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ok carb experts...

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gregsdrums

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Just had a valve job done on my 72 1275 and figured while it was down I'd put in carb kits. After getting it back together and to fire, it sounded like it was only running on 3 cylinders. Front 3 plugs looked good but the back one was black. Figured it was from running rich as the rear carb had a gas mist belching out of it every so often. I'm new to the twin carb set up as my 76 1500 has a weber down draft. Any suggestions on setting these up would be appreciated.
 
If you just finished a valve job, and the rear carb is belching, I would adjust your valves, and check your timing. After that you can move on to adjusting the carbs. The carbs being out of tune is unlikely to make it run like it was on only three cylinders. There are a few good step by step discussions on adjusting SUs on the interwebs. I will look for a link.

Brian
 
X3 on valve adjustment. A valve job can move the valves a good 0.005 - 0.010" (tighten up clearances). Maybe even more if the seats in the head were really bad. Installing hardened seats will move them back the other way (loosen up clearance). So check valve clearance to make sure.
 
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