millsy

You could talk to some tuners about porting, but be aware that the wrong porting can result in a backwards step and you can loose bottom end power very quickly. I have made some vast imporvements in this area on aircooled TY's and Montesa's. I have had a small play with the 315R montesa too, but to be honest, it's not bad if you run 100octane fuel and increas the compression ratio and advance the ignitian. I'd like to try a vortex 10 setting ignition modual as well. To be honest, I did have to start over with my first aircooled TY250 port job. I made it a little too agressive and lost all the bottom end power....was like an early YZ250 to ride...lol. Don't fit a larger Carb as this will result in reduced bottom end power too. Expansion chambers are probably best kept away from unless you have a good understanding of how they work. Again you can loose bottom end power. Keep us posted how you go and what direction you decide to take.

Sorry mate. Looks like you are up for a complete strip down and new crank seals at the very minimum! Look at doing conrod, main, big and small end bearinga nd piston/rings while you are at it. As mentions by someon earlier, check the water passages for corrosion and replace all gaskets and o-rings. Depening on budget, I'd look at doing the clutch and going through the gearbox while you are in there. Easier to strip it once and do the lot than find you have to pull it all apart again in 6 months time.

You say a wet exhaust, but do you mean watery or oily? I have seen on high usage and older bikes, the main crank seal going between the crank case and the gearbox. This results in excessive white oily smelling smoke from the exhaust because you are burning the gearbox oil. As said in an earleir message, it could be water, but this would often be seen as steam from the exhaust rather than smoke. You should be able to tell if it's water or gearbox oil by checking the level of both and checking the plug to see if it's oily or rusty (It may be neither but it could help). Check that the bike has good compression and is running on good quality two stroke oil at the correct ratio as well. Sounds like an engine rebuild may be on the cards anyway? Good luck.