Just bought 1st bike (TY175) -what basic checks should I do?

[jmorrocan]

After deciding I wanted an old TY to learn to do trials on, I foolishly rushed out and bought the first TY175 I laid eyes on, and not being terribly bike-savvy (I've owned a few old bikes over the years, but haven't progressed far mechanically beyond cleaning an air filter), I may have rushed the whole *inspection* thing. So now I'm attempting to suss out if I've got a decent bike retrospectively.

Here's a few pics. Apparently it hasnt been ridden much since a recent rebore piston and rings (have receipts). It looks like it's been tarted up a bit before sale. He gave the tank a nice lick of paint, but unfortunately seems to have used the wrong stuff, because as soon as a drop of petrol landed on it, it stripped it right off again. He even got a bit of overspray inside the tank, which is now proceeding to fall off, and i'm a tad worried it will wind up gumming up my carburetor.

It's missing one of the side cover things, which the prior owner is intending to get to me as soon as he digs it up.

So, how did I do?
Are there any other bits missing? Not original?

Also, what are the major things one should check/test when buying a used bike like this, so I don't wreck the damn thing. You'll have to go back to basics with me, for as I said - I am no mechanic!

[Hazza]

Nice looking TY175 JC you have there, I had a new C model back in 1978, the JC was the road registrable model with extra tabs for a battery box and lock ect,

See if you can get a toothbrush inside the tank and rub off the overspray inside, if it is coming off with fuel on it it should rub off easy. discard the fuel of course and rinse out with new fuel, a fuel mix of 80:1 should work well with but check with the manufacturers recommendations.

Take off the floatbowl and see if you have any rubbish inside the carb, get an inline fuel filter, to catch any bits you may have missed.

Check the gear box oil and change if is not looking 100% clean,fork oil may need changing also but get some riding in to see how it feels.

Check over all the bolts tighten if loose,

Tyre pressures 6 lbs front & 4 lbs rear for competition.

Most importantly ride often and have fun,

Steve,

[David Lahey]

I'm sure you will have great fun on your Ty175.
I suggest moving the fork tubes upwards in the steering clamps so that the top ends of the fork tubes are about 20mm above the top surface of the top clamp. That is the standard setting and the steering will feel nicer in turns than how the forks are set now.
The shockies look to be about the right length. They need to have a nice action and be balanced with the front forks to make it easy to ride in rocks. If you push down on the seat with one hand, the front and back ends of the bike should move down and up together.
When you put all your weight on the bike standing on the pegs, both ends should compress about half-way through their travel.
I see you have a TY175 B/C end muffler. The frame looks like a JC so your carby might be a TY175JC carby, which when standard has different jetting to the TY175 B and C models, and it is different because the JC model usually has a different end muffler and a rubber silencer on the airbox lid. The best test for the carburetion is to ride it and see if it runs well. If it goes well then no worries.
Gearing for trials is important. A 12 tooth front sprocket and 51 tooth rear is pretty good gearing.
The chain adjustment in the photos is set too tight.
Particular mechanical issues to look for on a TY175 are:
Play in the kickstart knuckle
Play or stiffness in the shifter action. The problem is usually inside the little compartment on the LH side of the bike where the shift shaft goes in
Have a look for frame cracks above the footpeg plates, front downtubes and at the front ends of the swingarm arms. Hard to tell but it looks like yours might have already been repaired on the LH side about where your ankle bone sits

[Hazza]

Get onto http://www.trialscentral.com/forums/forum/12-yamaha/ it will have some good ideas & tips on TY's

Steve,

[whitehillbilly]

Hi, Hazza,
fuel mix of 80:1 should work well ????
I used to run my TY 175 at 25:1
Have oils changed that much in 25 years.
My Boat and Stihl chainsaws, brushcutters run 50:1

whitehillbilly

[jmorrocan]

Beauty. Thanks for the input and advice fellas.

Is the dodgey air filter cover gonna do the job or should I be replacing it?

Also a few more closer photos including one of a chunk of metal missing out of the crank case cover, and a few cracks - are these any cause for concern ?

[Hazza]

Hi Whitehillbilly,

Yes I believe they have, I too ran my bikes at 25:1 30 years ago on Valvoline & Castrol 2 stroke but I know Guys back then who ran BELRAY synthetic oil at 50:1 , however I did say he should check before doing so and depending on what oil he is using.

I would like to hear from riders currently riding Twin shocks on what oil mixes they are using and with what oils, I use GRO on my Modern Bike but plan on getting a Twin shock at some stage.

Steve,

[David Lahey]

my air cooled 1970s two stroke trials bikes - 40:1 Penrite Hi-Per (semi synthetic)

[David Lahey]

crack in the flywheel cover - not important for strength, but seal it so it keeps out most of the dust and water. It's a good idea to loosen that cover off and let it dry out after you wash the bike or ride in the wet. The cracks can be welded if you want
crack in the screw boss on the clutch cover - not important
mesh lid on air filter - fine as long as the filter can't come loose while you are riding

[jmorrocan]

Ripper. Will do. Thank you!