TM 250 info

[Sorelegs11]

I have to rebore my TM250 after another seizure.
I am riding dirt track with it and the last set of rings only lasted about 10 laps.
I have checked the carb etc and it was spottless, Timing = mmmm was left as it was when I bought the bike and I got  a few meetings out of it without incident.
Can anyone tell me the correct bore clearance I should get it bored too, suitable ring end gap and some jetting sugestions.I  have the yammies sorted but I am lost with the suzy.

Cheers darren

[oldfart]

What piston are you running in it ..... I'm running Rm 250 A and work fine

[Lozza]

Wossner piston?

[oldyzman]

I had great results with wossner for many years, the last couple have been no good though. could be my tune. seems like a coincidence.

[sleepy]

The clearance depends on the piston brand. Stock should be .06-.07mm Wossner .08mm Wiseco about the same as Wossner.
If it is seizures after running ok for some time it will be something changing. Could be ignition going bad, crank seals gone , other air leaks , blocked exhaust , forgot to put oil in the fuel, changed mix ratio(25:1 would be best for it)

Wossner list a TS250 piston which is what I believe will work and make sure you get the bore job done by someone who has a good rep in your area.

[LWC82PE]

I did not think Wossner did a aircooled TM/TS250 piston? When ever i have looked at their catalogue they only list piston for the watercooled TS250X.

[Lozza]

I had great results with wossner for many years, the last couple have been no good though. could be my tune. seems like a coincidence.

Since 2012 when Wossner was purchased by the Dover Group, they seemed to have consolidated the amount of forgings they use and changed the machining to suit. That left domes/skirts too thin prone to cracking and sinking, small bore Wossners should never be used on a newly replated cylinder.

[Sorelegs11]

Piston is suzuki

Thanks for the info
Cheers Darren

[sleepy]

I did not think Wossner did a aircooled TM/TS250 piston? When ever i have looked at their catalogue they only list piston for the watercooled TS250X.

Part no is 8204 and it is list for TS250 1973-81 atleast that's what 2013 catalouge shows but the older catalouge and the Wossner web site say they fit 84-85 TS250. I'll have to do a bit more research. Anyone got a TM250 piston I can measure?

[pokey]

Suzuki use an ART piston stock, its a cast piston and thus doesnt suffer from the same issues as a forged piston. if your seizing you have issues that need to be addressed. are we running the oil pump? how are the seals and carb mountings? have we done a plug chop?

below is the chart for piston and end gap