Hi all


I want to mess a little with the jetting on my 2005 TT600RE. Wemoto.com do not carry carburetor jets it seems. Where should I buy?

I am thinking 160-165 main and raising the needle one notch on the left hand carburetor. Remove the airbox snorkel. The (stock) exhaust has already been opened up a little. The bike runs fine and does not overheat, I just want to see if I can get a little more mid-to-high rpm power. The bike is a tad lean as seen on the sparkplug in the picture. Any comments or advice??

If anyone has some extra jets for sale, please send me a PM.

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Yamaha XT600E '01, Honda XR400 '03, Yamaha XT550 '83

When my xt600e 2003 was stock, i opened the exhaust, and removed the top of the airbox, got in on a dyno, and it showed perfect fuel to air ratio...

Anywas, the carb has basicly 3 working curcuits.

from 0 to about 1/4th of throttle = CO/fuel screw and idle jet.
1/4-3/4th throttle: Needle.
Almost wide open throttle to wide open: Mainjet.

You could have a lean bike in the lower area, and rich in high area, or otherway aorund. So you need to test all three "curcuits" to find out where/if its lean.


The needle work in around 50-75% of the powerband, so if youre gonna do something, this might be it. But i guess going 1-2 up in mainjet would hurt (other than you're mpg)

But find out where its lean, and "cure" that area.

Some of the circuits overlap, so test everything once you've fiddled with something. Start every test by getting the bike nice and warm. The first test should be with the co/fuel screw and idle jet. Ride around very nice and easy, Id say around 2000rpm, in a couple of minutes, pull the clutch, hit the killswitch and pul over and check the sparkplug.

Do the same with the throttle more opened, and then again on the highway or something, with full throttle....

This sounds like much, but its done in a little hour. I dind't tighten my seat og fueltank, so they popped right of when I was testing.

I installed foamfilter, oversize downpipes, and a laser produro exhaust on my xt600e,togehter with the opened airbox.

It has 130/120 jets stock.

I raised both needles 1 notch, and installed 140/130 jets.

In the dynorun it showed lean in the bottom, spot on in the middel, and very rich in the top.

I've then gone one up in idle jet, and went down to 140/120. But im gonna go down to 132/120 which is juuuust a tad above stock.

Some exhasut actualle makes the bike run richer, I've heard about tuneups on sportbikes, where they went down in mainjets, for maximum gain in hp. So dont assume anything.

Hope it helps, KEDO - Performance Products sells different jets.

Hi,

I think the 160 main may be part# 288-14343-80-00 for the main carb, from a Yamaha dealer. There appears to be a 170 (288-14343-85-00), but I cannot see a 165 (which should be 288-14343-82/83-00, if the logic is correct? [Jet size / 2, rounded].

Have your local Yamaha dealer check out these part#s, just to double check.

If the theory stands up, then 5Y1-14343-nn-00 should be the part# for the main jet in the secondary carb.

Good luck,
Geoff

Jens, thanks. GREAT info. To be honest, I was hoping to hear from you since I know you have been working a lot on the XT…

Geoff, thanks. Good tip.

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Yamaha XT600E '01, Honda XR400 '03, Yamaha XT550 '83

Nowadays, reading the sparkplug colour is very difficult, as the modern fuels and lean burn engines don't display the same "old" colour range - brown, tan, etc

For carb tuning, always start by getting the main jet correct. Then you need to select optimum needle position & finally pilot system (air/fuel
screw).

I'm in the same boat as you with my 2005 RE. At present all I have changed is the tail pipe for a free flowing (nice raspy noise) s/s can

I'd expect you need to go up about 10% on mains as a guess?

When you get the main jet/s do us a favour and post a photo of it please.

Try Allens Performance Mikuni & Keihin Carbs they usually come up trumps