Thumper Racing ?
 

Hey guys I'm getting my FMF full system on Thursday. I'll Be jetting, Etc. next weekend. Have the FMF jet kit same as dynojet. Thinking 124 & needle at 4, no air box lid or smog. I'm at 4200 Ft.Any way my next adventure will be a bigger bore. I'm thinking about the Thumper racing 340 kit, or having Bill Blue do a 331 cylinder for me. Any info on either settup will be greatly appreciated. Like how do I find Thumper Racings website? [sm=feedback.gif]

RE: Thumper Racing ?
 

I looked on their website and didn't find the 340 kit. So I emailed them and theytold me to call their tech dept. 903-938-3340 The price is $497 for the 340 kit. comes with carb parts also. I considering the 340 also, I don't think I'll out grow it so it should last for yrs to come.

RE: Thumper Racing ?
 

Thanks for the Info. Anyone had anyexperience with jetting at or around 4200 Ft? HELP!

RE: Thumper Racing ?
 

I ride mine between 2500' to 4000' - those settings you posted should work, but I've never see two bikes run alike with the exact same jets and carb settings. See the posts on the difference's between the DynoJet (I think FMF uses) and the Keihin jets.

RE: Thumper Racing ?
 

Mark are you still runing the 40 pilot? If your running at that high altitude i'm thinking maybe i should venture over to at least a 38? Maybe even go up to 128DJ

RE: Thumper Racing ?
 

I've got about 1800 miles on my 340 kit so far, and haven't had any problems at all. With all of the mods that affect air flow (exhaust, freer-flowing air filter, proper jetting, etc.), you won't believe the difference. The extra displacement really boosts the low-end torque.

The carb parts that come with the 340 kit only consist of 2 larger main jets (I don'tremember what sizes, but they were Keihins and not DJ's).

RE: Thumper Racing ?
 

Is that good or bad on the brand of jets?

RE: Thumper Racing ?
 

It's neither good or bad, I guess. If you already have a DynoJet kit, they usually come with enough main jets to cover most situations. The only problem you might encounter is if you install the richest DynoJet main jet and you are still too lean. The DynoJet KLX300 kit comes with it's own needle, so I doubt that you can mix and match needles and main jets between Keihin and DynoJet. Even if you can, with all of the infohereon jetting using Keihin jets, it would be like reinventing the wheel.

Ifyou want to keep runninga Keihin needle and other jets, then you have no problems.