Carb Sync

[Dan88]

Hi, I want to sync my carbs using a Vacuum gauge kit. I hooked it up but then noticed there are only three (synchronizing screws) on the carburetors. . .I expected to see four!! Does one screw adjust carbs 1 - 2 while the other two screws adjust carbs 3 - 4 ?? There doesn't appear to be any info in the manual on this topic, so if someone could help us out outlining the best procedure to use for this task I would be externally grateful.

Dan

[Pat Conlon]

Hello Dan, you are correct, looking down from the top you see 3 screws, left, center and right, that adjust the throttle plate openings.

Remember what you are trying to do is match the throttle plate openings between all 4 carb's.
The process is simple, with the vacuum gauge hooked up to all 4 vacuum ports
1) balance carb's #1 and 2 with each other by adjusting the left screw
2) balance carb's #3 and 4 with each other by adjusting the right screw
The center screw adjusts both 2 left side carb's(#1/2)  and the right side carb's (#3/4)
So your last step is to
3) balance carb's 1/2 with carb's 3/4 by adjusting the center screw.

Work quickly. Don't let that big air cooled inline 4 cylinder idle too long. You can cook your exhaust valves. Our FJ engines need air flow to stay cool. If you need more than 4 or 5 minutes, get a box fan to provide air flow.

Hope this helps...Cheers Pat

[Capn Ron]

Hey Dan!

Welcome to the forum!  What you're seeing is a screw between carbs 1 & 2...You sync those two carbs.  Then you're seeing a screw between cabs 3 & 4...you then sync those two carbs.  The screw in the middle of it all then syncs the carb 1 & 2 pair to the carb 3 & 4 pair.  When you're done, you'll get a close-to-same reading on all four carbs.

[Pat Conlon]

Ha!
I got the Capn by 1 minute 29 seconds...

[Dan88]

Thanks a lot guys . . . Unfortunately I had a go at syncing the carbs prior to posting this blog ( silly bugger . . .) and now need to get things back on track. Pat will you steps still work? the bike starts and will rough idle. Cheers

Dan

[Capn Ron]

Ha!
I got the Capn by 1 minute 29 seconds...

First time for everything my friend!  

[Pat Conlon]

Fist time?

Ouch....I'm afraid to ask....you are one kinky dude.

[Pat Conlon]

Thanks a lot guys . . . Unfortunately I had a go at syncing the carbs prior to posting this blog ( silly bugger . . .) and now need to get things back on track. Pat will you steps still work? the bike starts and will rough idle. Cheers

Dan

Yes Dan, both Ron and I said the same thing. Follow the steps 1/2, then 3/4, then center to match left two carb's to the right two carb's.

[Capn Ron]

Fist time?

Ouch....I'm afraid to ask....you are one kinky dude.

Damn...thanks for the heads up...fixed it!  Phew!   

[Pat Conlon]

Good...I was starting to get concerned