feetupfun

maybe that one has been turned down - it might explain why it is so clean too

This might sound strange but have you tried the damping with them up the other way? Some shocks have damping that only works with the shock one way up

The standard nut does stick out past the flywheel, but yours appears to be sticking out a bit more than normal. It might be sometning as simple as there being too many washers behind it, or the nut may be longer than the original, or it may be standard and your photo makes it hard to judge exactly how far it is sticking out. It has to stick out somewhat, or you wouldn't be able to get a standard-walled socket on the hex. The flywheel appears to be much better-looking than the usual Bultaco flywheels I see which has me wondering if it is a non-original flywheel

I just thought of something else. Some people just call them "triples", which can get mixed up with another "triples" (three jumps in a row on an MX track)

Despite being a colonial, I don't know where the term "triple trees" comes from. I call them "triple clamps" because each "yoke" has three clamps (for clamping the two fork tubes and the one steering stem) I find the alternate spelling often used for "yokes" quite amusing ("yolks")

Roughness of the race will definitely cause you grief. I hope you know for about $50 you can buy a full set of tapered needle roller bearings, or if you are an originality-is-important type person, you can still buy the standard Yamaha races and use loose balls for about $80.

Yes it works but it is not by flooding the engine. It is by the fuel moving to the "top" of the float bowl, away from where the jets normall suck it from - so it just instantly runs out of fuel

The reason it gets tighter when you fit the top bolt is that there is a small amount of axial clearance in the threads of the stem and the castellated nut, so when you tighten the top bolt, the castellated nut moves downwards slightly, which tightens the clearance on the ball races. I find I have to set the castellated nut slightly loose so that when I tighten the top bolt it ends up perfect. Sometimes it takes a couple of goes to get it right. I suggest you leave the stem clamp bolt and the tube clamp bolts on the top triple clamp loose until you have got the top bolt tight and the castellated nut set in the right spot.

Even if a carb does not ice up, in conditions of high Relative Humidity, the water that condenses out of the air as it goes through the venturi can cause havoc. Have even seen problems with this in the balmy climes here when riding in just after a summer thunderstorm.

You can add a piece to a chain to suit different sprocket sizes, swingarm length etc. Using the rear axle slot would also make the rear suspension a lot softer if you used the same shocks as for the front slot.

may also have been to make it a better flat tracker. It wouldn't be the first TL250 to be used for that

I haven't pulled a Cota 200 apart so don't know the answer. Surely it is no big deal to work out what to do as the sides come apart and support the motor with the side down that you want the bits to stay in.

I used a piece of thin-walled rubber hose as a sleeve when I fitted a KT250 Mikuni to my 348

heat the outside of the case around the main bearing you want to come out of the casing. Use discretion to avoid overheating the aluminium. You are aiming for about 150 to 180 degrees celsius

I have a M49 (1968 model) with those tapered top forks and I can't tell any difference between the quality of the fork action of the M49 forks and M198 forks on an M198. The later type top triple clamp does make it easier to remove the tubes though. The later type (curved downwards) lower clamp is meant to provide reduced fork flex but I don't think many people would be able to tell the difference when riding. From memory of when I had both sets of forks apart, the damper rod assemblies looked the same.

247 front wheel is the same as 348 but 247 backing plate is different to 348 and brake arm may not clear 348 slider. 349 fork sliders are the same as 348.

I'm pretty sure this question has been covered a number of times on this forum or in the Twinshock forum. If there is nothing turns up in your searches, I will take a photo showing what a standard bike arangement looks like

Yes thankyou Jon, I am cogitating on it

Jon the TY250A model motor behaves nothing like a standard BCDE motor. For our conditions (dry - dry - dry), the A model motor is perfectly good to use and makes for a terrific play bike too.

The OSSA MAR forks are amazingly good for an early 1970s trials bike and the rear end works very well too with the right shocks. Yes I concur with lineaway the standard MAR 250 motor is quite amazing. The OSSA motor is a distinct advantage in muddy or other low traction conditions compared with the A model Yamaha. Both TY250 and OSSA MAR are both quite low under the motor compared with others of the same era. I'm not sure the terrific suspension on my MAR ever saved me any points compared with my TY250A, but it does make it feel more luxurious and steady to ride in places where the suspension get a workout.

Absolutely spot on Jon - my sentiments exactly

Good photos and location are needed if you want a serious answer to what they might be worth

Unless you are wanting the Cota just to be used for static display, plastic guards are the only sensible choice. You can buy the universal guards in grey/silver which looks good on a Cota 247. White and black plastic guards also look quite good.

cornishrockhopper do you really ride trials with 8 PSI in a rear Dunlop?

Sometimes people run an earth wire all the way from the stator backing plate to where the HT coil attaches.to the frame. This avoids any concerns about the resistance of the connection between the backing plate to the inner case, the engine mounts to the frame, and the frame to the coil. Sometimes that same earth wire is also run to the kill switch to avoid passing a current through the steering head ball races when the kill switch is operated. That current can cause damage to the bearing surfaces. Having an earth wire run to the kill switch also makes the kill switch more reliable for stopping the motor. The third stator coil is probably for lighting/battery charging. Some bikes have two or more lighting coils on the one core and others have two separate stator coils for the lighting. Bikes with points/flywheel magneto ignition usually only have one (stator) ignition coil.