getting the YZ490 rebuilt

[jaykup]

I am just wondering after it is rebuilt, How I should break it in.. low throttle, etc.. and for how long.

Also, should I let the bike warm up (air cooled) before riding it, and what is a good time? I want to see if I can get this rebuild to last as long as possible

Clutch too, is there a break-in time for that as well?

What is a good gear oil to run?

Thanks

Jake

[Kane]

All questions answered by various methods and opinions. First, it doesnt matter what the engine is or whether it's air or liquid cooled, you should always get an engine up to running temp, or close, before riding it. Break-in doesnt take too long on a 2-stroke. Vary the RPM's without allowing an idle and stay off the pipe, meaning don't wind it out. Just ride a decent surface for about an hour or so before beginning to open it up. Make sure your premix is a tad rich for the first tank, say 20% extra. Expect the plug to foul or look like shit after an hour or so. Can't say I've heard of a break-in for a clutch. Usually you just buff the drive/steel plates on some 600grit in an hourglass motion to remove the glazing, unless you're using new ones. Engine/tranny oil is so varied in opinion it's not funny. I use Castrol and Amsoil 20-50. For bean-oil I use Klotz, Amsoil, and Polaris Blue (which is made by Klotz anyway)