Ninja EX500 carbs on an XS650?

I believe the last post i saw from MrRiggs about his setup he was using the jjj needles but I don't remember what slot he had the clip in. I am using the gfh but there are a whole slew of jets in the jjj range that you could use to try and address issues with the different areas of the mid-range if you have the pilots and mains where you want them.
 
Hey Guy's ---Try post #454, Mrriggs describes his set up. tim
 
mrriggs said:
Just keep massaging it, you will find the sweet spot.

I was running GJH needles on clip #5 and getting 55-56 mpg. It was on the ragged edge of too lean. Still rideable, not surging, but unnecessarily lean.

I switched to GFH needles on clip #3 (1.5 steps richer). It was noticably "fat", both sound and feel, and the mileage dropped as low as 52 mpg.

Changed to #2 with a shim, bit cleaner and gained one or two mpg.

Removed the shim so I'm on #2 now (still GFH needle). It sounds and feels very good but I haven't got a good measure of mileage yet.

I wish they made a GFJ needle since the "H" diameter isn't quite as crisp on tip-in as the "J" diameter. I tried ordering GFK needles from Jets-R-Us but they sent me the wrong ones and wouldn't correct their mistake unless I payed shipping to return the unusable needles.
Click to expand...

To keep it current. Good find.
 
Here's a list of what I compiled from people's results with their jetting choices. Hope this helps some people, I'm still not 100% certain what I'll run, but it will probably closely resemble mrriggs. This list is not complete, but I think it helps to start showing a trend for decision making.

Well apparently the site won't allow my Excel or word file, so here's a PDF of the results. PM me your e-mail and I'll send you the excel file to play with on your own.
 

Attachments

  • EX Jetting.pdf
    113.3 KB · Views: 325
wannabridin said:
Ya, i searched and either scanned over it or it's not here... Anyone else have any luck? I'll send him a PM
Click to expand...

Post #312
mrriggs said:
I was looking for a spare set of carb tops that I could hack up for a little experiment. A search for EX500 tops didn't turn up much. Cross referencing part numbers showed that the same tops were used on CVK36 carbs. That really opens up the possibilities. A lot of bikes had CVK36 carbs, including the newer Bonnevilles.

I ended up buying some tops from a ZX750, assuming they were stamped steel. I was surprised to find that they are stamped aluminum. These things are light, less than an ounce each. Almost half the weight of the plastic caps.

CVKtops1.jpg


I'm not sure if I like the looks better than the plastic tops. Figure I'll run them a while and see if they grow on me.

CVKtops2.jpg
Click to expand...
 
those are the ones i came across too! might be worth a shot to see if they fit, couldn't hurt to try!! thanks for the info. I found some brass ones on e-bay too that looked nice.
 
Hello wannabirdin! The "140/40/HKJ/4th" setup was propably mine. The off-idle hesitation was cured by raising the needles higher. 5th clip wit 0.5mm shim if I remember correctly.

Pekka

wannabridin said:
Here's a list of what I compiled from people's results with their jetting choices. Hope this helps some people, I'm still not 100% certain what I'll run, but it will probably closely resemble mrriggs. This list is not complete, but I think it helps to start showing a trend for decision making.

Well apparently the site won't allow my Excel or word file, so here's a PDF of the results. PM me your e-mail and I'll send you the excel file to play with on your own.
Click to expand...
 
Just started going through a set of CVK34's, starting with thorough cleaning, new float needles, new bowl gaskets, new idle mix screw O-rings before putting in any new jets/needles. The Viton O-ring that fits BS34 mixture screws (McMaster-Carr #9263K511) fits these CVK screws also.

I did notice that the openings for the idle mix in the carb bores are two quite different sizes - left carb, maybe 2.5mm or so and right carb, 1mm at most (see attached pic). I've never seen this on twin-carb sets before - is this correct for these carbs or buggered up by some PO? I looked at all the EX500 carb pic's that I could find on eBay this morning, and found only two that showed this area. One in sharp focus showed the same small size hole on both carbs; the other pic was very grainy but seemed to show the larger size hole in the bore of the left carb. If anyone can enlighten me, I'd sure appreciate it. (The attached pic shows my carbs, not the eBay ones.)

I'd like to thank all who "pioneered" this conversion and worked out the usable combinations of jets and needles, cable hookups, etc. I'm looking forward to having mine ready to swap when the weather warms up enough to work in my garage.
 

Attachments

  • img_1045.jpg
    img_1045.jpg
    212.1 KB · Views: 216
The small should hole should be the same in both carbs. I would think someone might have fucked up that carb drilling out a stuck mixture screw.
 
aldo5468 said:
Just started going through a set of CVK34's, starting with thorough cleaning, new float needles, new bowl gaskets, new idle mix screw O-rings before putting in any new jets/needles. The Viton O-ring that fits BS34 mixture screws (McMaster-Carr #9263K511) fits these CVK screws also.

I did notice that the openings for the idle mix in the carb bores are two quite different sizes - left carb, maybe 2.5mm or so and right carb, 1mm at most (see attached pic). I've never seen this on twin-carb sets before - is this correct for these carbs or buggered up by some PO? I looked at all the EX500 carb pic's that I could find on eBay this morning, and found only two that showed this area. One in sharp focus showed the same small size hole on both carbs; the other pic was very grainy but seemed to show the larger size hole in the bore of the left carb. If anyone can enlighten me, I'd sure appreciate it. (The attached pic shows my carbs, not the eBay ones.)

I'd like to thank all who "pioneered" this conversion and worked out the usable combinations of jets and needles, cable hookups, etc. I'm looking forward to having mine ready to swap when the weather warms up enough to work in my garage.
Click to expand...

that looks like a drill bit oops to me. Both holes in my cvk34 are the same size.
 
Why do you want to remove those screws? Leave them in, no need to separate them. I just dunked mine in pinesol worked well just don't leave them too long.

If you need send me a PM I think I have some with allen heads, none of that JIS/phillips crap.
 
You have an allen screw that small? And I removed them to fully clean the carbs, which is what I do with any carb that I buy off e-bay. Soda blast everything to remove varnish and road grime and then a full ultrasonic clean in Simple Green Pro-HD (Al safe). Then some index drill bits and carb cleaner through all passages followed by compressed air. Well worth the effort.

If you have some pics of these butterfly shaft screws, please post them up and where you got them, i bet lots of people would benefit. They're tough to remove because they're designed to stay put ones installed. If I went with a regular threaded screw, you'd have to put some blue loctite on it at minimum to keep them from backing out and causing your carbs to stick open or close.
 
I used those on my BS38s when I still had them, I am not sure they will fit the CVKs (although I have used them on Honda SOHC carbs on the choke) but I don't mind sending you some I have a full box. Will take pictures later today.

Yes if you don't stake the ends or loctite them in place the least of your worries is that the throttle gets stuck open...
 

Similar threads

DogBunny
cracked carburetor -- thoughts?
Replies
18
Views
547
DogBunny
DogBunny
ForestHasAnXS650Too
New-Old XS650 Special journey - My initial problems
2
Replies
22
Views
548
jetmechmarty
jetmechmarty
ForestHasAnXS650Too
New-Old XS650 Journey - Carb exploring and wrong parts, pointers?
Replies
6
Views
175
5twins
5twins
E
Clutch, cam chain questions,
Replies
2
Views
148
Wingedwheel
Wingedwheel
J
Carburetors Mikuni ????
Replies
3
Views
477
Jan_P
J
Back
Top