Sorry guys
It's a 1972 model. I do have a 2nd hand TM top end, but it's already bored out to + 1.25mm. I may not get a +1.5 oversize so I'll have to re-sleeve. The (homemade) pipe also won't fit the TM barrel. Gear ratios are the same as the TM as I recall.
I'm a bit tight for time (race in 2 weeks) so I was looking to pep up the TS ports, stick on the 32mm TM carb and use it as an intermediate step.
Regards
David
David, I wouldn't be resleeving a +1.25 barrell. Wiseco make +1.5 & +2.0 pistons. I'd wait till I could find one of those. It'd be much cheaper.
If you want porting specs from back in the day, I have several mag articles. Typically they said raise the exh a couple of mms, lower the inlet (or cut the skirt) similarly, ramp the top of the piston adjacent to the transfers 1.5mm, widen the exh 7mm (but I wouldn't go wider than 49mm - 70% of bore). In general, aim for circa 180deg exh durat'n & circa 165 degs inlet. Use TM head & carb. Thats still pretty mild but should be a good starting point. I'm sure Lozza can do a lot better.
FWIW factory specs are as follows (from top of barrel):
Exh TS 39mm Kit Cyl 37mm
Tr TS 53 Kit Cyl 52
In TS 99 Kit cyl 103
The responsibilty for changes is all yours! I have no experience w TM/TS250 mods