[twinsRin]

I had the air box off my bike today to do some other maintenance but got distracted looking at the carbs, seeing how they work and such. I don't have much experience with duals so I decided to start the bike and see if I could learn more by watching stuff. I did, but came away with a question

When I revved the bike only the front carb vacuum slide moved as the rpm increased. Is this normal and is there reasoning behind it? The rear carb slide moves freely and I can't seem to find how/if it could be sticking. The bike runs fine so dirty carbs shouldn't a problem.

I knows there's someone out there in internet land who knows the finer points of SV carbs..

Thanks in forward.

 

[wacky_woodchuck]

When is the last time that you sync'd your carbs? The carb slides act on engine vacuum and the pull from each cylinder should be the same, hence raising the slides at the same time.

A carb sync uses some sort of fluid that interacts with the vacuum ports on the carb throat (front cylinder) and the fuel pump (you put a "t" in for the rear cylinder). Once the fluid is equalized (by turning the screw in between the carbs.

There are plenty of good instructions with pics on the web somewhere (bluepoof comes to mind).

 

[twinsRin]

I've never synced them and I have no clue if they ever have been. I didn't connect the fact that the syncing the carbs would affect the slides moving up and down, a slight oversight on my part. Carburetors are still somewhat black magic to me. I'm going to build a syncing contraption and see what I can do. Thanks for pointing a probably obvious cause.