woody

Fit Barnett friction plates, they don't stick. And because they are higher friction, the springs can be backed off a bit to help lighten the clutch pull. As mentioned in the first reply, the gear shaft can slide sideways slightly to the left meaning that the selector forks lose contact with the drum. Tap the end of the shaft to make sure it is fully home. Inside the clutch casing there is a circlip on the gear shaft and sitting against that on its outer side is a wave washer and shim. I'm not sure if this is supposed to stop the shaft disengaging from the drum as the washer should sit against the inside of the clutch case, but I don't think it does as it still seems to be able to move a little. Without it, it moves a lot more. A jubilee clip on the other end, as mentioned in previous post, stops movement. If this isn't the cause of the problem, it is a strip down as the selector mechanism is inside the cases. Possible causes are incorrect shimming, weak spring on the selector fork, worn or broken tips on the selector fork etc.

The bolt on peg relocation kit is from TY Offroad here in the UK who has been specialising in Honda TLR rebuilds and modifications for a good number of years now. Lots of Honda parts. http://www.tyoffroad.co.uk/

Had a quick look at my stripped engine this morning. The O ring on the sprocket side is seated 7mm inside the casing, that's measured to the inside edge of the O ring housing / groove. As you can only move the shaft by 5mm, even if you could cut it off flush with the casing, you still couldn't slide it far enough to clear the O ring. With the engine apart and the shaft out, you may be able to remove enough to enable it to slide far enough to get at the O ring with the engine assembled, but there would only be 2 to 3mm left of the shaft extending past the O ring and I wouldn't know if this would compromise the sealing effect.

Has yours got the 30mm diameter final drive gear? Some 340s had final drive gears fitted that were 30mm diameter instead of the more common 25mm which the 5 speeds also used. Therefore there are two sizes for top hat sleeve, seal and sprocket I'm only guessing, as I've never had one with a 30mm diameter, but the smaller diameter final drive gear could possibly be used by changing the final drive bearing to suit as well - but it is only an assumption

That's what I think could maybe be modified to enable the 5 speed gear to fit the 340. Machine the recess into it

Out of interest, as I don't need one, where did you buy them from?

Don't lose that shim off the layshaft gear...

The 5 speed final drive has the same number of teeth but is machined slightly different. I'm no engineer but would think it possible to modify the 5 speed to fit if you can't find original. That was my plan B if I couldn't get an original when mine broke.

I was going to offer that as a possible solution to avoid splitting the cases but I'm not absolutely certain there would be enough clearance, so didn't... When I'm back in the shed at the weekend I can try and measure up against a part dismantled engine, see if I can get a definite answer

Although you can push the shaft through from the sprocket side, it won't go through far enough to clear the O ring. As above post, you have to split the cases to replace that one. I wouldn't split them unless absolutely necessary

I don't think there is an answer to that as if I remember correctly, the people that helped Shirty build them have said no records were kept. One of them, Sam, has been on here from time to time, so he would be the one that may have an idea

Are you sure it's 10 on the front? 10:46 is very low geared, 11:46 is the usual gearing. A 10 tooth Bultaco front sprocket was never commonly available, they aren't available any more

The Clymer and most other manuals were written before the TR77 was in production. All earlier Ossas used electronic which is why they don't mention points. Can't help with the problem as electronics are a mystery to me but check that the wires aren't broken where they exit the crankcase and bend 90 degrees, if they still exit at the original point. This used to be fairly common issue, especially if they've gone brittle through age

Judging from the consultation paper that the Dept of Transport have issued, they have no desire to implement this. They could have implemented this years ago if they had wanted to interpret the original directive in the way that the EU Court of Justice did, which is what's kicked it all off now. It's not just competition that is affected either, it concerns any use of motor vehicles, even on private land

I think the suffix number was for external differences, such as on the MK2 and 3 Ossa MAR, which was a push in fit as opposed to bolt on like the other bikes, but the same inside. Also might denote which side the tickler or pilot and idle screws are etc. Most Ossa, Montesa, Bultaco trials use very close, or same, jetting specs I agree with Jon about Surrey Cycles. If Burlem don't have one built up they won't build one to order for you, you have to wait until the time they have scheduled to build that particular carb, which could be weeks away, which is a crazy way of doing business. Also just realised my first reply was badly worded as I meant the 427 suffix was for the 247 Cota. I remember the carb that came off the MK4b that I rebuilt a few years ago was the same internally as all the others I've had on Ossas and Bultacos, and I'm assuming it was the original carb as it was a two owner local bike that had sat unused for years

That is the original carb for the 247 from that period I think Amal have reproduced most of the carbs from that period so they may have them. If they don't have 27mm, the 26mm 626 concentric will work just as well

Just been having another look for M7 as I have some bar risers to fit on my MAR and the existing bar clamp cap heads aren't long enough. Searched ebay again but this time no sign of the M7 countersunk screws I saw before. If you're struggling you can replace those in the front of the sump with M6 which is what I've always done. At the rear you can always drill out the threads in the frame lug on the sprocket side and use M8 nut and bolt which also gives a bit more leeway than just trying to use a bolt if the sump is out of shape and holes don't line up fully. On the clutch side I've never had a bike, since the one I had nearly new, that has a sump that is still straight enough to fit the bolt on this side so mine are only ever secured on the sprocket side. If yours does line up you could always tap the thread out to M8 x 1.mm pitch, they should prove easier to find

They're not common in the UK either but when I've searched and bought them off ebay in the UK, I've also seen them available in the US on ebay. If you search for M7 Cap Head you should find them easy enough

I can't tell you if the Amal MK1 and IRZ cables are the same as I've never had an IRZ - best bet is to ask Alex Snoop or Keith Lynas as they are long time Ossa dealers

Are they different? I thought all plastic tanks were the same, there is only one tap for plastic tanks and that's the one with two 6mm screws? They screw into metal inserts on the tanks I've seen but they can pull out if you over tighten

I'm no electronics man but not sure the flywheel has a protective coating? Sometimes, flywheels are skimmed to improve engine pick up and if they are, the original finish of the surface is skimmed away. I've done a couple myself and they don't corrode. Still shiny in fact. I wouldn't worry about it but I guess you could always use engine lacquer on it

200 in a Sherpa leg is too much - 180cc max The hole in the top nut should work as a valve to release air and stop the forks pumping up with air pressure but in my experience, even when they new, all they do is spew oil in your face. The air leaking also reduces pressure in the fork on compression and softens the fork action. I just drop a blob of araldite in each hole and have never had any problems with pressure build up in the fork They weren't air assisted but you can by fork tops from In Motion fitted with valves which you can use to either add a bit of pressure which also acts as an increased preload effect or just use them to bleed off air pressure build up, if you get any. If you use them to add air pressure you only need about 10psi max and you'll need a mountain bike shock pump to do it properly as it has the correct adaptor to fit the valve without losing all the air when you release it Your springs may also be past it but 200cc won't help rebound so try again with correct volume and then decide

The fibreglass sumpguard was replaced with the alloy version sometime in 73. Alloy version is better

The MAR was introduced in 72 and didn't have a rear silencer. They were a bit crackly... The pickle silencer appeared sometime during 73 so both 72 and earlier 73 bikes had no tail pipe You can buy new pickle silencers, I haven't tried one but the originals did mute the exhaust effectively Alternatively, you could easily make an effective silencer that doesn't spoil the looks of the bike. I used an old YZ250 2-stroke rear silencer and cut the body to the required length, re-placed the internals with a 25mm straight through perforated tube with new wadding and replaced (or sleeve down) the inlet and outlets with 25mm (YZ inlet, outlet and core is 30mm if I remember correctly) I have these on my 250 and 310 MARs and they work very well I wouldn't bother repacking the centre section until you've run the bike as it's not a nice job and no point doing it if it doesn't need it. If it does need packing, as well as being a bit loud the bike will also be a bit lumpy off pilot as a well packed silencer makes them run very smooth. There are few bikes as smooth as a MAR off pilot Example of type of silencer body here http://www.ebay.co.uk/itm/2005-YAMAHA-YZ-250-SILENCER-PROCIRCUIT-A-05-YZ250-TWO-STROKES-/142162425062?hash=item21198a74e6:g:XSUAAOSw5cNYEkka

PMK - The rear silencer on a later TR77 is different from the MAR silencer. The TR77 rear silencer is stuffed full of wire wool and has two small exit holes underneath at its end. The centre boxes are the same, but on the TR77 the centre and rear are welded together whereas on the MAR they are seperate items