Jun 5, 2006
Alright guys, I'm in a bit of a pickle here! I took my bike into the shop a few weeks ago to get some things fixed on it. The shop got it running good, but it was running too lean. The reason for that is, I put a new exhaust pipe on it... The shop couldn't find the right jets for it through their supplier. One of the mechanic's that works there said it was the weirdest carb he had ever seen, lol.

I found a carb rebuild kit on e-bay and the gasket in the kit looks to be the same as mine. I'm really kind of lost here guys...

Bike is running too lean.
Need new jets.
Where can I find them?

Thanks! :)


Jul 6, 2004
I think yamaha only offers 2 jet sizes for those (that was about 7 years ago). Your best option might be to go one size at a time drilling them out with a numbered set of drill bits.


Sep 9, 2006
I've done quite a bit of work to my carb to solve a mysterious lean condition (after I replaced the intake boots) after it was stored for several years.

Here is a list of things I did.

1. Adjust the Pilot screw to 3 1/2 - 4 turns out. The screw is under a brass cap on the fromt of the float bowl. just drill the cap out to get to it.
-this will fix the idle and it will start MUCH easier. It will also help off idle response.

2. Shim the needles if it's lean at 1/4 to 1/2 throttle. Just get some small washers from the hrdware store

3. Replace the main jet on the primary carb with one from an XT600. I think I used a 140. If I remember correctly there are 2 sizes available for the 600 that are bigger than the 350

4. Installed home made Power Now inserts.
-I did this instead of trying to find a Pilot jet or drilling mine out.

I just posted pretty much the same thing over at thumpertalk in the vintage forum except I included some usefull links.

'90 XT350
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