woody

They might label them so but they aren't Sherpa tanks, they are Alpina

Both frames look like model M80 Sherpa from 71/72. (but could also be Alpina frames) Red one has a front wheel from an earlier model or something else, hard to see. Blue one has forks and front wheel from the next model, M91

Genuine OKO yes, I've been buying off them for about 10 years. For virtually every bike I've put them on they run virtually straight from the box with minimal change, usually drop the needle one notch and maybe down one size on the pilot jet. Jets are standard Keihin. They come with 112 main and 48 pilot. I've never had to change the main jet. Out of interest I bought one from Mid Atlantic a couple of years ago jetted for a 310 MAR, I wanted to see what differences there were in jetting from how I had mine jetted. It came with a weaker needle but bigger pilot jet. The bike ran the same with either carb

Nowhere, only copies Buy direct from here https://www.ebay.co.uk/itm/OKO-26mm-RACING-CARB-FLAT-SLIDE-CARBURETTOR/302886110025?hash=item46856b4349:g:rRQAAMXQHO9Re1yr

These can be an absolute bitch sometimes. I've never used the alloy/nylon bushes, only the bronze/steel but the same principle applies and there is more than one cause. Before the bushes are fitted the inner bush should slide and rotate freely in the outer bush. When the outer bush is pressed into the arm the inner bush should still slide and rotate with little or no resistance, but the ID of the outer bush can shrink once pressed in and this can cause the inner bush to bind up so they might need skimming to rotate freely. Once they rotate/slide freely the next problem can be the clearance of inner to outer bush when the spindle is tightened. The inner bushes contact against the engine bracket so that when the spindle is tightened the inner bushes tighten against the bracket and leave clearance between the collars of inner/outer bush. No clearance means the inner bush collar tightens against the outer bush collar and locks up the swingarm. There are two solutions, one is to put a shim between the inner bush and the engine bracket if there is enough room, the other is to remove material from the inside edge of the collar of the inner bush - both are trial and error as to shim thickness or how much material to remove. When working properly the spindle tightens the inner bushes up against the bracket leaving the swingarm free to rotate around the inner bushes. You can see the outer bushes rotating with the swingarm and the inner bushes remaining static when it is working correctly and the swingarm moved up and down Powder coating can be thick enough to stop the swingarm being fitted into the frame and sometimes it has to be removed from around the area where the swingarm sits. It shouldn't really be a cause of the binding up, it can just prevent the swingarm actually being fitted

That's the 'Victor' style frame that was used on the C15 competition models from 1964 whereas I think the road bikes continued with the usual frame with bolt on subframe. It's a genuine Pre-65 frame (C15 version that is, although early B25 is probably the same or similar, later B25 was oil in frame)

Looks like a MK1 MAR but I've nno measurements to hand. The MK1 MAR (and other models) had a smaller crank than '74 onwards engines, so could be MK1

Peter James will insure it on a classic policy

A better way to locate the wire and protect it from the flywheel is to run it behind the stator, to do that the webs behind it need to be ground back to make room

It sounds as though you've bought MK2 brake shoes if you've had to reduce the width to make them fit as the MK2 and later bikes use wider shoes than the MK1 Use the old shoes and have them relined with modern linings, oversize and then have them machined down to achieve full contact with the hub This is the nut for the 10T but you only want 10T if you like really low gearing, unless you have 42 rear, the 10/42 is not too bad https://www.inmotiontrials.com/product/mar-tr80-gripper-front-sprocket-tab-nut/

You'll need the specific case bolt for centre bottom of the casing as later casings use that bolt as the oil drain rather than a drain plug

The spring as shown in the picture is fitted correctly Are the pawls located properly in the selector plate? Remove it and check they haven't dislodged. When you fit them ensure that they are both held in position by the flange around the edge of the plate and clear of the gaps in the flange The gaps enable them to flick out and engage in the selector drum once installed. When the pawls are located properly, if you hold the plate in the position it will be fitted to the engine the peg on the selector will be roughly 2 o'clock (possibly 10 o'clock, depends which way the peg is pointing when you locate the pawls. Fit it in this position which will keep the pawls located and then move it to about 12 o'clock. There is some free play so it will move either side before the pawls engage in the slots in the drum. Then you should be able to just push the selector shaft in locating the spring either side of the peg in the crankcase and the slot should line up with the peg on the plate

159 is a pin type hub, I've not seen one with the threaded type.

The 15mm was measured to the inside edge of the basket teeth which is the closest surface to the case edge. Measured to the inner edge of the actual basket drum, yes that's 29mm You spacer looks correct to me as they don't sit flush up to the seal and if the chain. The positioning of everything else looks correct in this photo as well The way the hub sits in the basket looks ok from the pictures, so at the moment I'm stumped as to why there is a problem with the case fit The inner surface of the basket, which the hub sits against. Is this a completely flat surface or is there an inner recess into which the hub locates? Have you tried just fitting the hub onto the shaft on its own (it won't go all the way onto the shaft) and fitting the case? Is there clearance then? Try fitting the case (both cases) without the hub or basket and check the fit and see whether the splines on the gear shaft are fully visible which will at least eliminate a case issue, but as far as I'm aware there aren't different dimensions in that area for any of the cases

For info, dished sprockets are available new as 44T, works ok with 11T front. Original gearing was 12/46 on MK1 MAR (yours ) and 11/42 on MK2 onwards. You'd really only want a 10T front with a 42 rear. There is a specific nut you can buy for the 10T sprocket which has a shoulder on the inside to space the nut and prevent the chain catching it The wiring is old and brittle, if you leave it at the original angle where it exits the case it may well crack open the insulation and short out. Many bikes have been altered to run the wires out by the front engine mount, you're not devaluing it by doing that Brakes can work quite well if you have modern linings fitted to the shoes in oversize and then machine them down to fit the bub for maximum contact. EBC and Newfren are that thin on their linings that you barely get an inch of contact when the brake is operated

Springs are 24mm If the weight is fully home on the crank and the chain line to the basket is ok, then that should eliminate the basket and spacer as a problem, if either was wrong the chain run would be out. Which brings us back to the hub. Is it definitely fully home in the basket bearing with the back of the hub right up against the basket. I'd remove both from the engine and just seat the hub into the basket and make sure it is going fully home. Sometimes they are tight and won't push fully home by hand and need a sharp tap Something that can happen (if the clutch plate order is drive plate first) is that a drive plate can stick to the basket when plates are removed as probably most people do the same thing when removing the plates which is grab the tabs of the inner most plate and remove the pack as one - it's possible for the first drive plate to remain stuck to the basket. If the hub is then removed and the basket left in situ, the drive plate can slide downwards in the basket and if the hub is refitted it prevents the hub from fully seating. This is a proper long shot but it can happen

The top hat came with the 159 engine that I have so I assumed it is the correct one. So are you saying the basket isn't fitting far enough on the shaft and the chain run isn't in line? I'm not sure where you are now You could have the wrong basket, the engine I have in bits didn't have a basket with it. The inside edge of the cover plate should sit just inside the edge of the basket fingers I have two engines with the clutches exposed at the moment, a 199b and a 151. As a guide, on both of them, the gap between the crankcase edge and the inner side of the basket teeth is 15mm If you shorten the clutch spring studs you will never compress the springs enough to fit the pins and clutch action would be seriously heavy. That's not the way to go, there is a fundamental problem somewhere. Previous owners could have done anything to this engine over the last 40 years

Are you saying the basket is positioned too far to the right or asking if it could be? As you mentioned before that the chain run from basket to crank sprocket was in line, but if the basket is positioned to the right the chain run would be off if the crank weight is fully located, so not sure now if your saying the basket is to the right or asking if it could be The extra balls could be there for any reason really as it's impossible to know what someone has done in the past but yes, the basket being offset would offset the whole assembly. There are different length pushrods so that's another possibility, too short a pushrod I'd have to check on an engine, which I don't have one in bits at the moment, but I think It is only the basket (specifically the basket bearing inner race) that sits against the spacer. The hub pushes into the basket bearing but I don't think the end of the hub goes as far as touching the spacer so if the basket is too far to the right then the hub will be also, bringing the pins closer to the case. Is the bearing located properly in the basket. There is a circlip that retains the bearing, if that is missing has the bearing moved outwards which would push the basket towards the casing, but then I'm not sure if the hub would bind up when fitted and tightened Does the top hat definitely sit right up against the gearbox bearing? Remove the oil seal and just fit the top hat to get a better view Try fitting the top hat, then position the crank weight and basket with chain onto the shafts without the hub and push the basket against the top hat, turn it to tension the top of the chain and check the chain run Some pictures of the parts might help

Only one ball and that goes between mushroom and pushrod, but maybe the wrong pushrod is fitted and is too short. However, even if the overall length of the rod and balls is too long it can't affect the position of the spring studs as they are fixed on the hub which is not affected by the pushrod, If you leave the basket and plates off and just fit the hub and spacer, nothing else, what happens with the casing then?

A bit baffling this... If you fit just the hub and spacer, nothing else and then try and fit the casing what happens? The top hat spacer should fit inside the seal and up against the bearing, the hub then fits up against the spacer. Is there anything stopping the spacer locating against the bearing?

I've got a 159 hub in a box of bits so measured it as follows, overall depth 43mm, depth of the hub where the plates sit 22mm. depth of the boss at the back 21mm. Pin length 33mm, length of pin showing from edge of hub to end of pin 19mm. Behind the hub is a top hat distance piece that sits between the bearing and the hub. This is 13mm. These are also the measurements for the same parts fitted to model 80 and model 151. As far as I know, the hubs with the pins to hold the springs are the same on each of the Sherpas that used them, model 80 up to 159 type engine. Not sure about Pursangs though, they may be different Is the top hat behind the hub the right length. Later engines with the threaded pins have a longer top hat although if one of those was fitted it might affect chain alignment. Also some hubs with threaded pins are a few millimetres longer in depth Again, as far as I know all of the cases are the same in that area, the case shouldn't be a problem with the pins EDIT - I've just realised my use of the term pins might be confusing. By pins I mean the long studs that the springs and cups slide over, not the small roller pins that hold and tension the springs. I should have just said studs...

The model is as you've said, a 198A which is a 1979 model 250 (actually 238cc) No bottom frame tubes and alloy bashplate is correct for this model Rear mudguard loop has been cut off to copy the mod that Comerfords did to the bikes of supported riders at the time, although the bolt on mudguard brackets weren't, that is something a previous owner has done Rear wheel looks Honda. It's not unusual for the bearing housing on the brake side to break up or the chrome to peel off the braking surface in the hub on the Sherpa wheel which maybe why it's been replaced. Or, someone has fitted it so they can have a wheel with a right sided brake so that a right hand pedal can be linked directly to the brake with a rod, although this one has a badly done cable link. With the normal Sherpa wheel a right hand pedal needs a cable to the brake arm which isn't always popular, so some owners use a Yamaha, Montesa or Honda wheel instead to move the brake to the right

That's a TR77 exhaust complete

The damper rod itself is a loose fit in the alloy spacer that sits inside the bottom of the chrome stanchion, so even if the spacer has fused to the stanchion the damper rod should still move being a loose fit inside that spacer. However, the piston on the top of the rod is steel and although the entire rod assembly is not a tight fit inside the stanchion, maybe there is corrosion around the piston?. If the cone shaped bump stop is removed from the bottom of the damper rod, the rod can be removed by sliding up and out of the top of the stanchion ( in ordinary circumstances) leaving the alloy spacer in the bottom as that part will only come out of the bottom. As you seem to have nothing to lose now I'd remove the bump stop, screw a bolt into the damper rod and give it a whack with a hide mallet and see if it will force it loose and up through the stanchion. The spacer can then be tapped out through the bottom taking care not to break the shuttle valve which may still be in there and which are very brittle as I can't remember if that can be removed through the top of the stanchion or only the bottom

Your bike, a model 221, is a 175cc. The Sherpa 125cc is a model 185 and has a bore of 54mm The model 221 uses a 250cc engine which is sleeved down to 175cc so you can use a 250 piston and bore it back to 250 if you can't find the 61mm oversize piston