Hi boys. I've got one question according carb balancing. In service manual there is mentioned that vacuum difference between carbs is 20mmHg and base carb is front one. So:
-vacuum must be equal on both carbs
-vacuum in rear carb must be 20mmHg higher than front?
Manual for SP-1,SP-2 says clearly that vacuum in rear port must be higher. In manual for Firestorm this chapter isn't obvious for me.
Carb balancing
- LutonStorm
- Posts: 82
- Joined: Mon Jun 22, 2009 6:22 pm
- Location: luton Beds. & Litton, Somerset
Re: Carb balancing
Hi there,
I read it as there can be difference of 20mmHg between the front and rear. Phil VTwin and I just plaed around until the needles were in the same place. They were definately within the tolerance allowed!
Good luck.
I read it as there can be difference of 20mmHg between the front and rear. Phil VTwin and I just plaed around until the needles were in the same place. They were definately within the tolerance allowed!
Good luck.
Re: Carb balancing
When I checked first time carb synchronization, I suppose first time from factory, I found that rear vacuum was exactly 20mmHg higher than front. On synchronization adjusting screw and on throttle stop screw was paint lines(marks) perfectly aligned. Therefore I'm wondering how the carbs must be synchronized.
- Pete.L
- Forum Health And Safety Officer
- Posts: 7301
- Joined: Fri Sep 26, 2003 5:09 pm
- Location: Bristol
Re: Carb balancing
The Firestorm balance should be the same front and rear, just looked it up, haven't had to do it in a while
Pete.l

Pete.l
My new ride is a bit of a Howler and I love to make her Squeal