woody

Banana is noisy compared to the clubfoot. The clubfoot is fine and is not restrictive. Banana maybe a bit restrictive for a later (M159 on) 325 which have a bigger exhaust than the earlier 325. You can modify the clubfoot by cutting the back off the rear box part, cutting all of the baffles out and replacing them with a perforated tube and packing and converting the dual outlet to a single. It's debatable whether you notice any difference other than a deeper tone and maybe a few more revs on the very top end at wide open throttle. The only packing in the clubfoot is in the section that runs from its inlet to just in front of the rear shock. If the bike runs roughly off idle and has a tinny / hollow sound It's probably worth cutting open, cleaning and repacking both middle box and rear silencer front section. Depending on how the bike has run in the past, the middle silencer can either be dry inside and have blown out all of its packing, or be totally gummed up from poor 2 stroke oil and/or wrong mix. Either way the only fix is cut open, clean, ensuring all of the holes are free in the perforated tube and repack,

That one is longer than a MK1 MAR spindle but I imagine you can make it fit with a bit of machining and thread cutting

I have a triangle on my M49. It's an aftermarket Spanish one from In Motion, it quietens the bike down nicely and no loss of performance at all. It could be that there are no baffles in it, I don't know, but the bike runs fine with it fitted.

Page 100 in here might be what you want Hamish. I was looking for a model 10 gear lever and came across the brake pedal https://www.motosdelabuelo.com/pdf/bultaco.pdf

I'm confused as to what advice you're after as well ? You can just buy a barrel and adjuster nut from In Motion

No idea what the message problem was. Can't help with what difference white or grey primer makes sorry, mine was powder coated and a body shop did the tank for me. It normally says on the can which primer to use ? I'd always use 1021 for yellow, it's a nice deep, rich shade. Can't get a picture of my old Gripper on here but this Majesty was 1021

TY OFFROAD have got pistons as well as ring sets. The pistons are both standard and oversize. The oversize he had made and is a quality piston, it's more like a hone oversize than a proper oversize. A good number have been sold with no problems. Check the website https://www.tyoffroad.co.uk/store/c20/ENGINE.html

28mm is the correct size carb for the 199a (all Sherpas in fact with the 'new type' 325 motor from model 159 onwards as they have bigger inlet and exhaust ports than the original 325 engine) Mikunis are really difficult to jet from scratch, as someone else said, so many variables of carb type, needle jets, needles, all of which have to match as you can't just fit any needle to any needle jet. It probably is the right type for the bike but as they weren't standard fitment there is no base setting for jets etc. You rely on someone else having one on the same bike that works properly and using the same. They all have the air screw on the right hand side which is another pain in the a*** feature about them when you have a bike with a right hand exhaust like the Sherpa. Then there's the flooding... The Bing works fine as long as it isn't worn, as with any carb For the jetting you have, 130 is a bit small and you probably need a 150 / 160. The TY main jet size of 240 is misleading as they are sized differently. Put a 240 VM jet in your carb and you'll pour more fuel in to the motor than it can burn, it'll be flowing out of the exhaust OKO 28mm carb works very well and runs pretty well straight out of the box with maybe just a drop of one notch on the needle and pilot jet change. They cost about £65 from Scooter Assassins in Taiwan (ebay) and a set of 10 pilot jets is about £18 - free post. There are cheaper available but they're copies and useless. Or you could buy one from Mid Atlantic trials in USA for about £100 ready jetted, but to be honest they are an easy carb to set up, unlike a Mikuni. I see you're in Hednesford. I'm running a trial (Stafford Auto club) at Milwaich on Sunday a few miles north of Rugeley. Bring your bike up there and we can have a look, if time you can try the OKO off my Sherpa

Not sure there was a workshop manual but there is a parts list that you can download from various free download sites on the net. For engine strip, the engine components and layout are the same as the MAR apart from small updates over the years to gear selector shaft and layshaft bearings which went from bushes to needle rollers. This means you can't swap the gear train from a 'bushed' gearbox to a roller gearbox and vice-versa. They look identical but there are small differences in shaft lengths and diameter. The Gripper has the clutch weight that the MAR doesn't have They have a cush drive, it's behind the clutch crank weight Pistons are very hard to get, you'll probably have to trawl the specialists in Spain or USA, I don't know of any here. The 350 MAR uses the same piston but the pins are in a different location from the Gripper so there may be issues with them fouling in the ports. I guess they could be relocated. But the 350 MAR piston is probably equally hard to find

You say it should be between 1.3 and 1,8mm BTDC with the stator fully clockwise. That's fully retarded. If that is how you like it then that is ok but fully retarded isn't the Ossa recommendation for trials model which is usually 2.5 - 3mm before TDC Ultimately it's the owner's personal choice how they set it

There aren't any actual timing marks, what you do is line up the hole in the flywheel with the hole in the stator plate and that is the firing point, so you just move the stator so that they line up at whatever point before TDC you want it set at. The hole in the flywheel is about 5 o'clock with the engine at TDC (or about 8 o'clock if it has an earlier ignition fitted) To line them up there is an actual motoplat part called a timing pin but you can use something like a pushbike spoke or similar. Did you use a genuine TR80 piston if you have fitted a new piston?

Ultimately it's personal choice, you can set anywhere between 2mm and 3.5mm before TDC depending on the response you want from the engine on pick up from idle

Sherpa t 325cc 1972/73

It's just an earlier manifold from a 158 to take the M92 pipe as the early 325 and later 250 are the same fitting

The original bars for the 159 were about 8 inch rise as were virtually all of the bikes from that era, with no brace. The black braced bars came in about 1978/79 on the M198/199 I think

As Steve said, frame is an early frame, from the headstock and frame tube layout I'd say series 2 model 91/92 from 1973. The exhaust chrome pipe is an M92 type and is the same diameter as later 250 pipes. It's definitely not a 198 frame. Engine looks to be a 198 type so if the numbering is not altered it should be the original engine. Maybe the original frame got damaged and someone acquired that one and stamped it to match. I've recently had some issues with DVLA whereby someone was applying for a V5 for a model 92 Sherpa that belongs to me. Turns out he must have had the engine that my bike left the factory with and stamped a frame with that number to apply for an age related plate - I'm assuming he knew engine/frame numbers matched from the factory and that he could date it from the engine number. The frame number flagged up as already registered so I had to prove that I had the original. DVLA wouldn't show me photos of the bike that he was applying for but the police who came to inspect mine did and I couldn't believe what had been done. It was a later frame and looked as though it had had the frame number chiselled into it, so no surprise really if you have one that has been tampered with

No idea why he told you that about the gearbox, the 303 shares the same engine components as the TR80 Gripper and MAR trials bikes plus numerous other models. Not really describable as a hodge podge either, it's basically an evolution of the TR80, with frame changes presumably eradicating the weak points where they could break. The engine is TR80, exhaust is TR80 redesigned to go over not around the cylinder and a new slimmer tank seat unit was fitted.

Sounds as though you may have a case from an earlier model Pioneer as most early Ossas had small crank assemblies. The early MAR - MK1 from 72/73, engine number begins 34 - also had a smaller crank assembly than the MK2 onwards - yours will be a NK2 as it's 74. As it is a 74 model the layshaft will run in bronze bushes so you need one from 74 - 76 engine, in late 76/77 the layshaft assembly was changed to run in needle rollers not bushes and although the shafts look identical they are slightly different in length and diameter so won't interchange (they might assemble but the gearbox won't work properly) You need an engine from a MAR that begins 21, 22 or 23. I don't know much about Explorer specs but think one beginning 44 or 45 might match the MAR but not sure - if you could find one as they're rare in UK. Ossa ID chart here with chassis numbers (applies to engine also as they're the same) http://ossa.2y.net/ossa/reference/ossaref.html

Hi Sandy, no, sold it some time ago and it went to Denmark. I gave it a total refurb along with a Cota 350 at the same time. Rode both a few times and out of the two I preferred the 350,

Puma bike uses an exhaust from a 335, common mod in Spain

The regs have now come out for the first round, Cotswold Cups on 24th March. It seems this trial has two class categories, one for the new championship and one for the Cotswold Cup. They're available on the South Birmingham MC website http://www.sbmctrials.co.uk

Ossa MAR - probably my favourite trials bike, just glad to help if I can I'm reasonably sure it's a Whitlock frame but another thing that is missing is the rear brake pedal mount as that was located just behind the left hand footrest as the Whitlock didn't have the same brake spindle arrangement as the Ossa frame I think the swingarm is either modified or a replacement. The bottom shock mounts are the wrong type and their positioning is wrong. The Whitlock frame was made for upright shocks as on the MK1 and MK2 MAR and the s/arm mount was just about in line with the front edge of the rear hub, the same location as the MK1 and 2 MAR frame, although the MK1 had a 1 1/4" shorter arm than the MK2. On the TR77 they went back to a short swingarm like the MK1 but put the shock mount right over the spindle. On yours the shock mount is further forward than a TR77 Ossa arm which is why the arm is pushed down at such an angle. This has left the shock angle somewhere between that of an earlier MAR and the TR77 and a steeper angle on the forks with the raised back end, the mounts need to be over the spindle to match the top mount and put the shock angle right. I can't think of anything else but someone else may have something to add as there are other Ossa enthusiasts on here

Only bad if you're bothered about originality I guess. The Whitlock frames were said to be good frames, lighter than the Ossa frame. I've never had one so don't know. I'm reasonably sure it's a Whitlock from what I can see, but not sure about the swingarm as it doesn't look like the Whitlock one, but it could have been altered as well I take it you can't remember the reg number, if not and you're certain of the history of the bike, I'm assuming it would have been registered using the original frame, so you should be ok filling the V62 out and applying for the V5 using the frame number

No. it's not an Ossa frame, it's a close likeness but there are a few differences. It would explain the lack of frame number It could be a modified Whitlock frame as he made some for the earlier MK1 bikes.The footrest hangers look very much Whitlock. There are other likenesses with a Whitlock frame but then there are differences too - sidepanel mounts, additional mount for headsteady (maybe) top shock position moved, bottom shock mounts changed, Swingarm spindle slot is normally open ended on the Whitlock frame. Whitlock frames were nickel (or chrome, not sure) plated as yours is undernneath Miller didn't sell an Ossa frame but Cheney did although it doesn't look like a Cheney. I'd guess at modified Whitlock but not sure

The MK3 generally had black legs but some early versions with the normal up and over chrome front pipe may have had plain alloy (not a criticism of what you've done, I'm no purist or originality obsessive when it comes to paint jobs) The MK3 changed a bit during it's short run, early bikes had the normal MAR exhaust, then they fitted the longer front pipe and some later versions had the TR77 style rear silencer That's a good shine on that paint for silver fox - I might try some of that on a Cotton tank I have to paint