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Old August 8th, 2015, 07:33 PM   #1
VaFish
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Another Jetting/Carb Question

Ok as my signature block shows I have 2 Ninjettes that I have picked up recently. Got one for me and one for my daughter.

Both had been sitting a while and would kind of pop but would not run.

I got the carbs cleaned out on the 2001 and it seems to be running well. Now I'm working with my daughter on the 1989 which will be hers. I cleaned the carbs and got it running OK, but in top gear, at about 40 mph and from 6,000-8,000 rpm it feels like it isn't getting enough fuel, it bogs down, then picks back up and again, then bogs back down. But if you just give it full throttle and keep accelerating it does fine.

I read around here a bit and was going to try putting a couple washers under the needles and see what that does. I got the top of the carbs off and it has clip adjustable needles. So I'm guessing someone has been in them before. By the look of the jets it was a cave man with a poorly fitting screwdriver and a pair of pliers. Clips are in the third from the bottom slot.

Anyhow I'm reading up on playing with the jets and I see things like main jet is a 102 or 104, or get a 108 and 112. I looked at the jets and they have 094 stamped on them. Are their different types (or markings) on jets or are my main jets that undersized?

I'm guessing best thing is to get stock size jets and a couple sizes up and start from there.

Edited to add: Just found a conversion chart, looks like the smallest Dynojet is a DJ094, so I'm guessing I have a dynojet kit in the bike. Now what is the chance PO drilled the slides like dynojet recommends?
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Old August 8th, 2015, 07:41 PM   #2
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If the bike is stock, the stock jetting, maybe a washer or two under the stock needles.

This is assuming the carburetors have been cleaned and refurbished properly.

If your in need of carburetor services or parts pm @ducatiman

Personally from the age of the carburetors I'd strongly suggest getting them refurbished by @ducatiman Also someone has been playing with them, so who knows what else is out of wack.

https://www.ninjette.org/forums/showthread.php?t=226815




Quote:
I would highly recommend that you DO NOT REMOVE THE AIR BOX, the carburetors on the bike are CV type and need to box to function properly, buy a K&N that fits the OEM airbox(K&N KA-2508 Kawasaki High Performance Replacement Air Filter by K&N Amazon.com: K&N KA-2508 Kawasaki High Performance Replacement Air Filter: Automotive Amazon.com: K&N KA-2508 Kawasaki High Performance Replacement Air Filter: Automotive ) that's the short version.

Long boring but important answer, CV carbs stands for "constant velocity". The function of the carbs is dependent on having a calm reservoir (airbox) from which to intake air at said constant velocity. Pods draw from the turbulent, unpredictable air swirling past them as you ride, which is anything but constant. Other carbs work fine with pods. CV's = no bueno, save yourself the headaches.

Now onto jetting, first you need to tune the idle mixture screws first, I recommend 3 full turns out from bottom as a good starting point, then fine tune them afterwards. As far as buying a jet kit, I personally don't have one on either my 250, or 500 ninjas. I did got up one size on my main jets, due to they are lean from the factory, and shimmed the main needles with a small washer.
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Old August 8th, 2015, 08:07 PM   #3
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MOTM - Jan '16
The pipes are stock. The air filter looks like someone cut it themselves from a piece of green foam rubber and oiled it. But, at least the air box is stock. I'll probably end up putting the K&N filter in it.

Now I'm wondering if I should swap my carbs into my daughters bike to give her something more easily ride-able.
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Old August 8th, 2015, 08:12 PM   #4
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Okay, just keep in mind that a carburetor has consumable parts, float valves, O-rings etc.... If you plan on keeping the bikes, contact @ducatiman and install an inline fuel filter also.

Keep in mind, there is a major difference between a simple cleaning, and full refurbished.
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Old August 9th, 2015, 04:27 PM   #5
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Just a quick recomendation....

Hi guys, I had a lot of issues with my carbs, I pulled them and cleaned them myself, using a guitar string and carb cleaner, checked the needles and repaired the diaphragm on one, which made it work. But, there was something not right, so, Ghost recommended Ducatiman, who also lives in Long Island. I took the Carbs over, to him hoping he would at least tell me what was wrong, but not expecting much from him.

He cleaned the carbs much deeper than I could have ever reached, myself, replaced the diaphragms and even replaced the bowl screws I had stripped. He works amazingly, treating the bike as if it's his own. I Took it to him several times now, on different issues that only a pro can do, but he's more of an artist than a "technician". Bottom line is; My bike is running like New after Ducatiman's work.

So if you have a carb issue or other issues, contact Ducatiman and send him your carbs. Tell him Alex sent you! Thanks Ghostt for the recomendation, Ducatiman is the man!
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Old August 9th, 2015, 04:51 PM   #6
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He has my set right now. Pleasure to deal with too....and very reasonable on price for the work performed IMO.


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Old August 9th, 2015, 04:59 PM   #7
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MOTM - Jan '16
Well I placed one washer under the needle, cleaned it again and put it back together, I also made real sure to get the boots to the air box on properly. Bike is running much better. Still a slight bit of surging around 6,000 RPM but much better than it was.

I have a set of stock jets on order and will put them in when they arrive, but right now the bike is very rideable.
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Old August 10th, 2015, 05:51 PM   #8
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VA-

Strange the carbs would have Dynojet mains but stock needles ?? That may create a strange fueling mismatch, but I'd have to see/listen/ride to ascertain that.

Dynojet may also use shorter than stock diaphragm springs, I've encountered them on stock jetted EX500's...the major just-off-idle miss drove me nuts until I figured it out.

I'm not a fan of mismatching jet kit and stock components.

Beware "hogged out" pilot jets too. Folks have a tendency to over fuel in an effort to create power. Sized "pin drills" (the shanks) can be carefully used to index the pilot openings.

With previous hands in those carbs...I'd urge you to check all internals carefully, returning to a stock baseline, then fine tuning from there....i believe your posts indicate you are on that path.
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Old August 12th, 2015, 07:36 AM   #9
VaFish
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MOTM - Jan '16
Yeah I think getting it back to stock is the best thing, have the jets on order, should be here by Saturday.

This us for a 16 year old girl that is just learning to ride, smooth power and low end is more important than maximum power. When she is ready for more power a bigger bike will be the solution.
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