Rejetting Required?????

1990 XR600R :lol:

If I was to install an aftermarket free flowing: air filter and muffler, (which would bring a lot more air into the carb/engine, correct?), would I need to rejet my carb and bring in more fuel to compensate for an increased amount of air going into the combustion chamber? :banghead:

I would think that I would have to rejet the carb otherwise the engine would run to lean and overheat, correct?

In order to rejet the carb on a 1990 XR600R, would you buy new jets and replace the old ones with them, or would you drill the current ones out to a larger size? :banghead:

If your engine is backfiring, that is a sign that it's running to rich, correct? Because un burnt fuel is exiting through the exhaust pipe and igniting in there. :busted:

You will probably need to rejet. I would buy a jet kit, that way you can play around with different sizes. on my 650r it would pop on decel because it was lean.

NEVER drill out jets. Guys do this, and it works (sometimes), but the problems is in the swirl marks that are left in the jet orifice bore (which affects fuel flow) as well as the fact that after it is drilled out, you no longer know what size it is. and since a very tiny difference in jet size makes a big difference in fuel volume, it's got a very low chance of being right. You do almost always have to rejet larger every time a gain in the engine's flowing efficiency is made, or the engine will run lean.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now