10mm (3/8") above pressure plate face (as Haynes Cub Manual instructions) Refit Clutch Cable to lever and adjust to allow 2mm clearance. Pull and hold clutch lever fully in against handlebars with rubber band. Put DTI on outer circumferance of pressure plate at 3 o'clock position (Mag Base on footrest) Rotate clutch plate using Kick Start Lever and adjust springs until within 0.2mm deflection on pressure plate face. There are a couple of things I noted: The pressure plate can be moved over 1mm by just pressing it. This makes it difficult to adjust the spring nuts without disturbing the settings. Upon releasing the clutch lever, there is now more than 1mm difference in height from the top of the spring nut to the top of the pressure plate. I'm just off to try and start it with the cover off to see if it still slips. Bruce.

Totalshell, Thanks for you nice and simple reply. Gordon, thanks for your slightly more detailed reply. I have a couple of questions: Are you using a billet ally clutch cover and stronger springs? I presume you pull (and hold) the clutch lever in and then run the DTI on the top face of the clutch cover somewhere near the edge of the clutch basket. Finding a place to locate the mag base should be fun! By adjusting the spring adjusters so they only just clear the cover, you imply you use minimum spring pressure. Is that right? What oil and how much oil do you put in your clutch? I don't have anything to compare Alans Clutch Mod with as I haven't ridden another Cub. However, I can pull the clutch lever in easily with 1 finger. I guess the arm is about 25% longer so the clutch should be 25% lighter! I modified the arm myself, Alan just modified the case for me. Alan was also working on a mod that allowed you to fit an extra friction plate in the clutch basket to prevent slippage especially when using a 16T primary gear. Bruce.

Hi, I know this is a common problem and I have to get it past tdc before trying to kick start. I have a standard crank shaft duplex gear (19t?), low compression piston, 'R' Cam, strong clutch springs, ally billet pressure plate, primary chain tensioner and fill the case with about 100cc of ATF to keep the primary chain wet. I also have the Alan Whitton Modified (longer) Clutch Operating Arm Assy. The clutch slip when kick starting seems to be getting worse. This may be because the rings have bedded in and raised the compression. Should I just tighten the 3 clutch spring adjusters by a turn each and see what happens? Any advice appreciated. Bruce.

Doogle, Get a Beta Alpina(2 stroke trail bike?) and do some long distance trials. I've martialed 2 in Kent (Sidcup Club) and everyone had a graet time. Best of both worlds. Bruce.

It sort of depends on what you are doing with the rest of the bike. I made a Top Tube Oil Tank 'very similar' to a Sammy Miller one. However I made mine from slightly larger diam tube to increase the capacity. I also added an external oil filter (

Tim, Thanks for the information. After looking it up, the Caswell treatment appears to be a good solution. I will also try to contact the guy who manufactured the tank for his comments. It might be a goog idea if he included the Caswell treatment as an option on new tanks because he would get the required 'economies of scale' to keep the price down. I tested my tank for a couple of hours last night and the epoxy putty seems to be holding up well. The 'Plastic Padding Petrol Tank Sealer' failed almost immediately when tested! Bruce.

Bultaco & Bigshiney, thanks for your replies. My tank is slightly different to yours in that it was made less than a year ago in Vinylester rather than Polyester resin. This should give it the required resistance against ethonol. I used Vinylester products when I worked in the papermaking industry a few years ago and can vouch for there resistance to quite severe chemicals. I counter sunk holes where the bubbles had appeared and filled them with 'tank repair filler' purchased from Halfrouds(which included petrol tanks in the blurb). I waited 12 hours filled it up with petrol and watched it seep through the filler! (it went soft!) I have now removed that filler and repeated the operation but have used epoxy putty this time. I wait with baited breath to test it! If this is successful, I will also consider applying a sealant to the inside of the tank as I still believe I'm 'not out of the woods' yet! Has anyone got a decent Ally Cub Trials Tank spare? I may have to save up my pennies and contact Terry Weedy! life is too short. Bruce.

Hi, After running my newly built Cub for around 8 hours, it has developed a pin hole in the new Vinylester petrol tank. I drain the fuel after every use but I noticed petrol dripping from a small (2mm diam) blister on the inside section near the bottom(where it hangs over the Oil in the frame top oil tank tube). I'm assuming it has a pin hole that has leaked into the gel coat causing the blister. To be honest, I have a feeling the blister was always there and I may have popped it whilst cleaning the tank! My thought is to buy some 2 part 'chemical metal' putty, gouge out the blister and make a small counter sunk hole, then slap the filler in the hole. I'm assuming polyester glassfibre resin or normal 2 part epoxy (araldite) will not put up with the ethanol in modern petrol. Has anyone else had similar problems and found a good repair method? I wish I had paid the extra and bought an ally tank now! Bruce.

Tick over is steady and reasonably slow especially since reverting to the original jets. I seem to remember my old Cub being a little bit slower on tick over but that had a standard cam and this one has an R cam. I'll run it,do a plug chop and look at the needle adjustment if it's still sooty. Is there a seperate pilot screw adjustment? I thought you could only change the jet sizes. Thanks for your advise so far, it's given me a few more things to check. Bruce.

The pipe attached to the bottom of the float bowl on my Mikuni VM22 carb is attached to the float bowl drain outlet. It directs the fuel away from the carb when the drain screw is undone. Bruce.

Hi, I have fitted a new (

I don't know much about Montesa's but if you find the temperature switch (I'm guessing it will be in the top heater hose) and either join the wires or just short them with a screwdriver, the fan should start. If it does, it's probably the temperature switch at fault. If it doesn't, check for a fuse, broken wire or knackered fan motor. Hope this helps, Bruce.

The Cub on its first practice trial at Canada Heights last week. It ran really well with the only problem being an oiled plug after a couple of hours. this needed replacing before it would run properly again. In answer to your question, this is a standard Cub frame with modified tapered headstock bearings and various other minor bits done. I have seen Alan Whittons frames and they are very nice! I have retained the original head angle but have been told the Montesa forks I'm using are a bit long and will affect the handling. I still think they are infinately better than the Heavyweight Cub forks I had on a previous bike! I have also now fitted an external oil filter which adds about 1/2 lt oil capacity in addition to the 1lt of oil held in the top tube tank. This should help it run cooler!

A couple of photos of the cub on its 1st run! I ran the bike on and off for about 25 minutes this evening. It seems to rev and pull o.k. The tube fitted to the distributor hole breather has solved the oil leak there and the dowty washers stopped the rocker feed oil leaks for the time being. It did start leaking from the top oil tank breather (mainly because I haven't fitted a pipe to this yet and was going down a few hills!) I was also getting some quite impressive pops and flames out of the exhaust on over run once hot. However the front pipe had become loose so I assume pulling air in. It still smokes on start up but clears after a while. I'll modify the return feed in the tank to see if this helps. Overall a succesful evening. Thanks for your advice to date. Bruce.

Cheers for the information Charlie. This would make sense in so far that the exhaust front pipe turned blue after about 5 minutes of running (at which point I tuned it off anyway). Also the fact it seems to be 'breathing' so heaviliy through the new distributor hole breather pipe would indicate the rings aren't sealing properly yet. I can mod the top tube oil tank return pipe to prevent oil running back when the engine has stopped (or just dont fill it as high for the time being). I can also replace the leaking rocker shaft lube pipes but I don't want to start stripping the engine until it has had a good chance to bed in or I know there is definately something I've done wrong when I assembled it. I will run it up a few more times to see what happens. Bruce.

Thanks for your interesting replies gentlemen. I ran the bike again tonight for another 5 minutes or so with the following observations: I didn't cure the leakey rocker feeds so have fitted dowty washers both sides as a final attempt before buying new feed pipes. Oil flows back down my poorly designed Top Brace Oil Tank return pipe when the engine is stopped. The oil seeps into the rocker cover feed pipes until the level in the tank drops below the return pipe. This may explain why it is smoking on start up. I'm assuming this won't do any harm for the moment and the new Morgo pump should quickly return the oil to the tank. There is enough oil comming out the distributor hole breather to cover the bottom of the tank in minutes! I have now fitted a large diameter pipe running from the breather, up to the tank and back down the rear frame tube to just below the sump guard. My motto being, 'If you can't cure the oil leak, plumb it in!' So apart from leaking more oil than the Torrey Canyon and smoking more than Wintson Churchill, it's going well! I'll see what tonights fixes bring when I have another go on it tomorrow night. Bruce.

Alan & Peter many thanks for your replies. Going back (many years) to my Toolmaking days, I'm pretty sure you let copper cool slowly to anneal it. I'll fire it up again tonight on the grounds of 'what's the worst that can happen?' It will also give me another chance to play spot the oil leak! I think I may have made a mistake on my return oil feed pipe to my top tube tank. The feed does not stick up above the oil level so oil tends to run back down the rocker feed pipe when the engine is turned off. As the top tube tank only holds about 1 litre of oil, I was thinking about fitting the oil filter kit sitting on my work bench to increase the capacity or even fit a new trials/alloy oil tank. I'll see how hot everything gets first. There is the possibiliy of fitting a mini K&N type filter direct to the top of the Alan Whitton Crank Case Breather but I'd have to be careful in wet conditions. However, it would match the bright orange main air filter that came with the Miccuni Pit Bike Carb! Interesting point about the timed breather. I'm running PVL so I put a cap head screw up the middle of the Cam Shaft to block it off as I have removed all traces of the points set up. On a side note, I also fitted Alan Whittons 'clutch lightening mod'. I'm no expert on Cubs but the clutch is as light as my friends 2009 Scorpa! Shame the brakes aren't as good though! Bruce.

I bought a VM22 pit bike carb from ebay complete with insulator gasket, air filter and manifold (not cub) from 'Rhino' about 6 months ago for less than