Power boost at high RPM 8K

[firro]

Hey all,

So i got all new spark plugs, new intake manifolds, Stage 7 kit with VBOOST removed. Carbs revision done, ultrasonic cleaning etc, high octane fuel, full exhaust system Doma Racing.

Bike runs well, however i do notice that power is Ok'ish at low and mid RPM , i have never ridden another vmax so cant really compare, but something is telling me the bike should have more power at low and mid rpm, because at around 7,5 - 8k RPM at full throttle i get a insane power boost.. its like fast and furious when they hit the nitro button xD

I think i should have similair power also at lower rpm's ,, wondering what holds it back.. mixture screws?? or is this completely normal?

ps. db-killers are removed.

Thanks!

 

[Traumahawk]

Hey all,

So i got all new spark plugs, new intake manifolds, Stage 7 kit with VBOOST removed. Carbs revision done, ultrasonic cleaning etc, high octane fuel, full exhaust system Doma Racing.

Bike runs well, however i do notice that power is Ok'ish at low and mid RPM , i have never ridden another vmax so cant really compare, but something is telling me the bike should have more power at low and mid rpm, because at around 7,5 - 8k RPM at full throttle i get a insane power boost.. its like fast and furious when they hit the nitro button xD

I think i should have similair power also at lower rpm's ,, wondering what holds it back.. mixture screws?? or is this completely normal?

ps. db-killers are removed.

Thanks!

That is Normal. The whole point of Vboost was so you had basically 1 carb per cylinder. With Vboost opened, It allows basically a carb and a half per cylinder. (the intake is nothing more than an H that the carbs sit on) on top of the cylinders. So basically its over carbureted at the lower RPMS.

 

[gentsvmax]

And I think the Premium isn't necessary, I'm sure others will share on this.

 

[MaxMidnight]

Agree with both of the posts above.
How do you synchronise the carbs without V Boost?

 

[CaptainKyle]

Agree with both of the posts above.
How do you synchronise the carbs without V Boost?

I have a tool for it but it's a pain ! I always reccomend keeping the Vboost with stage 7 . It does not kill your low and midrange that way .

 

[Fire-medic]

I have Stage 7 and also kept the VBoost.

 

[maleko89]

Can use a Weber tool but why. Agree, no reason the remove vboost

 

[apsolus]

so maybe i can piggy back off thise post but my bike is mostly stock minus a slip on and k&n. i seem to have the idle set well at 40 pilots at 3 turns out. idle is pretty strong and steady. synced them aswell. ive installed 150 mains and top end feels good. but midrange is a tad soft and i also get a small rush as rpm increase. not normal vboost but earlier in the rev range and ive noticed when cold it take a little while till fueling is perfect going down the road in the midrange. ive got stock needles with one small shim to richen it up. i was going to add another shim to the needles and see how that feels. i also took out the dyno jet slide springs and went back to stock. is there a hot set up yall are aware of for midrange?

 

[Radioguylogs]

Vacuum pistons drilled for Dynojet springs?

 

[apsolus]

Vacuum pistons drilled for Dynojet springs?

they were but when i went back to stock springs i installed new china slides. they look identical to stock. i put the dynojet springs back in and removed the spacer real quick. bike seems better. im nitpicking here but i want it right right. i used to run that stage 7 kit but my bike ran really rich. and would stall out at lights. maybe i should reinstall the kit and retest. ive learned a lot about carbs sence then. do you have a good set up i can try?