A forum for owners of Yamaha TTR250 trail and enduro bikes!

Hi Mike

Ideally you need the simple Yamaha flywheel puller but if this is the only TTR engine you are going to take apart it probably isn't worth the investment. You can use instead the rear axle but make sure you screw it in straight!

I can't recall needing any other special tools apart from a device to hold the flywheel when assembling so that the flywheel retaining nut can be done up to the correct torque.

The main bearings come out (and go back) more easily with a bit of heat. Ally expand 3 times (approx) that of steel so should come out a little easier with heat.

Some brief details here http://ttr250.activeboard.com/t43805944/ttr250-fitting-a-325cc-big-bore-kit/

Your gaskets and seals are the same as for later TTRs so you can certainly order from the BOATs fiche. Don't expect to get your order quickly though if they haven't got the parts in stock. Customs at Heathrow can add another 3-5 days depending on whether they get the parcel just before a weekend or not.

AllBalls do a main bearing kit which Steve and I used on our 325 rebuilds - see here

Good luck and don't be shy about asking for help if you need it 

Brian

Currently rebuilding an engine and the main bearings are a bit "lumpy". Surfaces have gone grey and there are marks where it looks like swarf has been crushed into the surface. Anyway, I notice a slight difference in the numbers on the bearngs. Both are Koyo 63/28-3, but the left hand one also has SH stamped on the inner race. I know that the whole thing is designed so that the crankshaft stays in the left hand bearing during disassembly, so are the bearings actually different or is the crankshaft machined to different tolerances? Are the bearings different part numbers on the Yamaha parts fiche?

I intend to replace the bearings with more Koyos but that SH doesn't appear when you google 'em. Sorry Steve, just don't have a great deal of faith in Allballs.

Cheers,

Simon.