Topic: Suggestions for jet size

[grumpy]

My CB750 K3 is running a little lean.

The PO installed Mac 4-2s and didn't rejet.
I just got a K&N filter for the standard airbox which should increase airflow a bit more.

I already raised the needles one notch. Now I need to do the mains.
Stock mains are 110.
Do you think I should I go with 115s or 120s?

All else is essentially stock.

I've searched this and have found that some say the pipes won't make enough difference to necessitate a jet change while other say yes, new mains are needed. It  has some symptoms of running lean and now with the new air filter I figure it needs jets for sure...

[Johnny5]

Figure out what main jet to use first. I'd experiment with a 120 first. So buy a 120 and 115. If it's too rich at WOT with the 120, go down until you find the jet that pulls hardest at WOT. Then mess with the needles. I would put it in the stock position first.

Good luck

[coyotecowboy]

K2 750, 4 into 1, pods, 4th slot on mids, 125 mains.  Runs great everywhere except on the top end, still too lean.  I'm thinkin 130's are in order.

[EDIT]  whoops, just saw that you have a K&N replacement filter, thought it said pods.

[Johnny5]

K2 750, 4 into 1, pods, 4th slot on mids, 125 mains.  Runs great everywhere except on the top end, still too lean.  I'm thinkin 130's are in order.

[EDIT]  whoops, just saw that you have a K&N replacement filter, thought it said pods.

Yeah, with the k&n filter in the stock airbox, I would start with a 120 main. If you had pods, Coyotecowboy's suggestion would be perfect. Since im running 4 into 1 pipes, pods and have a 130 main, needle 2nd from bottom.

[coyotecowboy]

lol, nice to know I'm on the right track

[grumpy]

OK
120s to start.
Thanks guys.

[Rsnip988]

Since im running 4 into 1 pipes, pods and have a 130 main, needle 2nd from bottom.

I'll have to try that configuration since i got my new muffler

Rks