Ok, so I thought I was doing carb synchs and idle mix adjustments the right way but twice today, and at random other times I've seen people reference adjusting for the highest vacuum reading. Can someone explain to me the advantage of this method and how it works? Following are the two quotes that got me thinking....
Ok so this quote uses vacuum to adjust idle mix - seems like a way to "verify" the by ear method - the closer your mixture is to perfect the faster the idle and the faster the idle without opening the butterfly the higher the vacuum. This somewhat makes sense to me, and I might try it next time. For this method to work your carbs would have to close to balanced I think.
This one gets me, #3 has no adjustment right? So how do you change the vacuum on the #3 carb? With the main idle screw? Won't the highest vacuum be with the idle screw backed out as far as possible without the bike stalling?
How do you maintain this "high" reading? every time I've synched my carbs a tweak to the balance screw causes the idle to change, which causes the vacuum on #3 to change.
I'm eagerly awaiting the knowledge that is sure to flow......
The setup shown is used just to balance the carbs, not to adjust the (fuel mixture) vacuum level. I do that with something similar to the setup posted by Mr. Bill, except that I don't use an aquarium valve. I hook up the vacuum gauge to one carb at a time and adjust for the highest vacuum. After that I hook up the balance tubes to carbs 1/2 and 3/4 and synch. To synch carbs 1/2 TO carbs 3/4, I pick either 1 or 2 and synch it with either 3 or 4 with just one of the balance tubes. Sorry for the confusion.
resynched the carbs... but... we started w/ the #3, got the highest vac reading we could get, (instead of a low #, then trying to synch the other 3 to #3...) This made all the difference, and that's been the end of that problem. Bike runs so much better now. So, synch can really be a major issue... didn't know if you'd tried to get your highest reading on the first carb, then setting the others to that...
We could get all 4 synched fine at the lower vac reading... but it wasn't right, and the bike's performance sure showed it. Just a suggestion, may not be your deal... but it sure sounds like something's screwed up in that carb.
We could get all 4 synched fine at the lower vac reading... but it wasn't right, and the bike's performance sure showed it. Just a suggestion, may not be your deal... but it sure sounds like something's screwed up in that carb.
How do you maintain this "high" reading? every time I've synched my carbs a tweak to the balance screw causes the idle to change, which causes the vacuum on #3 to change.
I'm eagerly awaiting the knowledge that is sure to flow......
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