95 VFR750f Runs Rough at Idle

Picked up the bike for cheap it had been previously laid down and forgotten about. Had no papers when I got it I'm planning on turning it into a street fighter it didn't run when I got it. Cleaned everything on the carbs there was so much stuff in there had to do it twice. Everything looks good in there cleaned all jets and the choke valves. After all that for the first time it fired up ran ok then died. Couldn't keep it running from there on out the engine was filling with fuel. Cleaned the carbs again they have good floats and new needle valves for the floats the choke seemed to be a big issue. Bike runs pretty decent now but it won't idle. Loads up and stalls anything under 2k the regulator plug was melted and fixed don't know if that's good or bad and it's got no fuel pump just gravity fed. Looks like the previous owner tried a couple things and nothing worked now it's my headache. I'm trying to get it running good before I go register it and ride don't wanna be stuck somewhere looking to see if anyone's been through anything similar. Running above 2k the bike seems to run good.

 

I hate to say this but the carbs still sound like they are dirty.

 

Howdy Jacky. Is it possible that the gravity feed doesn't supply enough fuel? I know you said it stalls under 2000, so does that mean that it runs cleanly over 2000rpm?

 

That's what I thought at first they looked clean when they came apart the second time thanks though I'm gonna keep messing with it probably clean em out another time gonna get a fuel pump and all that for it too most likely. Spark plugs are next the didn't look too bad definitely a little old, gap looked good and all. It floods easy wouldn't start earlier if I torched off the plugs it would fire and barely idle like 1000rpm on choke any little throttle kills it.


Sent from my iPhone using Tapatalk

 

Yeah runs good over 2k when it starts I've got a fuel pump that my buddy has off of a 900rr plugs right in gonna see if that helps tomorrow.


Sent from my iPhone using Tapatalk

 

OOOPS JAcky... I just read your last line... at 2000, can you pull each plug lead separately and see if they all drop by roughly the same revs. Apart from checking the plugs for colour..it might only be one cylinder/carb that's a problem. yeah!

 

I don't know the whole history on the bike but I'm definitely gonna give that a try with new plugs. From what I've seen with it the plugs all look about the same. I would get a better result if it would idle a little smoother pulling plug leads. After the second carb cleaning it starts easier and until it warms up no throttle or it's starting to foul plugs. Then it sounds healthy. Gonna see what it does with new plugs and a fuel pump. When it does under 2k it's definitely flooding needs wide open to start again.


Sent from my iPhone using Tapatalk

 

If you pull those carburetors off again, you should blow air in the "black-tube" and see if the slides all rise in unison, if not, you have a vaccum leak. If it dont run right on choke, your passages and cleaning are suspect. You need a fuel pump on these bikes as the gas level goes down, gravity wont work. This is the case with Gen3 bikes, I think yours is the same. Get a factory service manual if you dont have one too. Just my two cents eace:

 

If your4 floaT NEEDLES are good and you're not using choke excessively there should be NO FLOODING, but pull the top of the airboxz off and--while engine is running--look for rAw fuel bubbling up from the main jet hole under the slide needle. Also check that ALL 4 SLIDES RISE equally in response to throttle.

Dija put A thin steel wire (.010") clear through the slow jets ??

 

Yeah I've gotta get it running again to try that stuff starts hard don't know why it floods. There was a bit of corrosion behind the choke plungers there. I was using a wire about .010 probably not prefect I'm gonna find a wire or like a set of torch tip cleaners in case I need to pull them out again . Haven't messed with it today a couple things came up


Sent from my iPhone using Tapatalk

 

If you pull em off, while they are on the bench, blow some air through the tube and see if the slides rise. You could also take the opportunity to bench synch em too. Things alway have a habit of coming up and screwing up your wrenching sessions.