The MX250 needed a bit more work and continued on from the tuning work I’d started a few weeks ago. In the end, the modifications for the first Llanthony meeting of the season are as follows:
– top-end polish and rebuild. I ended up not altering the port heights, but just went for a removal of the anomalies on the inlet, boost and transfer ports. New Wossner piston (they list the one for the 76 YZ 250 and on, which is a basically the same).
– thicker base gasket (home made paper gasket) and Hylomar blue to replace the top end gasket; more compression. Gasket paper came from http://www.gaskets-direct.co.uk/ , who I can recommend.
– PVL ignition, more on this to come in a separate article, but have sourced what I think is the best ignition for the MX and SC bikes. Also reasonable price, including having a stator plate made up.
– new tyres, Dunlops to replace the somewhat erratic Michelins, which were also showing the wear after two seasons.The front was an awkward bugger to do, and shredded the old tube in the process.
– handlebar risers; also on the SC500 and something I should have done before to make standing up easier.
– foot rests, replacement
– petrol tank, acquired a plastic Clark tank from the US and the tank strap from Motolink; looks good.
Still to do is the exhaust and waiting on Circle F to fabricate and then ship, maybe by the start of May.
Anyway, eve of race 1 of the season for me, and looking forward to it. The MX250 needs a bit more running it, but sounds okay in the garage.