GMB II Jetting

[Woody_393]

The thought just occured to me that I will need to rejet my bike for GMB II, and I thought I would ask and see what the locals are running jetting wise on the various bikes.

So please post the bike you have and the jetting so we can come prepared and not have to spend too much time trying to dial in our rides.

Heck I don't even know anyone in TX that has a CRF... seems like the whole country.. err I mean state is covered in blue with some specks of green mixed in... Maybe The jetting that Yardpro uses will work in houston??? Actually Vintage Dave rides a CRF I believe.

Anyway, would you guys mind posting your bike and jetting info based on splendora so we can come prepared. Thanks in advance.

[Yardpro393]

what about the tires? is the track hardpack of intermediate?

[Big Maico 393]

Woody:

your right Vintage Dave does ride a CRF 450, I'll let him know that you want his jetting specs.

Yardpro:

Most of the tracks here in Texas have sand & clay in them. So it an soft or intermediate tire like a Dunlop 756.

[Keetoman393]

Jet for sea level and use a soft to intermediate tire. The start gate is concrete but it drops off to really deep sand and then once you get on the track, it is loamy. It transitions from sand to hard pack and back but it's tons of fun! They prep the track well!

My jetting for my 00 426 is stock and it runs great!

[Yardpro393]

thanks guys,
i run 756 front and currently have a 752 rear. so i should be fine.

[IwishIcouldride]

Good thinking Woody. Anybody down there have any specs on the Cr 125??

[TexTwister 393]

Unless you live 3 or 4000 feet above sea level you guys should be okay with what you have....

[Woody_393]

I'm at 4200 asl, so I will need info if possible.

Thanks Big M. I'll look for his reply. Yardpro are you running stock jetting currently?

[Macho393]

I do believe you should run a................ou812 main jet with a ............br549 pilot I don't even think I've ever seen my stock ones. You also want to increase your tire pressure to about ...........32 lbs and adjust your clickers to the far right: Trust me Im really a pro racer down here in the south. You guys don't show off and bring them fansty helments and stuff we got plenty of buckets

[Woody_393]

LMAO... I'm be sure to do exactly that Macho... NOT!!! You are funny... I have a sneaky suspision that I will need to keep my bike locked in a trailer the entire time I'm not on it. Or it might get Machoized...

[bates393]

looks like we may be going back to 170 and 4th clip position.

[TexTwister 393]

Woody ill get you the jet sizes tomorrow and give them to ya for down here...

[Woody_393]

Thanks Twister... I think stock is probably the ticket, but I want to make sure.

[MotoMan]

Ooo, I haven't ever started on a concrete pad before.

Jetting should be the same as here, we are at something like 400ft above sea level. I am sure the M-12 will do well sounds like it should be right at home.

That concrete though....I am going to post a new thread.

[Vintage Dave393]

CRF jetting will be standard factory jetting. I haven't had to change anything on my 03 other than tweaking the fuel screw.

Tires should definately lean towards soft intermediate to soft sand. I run 756 front and rear on the CRF and 756 front/773 or S12 rears on my vintage bikes. My favorite tire is the S12 rear. It works on all the Texas tracks and transitions to the late afternoon hardpack just fine.

Temps will be in the high 60's early moving up to the mid-80's in the afternoon, humidity in the Houston area is usually 50-80%. Bring several sets of gloves and enough jerseys to stay dry.

[Woody_393]

Thanks Dave.. I'll bring the stock stuff and go from there.