best pipe

[yamaha11]

i have a 421 cub that i am setting up for draging, it is not ported and not sure if i am going to run gas or alky. i have cpi inframes right now. would shearer out of frame small bores be better than the cpis or would the shearer inframes be better? whats your thoughts thanks

[locogato11283]

if youre only dragging there is more power to be made with shearer oof pipes..

[firebanshee]

Plus oof pipes look cool and that is very important :biggrin: :cool:

[yamaha11]

Plus oof pipes look cool and that is very important :biggrin: :cool:

 

would i get small or big bore, and does it matter if there out one side or other or both sides

[locogato11283]

there seems to be a pretty fine line between small bore and big bore on the 421 cub motors.. i would say if youre gonna run out of frames to run small bore..

 

who is your builder?

[yamaha11]

there seems to be a pretty fine line between small bore and big bore on the 421 cub motors.. i would say if youre gonna run out of frames to run small bore..

 

who is your builder?

 

 

the motor is not ported, i got it from a guy who had rudy kurtzy put it together. then i had a friend at gbracing put a duneable trans and a slingshot in it. dont know what the domes are it has vf 3 reeds and came with 38mm pj carbs. im undecided about having it ported since i have never did any drag racing or even had a cub till know. what do you think

[moneybags]

I have a set of Shearer small bore OOf scilenced pipes that just came back from being replated it your interisted... their 2 out the left side.

[Wildcardracing]

I would say small bore for a non ported 421. If it's strictly drag then go with the oof's. The shearers are worth a bit more power, but at the expense of some midrange power.

[yamaha11]

I would say small bore for a non ported 421. If it's strictly drag then go with the oof's. The shearers are worth a bit more power, but at the expense of some midrange power.

 

its going to be a drag play bike