Honda VFR 750 RC24 '86 doesn't start after carburetors overhaul

I understand your feelings, but I’m pretty sure I didn’t miss anything during rebuild or did something wrong.
Now the engine doesn’t give me combustion sound anymore, I think I flooded again with all these attempts: gonna give it some rest and try tomorrow.

I think it’s something to tune

 

Is pretty much what you said Page 1, Post #16.

Floats are supposedly correct now and the pilot screws are at 2 turns out from lightly seated. And you performed a bench synch after splitting the carbs, which will get you to a starting / idling bike. Nothing else has changed on the bike, like a different exhaust or a wild new intake system, right?

Please tell me what is left "to tune".

 

That's my bad--I should have been more clear. Yes, the black knob that sets the idle speed. Looks like this:

 

Yeah I got it right after Captain noticed my misunderstanding, thanks.

Yes, I did everything like in that post (I’m doing this so many times, sadly…)

I do removed the mufflers for repainting, but just repainting: I covered the holes with paint tape and the air comes out from them when I try to start.
I’ll try with mufflers removed tomorrow, I doubt it could be the reason but I want to try all options.

The intakes are the same as when it started the first time, nothing changed and tightened them good.

Nothing left to tune, maybe gonna set the mixture screw at 3 and 1/2 turns like squirrelman suggested some posts ago

 

thats only as a test of your idle circuit, not a setting for daily riding use. since you have a nice float level gauge now, id suggest you reset to 9 mm as a test to see if it helps.

 

Yes I imagined that, but I’m on a test field now until it starts up again

 

^^^ your clear tube test isnt valid unless the carbs are level side-to-side and front-to-back. the proper fluid level is just at or 1 mm below the top of float bowl measured in the middle.

 

I wish I had known earlier...anyway I set them at 7mm straight, as manual says.

I don't mean to be arrogant but I'm confident about the carbs setup at this point: I've watched tons of videos, you guys told me so much informations, I've checked the slides needle and I don't see any fuel leaking from there, I even rebuilt them with main jet custom size (118).

I suppose now it's just a matter of trying over and over until it starts, and if I get tired before it does I'll call a mechanic.

 

didn't see your edits on this post. sure gonna try that if it won't start after 3 and 1/2 turns of mixture screw

 

Set all the floats at 9mm and done clear tube test:
the fluid of rear ones is over the line,
the fluid of back ones is below.

I guess I have to find the right height for each floats until they’re all at the same amount of fluid in the clear tube.

 

again, the carbs must be level and off the bike for the test to be valid. all floats must be set to the same level, 7 or 9mm.

 

Considering that I measured them in both positions and both gave me the same results, what do you mean specifically? Suppose the red line is the plane where I place the carburetors, do you mean

A) they should be positioned as if installed on the cylinder heads (option A) or
B) with the throttle valves perpendicular to the plane (option B)?

P.S. the carbs in the images are not mine and they’re not of a RC24, I used this just for clarification

 

on the bike, i dont think the carbs are level. A

 

Ok thanks, I’m gonna leave the measurements on B position then.

I started again from the beginning, starting from float height at 8mm:

Carbs #2 and #3 are perfect,
carb #1 and #4 have fluid respectively 9.8mm and 12.0mm above the ideal line.

Gonna set those two in order to make them equal to #2 and #3 (the number is the number of the head in which they’re installed)

 

GOOD LUCK

as youve discovered, a very small adjustment of the float tab changes height alot.

 

Some updates.

I found that the issue causing carbs #1 and #4 to overfill is NOT related to the floats. I swapped the float of carb #3, including everything (filter, float valve seat and its washer, float pin and float valve). Surprisingly, #4 continued to overfill, while #3 maintained the correct amount of fuel. I’ve already checked if #1 and #4 have all the components, thinking the issue might be a missing washer, but they have every component.

I’m going to investigate further on this.

 

check for a missing washer under the float needle seat maybe ? its necessary to loosen the needle seat to be sure. check in water that the float.... ... floats, check for cracks or holes.

 

Unencumbered by any knowledge, gunk/contamination on any of those seating surfaces.

 

That was my first thought, but the float valve is new and the problem occurs even after cleaning.

Yes, I checked for those washers as first thing but they’re all there.
As I said before, when I swapped floats with the #3 I swapped everything, even float valve seat and its washer.
The floats “float”, already done this check.
I’ll polish the housing of the float valve seat.

I’m still pretty confident that I didn’t miss anything, the washers are all still there.