Delayed reaction when turning throttle.

Hey peeps. Picked up a 84 VF750 Sabre that wouldnt fire up. Cleaned and rebuilt the carb and she fires up like a champ now. Just when i give it gas she only revs up real slowly and backfires alot and when i release the throttle takes while to return to idle. I checked out the cables and the grips and the carb assembly spring. All of thats fine so everythings returning properly. Can it be Fuel/air mixture setting? timing advance setting? air leak that i cant find cause i tried the spray trick? or what else is there????? Id really like to ride my bike soon :smile:

 

Since it's electronic and built into the CDI, spark timing seldom or never gets out of whack, but you should check (with airbox off so you can see) that all 4 vaccum slides move up and down the same amount and at the same time. They can get sticky. Maybe a bad diaphram ??

 

Oh ya about the vacuum slides can i check em without pulling em out???

 

So i can visually check em without opening the tops of each carb and pulling em all the way out??? That would be nice cause im getting tired of pulling carb assembly out and putting it back in altho i am starting to get real good at it

 

something else I just thought of as well. Could be the grease inside the cable itself has worn out if it was sitting outside.

 

+1 vacuum leak somewhere, check boots for good seal by spraying a little carb cleaner around each boot while running. if the RPMS increase, you have found your leak

 

Didn't he claim he tried that ??

It's all done with the engine running, so, no, you don't pull them out.

 

No i aint checked the slides while running. I rebuilt the carb finally got the bike to start. It aint the cables i lubed all that pretty good and everythings returning to normal. I gottta make me one of those little test gas tanks yall r talking abot. I did order a new petcock cause mine was defect its letting fuel flow even without a vacuuum. This is what i have lined up for this week an next. Adjusting valve clearance, synchronizing carb, changing out petcock. Plugs are new but im gonna double check gaps. Got the iranium type plugs they cost a arm and a leg hope theyre worth the money anyone know? And im gonna look through the airbox and see what i see moving and try to even film it hey when making a little test gas can, i can use a regular plastic drink bottle? Gas wont eat through it????? Just doublecheckin

 

Hey Squirrel how goes it? i took some vid and they workin right? All 4 are doin the same. YouTube - 84 VF750S vacuum slides in Action!!!!

 

Cool thanks for the tip!!! heres a short clip of what my vacuum slides look like in action altho i could only film the one!!!
YouTube - 84 VF750S vacuum slides in Action!!!!

 

you rock dude

 

Here ya go Brother 2 vids of just the Engine running. IS SHE SOUNDIN ALRIGHT FOR A SABRE OR DO YOU HEAR SOMETHING BAD????? :flame:

YouTube - 84 VF750S Motor Sound1

YouTube - 84 VF750S Motor Sound2

 

I cant see all 4 vacuum sliders at the same time cause the frames and components are in the way. But no sir i havent synced yet. I finally saved the money for a 4 carb sync gauge and it should be in by this weekend so we will
Sync her and then ill definately tell you if i notice a difference or not.

 

I also have a compression gauge so i can get all cylinders checked out before the end of the weekend also will be in touch

 

As far as the valves go i ordered a couple feeler gauges from the States and i didnt know that .12 was a special size not included on just any feeler gauge so now i ordered the ones i got for nothing and have to re-order. Will take awhile till i can gap the valves!!!!!