ported cyl jet question

[99 shee]

I'm having my stock cylinders ported and my stock crank true and welded. A +4 timing plate. And a cool head also added. I'm running stock carburetors with the toomey perfect jets 280 Main now. I'm wondering what jets I may have to use with my new setup. My pipes are to me t5.reeds are vf4. I am at sea level. Thanks guys

[Coupelx]

Probably have to double the jet size.

[Young Guns Racing]

start off with needle on middle clip, 30 pilots (vf4's like a larger pilot than ussual) and start with 320 mains. That should get you going. Id count on having 320, 310, and 300 mains. Naturally you're going to have to play with things and see what your setup likes.

[Strm Trpr]

start off with needle on middle clip, 30 pilots (vf4's like a larger pilot than ussual) and start with 320 mains. That should get you going. Id count on having 320, 310, and 300 mains. Naturally you're going to have to play with things and see what your setup likes.

Good advice ^^^.

My mods are in my sig.

I'm at Sea Level on 300 mains and I'm not ported.

Who's porting your cyls?

[dirtydownunder]

ask the porter, they will get you close.

 

when i ran t5s on stock port. i was at 280's,  then with a dune port and t5's with pods, i ran 330's.    both on 25 (stock) pilots.

[99 shee]

My stock port had 280 mains im sending the motor out to fast. I just blew it last week. Still have to rip her out

[Strm Trpr]

Are you guys both at sea level?

[camatv]

280-350 will get you there.  the 330 is i bet where you end up with the toomey needle. 

 

try 27.5 and 30 pilots also.  easy to tell if they are right with the air screw.

 

with it all the way down like that would be a great time to look at transmission modifications also!

[Strm Trpr]

280-350 will get you there.  the 330 is i bet where you end up with the toomey needle. 

 

try 27.5 and 30 pilots also.  easy to tell if they are right with the air screw.

Cam, what are your thoughts on toomey needles vs. stk needles?

We can take it to PM's if you have time.

 

I'll ask it again OP, who is porting your cyls, and where do you ride?

[99 shee]

F.a.s.t is doing the porting. I ride moto and trails.

[Strm Trpr]

Then they can give you better jetting recommendations than we can.

[camatv]

i personally like the toomey over the OEM needle anyday.  with stock carbs  play with the jetting just a tad and that "BOG" can be easily jetted out..  i ran 27.5/ 410 and toomey needle in my old 421 "trail" motor