Is it possible the ignition advance is what's pushing it up to >2000rpm?
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Ninja EX500 carbs on an XS650?
- Thread starter Highside
- Start date
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- cafe carburetors custom engine
and revisit your carb synch.
It's running on just one side at 900 then the other side "catches" and zoom 2 grand been there fought that.
I'll vote for the synch.
Bjorn
XS650 Addict
Just checked the sync. Looks spot on if you ask me.
Regarding that advance. I need to check. Seems early for the advance to kick in right?
Regarding that advance. I need to check. Seems early for the advance to kick in right?
with it at 900 RPM which side is dead?
Try a bit of synch adjustment, go both ways see if it gets better or worse. genuine brass or aftermarket parts? re-check valve clearances also.
Try a bit of synch adjustment, go both ways see if it gets better or worse. genuine brass or aftermarket parts? re-check valve clearances also.
Man that bike looks sharp.
Bjorn
XS650 Addict
I redid the valves, after I retorqued the head.
"What side is dead"? You mean it's running on 1 cilinder? Because it doesn't sound like it. It just barely keeps running and sometimes it coughs and stalls.
Yeah the looks are great but I want to drive it haha. Thing is driving me nuts (again lol)
Edit: I only use original Keihin brass
"What side is dead"? You mean it's running on 1 cilinder? Because it doesn't sound like it. It just barely keeps running and sometimes it coughs and stalls.
Yeah the looks are great but I want to drive it haha. Thing is driving me nuts (again lol)
Edit: I only use original Keihin brass
Yes. Ideally you want the advance to start just off (above) idle.... if it starts advancing "at" idle, you can chase your tail all day long and never get a steady, repeatable idle.
Bjorn
XS650 Addict
You are running that Vape ignition to right? It's not really tunable...
No, I go back and forth with the Gonzo mod and the factory TCI. Right now it's on the TCI.
Not familiar with the Vape, so I don't know how the advance is set up or if it's adjustable.
Here's a scenario I've run across in the past on various different engines with faulty advances.....
Idle is at 1000rpm and you want 12-1400rpm. So... you turn the idle screw in to bump it up to 1200. Just before you get to 1200rpm, the ignition starts advancing and pushes the idle up another 2-300rpm. now you're at about 16-1800rpm. You turn the screw back out to lower it back down.... and the advance retards a bit.... and now you're down below idle again. You can rinse and repeat all day long and never get the idle where you want it.
maybe random but was really chasing my tail on my lawnmower last two days it was running but not well and gradually getting worse, finally a HUGE backfire and it was done running. Did all the checks, it would stop crank, stop, crank when choked. Finally light bulb came on. I had replaced the stator last fall, stripped it down and yup... the flywheel had sheered the key, timing was slowly going retarded, then the big back fire took it all the way out of time. made a new key, runs great now.
Bjorn
XS650 Addict
Just went down to 38 pilots. Started with 2 turns on the mix. That's where I started last year with these carbs.
The bike was half warm, needed some choke to start en keep running. Would run really nice at 1200 rpm!
After a few minutes started to run less nice so I reduced the choke. Idle would be low. I figured I l need to warm up the bike properly by riding. Came back to the house, idle would be low, and very high again when i revved it.
Tried to tune the mix screws. Got I running at a decent 1100 rpm! When I rev it, they come down but slow. That's when I found that if I press on the RHS throttle shaft, the idle goes down quickly to 1100... Wtf!?
Made a video, share it here later. But I got me thinking, did I forget one of the sync mechanism springs??
The bike was half warm, needed some choke to start en keep running. Would run really nice at 1200 rpm!
After a few minutes started to run less nice so I reduced the choke. Idle would be low. I figured I l need to warm up the bike properly by riding. Came back to the house, idle would be low, and very high again when i revved it.
Tried to tune the mix screws. Got I running at a decent 1100 rpm! When I rev it, they come down but slow. That's when I found that if I press on the RHS throttle shaft, the idle goes down quickly to 1100... Wtf!?
Made a video, share it here later. But I got me thinking, did I forget one of the sync mechanism springs??
Bjorn
XS650 Addict
That or something's binding on that shaft. At least now you have an good idea where to look.
Bjorn
XS650 Addict
There should be 2 springs. Just like Gary s picture. I can see I got two springs in there!
So weird. Pushing on it closes the butterfly. Maybe when the idle is high, the play in the sync mechanism allows me to push and "choke" the RHS cylinder, resulting in the idle dropping faster. This should be controlled by the throttle stop....
But when I retract it, the idle just goes lower and lower...
Back off idle speed screw, loosen the butterfly screws a bit, snap the throttle shut a couple times, tighten screws.
Spray a bit of thin lube, rust buster on the throttle shaft at the throat, work it a few times.
Bjorn
XS650 Addict
I'll try the lube First , much easier haha.
About those butterflies. Is that when they are not centered properly? I never loosened those screws before.
About those butterflies. Is that when they are not centered properly? I never loosened those screws before.
Bit of a warning . The the pilot air screws included in the Cruzin Image carb kit for the 1988 GPZ 500's is too short and has the wrong thread.
I had to drill an old one out and bought the kits from him as they included the pilot screw and in the past stuff from him has been good.
A new genuine part is NZ $64 , I have taken a punt on a pattern part the dealer offered (from Kawasaki NZ) for $20. There are a few genuine parts on e bay if the pattern on is a bust.
I had to drill an old one out and bought the kits from him as they included the pilot screw and in the past stuff from him has been good.
A new genuine part is NZ $64 , I have taken a punt on a pattern part the dealer offered (from Kawasaki NZ) for $20. There are a few genuine parts on e bay if the pattern on is a bust.
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