cvgmmartin

It looks like a Pathfinder trials frame with the bottom loops removed and replaced with a bash plate

It sounds as though his engine is just not in as good a state of tune as yours, and if that is the case then you have all the possible problems related to exhaust systems, carburation, ignition timing, engine condition, etc (or as you say possibly something stupid) to look forward to fixing.

Does he also have an 11 tooth engine sprocket? If so then his gearing is slightly lower than yours and you would expect his engine to pull a bit better than yours at low speeds, if it doesn't then it is an engine tune problem. If he had a 12 tooth engine sprocket then his gearing is almost the same as yours so there shouldn't be much difference. If he had 13 teeth at the engine then his would be higher geared than yours and perhaps not pull so well at low rpm.

Contact Charlie Prescott through the The BSA Otter web site, he must have a barrel on his bench somewhere.

There is a web site for Progressive Classic Products located in the West Midlands at Brierley Hill Phone 07713 106 278 or 01562 229 049, e-mail progclasprod@yahoo.com and they advertise spacers for BSA singles from 1mm to 15mm thick. I assume they still exist. Good Luck

The conrod length has no effect on stroke only the crankshaft sets the stroke, and if you are currently measuring a stroke of 90mm then you don't have a B40 crank. A 79mm bore with 90mm stroke gives a 441 cc engine.

Any tiller action is due to the relative position of the handlebar grips and the steering pivot and not to the position of the bar clamps on the yokes. By rotating the handlebars forward it is possible with some high rise bars to position the grips over the steering pivot and hence there should be no "tiller" feel.

You seem to be sure that it is ignition, but have you tried both raising and lowering the needle by one notch just to see if it changes anything? It is such an easy thing to do and may help confirm that it is an electrical problem.

You say it has a spongy feel, this sounds like clutch slipping and the fact that it kicks over with the plug out suggests everything else is O.K. other than the clutch slipping ( but you also say it is locking up ? does this mean the kick start lever locks up and won't move? ). Can you push the kickstart through its full travel yet not turn the engine over?, if so this would be the clutch slipping. With my BSA, sometimes the kick start locks up but that is due to worn teeth and it is an intermittent problem. If tappets are too tight then you would just loose compression and it would be easier to turn the engine over.

Jimmy is quite right that the bolt is there to just to provide a clamping force and if the bolts are tightened properly then it is the friction between the sprocket and hub that stops any relative movement and not the bolts resistance to shear. Bolts for connections like this are not meant to act in shear, they act in tension. If the elongation in the hub holes is not too bad and the sprocket can be centered on the hub, then you may not have to do anything other than bolt it up to the right torque settings. Make sure the surfaces of the sprocket and hub are clean and flat first. Check the manual to see if there is a tightening sequence and torque setting for these bolts.

I have been riding a 500 Triumph for many years here in Canadian vintage trials. We let anyone ride that wants to, and don't have a pre-65 or similar class, so don't worry much about the types of rules/regulations that are so well discussion on this forum. This means that my bike would probably not be well received in the UK other than as a special, however I have written about the engine modifications I have made and some of these may be of interest to you (eg cam type and valve timing). If you are interested you can find this in Charlie Prescott's Otter forum under the Readers Page. Mick Andrews was complementery about the engine when he tried it.

Thanks to everybody for your advice, there were some positive comments that give me hope for a reasonably chance of riding again, and I won’t be a burden on the NHS since I am in Canada. Thanks Billy for the offer of advice re physiotherapy, I will contact you after the operation and have found out from the surgeon how successful he feels the op went. I had both knees replaced in 2007 so I know what sort of patience and work is needed when recovering from surgery, and although I recovered full strength on them, I don’t expect it to be the case for the shoulder. The quality of the repair will obviously depend on the condition of the tendon so I will only know what level of recovery I can hope for until after the operation. It was the left shoulder and I am right handed so it could be worse. I have given up any idea of riding this year so will concentrate on recovering for next year. Unfortunately I will miss Mick Andrews trials school in Quebec this year but maybe he will come back again next year. Vintage trials in Ontario are not particularly strenuous and typically we only do 24 sections in a trial, however silly falls which hurt, usually occur in the most innocuous sections, which is what happened to cause this injury. I will have to put the 500 Triumph away and stick to my BSA to start with and see how it goes and at worst I may have to build a Bantam to continue riding. Thanks again to all your comments and good wishes.

Hopefully Billy Craig is still reading this this forum. In a recent fall I suffered a complete full thickness tear of the supraspinatus with retraction on my left shoulder (this is one of the rotator cuff tendons), there is also some damage on the infraspinatus. I will be having an operation to re-attach the tendon. Has anyone experienced this sort of injury and if so what sort of recovery have they made with regard to riding eg what % of previous strength was recovered, and how long did it take to recover, are there any protective braces that exist for the shoulder that are worth wearing when riding? Any advice/help would be appreciated. The quack tells me I shouldn’t ride again but what the hell does he know. I am 63 yrs old so don’t expect to recover as quickly as a younger person but figure I still have a few years left riding.

Absolutely get rid of the AMC engine and get a Villiers. I had the 250 version of the AMC engine and it was horrible

In answer to Woody's comment about the old FB and the new old James, those bikes are from different planets.My first trials bike was the James version of the FB. It had 8 gears, 4 forward and 4 reverse and the engine was the heaviest piece of gutless crap ever put in a trials bike. If anyone has ridden one of these recently in the Scottish pre65 they have my utmost admiration. My next bike was a B40 which was a huge improvement over the James, that's how bad the James was. The big differences between the bikes is that the new James, although starting with an old set of crankcases (probably with Alpha bottom end), everything else has been significantly developed with modern know how. The barrel has probably been re-ported, the modern exhaust system no doubt improves the bottom end and electronic (with or without advance/retard) puts the icing on the cake. The FB would weigh around 250 lbs and I imagine the James with replica frame comes in under 200 lbs. I am not against modifying bikes but these two examples shouldn't be in the same class ,and a set of Ossa forks on the FB wouldn't make any difference, the engine is the achilles heel on this bike.

A question for those people who have fitted reeds and feel that they have improved the slow running, have they just fitted them to the standard barrel or have they modified the porting aswell?. I have briefly tried a 340 with reed and the engine was very smooth, however the porting had also been modified.

OTF's comments are particularly well thought through and sensible, however a few other comments seem to suggest a very negative attitude to some of the tricked up bikes and riders. I believe there are no bad trials bikes and that anyone should be allowed to ride what they want, unless of course trials are so oversubscribed that you can have the luxury of turning away riders. The only issue seems to be classify the bikes so that those riders that want a competion can fairly compare their scores. Nobody should ever turn up to a trial and feel that they or their bike is not welcome, and riders should be allowed to ride the level of difficulty thet choose. A rider with a bad back, sore knees, etc should be able to ride a tricked up bike without being told he had to ride the expert line, if that is what he wants then just tell him his score will not be counted in any competion. I am not sure why this issue upsets so many people, the reality is that not many people really want to ride a true pre 65 bike (particularly a 4 stroke)so we shouldn't be surprised that trick bikes have developed.

Hi Ben, The triumph twins are great fun to ride, but like any other pre-65 bike, only as long as the engine runs cleanly without spitting back, and stalling. I would strongly recommend putting a PVL electronic ignition system on and get rid of the old points and mechanical advance/retard mechanism. I ride a 500 in a frame of my own making so can

When my Bultaco just won't start I try heating the plug tip with a propane torch and get it as hot as possible (too hot to handle without gloves), some times this works since it helps to keep the plug dry for a few extra kicks before it gets too wet again, once running it usually smokes for a while until the crankcase is cleaned out. You seem to have tried everything else.

If the bike has been out in very cold weather then maybe the aluminium yoke has shrunk and effectively incresed the tension on -the bolts. Suggest that any similar bolts be loosened and re-torqued if subjected to cold weather.

If you have 25mm (1 inch) sticking out then you could try grinding a flat on one side of the shaft and make a gear lever with a cotter pin, i.e. same as a BSA kick start.

If it doesn't turn out to be a carburation problem then you may consider the following. I had a similar problem on a grass track JAP engine which would rev if the throttle were opened slowely,the problem would show up half way through a meeting when the engine was really hot. Turned out to be the valve clearances that were closing up as the engine got warm. Since you have put a new engine in perhaps it is not carburation. If the bike is missing badly then it may still show a sooty plug even if the carburation is O.K. regards Martin

Hi, I have posted a comment on this subject previously but can' remember on where. I had both my knees replaced at the same time about 4 yrs ago and still ride vintage trials on Canada. I ride the A line on a 500 triumph and don't feel at any disadvantage compared to before the operation. I was useless then and still am. If you are riding classic type sections then I don't think you should worry. It will take a couple of years befoer you feel totally comfortable. In my opinion during your recovery period, i believe the most important issue is to get full bending motion which is a 135 degree bend of the knee, don't do more because the joint is not designed to do more. A friend of mine did lots of walking and cycling but didn't do enough knee bending execises so he only has about 90 degrees of movement, but then he only plays golf so it doesn't matter to much. The bending exercise is simply to lie on your back and pull your knee into your chest until you get that 135 degrees of movement, it hurts but you must do it. It took me about 6 months before I rode and even then just practicing and letting go of the bike as soon as I was unsure. I rode my first trial 16 months later. You can always rebuild muscle strength at a later date, but it is virtually impossible to get more movement unless you do it at the beginning. If you want more info about how my recovery period went let me know your e-mail address. best of luck Martin

When you push down with the brake on, check to see if there is any relative movement between the lower fork yoke and the steering head frame. You can get a clonking sound if the steering head bearings are loose, though I am not sure how a fall would have done that. regards Martin

Is putting a spacer below the cylinder a recommended way to soften the engine and how thick a spacer did you install. I can understand the spacer on top to reduce the compression, but a spacer below would change the port timing, eg the exhaust port would open earlier and close later! Is this a proven method for this engine?