feetupfun

mine has an MCS universal two stroke muffler with one side flattened a bit to clear the tyre. It is not particularly quiet either

what carby is it?

I would check the diameter of the barrel spigot on the 175 before you get too excited about using a 250 barrel. It might be OK but it would be a very thick sleeve in the 175 motor if they are the same OD By the way, there are quite a few Sherpa Ts out there with Alpina bottom ends and they go fine in sections once geared down

yes the bearing seats lose metal when people replace the bearings without heating the hub. What you have is quite common on old motorbikes with aluminium hubs. If there is no radial play, you can fit them with a retaining compound to prevent them from moving and making the fit even worse. If there is radial play, the hub can be sleeved. If there is radial play and you use a retaining compound, the brake drum surface may not run true Cota 348 trials bikes were sold in 1976, 77 and 78. There were trail versions (348T) sold later on (probably to use up the unsold 348 frames after the 349 frame was released) The piece of perforated plate may have been removed from your frame to allow easy cleaning of the underside of the motor. Another possible reason was that one brand of aftermarket bashplate made for 348s fitted between the motor and the frame tubes, so they might have taken the mesh section out to prevent debris building up above the mesh plate

Brake pedal looks like 1977 or 1978 348 Someone has removed the drilled steel bash plate that is normally welded between the frame tubes under the motor Looks like the ignition flywheel cover has been cut away, probably to allow easy cleaning around the sprocket Can't see much in the photos but from what can be seen, the rest looks like normal 348 to me Have a good look at the frame while the paint is off, looking for cracks and bends One of my 348 frames has tubular ears/loops welded to the frame tubes under the front of the engine as a protective measure, but I don't know which year it is. My other 348 frames don't have those ears

suggest you post photos of (at least) frame and motor

There are second hand magneto covers available but I wouldn't call them cheap. The alloy bashplate from the BCDE models and that engine cover are probably the most commonly cannibalised parts on TY250s wrecks

I made one from 5mm aluminium plate that was a simple curve (not fancy, no welding) using a piece of wire as a template to do the curve at the front. It cost about $40 for the piece of aluminium. It could also be made with two creases instead of a curve if that is easier for you to bend

I run TY250A twinshock forks on a TY175, and found that the standard TY250 spring rate and preload were a bit high for that bike. I reduced the spring rate and preload by replacing the standard preload spacers with springs. I have not fiddled with the damping as the standard damping seems to work fine with the reduced spring rate and preload

looks like the wheelbase would be a few inches longer than standard

yes

Even if they did fit, they would look very strange on a TY50, because they are made for bigger diameter wheels

also the slide looks quite worn so I'm thinking maybe the slide needle and needle jet might be worn. That would make it run too rich from about 1/4 to 3/4 throttle. Maybe you could take a photo showing the slide needle up close. You seem to be pretty good at close-up photos, if possible can you also photograph the hole through the needle jet?

There are still quite a few possibilities for what is causing the smoke. Did you work on the bike at all between your first ride (when it didn't smoke) and the second ride (when it did smoke)?

The best test for clutch slip is acceleration in top gear It is extremely unusual for a clutch to slip when the engine is working as a brake, because there is much less torque being transmitted by the clutch in a given gear when the engine is used as a brake, compared to when you are accelerating

Glenn are you sure it is the tyre that is moving? I had a tyre/wheel combo on one bike (KT250 I think) a few years ago that I tried different locks, and even put screws through the side of the rim to grip the tyre, but the tube stem kept leaning over during a ride no matter what. Because it still happened without the screws moving in the tyre bead, I figured it was actually just the tube creeping around inside the tyre. After that I got a lot less fanatical about rimlocks and have even been riding a twinshock for over a year now with no rimlocks or screws on the rear wheel - TY250D rim and Michelin X11 tubeless with a grooved rim bead seat.

I run the standard springs and preload spacers in the majesty modified TY250 frame and that seems to work fine to me. I also have a Godden Majesty 250, which carries a more weight on the front end than the Yamaha frame, and it is still fine with the cartridge emulators, standard springs and standard preload spacers. Yes 1/2 inch to 3/4 inch would certainly help. If it was me I would extend the swingarm on the TY250-framed bike by 25mm, which would make it the same wheelbase as the Godden Majesty

squirt things near the front sprocket with WD40 one at a time with a test ride in between until you find the culprit Yes it could be the bearing behind the sprocket, if the bearing inner is spinning on the gearbox shaft for some reason. The sprocket nut is meant to be tight. If it's not tight the shaft can turn inside the bearing inner. Could also be the chain adjusted too tight. The chain gets tighter when you get aboard. The WD40 will find it whatever it is

Both are hard to get some parts for so make sure they are complete The Aprilia is rare and may be seen as desirable by a collector Italjets are not rare but are not commonly seen in competition

Standard KT caps are vented. Standard KT forks also have very clever oil deflectors inside the top ends of the springs that stop oil going near the vent holes unless the bike is almost upside down. They also work fine without vent holes. I fitted TY250 caps to my KT (TY caps are not vented) because I like to tune the forks using oil volume.

guy53 and I did the TY250 Yamaha frame Majesty mods at about the same time a few years ago and yes it is better to ride (for me the benefits are more clearance under the motor and a softer rear end). On mine the footpegs were lowered back to the same height off the ground as standard (the footpeg mounts go up the same amount as the motor with the majesty mods), and it does not feel top-heavy to me in turns. Maybe if the footpeg mounts were not lowered the C of G might feel a bit high. Mine did seem to feel as if the wheelbase was a bit shorter than standard (it is actually the same wheelbase) in that it is slightly harder to manage the front end in some circumstances like when turning up hill. Because of this I would say that the majesty frame mods combined with a modest lengthening of the swingarm would probably be a good thing. I haven't done swingarm lengthening yet on that bike

Here is what I use to take that gear off

Does anyone have a photo of a bike with the standard OSSA frame converted to cantilever by Cheney?

Pretty sure the last model Alpina tank will fit ( M212/213) I have a 212 frame I could test my 198 tank on if no one knows for sure.

yes mine also has flat spots for the OSSA badges, but I trimmed the decals to fit right up against the OSSA badges so it is hard to see the flat spots