Hi all,
I am new to Airheads and this is my first post. Yeahh! I was the lucky winner of an 1980 R65 at a bike show in Raleigh NC back in April. I've been sorting out the bike mechanically and am just about done but am having issues balancing the carbs. I can tell both cylinders are running a little differently. I have already set the points and timing, adjusted the valves, replaced the spark plugs, and air filter. I am running non-ethanol 90 octane fuel. It always starts reliably on choke with no throttle needed. I did have an issue early on with rpm's accelerating up to about 3000rpm after start and traced that to the mechanical advance flyweights needing lubricated which now works normally and decelerates when getting off the throttle.
I checked compression on both cylinders, and its good--both at 126psi. It runs out pretty good, although there is a flat spot where acceleration begins to taper off at about 4000rpm. Also, when holding throttle stationary (in neutral) at say 3000 rpm it hunts a bit up and down--not steady. I used a heat gun to measure exhaust nut temperature to get an idea how each cylinder was doing , and the right cylinder was always about 50 degrees more than the left.
Throttle cables and choke cables all have about 1mm of free play. I turned the mixture screws in to see how far out they were, and both were close to 11/2 turns out .
(Clymer manual says start at 3/4). I did the propane test all around the carbs to look for vacuum leaks but found none.
So...in attempt to see eliminate the carbs as a problem I cleaned/rebuilt them with all new O-rings/gaskets (Thanks Bob's!). Everything looked good inside. No clogged jets. Replaced floats too. I recently purchased and attached a Carbtune to measure vacuum. The right (hotter) cylinder is pulling way more vacuum than the left, even though both throttle plates are about same, and mixture screws are the same. Any ideas on how to better adjust the vacuum and mixtures?