Finally!

[David Lahey]

OK Nathan there are two steel 428 rears of about the right size you are welcome to either or both.
A is 54 T and will bolt straight on with standard bolts but the teeth are quite worn.
B is 54 T and the mounting holes have been modified to suit countersunk screw heads. It has no detectable wear on the teeth.
They are pretty heavy so would cost a bit to post. I don't know if this suits you but I could get them to Brooweena (early July) or the Aussie Titles - Gold Coast (mid August)

You would be one of very few trials riders with an O-Ring chain of you do fit one. The drag would probably make a difference to the performance on a TY175 and non-o-ring chains and sprockets last many years anyway unless the bike is road ridden. The rear alloy sprocket on the bike I ride the most (a hod-rod TY175) is about 11 years old now and has just started to show signs of wear.
David

[Nathan S]

Thanks again David.

For some weird reason, I am now faced with the odd problem of having several new O-ring chains, and no decent non-O-ringers.

Anyhow, I fitted some 340mm long shocks along with the rebuilt rear wheel, and took it for a couple of laps around the back yard. It turns better now (it was previously lacking castor and felt very weird) and the lower gearing makes it MUCH easier to ride.

I'd forgotten how damn loud it is though! That's definitely next on the list of things to fix.

Unspectacular pic that I only took because I was outside with the camera:

[David Lahey]

Your unspectacular photo looks fine to me.
I can suggest a couple of things from the photo:
Slide the forks up 20mm through the clamps if you are still using 340mm shocks
Turn the front guard around the other way
Regards
David

[Canam370]

Looks good Nathan. The graphics off a Pinky TY mono?

[Nathan S]

Turn the front guard around the other way

OMG -that's so obvious now that you've pointed it out, but I hadn't realised until now.

The thing steers far more tightly than my brain can comprehend already. I literally cannot turn the thing on full lock as it is (admittedly without a whole lot of time practising).
Will sliding the forks up make that better or worse? I'd halfway figured that once/if I learned to do that, then it would be time to slide the forks up. Yes/No?

Paul, yeah they're late model stickers *barf*.

[Canam370]

Nathan. If you can't get to lock on a TY you need more body english. Get out in the yard and start doing figure 8's and practise weighting the pegs. Get nice tight turns then! Its great fun and hones the skills.

He He He....guard on backwards  exposed on the forum! hehehe LOL

[David Lahey]

Canam370 is right. Practice, proper weighting and bike lean will allow you to do the turns as tight as you like. A standard TY175 would have to be the best trials bike ever made for learning how to master tight turns without hopping the front.

About the steering geometry: In my opinion, 340mm shocks and 20mm tube protrusion feels the best with the standard rake. Probably not surprisingly, that is where the factory set them on new bikes and was the setting preferred by Mick Andrews. I suggest you try them at both settings and decide for yourself which feels better.

Here are a few things that may guide you in the process that I wish someone had told me 35 years ago:

Don't try and use the front tyre to turn the bike. Think of it being there just to hold the front of the bike up. Turning comes from you leaning the bike over and keeping it balanced left/right at the same time - use your body mass to weight the footpegs to provide the balance. Your outer leg should carry most of your weight in tightish turns. The inner calf rests against the bike and the outer calf moves away from the bike. Practice the technique with less than full lock until the technique is automatic before moving on to full lock.
Use the rear brake to control the speed of the bike in turns (hold throttle steady and modulate brake to control rear wheel speed). Remember that to do full lock turns the front wheel maintains some speed but the rear wheel has to be almost completely stopped.
Common mistakes for learners in tight turns:
Trying to control the bike speed in turns with the throttle or the clutch
Riding with knees together
Not leaning the bike over enough
Going too fast in turns

There is a good training guide available for free download on the trials.com.au website

David