Trials Australia Forums

RestoreMaz, both the DT125 race bike and the 175 'trials bike to be' are 1974 models - twin shockers. I've also got a late 1977 175 twin shocker (just before the monoshock came out) awaiting restoration.

The 175 owes me literally $20, and I've got a shed full of old Yammie bits - so I'm still expecting to have it finished for less than half the cost of a TY80....

Yours was a 78~81(?) model. They got a big cosmetic update in the early-mid 1980s, but were the same basic bike until 2006. I know a guy who has a few wrecks sitting around - I'll ask if there's enough bits to build up a bike next time I talk to him. It will be cheap - I gave him a token amount of money and got my pick of all his Yamaha stuff (admittedly there was a bit of mutual back-scratching going on there).

DL and Subby, thanks heaps - good to know I'm not totally mad! :)

yeah no wories nathan, check out what hes got, ............i would prefer a complete bike ,the exact same as i had though, keep an eye out!

And so it begins:



Don't expect overly rapid progress, as it's one of... let me see... one of four consecutive bike projects*, but I'll post more pics (and questions, no doubt) as it progresses.

*Others are AT2 resto, YZ250K rebuild, and DT175C paddock bike, if anyone cares.

The most common mistake made was to let out the fork legs so the top was flush with the top triple clamp. The factory setting is in fact 22mm from the top of the steel fork tube down to the top of the triple clamp.

Chassis geometry is as follows :-
Caster/Trail 63 1/2 degrees / 97mm (from TY175C Owners Manual).

See also attached pic of recently sold TY175D (1978). I owned 2 B models new and have always liked them. Much more nimble than the 250.

Clean out the ports, clean out the exhaust and ensure the points are nor worn as the timing retards as the points wear (so put in a new set and advance the timing to 1.8mm BTDC, this is more important than the point gap, which is stated to be 0.35mm - 0.4mm.

Also it is beneficial to replace the ignition coil (under the tank) with a marine unit from (I think from memory) a Suzuki outboard twin sylinder 20hp model, as the ratio of primary to secondary windings is 70:1, the TY coil is 50:1, so you get better spark at low revs.

Hi Nathan S

Here's something to look at!!

Gives you a bit of an idea what you can do with an old TY!!

Any questions feel free to ask!!

Yamaly

Inching along with this, but had a bit of a bust of inspiration last weekend after riding my little AT1 around in the rocks at a mate's property...

I've got a choice of rear wheels - should I go cush drive or not? I can see arguments for both, but lack the experience to make the decision...

Hello,

I don't know what you mean by crush drive!! and the alternative is what?

keep ya feet up!
Yamaly

Nathan S wrote:Inching along with this, but had a bit of a bust of inspiration last weekend after riding my little AT1 around in the rocks at a mate's property...

I've got a choice of rear wheels - should I go cush drive or not? I can see arguments for both, but lack the experience to make the decision...

For competition use you should use the lightest wheel assembly you can get. Cush drives usually add quite a bit of weight for very little benefit. I've never seen a serious trials bike or an MX bike with a cush drive in the hub.

OSSAs had one on the crankshaft but the design concept didn't catch on!

Hows it comin along nathan? any progress photos?