[supdawg234]

Hi, I'm new to this forum and pit bikes. This site is awesome and what i've been looking for to get advice. I just installed a Honda TB 88cc big bire kit with cam, race head, 20mm carb, air filter and a fmf power core 4 exhaust. What size main jet should I run? I haven't even broke in the bike yet because I didn't know what size to use. also any break-in tips? Thanks guys! -Evan

 

[PTECH]

I have that exact same setup. I run a 38 pilot, needle clip one down from the middle and I was 1 size up on the main though I don't remember what number that is. I think I might need to go one size richer again on the main since it got cold since last time I rode it had a tiny sputter at WOT. I usually have the air screw somewhere between 1 to 1 and a 1/2 out but I pretty much have to adjust that all of time. I live in phoenix so all of this is for about 1700 ft elevation. If you don't have the pilot jet kit the stock 35 pilot worked ok for me but I had to run the air screw all of the way in pretty much in order for it to have any kind of throttle response.

 

[supdawg234]

ok thanks, when u mean one size richer do u mean one size richer than the jet that comes in the carb from Honda TB? Thanks, Evan.

 

[dirtbkr188]

The stock jets in the TB 20mm carb are an #89 main and a #35 pilot.

 

[supdawg234]

Thanks but still wondering what main set size i should use with this set up. I am ordering the pilot jet kit 2night. Thanks

 

[Towlieee]

89-91 main jet is 'around' what I think you'd wanna run



although you have to test the bike yourself and tune it yourself and see what is best for your specific setup/altitude/ and temperature.



at 800 foot elevation, 89 main jet wokrs great in my 88cc race head setup, although I have a 'ghetto' exhaust.



My friend has a FMF pipe and also a race head 88cc setup and he uses a 91 main jet



were at 800 foot elevation

 

[dirtbkr188]

Actually, the TB main jet kit does not list a #91, but it does have a #90 and a #92, among the others included in the kit. Click HERE

 

[diggin dirt]

92 main,----35 pilot-------1 clip up from bottom on needle.i have the same setup.runs great.----make sure to check valves.i had a problem with this setup until i adjusted the valves.thanks to all the members that help me out with that.

 

[supdawg234]

Thanks guys! I really appreciate all the info and now I can break in the bike! Ok, after I run it a little bit I will check the valves. I adjusted them to the specs in the directions from danosbikeshop.com What are yours set at? Thanks, Evan.

 

[dirtbkr188]

.003" - intake

.004" - exhaust