cvgmmartin

I believe his number is 07523 913716

Perhaps your crankcase is flooded with fuel and until your clear it of fuel, the plug will keep becoming saturated with fuel. Does the carb and inlet manifold slope down so that any overflow from the carb goes into the crankcase?

Mokwepa has rather over simplified the issue with his initial statements. A trials bikes will generally go faster as you gear up (i.e. smaller rear wheel sprocket) since the engine produces "excess" power for the speeds they run at. Do that on a road bike and it will probably drop the top speed since the engine torque won't be sufficient to overcome the wind resistance. Were the so called experts he was talking to referring to trials bikes or road bikes? Road bikes were always geared slightly high to give good a good cruising speed without over revving the engine, and most road bikes used to gain a couple of mph by dropping the gearing. Trials bikes are a completely different animal and as most of you pointed out changing the gearing is all about making the bike rideable rather that looking for either more acceleration or more top speed.

Some MX bikes use between 32:1 and 40:1, but if you are not running it that hard then perhaps something closer to 50:1 would provide better protection for enduro riding. Maybe someone else can give a more expert opinion. The oil helps dissipate heat so the harder you run the more oil you should mix. You could check your enduro manual (if it is a 2 stroke) and see what it recommends, that should give you a guide.

If you choose to use your trials bike for an enduro again you may want to re think your fuel/oil ratio for such events.

Borus is probably correct about it being tennis elbow, as he says don't ride through the pain. It probably hurts more when you grip hard, if so then don't practice hops or anything that can't be done with a loose grip. Mine has taken about 2 months to ease up but is not completely cured. you have to take it easy for a while or it can take a long time to get better.

Hi, I live in Toronto (west end). For a beginner I suggest you join the CVMG (Canadian vintage motorcycle group). You can find them on the web. We have about 8 trials a year mainly in areas west of Toronto and Hamilton so within an hour and a half for you. Although it is called vintage, many riders come with modern bikes and we welcome all, some children also ride. Sections are marked for different skill levels so you won't find them too difficult. There will be a trial close to Orangeville Oct 20th (I think). You should come along and see what it is like. The CMA also put on trials, but for the beginner I suggest the CVMG would be a better start.

The angle of the photo distorts the size of the tank and seat making them look much bigger than they really are in relation to the rest of the bike. What you can see of the subframe and the frame tube under the seat look similar to the picture in Don Morley's book, the exhaust pipe (though not the silencer) is also similar. As others have mentioned, it needs better pictures and more than just one to accurately determine what it is.

I hope a few hundred people used the complaint link posted above, then the BBC may get the message and get it right next time. I did.

I assume you swapped the reeds when you switched carbs, so now it would seem the only difference could be either the exhaust system or the barrel and piston porting, although you would have thought a plugged exhaust would affect the high end more than the low end which doesn't seem to be the case. Try switching the exhaust first since it easier, after that it looks like you are left comparing the porting. Can anyone comment whether a weak ignition system could cause poor low speed power yet not appear to affect high speeds?

I think it is a Rickman hub

I have done the bend trick described by Copemech above on a Bultaco rear wheel but still had grind a little off the threads to shorten it so that bending didn't leave a permanent kink in the spoke, but as long as there is enough thread left then that shouldn't be a problem. regards Martin

Contact Rex Caunt Racing, they sell PVL systems and are very helpful. .

Had a similar problem with my engine, couldn't get the nut off even with the shop's biggest impact gun. Managed to remove it by heating the nut with a propane torch and then using the impact gun, it eventually came off.

I have "buffed down springs for both front forks and rear shocks and yes it works as far as softening the springs. In fact if you were clever and had a good reason to do it, you could grind down different amounts over the length and create a spring that has a non-linear load-extension curve, but try and find someone who can tell you what that curve should be! That is why it is usually best to just go out and buy what others have proven to work. Also grinding down external springs produces a pretty ugly appearance.

The following is a conversation (by e-mail) I had with Charlie Prescott some time ago which has some relevance. Charlie, In a recent post on trials central someone commented that Sammy Miller felt the front and rear wheels didn't need to be in line and that a little offset made it easier to balance. On a BSA, to get reasonable chain to rear wheel clearance, the engine looks as though it's C of G of the engine is significantly offset from the centreline of the two wheels! Are the otter's wheels exactly inline? Charlie's response Yes the Otter wheels are in line? Or should be! The engine is offset to the left, and does look more bulky that side, But the centre of weight is not that much different ,because most of the bulk is only the primary chain case, and with PVL ignition fitted? this item could be slimmed down. As you know on modern trials bikes this situation does not arise as the engine gearbox layout is a lot different, and the clutch is in a different position and not outside the gearbox drive sprocket, Progress Ahh. Regards Charlie.

Just Google "Bultaco model numbers" and that will lead you into a model reference guide

If it is just a crack you can actually seal it with solder and it will last for a while assuming you don't need the solder to provide any structural strength. It doesn't get hot enough to melt the solder.

It is not the position of the mounting point on the yoke that counts, it is the position of the handlebar grips relative to the steering stem. You can get some of the effect you want by just rotating the handle bars forward. You will need bars with a bit of rise to make much difference.

Suggest that before you weld it up, get a heavy piece of flat steel plate and drill holes to match the holes in the casing and bolt the 2 pieces to it, that way, when it is welded up the gasket face should stay flat and the bolt holes will all line up with the crank case. Do this yourself and you will save some money instead of the welder spending time leveling it up, plus you know it will be right. If you then weld the inside it may distort the casting and you will have to machine the gasket face flat.

It looks more like an old James based on the tank and exhaust system. Does it have a rigid end?

A shed doesn't sound like a very safe place to keep something of this value now that everybody knows about it. It's value is difficult to estimate but I doubt if there is any other trials bike that would be worth more than this one.

Thanks for the interest, I had an operation in June to reconnect both the supra and infra spinatus tendons which had fully separated.( I now have a 2 inch scar as a reminder). The connection was made by putting metal pins into the bone and sewing the tendons back onto these pins. Although the recovery has been slow and it gets sore after exercising it does seem to be on the mend. I tried riding about gently at the end of November and although the jarring through the handlebars made it sore for a week but it did get better quickly. Currently I am doing repetative light weight (4 lb max) lifting exercises and the strength is coming back slowly. One think I have noticed is that with the lack of use, all the other muscles have shortened and atrophied so stretching is a key part of the recovery process. I feel fairly confident that I wlll recover most of the strength back but I will always have to be careful to avoid as much as possible lifting loads above shoulder height. Fortunately the normal riding position is quitre comfortable. I will be getting some shoulder pads since any impact, even a little bump against a tree just where the metal pins are could be disasterous. So I have until April (our first trial of 2013) to build up strength which will be almost 11 months since the operation and 12 months seems to be the norm for this sort of injury. Meanwhile the Triumph, BSA, and Bultaco, have been rebuilt and are waiting for the snow to melt. Bantams however are an unknown species around here. Happy New Year to you all.

Just incase you haven't done this, the top yoke clamp has to be loose. I can't remove the top nut on my Bultaco forks if the clamp is tight,there is enough compression to tighten the tube threads on the nut. When loose it comes undone easily.

About 20 yrs ago I put a 500 triumph in a Bultaco frame by cutting out the bottom tubes and dropping the farme over the engine, it lost a bit of ground clearance, it didn't steer properly, and was pretty useless as a trials bike. I had kept the original Bultaco geometry but the weight distribution was all wrong, too heavy on the front end. I then made my own frame around the engine and it now works quite well. 2 stroke frames and 4 stroke engines aren't generally compatible, the top frame tube from the steering head to the seat is usually too low on a 2 stroke to fit the taller 4 stroke engine, unless of course you drop the engine so that you have very little ground clearance. Be prepared to do a lot of cutting and welding around the main frame loop in order to fit the engine and oil tank. By the time you have finished you will probably find the only thing left from the original frame is the steering head, swinging arm, and a bit of the subframe. A small engine such as a Cub or 125 Honda may be possible with less modifications.