Sir Puma Posted October 18, 2012 Author Share Posted October 18, 2012 Couldn't understand a thing that guy said. Nor could I tell exactly what he was doing. However by viewing some of the other videos I'm guessing you want to adjust to have the same vacuum level on each cylinder with the engine hot. But what I don't reallly understand is that if I sync the butterfly valves on the bench to the exact same timing. Do I then adjust them or the mixture screws when doing the dynamic sync? In theory, I could get a dial vacuum gauge, measure each cylinder then work on adjusting. O I could get two so I could synch two cylinders at a time. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 18, 2012 Moderator Share Posted October 18, 2012 Not that easy... Carbs are a dynamic thing. The carb balance has to be set just off idle. That way the vacume in the inlets is enough to lift the slide and Have the carb in its working range. Because all the cylinders will be subtley different in the vac they generate You will need to ajust each carb to work on a different level of vacume but give the same performance. Because of that its impossible to do on the bench. Most bikes will balance 2 to 2. That means match 1 and 2. Then match 3 and 4. Then match both pairs together. A basic set of useable gagues dont cost much. Certainly not enough to worry about using a shitload of hose. You will see a big difference in the bike though. Link to comment Share on other sites More sharing options...
dt502001 Posted October 18, 2012 Share Posted October 18, 2012 First did you try to run the bike on prime first? I still think your having a fuel problem. Don't adjust the mixture screws ..just the butterfly valve's..if they aren't pulling the same vac it's like having 1 or 2 carbs running at half untill the bike revs up enough to compensate for the vac loss to raise the slides. While the hose method isn't the most acurate way it will give you a idea as to how far off the carbs may be and for 5-8 bucks its a easy way to atleast get them close. As Cynic pointed out they must all be working together and the only way to tell is to check them all at once and adjust them as a set.Adjusting 1 will change the others as rpms will increase with each adjustment that get them closer to working together. Link to comment Share on other sites More sharing options...
boon Posted October 18, 2012 Share Posted October 18, 2012 It's ''CV'' carbs on the xj650, have you checked the diaphrams? All it takes is a tiny hole in the rubber to totally mess up carburation. Link to comment Share on other sites More sharing options...
Sir Puma Posted October 19, 2012 Author Share Posted October 19, 2012 It's ''CV'' carbs on the xj650, have you checked the diaphrams? All it takes is a tiny hole in the rubber to totally mess up carburation. I've gone through my carbs twice to clean them out and didn't see any issues with either the diaphragms or the floats. Haven't played with the prime setting yet. Link to comment Share on other sites More sharing options...
Sir Puma Posted October 22, 2012 Author Share Posted October 22, 2012 Recorded a video this morning of how it runs. Link to comment Share on other sites More sharing options...
dt502001 Posted October 23, 2012 Share Posted October 23, 2012 All speedos lie by 10% Yep you need to sync your carbs classic example of carbs out of sync. Link to comment Share on other sites More sharing options...
Sir Puma Posted October 29, 2012 Author Share Posted October 29, 2012 I think I have my problem licked. Thanks for the tips and suggestions. Link to comment Share on other sites More sharing options...
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