woody

11 : 42 will feel high on the M92. If you ask Talon they will make you a sprocket in the size you want as they will already be set up to machine sprockets for that wheel. It's just a one-off order for a non-standard size.

I'd agree your original speed estimates were too high - I'd struggle to trigger the 30mph sign in 4th on mine, never mind 1st. The early Sherpas were never very quick on the road. Anyway, back to the matter of gearing. Your gear ratios are all correct so there is no problem with the wrong gearbox. The clutch gearing is the same for all Sherpas I think, so I don't think it is possible to alter gearing that way. However, yours is the right ratio so nothing wrong there. The final drive gearing was originally set with a 428 chain on this model and you don't say which chain size you are using. With the 428 chain the gearing should be 13 : 52 (14 : 52 is also quoted) The later bikes had the same gearbox ratios but when they switched to the 528 chain the gearing became 11 : 46 which is what you have. I've just rebuilt my M92 and had a first proper ride on it on Sunday. I think I'm running 11 : 46 as well but I'll have to check. When I got the bike it was on 428 chain, so when rebuilding I think I woould have opted for the standard 528 sizes. First thought was also that it is a bit too high, but I think this was exaggerated by the fact that the bike wasn't running well and was very woolly off the pilot jet. It also had two flat spots at aout two thirds and at full throttle. Ignition or carb but don't know which yet but the affect on throttle response can completely alter the feel of the bike. Trying to pick my way up rocky streams with a woolly throttle response makes the bike feel very lethargic which can also make it feel too long in the gearing. If the bike picks up crisp and cleanly it will feel much lighter and responsive and maybe the illusion of a too high 1st gear will disappear. Sorting out the running is this weekend's job. So on your bike, 11 : 46 is correct. As Feetupfun mentioned, make sure the bike is running correctly and try it again, you may get used to it quite quickly, if not all you can do is try a bigger back sprocket as you can't get a 10 tooth front for the Bultaco The last 5 speed model, the 199a used 11 : 39 according to the info sources, and had a lower first gear, although 2nd, 3rd 4th were the same. Not sure how that works out as 2nd - 4th would be quite high compared to 1st.

Difficult to get here in the UK though as there is no internet or ebay shop. The other problem with the right hand brake pedal is that if the footrests have been lowered, it is difficult to get the right leverage onto the standard brake pedal with your foot and this also contributes to the poor braking affect. Ideally the brake pedal needs to have a different shape when the footrests are lowered.

They stock Venhill who are the only company with off the shelf cables in the UK. The point being the Venhill rear brake cable is crap.

The kickstart hitting the gear lever is more of a problem on the 199a and b models because they have a shorter kickstart shaft with the 'thumb' timing cover. Therefore the kickstart is closer to the frame than on the earlier bikes. On both my 340 bikes, the kickstart actually touches the frame. I've broken off two right hand brake pedals on rocks on my 340

If you can get used to the left hand pedal stay with it. To fit a cable you need to put a cable stop on the frame above where the pedal locates and another on the swingarm. It's a fiddly job. If you search this forum you'll find a similar topic with pictures The Venhill rear brake cables are rubbish and have too much flex in them. I've ridden on one leg using the rear brake as the footrest with all my weight on it and I don't think it even moved the shoes into contact with the drum, never mind slowed it down. All that seems to happen is that it takes up flex and then stretches.The brake works perfectly using a left hand lever / rod so the cable appears to be at fault. The orginal Bultaco cable had a stronger inner cable and the outer cable had a solid bend where it bends onto the swingarm. This helped keep the cable from flexing when using the brake. The venhill cable doesn't have the solid bend, so not only is the inner cable too weak, the whole cable flexes when the brake is applied. I asked Venhill to make me a copy of the original, using an original as a patern but they won't do it.... !! I looked at making a cross shaft, like Aprilia, Fantic, Armstrong, but don't think it is possible because there is too much in the way to get the shaft from one side to another.

The one on the angle is the throttle stop screw because the throttle slide rests on it, so when you screw it in it lifts the slide. This lets air in and increases the engine revs by drawing through fuel with the air. Screw it out and the slide will eventually close shut - no air, no fuel, no tickover. The other screw is the mixture screw (air screw as it controls the amount of air passing through it) which will also increase and decrease revs as it richens or weakens the mixture through the pilot system which controls slow running. Screwing it out lets more air in which weakens the mixture. In shuts the air supply off letting more fuel through which richens the mixture. Set the mixture screw to 1 1/2 turns out from fully screwed in. Then turn the stop screw in or out to get a slow tickover. While it is ticking over again adjust the mixture screw by turning it very slowly either in or out about 1/8th to 1/4 of a turn. Listen to the engine as it will either run faster of start to stall. Turn it in the direction that causes it to run faster and keep turning until it starts to run slower again. Turn it back to the point at which it runs fastest. Then turn the stop screw out to reduce the tickover to the level you want. Leave it for a while to see if keeps running. If it falters and dies start it up again and while ticking over repeat the above process. If the carb is in good condition and the engine is in good fettle, particularly the crank seals, you should now have a smooth tick over You should find a tuning guide here http://amalcarb.co.uk/downloads/

Not specifically no, just check the events calendar on this site and buy Trials and Motocross News newspaper from local newsagents or WH Smith as that also has a list of events that are on over the following 5 to 6 weeks.

There's an AMCA trial at Bracken Rocks, near Matlock, tomorrow (or today, given the time...) Details are on the Calendar

Shouldn't make any difference to the tyre seating on the rim, it just denotes the strength of the rim

Yes, indeed. I was following him through most sections and he was riding really well. Fine achievement to go feet up on any bike, let alone the big Ariel.

Can't notice any performance difference between the two, or the Bing when it was new, OKO is just a lot cheaper (or was) to buy as a new carb. Mikunis are a pain as they have the airscrew hidden by the exhaust I have a Dellorto on my other 340 which works just as well

If you search the forum (Bultaco) I put the jet sizes on here from the OKO on my 340 some time ago. Must be pretty much the same for the 250

Perhaps you don't like tennis when you hit the ball into the net - remove the net? Make the holes 2 feet wide in golf for those who can't hit it first time? Does anyone apart from Fuji care that he stalled and had a five?

Try Sammy Miller products as I think they may be agents for Magicals now Or you can buy them from Todotrial in Spain http://www.todotrial.com/ttshop/indexttshop.htm

Tubed IRC have softer sidewalls and can roll off cambers or the tops of rocks and can even skew the bike sideways under hard acceleration when run at normal trials pressures of 3 - 5psi. How badly this is evident depends upon the type or level of sections being ridden and the weight of the rider. The heavier you are the worse they'll be as rider weight will squash the sidewalls more making them more prone to roll. Increasing the pressure to hold it on the rim doesn't work for trials because as soon as you go over 5psi grip is lost. So you either roll around on it or spin up... It does seem though that they are inconsistent and some aren't as bad as others, although a few road trials will soften the better examples up a bit. On the Jap rims they stay out on the bead until you let them down to about 10psi and then 'plop' - any lower and a section will drop into the well. Generally they are ok on the old Akront rims with no need to trim the bead. Trimming it would make it a more sure fit I guess but I've never done it in the past. Most of mine are tubeless rims now.

Agree with Mick, looks like a MK1 from the swingarm length, rear silencer, unpainted hubs and forks. Also the tank is the factory fibreglass one whereas the MK2 onwards in the UK had an alloy tank fitted, plus the side panel under the seat had a toolbox from MK2 onwards. Admittedly those things could be changed but they tie in with the other things. MKK1 also had bolt on carburetor mounting to cylinder and the outside fins each side of the head were split not solid. The engine number will confirm the model, most MK1 bikes didn't have the frame number stamped on them, it was on a sticker on the headstock which is usually long gone. The engine and frame number matched when built so you can use the engine number to check against the frame number charts that list the various models. http://ossa.2y.net/o...a-frame-nr.html MK1 Ossa They were only ever white and green as production bikes. Mick had a red stripe on a works bike.

I assume the FIM have a representative at these events. The FIM rule is that you complete the section without stopping. What was his reaction at the observers briefing when some clown told them that the riders can stop for a couple of seconds without being penalised. In the video there are 3 blatant stops inside 10 seconds and another 2 inside 20 seconds The only thing that surprises me is that anyone cares what they do with WTC observing....

I haven't seen it no, but it's not going to tell you anything about electronic ignition, all you'll see is someone riding a bike... It may fire up with the first kick but they'll do that on points too. The main reason most fit it is to do away with points maintenance, it doesn't transform the power of a bike to GasGas like levels, most you ca do is alter advance curves. I have a model 92, so does a mate of mine. One has points, the other electronic. If you rode them both you wouldn't know which was fitted with which. I'm not saying electronic isn't worth having, I've got it on two of my Sherpas, soon to be three, but don't expect it to transform the bike into a 280 GasGas

If you can get a copy of the Clymer manual that covers Ossa, Montesa and Bultaco in one volume, they give the length of the pins in the gearbox reassembly chapter. I thought there were three lengths, not two, but it's been a while since I did a Montesa There has been a topic on this in the past, I did a quick search but couldn't find it

Yes, they can't bore it without the new piston... The cylinder is blasted clean and returned ready to fit to the bike although I rinse them out anyway. All the ports are dressed properly. They have a backlog of work, so they must be doing it right and they've been around for quite some time.

PJ Engineering in the Midlands did a good job on fitting a new liner and reboring to new piston on my Bultaco. Fired it up last week for the first time and it is as quiet as you can get.

To convert to plated bore, first, don't you need an alloy liner, then plate to that? So it could cost £150 ? for a liner (based upon replacement cast liner from PJ Engineering for my Bultaco) £130 ish for the plating plus the cost of the piston. Expensive for no gain? I'd just use a decent piston like a Wiseco and get it bored. I had a rebore on a 250 Majesty using a pattern piston because it was all that was available at the time and it rattled within minutes of start up. That happened on two bikes and was nothing to with the quality of the rebore as I've had many done by the same person over the years.

The later 250 ('76 on) was sleeved down from the original 244cc 72mm standard bore to 238cc 70mm standard bore. You can still use the original size 250 pistons that start at 72mm standard and there are 4 oversizes, so you won't run out of 'meat' on your liner. So you aren't limited to a 71mm piston

They aren't aluminium bodied - only the end caps are aluminium, the body is steel. Which is better, Falcon or Betor is subjective. Personally I'd never by Betors in preference to Falcons and just my opinion, but you'd be fortunate if you bought a pair that worked as well as Falcons.