Join Date: Jun 2015
Location: Bury St. Edmunds
F3 carb synchronisation
My bike has been running a bit rough for a while, popping and farting on de-acceleration and sounding like a Harley on idle. I know some of this is because of the race system that the last owner had fitted and I've got a dynojet for her. As dynojet jet say in their instructions that the bike should idle properly before fitting, I thought I would have a go.
Well, I watched videos on YouTube and read as many guides as possible so that I knew what I was doing. Warmed her up and dismantled the tank etc, to get to the carbs and attached the vacuum gauges. Started her up and adjusted the fluttering to an acceptable 1 increment.
I adjusted the idle to around 2000rpm and adjusted carbs 1 & 2. When I went to adjust 3 & 4, the revs went up and whatever I tried, they would go up more and I couldn't adjust the idle down as the stop was about 2mm away from the screw.
After about 2 and a half hours of fiddling with all 3 screws, I have managed to get the idle down to between 1000 & 1500 (the idle screw won't turn it down anymore) and I have carbs 2,3 & 4 almost spot on synchronised. Carb 1 however has other ideas and has decided that it will sit approximately 1/16th to 1/8th higher on the gauge than the others.
How do I adjust this so that I can bring carb 1 in line? She sounds a lot better than she did when I started but it's annoying that I have one carb running (I think) lean.
Any advise is greatly appreciated.
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