Ninja EX500 carbs on an XS650?

[xs650dreamer]

alright man. i have getting some vm36 tuned in ill see how they do but if i decide to switch over to these carbs, ill be well informed. thanks for the info

 

[scabber]

Good luck on the VM 36. The CVK carbs are great carbs and as Mriggs said all the needles worked and ran well. The trouble with changing needles midstream so to speak. Hard to tell what runs better. The JJJ worked really good seemed to pull harder.

 

[derrickjeff]

were can i get jets for my cvk keihin carbs.the carbs are off a kawasaki ER5,fitted them to my xs650,it will run but only on choke.the bad starting was an electrical fault.

 

[derrickjeff]

has any body fitted one of these pit bike hydraulic clutch kits,if so are they any good.

 

[pekka]

Try Allens Performance in the UK. Thats where I got mine.

Pekka

 

[pekka]

Proper test run today. 20km's. Still need to check float levels, sync and adjust mixtures.

Still some hesitation when cruising with very small throttle opening (about the first 1/8th of the throttle travel). Seems it's not really sure if it should go or not. Little black smoke when revving the bike in neutral. Plugs black and sooty. Maybe the #40 pilot is just too big.

Fast WOT acceleration was great! No hesitation or surging just nice steady pull.

Pekka

Setup:

• Stock bore
• Light porting
• 1 1/2 turns on the mixture screw
• #40 pilot
• #140 main
• HKJ needle 4th slot from top
• gutted Dyna mufflers
• 35mm ID 2-to-2 pipes
• Pipercross foam filters
• 50mm piece of 50mm ID rubber hose acting as "velocity stack"

 

[pekka]

I'll continue my monoloque...

Checked the float levels. Left side ok. Right side about 6-7mm too high! Actually not sealing at all. Overflowing. I just put in new needlevalve from a repair kit a week ago.

Removed, cleaned, tried again, still leaks, repeat, leaks, put in the old worn out OEM valve, does not leak, fuel level ok. Another

Also the new float bowl gasket had swollen so much it was nearly impossible to put back on. I'll get OEM spares next time...

Will test drive tomorrow.

Pekka

Proper test run today. 20km's. Still need to check float levels, sync and adjust mixtures.

Still some hesitation when cruising with very small throttle opening (about the first 1/8th of the throttle travel). Seems it's not really sure if it should go or not. Little black smoke when revving the bike in neutral. Plugs black and sooty. Maybe the #40 pilot is just too big.

Fast WOT acceleration was great! No hesitation or surging just nice steady pull.

Pekka

 

[ippytattoo]

One thing I have done to all of these older carbs when i take them apart is to use a little piece of 0000 steel wool on the end of a q-tip turned by hand and polish the sealing surface of the needle valve seat. It removes any varnish that may be there and also smooths out the surface of any minor imperfections.

 

[XSLeo]

I finally put the EX500 carbs on my 75 today. It's been awhile since I got them and set them up. I can't recall how they are and I can't seem to find my spare parts. All that's together somewhere.
Got them on and found the float bowl gaskets leaked a bit. Pulled carbs, found a bit of dust in things. As well as float bowl gaskets/ O-rings bad. The leak stopped after a bit of gas soaked the gaskets.
On to the test ride, very nice. Started right up after the carbs got full. Idled well. A quick blip of the throttle revs came up very quickly. Exhaust sounds a bit throatier.
Out on the road the WOT pull was great, mid range pull was great, pull from idle was great.
The transitions from one range to the next are smoother than the BS34's. This improved the drivability.
I'm very pleased with the way it ran.
I topped of the tank and did a 105 mile ride on 2.1 gallons of gas. That's 50 per. About the same as with the BS34's. It may be better once I get used to the new carbs. You know how it is, the first few tanks never get the mileage, to busy testing the improvements.
The set and tuning was easy, much better than the BS carb, 38's or 34's. Being a newer carb and a better design I think they are a very good upgrade.
Leo

 

[troopthrowback]

Thanks for the report, xsleo! Now of only you callus remember your jetting and needle setup specs....

 

[mrriggs]

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.

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.

 

[troopthrowback]

Wow, thanks for sharing! Those aluminum ones would likely polish up really nicely. Much brighter than the stock ones, anyway ; )

Thanks for doing the homework on the cross reference.

 

[pekka]

Will test drive tomorrow.

Problem solved. No hesitation now that the float levels are correct. Twist and go!

Pekka

 

[Maurice]

Mrriggs, man, I felt guilty for letting my bike get dirty, you make me feel a lot better

Can you share a bit more about your experiment? Curious minds...

Cheers

 

[mrriggs]

Mrriggs, man, I felt guilty for letting my bike get dirty, you make me feel a lot better

Hey now, I wash this thing once a year whether it needs it or not.

Can you share a bit more about your experiment? Curious minds...

Cheers

I plan to fit a sensor so I can record the slide position during dyno pulls.

 

[troopthrowback]

Washing? Why?

 

[56nomad]

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.

I reckon those flanges look really delicate and likely to distort if you're not careful. You'll have to have a soft touch with the screwdriver. I'd always be thinking, "Are the screws tight enough?" or "Are the screws too tight". Me, I'll stick to the black plastic ones - nice and rigid and with locating spigots. But as they say, "Y'pays y'money, y'takes y'choice!"

 

[mrriggs]

I reckon those flanges look really delicate and likely to distort if you're not careful. You'll have to have a soft touch with the screwdriver. I'd always be thinking, "Are the screws tight enough?" or "Are the screws too tight". Me, I'll stick to the black plastic ones - nice and rigid and with locating spigots. But as they say, "Y'pays y'money, y'takes y'choice!"

I had that same thought originally but, after putting them on, I realize that the extra thickness is not needed.

The flanges are flat on the carb body, metal to metal. There is no gasket or diaphragm between them that can squish down and allow the flanges to distort.

These are vacuum chambers so the only force they will experience is atmospheric pressure pushing down on them.

There are locating dowels on all four of the bolt holes.

I put these covers on with the same care as the plastic ones. Hold cover down firmly with one hand and start all the screws. With a criss-cross pattern, tighten the screws, slowly and evenly. Do not crank them down tight, just snug enough that they won't fall out.

My only complaint is that it is harder to start the screws. The screws are shorter and you don't have the deep hole in the cover to guide them straight.

 

[XSLeo]

I found my spare parts. I have 38 pilots, 138 mains, JJJ needles #3 slot, 1 3/4 out on the air screws.
Very pleased so far. I'll try some of the other jets and needles just to see what may be better.
Leo

 

[56nomad]

I had that same thought originally but, after putting them on, I realize that the extra thickness is not needed.

The flanges are flat on the carb body, metal to metal. There is no gasket or diaphragm between them that can squish down and allow the flanges to distort.

In that case, don't just stand there, get polishing! Oh, forget that, I remember what you said above:

Hey now, I wash this thing once a year whether it needs it or not.