correct jetting xr600

sorry to ask which is probably such a frequent question. At present my XR600 has splitfire plug with airduct from top of air box removed, WB airfilter, WB hotip with 65 and 155 jets.

My question if I remove 2 of the 3 layers of gauze from air filter mount what new jet sizes do you recommend and could I then check mixture with any device. I remember that I used a spark plug type device on a car,years ago to check mixture.

There are different jetting specs for different models. For starters, the RF-RH models (85-87) ran dual carbs, so the jetting will be obviously different. 88-90 models ran a different shaped airbox-carb boot to the 91 onwards models, these models ran 60Pilot- 165Main jetting, which should be very close to spot on if all restrictors are removed and the engine is stock. The 91 on models had a 152 main & 62 pilot jets stock, but on my 94 model (stock engine) I ran a 155 main and had the airscrew 2.5 turns out which was closer to the mark. With all models, if you experience popping or missing on a slightly open throttle down hills, your needle could be worn and if so, you can fix this by dropping it one clip position (second counted from top). The middle (third) clip position is standard.


sorry forgot to mention yr is 1997. thanks for reply from i bet you have got great places to ride other there.

RB, I have a very similar set up on my '96. I am running 70/170. I installed those jets before I took off my WB E series pipe and re-installed the factory pipe with the hot tip. At first, I thought it might be too rich with the stock pipe but the bike runs great. It has more bottom end too. After each ride I pull the plug to get an idea of how the insides look and so far so good. I would start with a 68/165 and see how that goes.

Mike :)

thanks a lot xr rider member 8553 for your help. will try 68/165 as you suggest and let you know how i get on.70/170 does sound big could it be that our fuel is different ie in uk . thanks again and keep on thumping.

RB, not too sure about the fuel. I would guess octane is octane however, California refineries do oxygenate their fuels for emission requirements.Good luck

Mike :)

thanks mike.

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