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

My guess now would be maybe some air leaking somewhere, gonna screw tight the intake mainfolds.

 

It’s alive!! Finally!
Now the problem is that the idle is at 3k, do I have to tight a bit the mixture screw?

 

What changed?
Why did it start now?

But congratulations


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I really don’t know, actually…maybe cleaned better, and give more throttle during starting attempt, nothing more new.
Now I’m going to set this super high idle, but I think this is another thread now

thanks to all of you, guys!

 

If it can help to diagnose, I started it with full throttle, and when it started it made a big bang from the mufflers. Maybe the engine was just flooded?

 

I set the mixture screw now at 1 and 1/2 turns but it starts always at 3.000 rpm (without choke): any suggestions?

 

intake leak....

 

I tightened them good, but how to check it?

 

Make sure you have proper freeplay on those throttle cables.
Make sure throttle linkage is free of obstacles and returns freely

spray quick start aroud intakes and listen for engine rpm to rise... if it does you have a intake issue

 

when cleaning did you do this ? its essential to be certain the idle jet is clean.

 

back the IDLE SPEED screw out until rpm stays at about 1200. not mixture screw.

 

Good catch squirrel


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what did you do to synch the carbs ? if you cant get a smooth idle at 1200rpm, synch [or someting else] might need fixin.

 

yes, with a needle, I did it even the idle jet was brand new

Gonna try it

 

Lowered the idle speed screw and now setted at 1.200rpm, but the sound doesn’t seem fluid to me. I think I need to sync the valves with the vacuum gauge

 

Something I noticed is that the bike starts without choke, and every time I give some choke the bike tends to stall. Any ideas?

 

Then you are likely rich in the idle circuit, ASSUMING all the work has been done correctly and you do not have other issues. You said you put the fuel screws at 3-1/2? That is usually excessive unless you are having to overcome another issue or are experimenting to see if a symptom gets better or worse. 1-1/2 to 2-1/2 is usually the sweet range for a correct pilot jet. If you have to go outside of that range, then a pilot jet change is a good idea, in my opinion. I will say that almost every VFR if used in a normal altitude/temp setting can benefit from going one size up on the pilot. They are often lean for emission reasons, especially here in the U.S.

Did you maintain the stock size pilot jet?

 

I set 3 and 1/2 at first, but now I’m at 1 and 1/2 turns because I was assuming this could be the reason of high rpm at idle.
The pilot jet is brand new and the size was the same as the stock one.

I still have to do the leak test as sixdogs suggested: can I use fuel in a spray can instead of quick start?

 

That sounds dangerous as fuck.

 

A stock pilot jet and screw @ 1-1/2 that can start without choke and dies when applied.... something's not right. How does your air filter look?