Ninja EX500 carbs on an XS650?

Hard starting when cold can be a number of things. Compression loss due to linear expansion/retraction, too rich, too lean, weak battery or spark, or an air leak that has developed due to cold weather and material shrinkage resulting in a lean mixture.
 
jd750ace said:
Hard starting when cold can be a number of things. Compression loss due to linear expansion/retraction, too rich, too lean, weak battery or spark, or an air leak that has developed due to cold weather and material shrinkage resulting in a lean mixture.
Click to expand...


Well,
  • I've got a big ass Harley battery that stays charged nicely...
  • new gaskets and good boots...
  • I've got good compression
  • New High output coil (Mike's XS Green Coil)
  • Valve Lash is in spec
  • TCI Igniton... so timing is :thumbsup: (Verified with a light)
  • Throttle is really snappy off idle, no hesitation or low speed break up.

Air/fuel Mix screw is about the only thing left... I can try to dial it in there a little closer.

hmmmm
 
I usually open the enricher and kick twice with the ignition off. Then it usually starts with first kick after turning the ign on. But my bike also runs ok with the enricher on when cold.

Pekka
 
Check out scabber's signature block Big G. He's running a 750 kit with 09 EX carbs. I know his tuning evolution is posted here too, although 29 pages is getting kinda deep to thumb through!
 
I have 05 carbs on my 75 with a 750 kit. Stock cam, Uni-Filters, Home made 1.5 inch headers, Emgo shorty megaphones.
38 pilot, 138 main, JJJ needles, third slot. Using the ends off the stock needles as spacers.
Runs very well. I could go bigger on the mains, maybe try different needles but it runs great as is.
From the experimenting I did on the BS38's and BS34's After the 750 kit was installed. I thought it would need changing, I spent two weeks tuning the carbs and ended up right where I was.
If you have a set of carbs set up and running on a 650 it will work just as it is on a 750. Unless you make other changes to the air flow. Such as a more free flowing intake or exhaust. Changing the CC's by itself has little effect on the carb tuning.
Leo
 
Just waiting for my jets to show up. I have a 138 main and a 140 not both...figures. The jjj needles are in. Had it running with 42 pilots, to rich. 38 and 40 on the way. They are super responsive though. Impressed already!!!

Broke the new engine in with the bs34 this weekend. My old one i yanked out musta been worn. 670cc, new trans, rebuilt clutch hub, elephants feet, upgraded clutch basket bearing. Deleted estart system. Forgot how nice it is with no leaks, power and smoooth shifting.
 
Will these EX 500 carbs out perform my 78 carbs. Which are supposed to be the best of the BS 38's.
 
So far, after a night of tuning. 138 mains, needles on 3 with a very thin shim, and 38 pilots. Screws set roughly between the to rich and to lean setting. Bike feels pretty good. Nother test ride tomorrow. Wicked throttle response from these carbs!

Oh yeah, commando mufflers, mikes head pipes, and uni filters.
 
Alright fellas, i cant get the mid range right at all. Idles fine on 38, responsive mix screws. Float height is close to bowl seam, like right there on both carbs. 138 seems to work fine around 6000 rpm. But needles on the richest setting still wont pull cleanly. I tried every notch. Suggestions?

Pamco, with e advance, mikes head pipes, commandos, unis, jbm boots. Charges fine, fresh engine just broken in. Carbs synced.

On the leanest needle settings, you can tell its lean, and no good. Around 3 it defietly cruises better. But from notch 3 to 5 when i get on it, it definetly isnt right. Plugs acrually look a nice color too.. so i wanna say to lean still? Im about 1900' a.s.l incase anyone wants to know.
 
CDNTX650 said:
Alright fellas, i cant get the mid range right at all. Idles fine on 38, responsive mix screws. Float height is close to bowl seam, like right there on both carbs. 138 seems to work fine around 6000 rpm. But needles on the richest setting still wont pull cleanly. I tried every notch. Suggestions?

Pamco, with e advance, mikes head pipes, commandos, unis, jbm boots. Charges fine, fresh engine just broken in. Carbs synced.

On the leanest needle settings, you can tell its lean, and no good. Around 3 it defietly cruises better. But from notch 3 to 5 when i get on it, it definetly isnt right. Plugs acrually look a nice color too.. so i wanna say to lean still? Im about 1900' a.s.l incase anyone wants to know.
Click to expand...

Which needle are you running? I know there have been a few different ones that work. Those being jjj, gjh and gfh. Although they all have their little differences.

Never mind the question I read your earlier post about having the jjj needles. Does it seem to get better the more you raise the needle? You could try to go up to a 140 main (that is actually what I run and I think I am a little rich above 5500 but I am using different needles).
 
There is a chart on jetsrus that shows the different needles and their relationships as far as leaner and richer goes. It sounds to me like you are talking about the upper mid range. I myself am running the iirc the gfh on the second clip position from the top with a 38p and 140m and I seeing a bit of breakup above 5500 now that things have cooled down a little bit down here. I remember a little bit about a discussion regarding the gfh and gjh needles. I know just enough about needle specs like taper, length and diameter to be dangerous so I would look for MrRiggs posts and see what his last setup is as he was the one that figured out using the pwk needles and did the most testing of different needles. Sorry I couldn't be more help.
 
Well, i think ill resort back to my bs34 for now. They have only caused me grief in one area, and that is overlap. 45 pilot, 140 main, and since they are murican non adjustable needles i cant make it 100%. I thinned a step out of the plastic donuts that they sit on, and its better, but anymore makes a lean surge which maybe a 47.5 pilot might fix. Think ill try the canadian needle and jet, and see if the proper taper and adjustablility can get rid of the rich condition. I can almost get rid of it with a 137.5 main or stock pilots, but it is to lean north of 6k and wants the 45 pilots. So i think those needles are the ticket.

Later in the next riding season, ill invest in a few other needles for those cvks and play around. Our riding season is really so short, wish had alot more time to play.
 
That will be adjusted above then. Doubt ill get out again this season on them. But ill add it to my list of checks now that they are back off. Would be awesome if that was the problem.
 

Similar threads

DogBunny
cracked carburetor -- thoughts?
Replies
18
Views
625
DogBunny
DogBunny
ForestHasAnXS650Too
New-Old XS650 Special journey - My initial problems
2
Replies
22
Views
621
jetmechmarty
jetmechmarty
ForestHasAnXS650Too
New-Old XS650 Journey - Carb exploring and wrong parts, pointers?
Replies
6
Views
194
5twins
5twins
G
Weird Clutch Issue
Replies
9
Views
220
Jim
Jim
E
Clutch, cam chain questions,
Replies
2
Views
170
Wingedwheel
Wingedwheel
Back
Top