feetupfun

I'm stuck in the 1970s with my welding. Oxy-acetylene and stick. I tell people that the welding technology fits perfectly with the age of the rider and the age of the bike.

They can both be made a lot lighter than standard

A standard TY250 weighs about 11 kg more than a standard TY175 and 10 kg of that difference is the weight difference of the motors

The hubs are exactly the same on 175 and 250. The 250 uses a dished sprocket and the 175 uses a flat sprocket because their front sprockets are at different distances from the centreline.

If there is side loading on the main bearings it will be hard to rotate, thrust washers or no thrust washers on the big end. If the rod was free before you put it in the cases it should still be free because the force required to move the crank wheels on the big end pin is usually way too much for reassembly in the cases to move it. Maybe clarify what you mean by "now I've put it together when I put the 2 crank cases together and nip up the crack is stiff and will harden move without force" so are you meaning it is hard to rotate the crankshaft or hard to move the rod?

It looks like the front half of a 250/320 Godden main frame has been attached to the rear half of a TY250 main frame and some even weirder stuff has been done with that single shock and the rear subframe

Photos please

I've not heard of anyone using that sort of additive to bowser petrol/pump gas but there are plenty of trials people using a long-life fuel called "Aspen" which is available from lawnmower/chainsaw shops. It suits people who have to store their bikes for extended periods. I haven't tried Aspen myself but have read plenty of things on these forums about it. Sounds like it is readily available in countries that have cold winters.

If there were no hiccups along the way like siezed bolts etc about 2 hours. However if the bike is 10 years old with an aluminium frame, you could expect some hiccups

Magical fork springs are available for your OSSA. If you need help finding them you can message me

Steve measure the axle and post it up here. You may find it is the same size as a more readily sourced axle. For example, my OSSA trials bike has a rear axle that is a swingarm pivot bolt from a TY250.

Keith Lynas in the USA sells weld-in inserts. I bought one from Keith and had it fitted locally. Yes the Wayne Weedon method is good too

If there were two trials riders of any ability and one of them was required to wear MX boots, the one wearing trials boots would enjoy themselves more

My memory has it slightly different to st pauls. The "Sammy Miller Parts" business was sold to a husband and wife team who commissioned the manufacture of a small batch of new (close to replica) Highboy frames for the TL125/TLR200 motor. They were all sold including one that I've seen that came to Australia. That business later became Feked. I've just remembered the blokes name who bought SM Parts years ago - Richard Jordan

It's fairly dry here and the original zinc plated spokes on trials bikes made in the 1970s are still serviceable 45 years later but do look dowdy. New zinc plate spokes here look good for about 15 years. If you live in a wet area or at the coast they will start to look dull sooner than that. Stainless steel spokes will look great for hundreds of years but how much longer do you think the bike needs to look nice? I use both types, chosen mainly to provide the original look of the particular bike. Most of my Spanish bikes came with stainless spokes so that is what goes back on and all of my Japanese bikes came with zinc plated spokes and that is what goes back on. One Spanish bike came with plain steel (uncoated) spokes and I used stainless spokes on it. If I lived somewhere that it rains a lot or near the coast I would use stainless steel spokes on every wheel rebuild. Maybe you have access to very cheap zinc plated spokes to get your costing of double for stainless, but what I've paid recently is for genuine TY spokes, one wheel costs about $120 while a set of aftermarket stainless spokes for a TY or a Bultaco is between $120 and $180.

To replace the external spring you need to take the magneto cover off. Unless there is something strange about your bike, one end of the external spring hooks over a bolt that sticks out through the casing and the other end goes through a hole in the kick shaft. The head for that same bolt holds a piece in place inside, so don't let the bolt slide inwards while you are replacing the spring

Depends on which kickstart spring you are talking about. There are two. The return spring is external and can be fitted without spiltting the cases. The ratchet spring is internal and requires the cases to be separated.

Would be worth about 500 UK pounds where I live

Looks quite attractive for a bitsa

Slow action throttle requires less force to overcome the return spring. Fast action throttle can be more ergonomic because the rider's wrist does not need to flex out of the ideal position as far. Changing from fast to slow can help new riders adapt more easily to a responsive motor. New riders sometimes buy a trials bike that is not the easiest to learn trials on and changing from fast to slow is much more economical than buying and selling bikes.

TR80 (250) felt OK to me but didn't feel as light to ride as other bikes of that era that I had ridden

There is a bloke on these forums who did a few frames very well a few years ago and I'm sure he will see your posting and reply if he wants to. If you just want the look it is pretty easy to make a TY250 look like a Yamaha-framed Majesty without doing the frame and swingarm mods.

That depends on a couple of things: The "new" cylinder may come with it's own piston. The condition of your existing piston and rings. Do they have enough life left to be worth it? Is the "new" cylinder diameter small enough to be bored to suit your piston? It's likely that a 198 cylinder will have been rebored at least once by now. My own choice would be that if a new piston was available to use as part of an engine rebuild, I would use a new piston to reduce the risk of having to do the job again.

What do you mean here about the Clake?

Sorry Graham yes I was wrong. I've been working on too many engines lately