Ok i am i the process of putting a jet kit in my bike. When i am taking it apart i am looking at the jets. The jet kit wants you to put a DJ122 for stock pipe and a DJ126 for slip on's. The problem is my carbs have a 135 jet in them already! The hole looks to be bigger than the ones in the kit. I might be mistaken but i thought when you changed jets for a pipe the hole was supposed to be bigger. So now i am all confused on if this is even worth my time. Anybody run into this before??? Thanks in advance for the help!!!!

 

when f2s came from jap the epa was ultra strict on them and tested them at highway speeds in cruising gear i.e. midrange (pilot jet) so honda made em run ultra lean to pass the test they compensated for this by making it rich up top (mains) so in other words youll gain power by leaning out your top and richining up your mid. a side note though all controversy aside you WILL lose power by switching to a k n filter, papper is the way to go.

 

To answer your question, the Dynojet numbers do not correspond to any other jet manufacturer other than Dynojet. The number on the jet may be smaller but it doesnt mean its hole is smaller as well. There really isnt a conversion chart you'll find. Dynojet has done their research and Cowboy is correct, Leaning the top end and richening the midrange is the goal with a jet kit.

 

I don't know how this figures into the mix, but my bike had a K&N, D&D slip-on, and AFAIK, a Factory Pro jet kit, with 135 main jets in it when I got it, and it was definitely lean. I wound up with 138s to gt it running right, did a best of 7.29 in the 1/8thlike that, then cut down my D&D and started jetting again. Now I'm at 152s, and so far I've run a best of an 11.36 @ 118.8 mph. Been using genuineMikuni jets though, and I'm not done yet, so far I haven't touched the mids, just the mains, jetneedles, and pilot screwsettings. Next time out will be Jan 11th, we'll see how she does. [8D]

 

Ok i will go ahead and put them in and see how it runs. Thanks for the help, i don't know too much about carbs. Does anybody know if you can sync your carbs with a vac. guage instead of a manometer?

 

i went that route with keihin and realized that huge mains were makinging it seem faster but it was only helping my mid alittle till i ran outta needle tapper up top (wide open main) then the dyno numbers dropped dramaticly iam sure theres ways to make huge mains work using high flow filters and cutting exuast but at the track we needed ours not with the most peak numbers but with the most linear ones after much hard work i found 124 mains and .40 pilots (canibalized outta a 95 f3 parts bike we had)paired with a papper filter give you the best power all the way across the revs. a word of warning changing the mains your leaning out your top so will a k and n so be careful......

 

Isn't this desirable as per your post above this? (to lean top end and richen midrange?)

 

yes lean your top and richin your mid but throw a high flow filter in the mix and your further leaning it...............in other words these kits arent dynoed with k and n filters.

 

Oh ok, but aren't these kits targeting setups in which a hi-flow filter is being used?

 

so it would be a good idea to put a paper filter back in? Oh yea any ideas on using a guage instead of a manometer for a carb sync?