Mikuni 38mm TMX baseline jetting

[bholmes]

I have a bunch of parts commin for my TB250 and I'm trying to get a consensus on where to start my jetting. I'll be running a cyclone cylinder w/ stock ports (essentially ported reg TB cylinder) with a milled head, HPD pipe and MTQuiet silencer and 20" tires. my carb is/will be a 38mm TMX and running just a clip-on foam filter element. w/o air box. Altituide is about 650-700ft above sea level.

Question is: What jetting do you guys runnin 38mm's on EITHER TB or Scrammys suggest starting with? I'm just trying to get an idea where to start jetting at.

[WaaHeHe94]

Back in 1999 when I first bought my Sport 400 and only had a Hot Seat Pipe, Hot Seat 12-1 billet aluminium head, 38mm TMX, V Force Delta 2 reedcage w/spacer and clamp on K&N filter I was running a 320 main jet at around a 1200' elevation.

Not really sure what a Trailblazer 250 should be jetted at.Your best bet would proabably be to call a company like Hot Seat or Aeen that sells prejetted 38 & 42 TMX's and ask them for their advice.

[bholmes]

Sounds like a plan, thanks for the input. I'll probably have to do that as this post is not getting to many replies.

[bholmes]

for anyone out there searching for the same thing, Aaen was able to help me out on that. Run a 4.0 slide, 25 pilot jet, 270 or 280 (depending on elevation) main jet, and a 6EJ12-58 needle. I used this set up on mine and it runs like a champ