The Dynojet stage one kit will work for the track. You may have to go up on the main jet as you will be at WFO for longer periods of time. I did Laguna Seca with mine and it worked well. The stage 7 kit probably sacrifices streetability (low revs) for more peak power. May include airbox mods. Strictly for track.

The factory jet kit does without the gluing off the slide holes. The give you two sets of needles.

Stiffer (shorter) springs on the slides are supposed to help with throttle response. It would slow down opening (more resistance) and speed up closing (rpm drop).

My Dynojet kit runs rich on the pilot once it is warmed up. There is a specific kit for California bikes that adds needle jet shrouds. My kit is old (92) and doesn't have the shrouds. My kit was actually badged as a K&N kit.

 

your saying that the factory kit gives 2 sets of needles and springs??

 

Just the needles have two sets.

 

no kidding.. i only got one set with my kit.. gp have you ever tried running the 138 mains with a k&n fillter?? it was one of the set ups from factory..

 

When I ran 138 Jets with my K&N filter it was way, way too rich. Had a stock exhaust on at the time. It was so rich that when the bike was warm, it would actually bog under full throttle. I am currently using 128's. These are all factory pro jets.

 

I cant remember the number, but I know I used the smallest jet for my mains, (I want to say 125, not sure though) even though they recommend higher. I run my bike on the track constantly at 13k RPMS and my spark plugs show no signs of being lean, no over heating, no damage, no detonation signs on the plugs, they look perfect tan.

A K&N and a pipe does not increase air flow THAT much to make a drastic change to your jetting. All you are going to do by running richer is reduce your gas mileage per gallon

 

138 would be too large for mains. The largest jets in either kit were 128. I went with 126 as I recall. With a K&N and Yosh slip on.

 

thats my thoughts also.. i was reading factorys set ups and they were saying use 138 mains when running a k&n fillter...imo it sounds like she would run rich when just running a slip on..i did get the kit becouse i wanted to see if the needles were better then stockbut so far im thinking that if they are better its not that much.. ill be going to my old shop to spend some time with the dyno and im going to try bolth and will see the difference..

 

thats a dynojet kit right??

 

138 mains would work for track only, because of the high percentage of WFO on throttle. Plus the bikes were set up with racing ignitions that didn't have the rev limiter that our stock bikes have.

Both Factory and Dynojet kits have 122 to 128 size jets. Their needles are similar in taper. The main difference between the kits is the work on the slides required by the Dynojet kit. Either kit works for the street. Extra parts appear to be easier to get from Factory.

Stock jetting is 135 and the stock needle is much thicker in diameter than the needles from the jet kits. Both the jet kits and the stock flow about the same since the smaller jets of the kits have thinner needles to block the jets. The big difference will be in the low mid range where EPA testing was done. Most dyno charts will show the dip in horsepower of the stock set up to be improved with jet kits. Peak horsepower will improve if an exhaust is added on, but, you usually give up some hp elsewhere.

Enjoy.