Problems after uncorking '02 XR650R

Just finished rejetting to the guided specs here, replacing the intake boot with the open one, removing snorkel, and drilling out the stock end cap. Bike starts great now, sounds good, but I think it's way too rich? It won't rev any higher than 1/3 throttle, just coughs and sputters. I checked to make sure the carb vent tubes aren't pinched and they're not. The problem gets worse if I put the choke half-way on, and the bike doesn't even want to run at all with the choke on all the way. This is after warm-up, choke works as it should when the bike is cold.

I used the 175 main. Close to sea level here and weather in the low 60's right now.

Any idea what I might have screwed up here?



Did you change the exhaust?

After opening up the intake/fuel, it's gotta go somewhere.

There's plenty of info on exhausts here, personally I run a BIG GUN quiet series along with the uncorking..

Any idea what I might have screwed up here?

I know this may sound simple, but check to make sure that when you're flipping the lever the right way (turning the choke off instead of turning it on).

You might want to check the float level, it may be too high.

it shouldn't be way too rich at your elev. I'm running a 180 main jet at 650' elev. and it runs perfectly. Did you open up the airbox? By not only removing the snorkle, but also the plastic baffle plate? If not, try that.

Whatever the case, you have to remember that jetting it rich with the 175 or 180 means that you have to bring in more air, and get the exhaust out faster through a more open exit.

from the newbe...I had the same problem try a 155 main it worked for me. I am at sea level as well.

By the plastic baffle plate do you mean the carb insulator? (the rubber boot between the cylinder head and carb) I replaced that with the free flowing one. The only thing I did with the actual airbox was removed the snorkel, that was all that I could see restrictive there.

If that's not it, where exactly is this baffle plate?

Do you guys remove the backfire screen too?

PS, did modify the exhaust, used a hole saw and cut the insert out of the spark arrestor so the exhaust just passes through the screen and straight out now.


Where you took off the snorkel in the airbox there is a space for your sidepanel attachment. There should be two rivets. To the left of that is a plastic plate held in with some clips remove that also. You should also change the pilot jet to a 68s and the needle to a B53(3rd clip). With the bike just having the drilled exhaust I recommend gonig to a 172 main rather that a 175. I have the HRC tip and find the 172 to serve it better. Good luck.

Thanks for the help! I went out and looked again and saw that other piece held in by the clips. Doh! Don't know how I missed that before! I popped it out nad the bike runs great now. Thanks for the help everyone!

I'm going to stick with the 175 as colder weather is coming, maybe drop to a 172 when it gets hot again next year.


If I remember correctly, there are two restrictors that must be removed from the air box. Make sure you got them both. One is rubber and the other is plastic. Checking your choke is a good idea. When the choke lever is in the horizontal position it is choked (closed). When the lever is in the vertical position it is unchoked (open). You probably know that but just in case check it. :cry:

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