feetupfun

It is possible to avoid oily gunk depositing in the exhaust by running with very little oil in the fuel. Trouble is, it is not kind to the motor to run with so little oil. It will run fine but will wear out much faster than it would with adequate oil in the fuel. How little oil you mix with the fuel depends on what life you want to achieve from your motor. Because of this, you will find a variety of opinion about what is the ideal amount of oil to add. I use 40:1 semi-synthetic If your M198 has a standard exhaust and you burn out the gunk, the main (first) muffler section will need repacking to run properly. It will run but not very well without packing around the inner tube. To repack the main muffler it will need to be opened and there are many ways to do this.

Roger if you become a "Supporter"of this website you can post photos directly within your postings. Alternatively you can upload your photos to a photo hosting website and include a link to your photos in your postings. Regards David Lahey

The first TY250 twinshocks were made in 1973

The black goo on piston and throttle slide sounds like residue from incomplete combustion to me. If you clean it off the carby slide and it comes back with use, the piston rings are not sealing well. The lack of ring sealing may self-correct if you get the motor nice and hot in use. I have seen plenty of two stroke trials bikes that suffer from the rings being stuck in the grooves, which prevents them moving as required to seal against the bore. It usually happens on bikes that are only used gently and don't get hot enough to burn the goo out of the ring grooves (and other places). Riding up a long hill (a continuous minute or so at half to full throttle) should clean it out

C = compression damping adjuster E = extension damping adjuster If it doesn't bottom out on the biggest drop-offs, you are not getting full use of the suspension I would say you problem is with the mounting bracket hitting the exhaust, because even with forks fully bottomed, nothing should touch anything else. Another possibility is that someone has moved the fork tubes up through the clamps a bit too much, causing the mudguard bracket to hit the exhaust on severe compression of the forks. Another possibility is that the frame might be bent. There are more possible causes but I'm sure you will work it out soon.

There are pictures of such a tool in Bultaco workshop manuals so you could replicate one yourself, or buy one ready-made from a Bultaco parts specialist

I did wonder that but the brochure shot you posted of a 348T has the fuel filler in a different spot Isn't it amazing how a slightly different shape to the fuel tank can change the looks from sexy n sleek to yuk city?

To me it looks like some other tank has been grafted onto the seat section of a 348 tank

Sorry I can't help with your question but I thought "thanking you in advance" was a pretty good line for a question about ignition timing

I'll have a few wild guesses at what squid's squeal is If it is only when the bike is moving along, it might be one of the brakes dragging If the pitch changes when you move the throttle, or as the revs change, it might be an air leak Again if it is only when the bike is moving, a wheel bearing or the drive chain might be very dry or siezed

We have used an OSET 16 for nearly three years now. We have not had any problems with the charging and we have not taken any precautions regarding the connection and disconnection sequence to bike and mains power. How hot is the charger getting? Our charger casing gets to about 45 degrees Celcius. Ours hangs in space from the mains cord so is well ventilated.

Maybe someone has raised the pegs on your bike because if you fit them any lower than they are standard they will be lower than the bashplate. An option for your tallness is to either fit higher bars, or modify the bar mounts to get the grips higher. On a Sherpa T this usually means quite drastic mods to the top triple clamp.

Why are you so sure it is a 1974 model? It sounds like an Ulf Karlsson model to me. That would line up with how you have described it so far.

The cable lug is probably for the clutch cable for when an earlier model 247 motor is fitted. It sounds like your bike has the later type cases on an early 247 motor or is a later type 247 motor.

Yes you are right Neo - I should - sorry mate

I think all Yamaha PW50s had the same cap design. Another option even cheaper is to get an aftermarket (Chinese) PW50 cap. I bought one of those at a Yamaha shop for my 1983 Yamaha PW50 and it was under $10.

Neo I wish people spelled coarse and dual correctly but its not likely to happen anytime soon

Two answers Some people do make their own scale model trials bikes from scratch. There are some particularly well done Sherpa T models that have their photos on the web. There were at least two brands of plastic scale model kits for the TY175 made in the 1970s and 1980s and some of those kits are still available new-in-box. I found one in a hobby shop in NSW, Austraila (by searching on eBay) to give out as a rider award a couple of years ago.

Twinshock, air-cooled monoshock or water-cooled monoshock TY250?

A 200 Beta is probably the same weight or even slightly heavier than your Sherco. A Beta 200 is not a zappy bike and would haul you fine, as mine did and I am 51 years old and well over 13 stone.

If the problem was the perforated exhaust tube being displaced sideways then yes there would be an effect on how smooth it runs, but I would be surprised if it could cause pre-ignition. You said that you had a new ignition and had tried different settings, but have you checked what the timing is doing at different RPMs with a strobe?

Alan there is a steel sleeve that rotates inside plastic bushes. The bolt you are trying to move siezes inside the steel sleeve. The recommended way to get the swingarm out is to cut through the bolt with a hacksaw (bike upside down, swingarm rotated out of the way and something to hold the frame away from the swingarm enough to get the blade in). The sleeve comes out easily once the swingarm is free of the frame. That bolt freezing in place is a very common problem with TY250s and TY175s.

The standard Ty80 shocks have very soft springs so if they are not moving with an adult on the bike then one or both are probably bent or seized. Standard TY80 shocks are not meant to be rebuildable. If you can free them up they may be OK for a youngster even with no damping. Our TY80 has the original standard TY80 shocks with zero damping effect but they move freely and seem to work well with my kids (35kg and 22kg) riding it.

Whether your shocks are worth rebuilding or not depends on what shocks they are and you don't seem to have included that info in your posting.

I will bet that it didn't run with a plain big end for long