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Join Date: May 2006
Location: Tampa, Florida
From another post:
"I built my own manometer by taping clear plastic tubing (1/4” id) to a yard stick and using automatic transmission fluid. I let it hang on the garage wall for several days to make sure all the A/T fluid had settled.
When it came time to do the sync, I ran the bike to let it warm up. I then shut it down and hooked up the manometer to the carbs. The bike was on its center stand. Since I was in my garage, I set a box fan in front of the bike to help with cooling.
My pre-determined approach was to run the bike, read the manometer, shut the bike down to make the adjustment, and then start it up again to see the effect of the adjustment. I used a small 9/32 wrench (I didn’t have a 7mm) to turn the adjusting screw/bolt. I had decided to make the adjustment with the bike off because I found that opening the throttle moved the adjusting screw/bolt to a better position for turning the bolt from the right side of the bike. I hooked the vacuum hose on the petcock to an external vacuum source to keep the fuel flowing.
Starting the bike with the manometer attached for the first time indicated that the carbs were very much out of sync. Before the A/T fluid got sucked out, I shut the bike down and made my first adjustment turning the bolt in the appropriate direction as indicated by the Clymer’s manual. I restarted and found that I had improved the sync, but not enough. I don’t know how many times I repeated this procedure because I tried to make small incremental adjustments and usually did something like this: not enough…..not enough….Oops! Too much! I would then adjust the bolt in the opposite direction and repeat the ”not enough…..not enough….Oops! Too much!” scenario multiple times.
The end result was that the fluid in the tube would stay at the same level on each side of the manometer at idle. I did run the throttle up to see what it would do and one side would be higher than the other depending on the throttle position. First, one side would be higher. I would then open the throttle a little more and then the other side would be higher. It was interesting to watch, but as long as they were even at idle I considered it good enough. After disconnecting the manometer and reconnecting the vacuum hoses to the carbs, I found that the RPMs at idle had increased. I adjusted the idle back down and the bike seems to run fine. At least I don’t think I hurt anything. For me, that’s a job well done…"
I have done just about exactly this. I used 2 cycle oil rather than ATF. Search the site for other "sync" threads for even more info. Post up any questions, we will be glad to help.
93VN750, under re-construction
vn750.com Member # 828
Rick's Stator and R/R
MF AGM Battery
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MAC Tapered Staggered Pipes
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23,XXX miles and holding pending gasket change (underway!!!)