1979 gs750 need help with syncing carbs?!

[NBraun]

Well, i finally have the bike running, and i tried to sync the carbs. I couldn't find a definative way to do it on the VM's so im trying my best. Right now on the carb tune its showing all the bars level at 18, yet, when i rev the bike it pauses, then takes off. To me this sounds like a lean problem but havn't been able to read the new plugs. Any ideas?

 

[AlphaDogChoppers]

You are not giving us much to work with. Pods or stock air boxes? Has it been rejetted? What exhaust? What was the last carb work done other than synchronization?

 

[NBraun]

sorry, i was frustrated and just flustered with my self.

I tore the carbs down, dipped and rebuilt them. Set the carbs to stock settings and when put on they would start up and idle fine.

Right now im running with cheaper pods and headers.(Haven't gotten to putting the mufflers on, but i will when i go back out and try again.) I'm running stock pilots and 110 mains. Needle moved up one clip. Pulled the 1 and 4 plugs and they're starting to turn black, witch indicates a rich condition.

Before i tore them down a second time i had the same settings and it would pull find throughout the rpm range, but just take a while for the rpm's to go back down.

Hoped that helped.

 

[AlphaDogChoppers]

What was the original main jet?

Throw away those cheap pods. Many cheap pods block certain ports in the filter flange of the carburetor, and you will NEVER get them to tune right.

 

[NBraun]

I think it was a 102.5. Ill see what i can find.

 

[AlphaDogChoppers]

Reading plugs is not a very reliable way to tune carbs. I tune by how an engine runs. If it is hesitating off idle, that suggests that it is lean coming off idle. Go up one pilot jet and try again.

I like to tune main jet by going richer until it breaks up on top end, full throttle, than back off a couple jet sizes. Then I work on the midrange with the needle.

 

[NBraun]

Thanks alpha! I put the bolts back in the intake and now the problems gone. I also put the muffler on. It revs fine, but does seem to slow down towards 1-3k rpm. I'll also need a larger pilot, there is some hesitation off idle.

 

[AlphaDogChoppers]

Are you saying that you had the symptom with the vacuum ports unplugged?

 

[NBraun]

No, i had the adapters for the synchronizer screwed in.

 

[AlphaDogChoppers]

Was the synchronizer still connected?

 

[NBraun]

Yeah, Thats why i don't understand why it was acting lean? I checked the carb boots too by spraying them and so i really don't know why it was doing what it was.