another jet question... :P

I can't seem to find any definitive information about Hitachi jets vs. Dynojets.
For example, does a 120 Hitachi flow the same as a 120 Dynojet?
I have 124 Dynojets in the bike now, and I'm positive that it is running too lean at full throttle. The plugs look too white to me. The only mod is set of emgo upturn Dunstall style megaphones.

 

Be helpful to know what kind of bike you have. Throw it in the signature that sits below your posts. To me it seems going up from 120s to 124s with just a new exhaust would mean you're probably too rich. I went from 110s to 112s with an aftermarket 4 into 2 exhaust and it runs a bit too rich now. Have my needles set to the leanest settings to get the bike running well. Probably end up putting the stock jets back in truth be told.

If you're running stock jets it may not hurt to try adjusting the needles; seemed to make a huge difference, at least on my bike, so if it is indeed lean you may want to raise the needles. This is assuming you've gotten everything else in order.

 

The Bike is an xj750rh Seca (Canadian model). Ya, I reinstalled the stock jets and it seems to be better so far.
I have tried running with the needles up a bit and it ran too rich. Hitachi carbs are finicky things, but i think i have it tuned really close now.

Thanks for your post.

 

take a look here
http://www.jetsrus.com/FAQs/FAQ_mikuni_ ... _sizes.htm

and here
http://www.jetsrus.com/FAQs/FAQ_drill_s ... lents.html

pretty sure Hitachi jets run mm sizes like 120 jet=1.2 mm