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-   -   07 klx250s carby/jet question (https://www.kawasakiforums.com/forum/klx-250s-71/07-klx250s-carby-jet-question-39192/)

Tri-Polar 10-31-2012 01:10 AM

07 klx250s carby/jet question
 
Hey guys. I just finished messing with the bike. Dropped about 5.6kgs of fat so far and decided to do some mods. I got myself a twin air filter, KDX200 snorkel, Q4 FMF slip on and a dial a jet to suit. Apart from no one in Australia hearing of the dial a jets im pretty stuffed. Im also new to dirt bikes and have no idea on how to set it right.

So i got all the new parts installed and turned the dial one notch richer. I then went for a ride. Apart from it being a struggle for it to stay running for its first start in a week or so, it ran good. Untill upon deacceloration i was getting alot of back firing. As well as when i tried to pin it whilst in the higher gear then i should have been, it found a flat spot then took off.

I believe the carby is stock and hasnt been touched. Also i had it out and went looking for the 2 holes in the slide but found none? With the information i have provided, do i need to lean it out more or richen it up?

Thanks for your help in advance.

IDRIDR 10-31-2012 03:11 AM

Congrats on losing the fat!

There's at least one or two members here with dial-a-jet experience. I'm not one of them. Normally, with the mods you did, most of us tend to bump up the main jet to prevent lean running. That's where the dial-a-jet is supposed to work its magic, but I can't tell you anything about DAJ settings, or if you still need a larger main jet. Hopefully someone else can help.

Is your Aus carb needle adjustable? Ours here in the states are not and some of us get the Kaw N1TC or DynoJet adjustable needle. That may help with the flat spot.

Did you remove the plug from the pilot/idle mix screw so that it can be adjusted? Adjusting this mix screw out (richer) could help with the decel popping. But if you have any leak in the exhaust, such as at the header/Q4 connection, decel popping is very likely even with a perfectly set carb.

Sharan 11-01-2012 02:09 AM

Aussie needle (N1RX) is not adjustable, it needs to be shimmed by spacers to 1.5mm. Also the slide needs to be drilled to 2.8mm.

I had carb "done" plus aftermarket exhaust + UNI air filter by local Kawi dealer. The bike was running like a wounded dog, popping on decel like mad. So I took it to the other mechanic who diagnosed the problem without even looking at the bike- missing hole in the slide and something wrong with needle setting.

So I left bike with that guy - he was right, he drilled the slide and shimmed the needle. That's what Kawi dealer was supposed to do. Now bike is much, much better, very responsive. The popping on decel was reduced, but it is still there, so I'm thinking that this idiot Kawi mechanic did not put a sealant between header and slip-on and I have an air leak there. :mad: Any easy way to confirm that without pulling the exhaust apart?

I should go back to Kawi dealer and complain about his s***ty job. Although it is also the biggest bike accessories shop around but I decided not to go there anymore, no more bucks from me, ever.

Edit: The pilot/idle mix screw is not plugged on aussie carbs. But the access without removing carb is almost impossible because the carb de-icing plumbing runs underneath the screw hole. Why did Kawi decided to make de-iced carb for Aussie climate is beyond me.

linkin5 11-01-2012 03:42 AM

Some bikes pop and some don't it doesn't have to be a jetting issue. Mine with the dynojet kit has none at all.

IDRIDR 11-01-2012 04:35 AM

Sharan,

Thanks for posting. Hope that helps the OP. I didn't know the de-icing unit messed with adjusting the pilot. You Aussies get a better performing bike, but why the de-icing stuff? Are you flying with them?

Don't know what to suggest on the exhaust except for pulling it apart and sealing it up right. My FMF header and HMF slip-on leaked there without sealant, and the stock header/HMF setup was even worse. Now have FMFQ4/FMF Powerbomb and those buggers fit together tighter than...well...let's just say they are tight. I used RTV high-temp sealant on the prior setups with decent success. Read the directions. Apply, let set for a day, then tighten town, set, then run.

Sharan 11-01-2012 10:12 PM

Thanks for suggestions IDRIR. I most likely do it sooner rather than later.

One would think that de-icing carby would be more appropriate for USA/Canadian models.

There are places in Australia where temperature drops below freezing point, but those regions are pretty remote and I doubt there are many KLX's roaming these places. It is not difficult to remove de-icing plumbing, but still some plugging hardware and hose joiners are needed and because this thing does not impact performance, people just leave as it is. Just an extra cooling circuit that can go wrong and start to leak in the middle of nowhere.

Tri-Polar 11-02-2012 03:21 AM

Thanks for the replys guys. I had time to play with it today. I set the dial ajet to the middle setting today and went for a ride. Flat spots everywhere and no decel pop. So then i tried the one setting richer setting (the same as i had it set to when i installed it) and not as bad flat spots, more decel pops. I then tried 2 settings richer then the middle one (one setting richer then last tried) and about the same amount of flat spots and more decel poping. I dont understand whats happening?

I thought dial-a-jet was ment to make things easier?

RimBender 11-02-2012 03:48 AM

you need to liberate your idle mix screw and tune it to help the off throttle popping. It being a bit lean will make the heat that ignites the unburt fuel in the exhaust. A lean problem

if you chopping the throttle closed from a certain throttle position that makes the popping worse. That throttle position may be too rich, adding to the unburnt fuel. A rich problem,

Not a fan of dial jet (or other variants) but have tuned them. They will fuel where the main circuit is and overlap more into the needle. So you may be better using a stock un shimmed needle, and closer to a stock size main jet.

If you add fuel with daj to make the wfo setting work well, and it make the midrange too rich. Go to a bigger main and turn the daj down a little.

The aussi slide fix should be fine? (they don't do that here)

IDRIDR 11-02-2012 04:06 AM

The way I understand it, the DAJ is designed to keep the motor from running lean at wide-open throttle or near it, but it's not going to necessarily do much at idle and mid-throttle. I think you need to work on getting the pilot jet size and pilot mix screw correct, then work on needle settings for the mid-range flat spots, which may be due to a lean condition and the needle needs shimmed or replaced with an adjustable type. Hope you get it all figured out, and let us know if you do and what it took.

Tri-Polar 11-02-2012 04:07 AM

Thanks for the reply. Everyone tells me its getting to much fuel. Tho it gets worse when i use the lean settings. So im very confused. No matter what setting, it has its positives and negatives. Im seriously thinking of ripping the carby out and either jetting that or saving my bikkies and getting a Mikuni TM33 and jet that. The TM33 has been mentioned just as many times as iv seen dial-a-jet. The only reason i got DAJ was because so many people had used it and was stated it was the easiest and accurate way to compensate for the mods. Which is why im disappointed about how im going as its not cheap to get things from the states and the wait times are killer. It doesnt help that i now have spend all my bikes money on parts and didnt allow extra cash from issues like these.

However the one people talk about from B & B Cycle Restoration cost just under $400USD and thats before postage. I honestly dont want to spend that much coin on a carby...


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