How do I sync engine RPM when on the throttle? 98' Sportster with twin 717's

[trdehmer]

I just had my fuel pumps and carburetors rebuilt - engines seems to run good and strong, but I have noticed that if both my throttle levers are in the same spot, my right side engine is probably 500-1000 RPM's more than the left engine. They both idle the same. How and what do I adjust to get the engines more in sync when throttle levers are in the same position?

Thanks!

 

[Ankeneyou]

I bet there is slack in one of the throttles when at idle. At idle, there is a set screw on the carb that sets the idle, so you need to adjust the throttle cable at the carb so that each cable has very little slack when hitting the idle set screw.

 

[Dvesky]

I'm also dealing with an issue with the port side rpm gauge. It reads zero at start up and only registers at 5500 rpms+ and doesn't seem to accurate. Is there a fix for this issue

 

[Ankeneyou]

Swap with the other gauge first to rule out the gauge itself.

 

[Lumps]

Ok so I had exactly this problem. I had it for a really long time after I slammed the lid too hard. Anyway I thought I would crack it open and see if there was anything loose or corroded stuck etc. I unscrewed the brass nut On the back of the gauge and attempted to pull it apart. I didn't get it apart. When I put the nut back on I left it loose because I thought I would try again. Anyway it worked ever since. Maybe just luck but may work for you

 

[trdehmer]

I was informed the service manual states to put the boat in the water, and bring the RPM's up to 3000 RPM in neutral, then adjust cable(s)at the throttle levers/controls to get within +/- 200 RPM's. I plan to try that as my idle is set to spec. and seems to run just fine. This is for throttle synchronization...