woody

What's the spacer sitting on the end of the mainshaft in the last but one picture? I've never seen one of those in any Bultaco I've had apart. The only spacer on a 5 speed model I've ever seen is on the kickstart shaft, although I've never had a 198 apart. Never seen one on a parts diagram either. Only the 340 has a spacer on the end of a gear shaft as far as I know and that's on the layshaft. Do the crankcases bolt together and the shafts turn with that spacer fitted?

The rear of the slide has a D shaped cut out so even when the slide is fully closed, it may appear as though it is 'open'. It isn't as the front of the slide is flat at the bottom and when closed it sits flush with the bottom of the carb and stops airflow. There are slides with different size cut-outs to vary the airflow - are you sure it isn't this you are looking at? If the slide is raised 10mm in the carb body and you can see underneath it through the carb, then either the throttle cable is incorrectly adjusted or too short, or, the slide is stuck open in the carb body.

Yes, it unscrews. They can get tight so it's just a case or working it free. If you can't do it by hand use grips to get extra leverage but don't grip it too tight or it will crack If it does break, new ones are available

Somewhere around 1973 the gearbox mainshaft diameter changed where it sits in the clutch side bearing, therefore so too did the bearing size. Can't be any more specific than that though, sorry, no idea if there is a specific model number this occured from. Crank bearings and seals are all the same size Clutch hubs and baskets differ, as does the spacer the hub sits up against Later gear selectors forks are thicker than early ones and won't fit early gears Bultaco UK is your obvious source for this info

The tank seat unit isn't a recognised Bultaco one. But, I had a basket case model 92 a few years ago which came with an identical tank to yours (sold the bike on) Yours is the only other one I've seen. I'd assumed mine had been adapted from another bike to fit but no idea what. It's very similar to a Honda Seeley but they are just a shelter that fit over an alloy tank. Mine was all fibreglass. Maybe someone was making aftermarket tank units for Sherpas that have long been forgotten about. Whatever it is, they fit the Sherpa pretty well. The boomerang silencer was fitted to bikes around 1974 so it's fine for your bike if you're bothered about period fitments. The bike is in original condition apart from the tank and mudguards.

Steve, kickstart assembly is how it is because the cases are split and the ratchet gear has moved on the shaft, it's no longer seated behind the stop. Neutral is easy to find without the manual, although I agree, working with the manual is far better. Only takes a bit of logical thought to position the drum correctly

From memory I don't know but look at it logically. If that's how they came out then they are the right way around as if they weren't you would only have had 3 gears.... Look at the selectors, there is only one that can be fitted the wrong way around for them to fit back into the gearbox, the one furthest away. If you turn the other two around their pins won't fit into the selector drum when the fork is located on the gear.

It doesn't matter if you're putting the complete cluster in, they're all interchangeable on the later bikes. If you're swapping individual cogs just count the teeth but the ratios should all be the same on the 198a / 199a. I think the 198b is supposed to have a slightly different 1st gear, same gear as the 175cc engine. You should find out what the problem was before just swapping out the cluster. If the selector drum is stiff in the casing for example or something similar you may be back to square 1 when you put it back together. It's easy enough to check that all gears select smoothly whilst they sit in the left hand casing and then again by just reassembling the cases without the crank, before final assembly. You could compare the action of the two gear clusters.

What spacers? If you could select 5 gears the selector forks are in the right way. If the fork that can be fitted the wrong way around was the wrong way around, you'd only have had the first three gears, no 4th and 5th. Did you check the selector shaft before pulling it apart

Have you checked the selector shaft isn't bent. Take the clutch case off and ride it around the garden and see how it selects. If it selects ok then your shaft is bent on the clutch side. It's not going to damage anything riding it briefly with no oil If it's still difficult to select gears take the shaft out of one of your bikes that selects gears ok and try that. If it selects ok with that shaft your original shaft is bent on the ignition side. If it's still difficult to select and your selector drum and pawls all look ok then you're going to have to strip it and look inside. I'm assuming you've had it apart already and the gears aren't rusted up on their shafts.. You could have tar in the gearbox and it wouldn't cause the problem you're describing, never mind the wrong oil. Also, the condition of the clutch won't make any difference as the gears will select very well without the clutch when riding.

Bugger the WTC, I wish they'd use them in the Miller round next year...

The Bultaco hose is shaped to go around the frame and it's still a tight fit. A straight piece of heater hose, given it's thickness and inflexibility could be a real pain to fit. The proper hose is worth the money over the possible aggro.

I left the brake pedal as it is. In reality, there is little you can do with it due to the design but I can still get to it ok where it is.

Yes, that's a standard 350 flywheel The flywheel itself may be balanced, I don't know, but they aren't balanced up to the counterweight on the clutch side as they vary in weight, shape and size for different models whereas the ignition flywheels didn't.

The sump bolts were seperate bolts each side originally but I can't remember the thread pitch from when I had one back in the day. The bikes I have now have long since lost their original bolts. I just use standard 8mm bolts. Fit them so that the nuts are on the outside, that way, if you need to remove the sump you can just push the bolts through far enough to clear the bracket instead of having to to remove them completely. The sidepanels are fibreglass originally and new patterns are available. On the inside of the airbox cover is a straight bracket which is held by a rivet (from memory) There is a conical shaped spring that sits between the airbox cover and the gauze panel. The smaller end of the spring tucks in behind this bracket. When the sidepanel is attached and screwed onto the frame, it closes the airbox cover up and the spring holds the gauze sheets and filter in place. In Motion sell a new airbox but not sure if they have the spring. You may find a spring from USA suppliers if In Motion can't help. Hubs are normal steel liners It's possible Ossa may have reverted to electronic with the later green bikes, they definitely had with the Grippers. Or someone may have fitted electronic to replace the points. The same ignition fits all bikes so not an issue.

Some of the frame/engine number sequences can't be found on the ID charts. My 350 MAR has matching frame/engine and starts 43 but it doesn't appear on the charts, it should begin 24 according to them. Same with the 700 sequence, it's not on any chart I've ever found. I had a bike with the same sequence. It definitely relates to the green MAR but whether it's the black frame or the all green bike I don't know. Mine appeared to be the all green model (it was in bits) and the gold wheels on yours suggest the same as the black frame bike had silver wheels as far as I know. Apart from the colour, they're the same bike really, which itself barely moved on from the earlier MAR. Same frame, different shock location, same engine, longer forks and points instead of electronic ignition. Timing between 2 and 3.5mm TDC. Carb should be an Amal on the 240 but don't know jetting. The shock length you should get off the Falcon Shocks website

Guys, I wasn't trying to prove you were wrong, it's just that the Haynes manual says one way and the Clymer says the other, but the proper Bultaco manual would show how they came from the factory. I have Barnett friction plates which are thicker than the standard steel plates, but I fit them slightly different from how you do it. I still use the steel drive plate as the first plate in the clutch but only use 4 of the Barnett plates with one of the original Bultaco steel plates to get the pressure plate in the correct position. Same result, just a different method.

Yes, but the other manual shows the plates fitted the other way. What you really need is the Bultaco manual.

Generally the 350 Sherpa flywheel looks like this. It has a squarer edge to its face than the 250. and is a lot deeper front to back http://www.ebay.co.uk/itm/Bultaco-350-Magneto-flywheel-/181180646350?pt=UK_Motorcycle_Parts&hash=item2a2f3543ce The 250 generally looks like this, it has a more rounded edge to its face than the 350 http://www.ebay.co.uk/itm/BULTACO-SHERPA-T250-1972-IGNITION-ALTERNATOR-GENERATOR-STATOR-FLYWHEEL-/400528679177?pt=UK_Motorcycle_Parts&hash=item5d415ea109 There are slight variances but generally, that's how they look. The 350 is thicker front to back than the 250. This is for the FEMSA ignition, the Motoplat from the later bikes is different again.

I'm sure it's 5 as standard, but, I'm going from memory and I have Barnett friction plates which are thicker than the Bultaco steels. I can't check until I get back to the bike which will be the weekend. I think the Frontera had 6 plates but they were thinner, so the overall thickness of the pack was the same. Visually, the inside face of the cover plate seats about flush with the edge of the basket. The Haynes manual shows the plates fitted one way, the Clymer shows them the other way.... I've always fitted the drive plate first and never have any clutch issues. If you speak to Bultaco UK they'll confirm it for you.

Don't forget the large O ring that fits in the housing before you refit it.

They go in the housing back to back - ie: the 'open' side of the seals face outwards and the solid face of the seals sit against each other on the inside.

12mm longer springs.... I'm guessing these are new too, so they would be right but 12mm longer...? What was in there...?? There's no reason for it to drag, have you put new plates in? Have you got the right number of plates? The first plate to go in is a drive plate, the one that locates on the hub. There are 5 drive, 5 friction plates and the cover plate. Too many plates and it won't free off properly. With your engine, the clutch springs are held by pins so there is no way of getting unequal tension on the springs as there is with the bikes that are tensioned with nuts. The clutch plates should seperate evenly when the pushrod pushes back the cover plate. Obviously the clutch cover has to come off again to check this. I ride mine around the garden with the cover off until I get the clutch set right so I can see what's going on with it. Also, have you got the clutch arm set in the right position on the timing cover. Make sure it is positioned so that the arm is being pulled by a straight inner cable. To far back and you are pulling against the pivot, too far forward and there isn't enough movement to free off the clutch. The pushrod is 185mm long by the way, I found one to measure.

It's essential so that the casual spectator can identify with it and might be encouraged to watch it, as they understand words like race and grand prix. Talk about observed trials and they are lost. Something to do with watching barristers isn't it (no, not whilst they're out dogging...) Its the kind of bollocks that happens when promoters and money men run the show and want to turn it into exactly that. A money making show to line their own pockets with no care at all for the history or roots of the sport or what happens to it once they've p****d off. The same people presumably who tell Cal Cruthlow and Dougie Lampkin back in his day to give media interviews in a ridiculous euro accent. And who tell today's Motogp riders to pick up their drinks bottle and have a fake swig every time someone pokes a camera in their face, The sport sold out to money years ago and 'race', 'fiasco' and 'grand prix' is the result.

I'm interested to understand this as well.... but bare in mind these bikes do get hot if you clutch case or magneto case gets hot then somthing is wrong. They run hot but there's something wrong if they get hot? I'm sure there is a typo in there somewhere but I still can't make it out... They're going to get hot due to heat transference from the cylinder... You don't need the vented plug for the gearbox. And if you fit one the chances are that the gear train will try and throw most of the gearbox oil up it - just like the clutch does on the later bikes with the vented filler plugs. The only damage you're going to do to the gearbox is if it runs dry and seizes the bearings. It's not going to run hot because of a blocked breather.