XJ650 dies while braking

Recently did valve clearances and I just got done with a carb rebuild and float level set. Now my bike is acting strange.

I cannot get the idle lower than about 1700 rpms and also the bike dies under moderate or hard braking in neutral/with the clutch in. Any ideas?

 

Your fuel levels are likely too low. Time to get the carbs in shape.

 

Float levels are likely off, but I don't see anything about syncing.... Did you sync things properly?

 

I just got done rebuilding my carbs this weekend. I set the fuel level to 3 mm from the top of the bowl. Before they were like 12 mm from the top and the bike ran well...

And i did a bench synch, I will vacuum sync soon. This was a major issue when i tried riding the bike around to warm it up.

 

for what its worth is your throttle cable to tight, you should have a little slack in it when closed? and you are trying to adjust idle with the idle adjustment knob.
with your carbs running better than before you rebuilt them the cable may have been tightened to keep the idle up .did you set your mixture screws to 2-1/2 turns out from a light bottom?
just want to know ,why are you braking moderate to hard in neutral?

 

I set them to 2.5 turns out. The throttle cable has some slack. The braking is a result of slowing to a stop going down hill with the clutch pulled in.

 

Downhill + moderate braking + stalls = fuel levels too low.

Does it still do that when fully warmed up? If you're trying to pull away before you can take the enrichment lever about 1/2 way off, then the bike will easily stall regardless.

 

Just wondering if you could explain why the low float level would cause stalling while braking downhill?

Also, the bike starts and runs without the enrichment circuit, aside from the high idle that I mentioned.

 

Did you put the air jets under the diaphragm in wrong holes? Larger one towards front

 

No, I verified that they are correct.

 

I could be wrong, but I'm still going to take a shot at this. If your fuel level is low in the bowl then you're going to run lean, if it is high then you're going to run rich. So if you're fuel levels are low you're already running lean, then when you go down hill the bike tilts forward, that forward angle changes the level of fuel in the bowl which cause the fuel level to go even lower which in turn makes you run even leaner and starves the bike for fuel choking it out.

 

Even if this explanation makes sense, I don't understand why the bike would run properly under accelration and every time except when breaking hard on neutral. Low fuel levels in bowls should make it run bad all the time, the way I see it, and probably worse under hard acceleration than hard deceleration.

 

1. the fuel levels can be 1mm low and still run well.
2. the fuel levels can be 2mm low and still run well except while braking.
3. the angle of the carbs changes under acceleration, and while under braking.
4. That change of angle is not equal; the front dives more under braking than the rear squats under acceleration.
5. fuel levels are CRITICAL and there is only a +/- 1mm variation allowed. Outside of that range there will be fuel starvation problems under various conditions. This is why we consistantly and emphatically recommend wet-setting the fuel levels.

 

deceleration would push gas towards the engine and make the fuel level at the pilot jet higher.....richer.
is it hard to start after it stalls, hot engines don't like rich mixtures to start

 

Sometimes its takes some extra cranking. Other times it fires right up again.

 

You have to do a running sync.
Set the idle with the engine fully warmed up.
Make sure the enrichment plungers are closed all the way.
Turn in the mixture screws to peak the rpm, then out the width of a dime