Ninja EX500 carbs on an XS650?

When I ordered the parts for my carbs I got pilots of 38, 40 and 42.
mains of 138, 140, 142, Needles, JJJ, JJH, HKJ. I wanted to be sure I had the most recommended parts on hand, sucks to decide you need something more after you start.
With 38 pilots, 138 mains and the JJJ needles on #3 slot it runs very well. It could be a bit stronger on the 3/4 to WOT. I may experiment with bigger jets, different needles in the spring.
And your right on the response, quicker and smoother transitions.
Leo
 
Better news....and a lesson. Double check your work. Checked my heights with the clear tube again, left was low around 3.5mm from just above bowl seam. Right was about 2. So im really hoping that me being tired and not dpuble checking my work is why even on notch 5 of the needle it wasnt running right. One more nice day before snow would be great.....ha.
 
well, it runs better with float height set properly with clear tube. but not right with those needles. Notch 2, is lean, 3 cruises pretty good, as long as you dont go 3/4 to WOT. pops and spits around 4500, but once you back off or ride out of it it flies like it will keep going past red line if i want too. notch 5 is just pure blubber. 4 seems a bit better...but not real sure.
 
any suggestions would be greatly appreciated!
got the carbs all cleaned up but getting a slow return to idle when blipping the gas.
carbs have been synced, float height checked, was running a 40/140/needle in middle position/mix screws out 2.5 turns.

i've got Uni's and HHB speedster pipes as well.

not getting any idle changes when checking for air leaks.

was thinking it was a lean pilot circuit so i bumped them to 42's but not really any change, plugs are black so obviously its running rich. i have a set of 38 pilots i could try, other than the slow to return idle it pulls really hard all the way to the top, although i do notice more crossover between the jets than i did with my old bs38's...
 
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Are the holes in the slides clear?

I borrowed your manometer from K. I'm going to recheck my valve lash and sync... Hopefully that'll sort my cold starting woes out.
 
jkocr2,

As you say, a hanging idle is usually due to a lean condition. I had the same and cured it with #40 pilots (up from #38). What are you using to leak check? Carb cleaner or cold start fluid work very well. WD40 isn't to be trusted as it's not very combustible. If defo no air leaks, have you overhauled the carbs with a refresh kit and replaced the mixture screws, O-rings and washers?
 
jkocr2 said:
I did not replace the mix screws, o rings and washers
Click to expand...

If you've tried all the above suggestions and you've not had much success then I would unless you can be certain that they are all in good condition. Worn, split or missing O-rings can be the cause of an air leak. Missing washers will cause the spring to rip up the O-ring too. Did you squirt some carb cleaner up the mixture screw 'tunnels' when you were leak testing? Did you spray around the head gasket joint?

Did you strip the carbs of their jets and emulsion tubes and clean the inside of the carbs and all the air/fuel passages?

Did you say you had air filters fitted? Forget that, I see you have UNIs.

I'll keep thinking....
 
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the only thing i did not do was spray cleaner in the mix tunnel while it was running. i did completely disassemble the carbs and made sure all passages/jets/tubes were clear of any grime/grit. i also took the mix screws out and sprayed those holes while cleaning them but did not remove the springs/washers/o rings.
 
Not wanting to sound 'arsey' (but I'll risk it ;-) ) but I'd recommend removing and replacing them as a matter of course because you just don't know what condition they're in. If they're not inspected they then become an unknown quantity that may have you running around in rings. Cheap insurance.

Are you running vacuum petcocks? If you are, try disconnecting the vacuum hose from the barb on the carb/carb boot and fit a blanking cap to the barb.

Incidentally, you've not capped the carb vent (black plastic T pipe between the carbs) have you?

Still thinking....
 
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no vacuum petcock....no on vent cap although one would think you would.....the carbs like to spew gas everywhere if you do that though...dont ask me how i know
 
jkocr2 said:
...was thinking it was a lean pilot circuit so i bumped them to 42's but not really any change
Click to expand...

#42s should have made a great difference to idle quality. How much did you have to readjust the mixture screws by after you changed to #42s? How many turns out are your mixture screws currently with the #38s?
 
Yep did that and was still getting the throttle hang so I went back to the 40's as the 42's then caused breakup in the midrange on the pilot to needle overlap
 
jkocr2 said:
Yep did that and was still getting the throttle hang so I went back to the 40's as the 42's then caused breakup in the midrange on the pilot to needle overlap
Click to expand...

That it's still hanging even when you tried #42s and if you've not got any air leaks, the carbs are clean otherwise and the slides move freely I'm still thinking the pilot circuit on one of the carbs is the culprit.

IMHO, to be able to properly dial in these second-hand carbs (or any other pre-used carb for that matter) we have to ensure that they're in top condition before we start swapping jets 'n' needles trying to chase an optimised set-up. In your case, jkocr2, the state of your idle circuit is still an unknown quantity which needs eliminating. Removing and inspecting the mixture screws, O-rings and washers then thoroughly cleaning out the idle circuit and fitting a couple of refresh kits will sort that. If you go this route let us know what you find (or don't find!).

Because your engine set up is very close to mine when I experienced a hanging idle I'd baseline your carbs at what I had at the time:

Float level: 0.5mm - 1.0mm above the gasket line
Pilot: 40
Mixture screws: 2 1/4 turns out initially
Main jet: 140 (mine was 138 but better to be rich for now)
Needle: JJJ on #5
Sync with a manometer or propriety carb balancer

One last thought. Are you running push/pull throttle cables? If you are, disconnect the 'push' return cable at the carbs and ensure you've got a little slack in the 'pull' cable. Try this before you do the above.

Good luck! I'm rooting for you. Go, jkocr2, go!
 
56nomad said:
That it's still hanging even when you tried #42s and if you've not got any air leaks, the carbs are clean otherwise and the slides move freely I'm still thinking the pilot circuit on one of the carbs is the culprit.

IMHO, to be able to properly dial in these second-hand carbs (or any other pre-used carb for that matter) we have to ensure that they're in top condition before we start swapping jets 'n' needles trying to chase an optimised set-up. In your case, jkocr2, the state of your idle circuit is still an unknown quantity which needs eliminating. Removing and inspecting the mixture screws, O-rings and washers then thoroughly cleaning out the idle circuit and fitting a couple of refresh kits will sort that. If you go this route let us know what you find (or don't find!).

Because your engine set up is very close to mine when I experienced a hanging idle I'd baseline your carbs at what I had at the time:

Float level: 0.5mm - 1.0mm above the gasket line
Pilot: 40
Mixture screws: 2 1/4 turns out initially
Main jet: 140 (mine was 138 but better to be rich for now)
Needle: JJJ on #5
Sync with a manometer or propriety carb balancer

One last thought. Are you running push/pull throttle cables? If you are, disconnect the 'push' return cable at the carbs and ensure you've got a little slack in the 'pull' cable. Try this before you do the above.

Good luck! I'm rooting for you. Go, jkocr2, go!
Click to expand...

thanks! i guess i'll order a idle screw refresh kit. my floats check out and i'm running the 40/140/#4 clip jjj (too rich, getting breakup on the crossover between the pilot and needle transition) but i can tune that out. carbs are definitely in sync, that was the first thing i did, i also am only running the pull cable and verified i have slack.

the idle screw itself looks good (not bent/dented/etc) wondering if i can just get away with this

http://www.cv-performance.com/cvp-mixture-screw-packing/

or if i should go with the easy adjust longer screws as well

http://www.cv-performance.com/ez-just-mixture-screw/
 
found them cheaper at factory pro...got the long boy extended mix screws and o-ring/spring/washers on the way. I'll let everyone know how it goes if i ever get another day to mess with it....our weather in illinois just took a turn for the worse...HELLO winter!
 

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