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new 06 cr125 fouling plugs

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My caliper says:

Blue = 2.68 mm

Red = 2.71 mm

I think I may be able to get a more accurate reading...

I thought you were using needles from some other kit? If those needles you measured are the same needles that comes in the CR125/250 kit, I'm wondering why you measured the Red needle at 2.71, when James Dean, the guy who made the needles, tells me the Red needle measures 2.68 (I have an email from him too).

My calipers tells me the stock needle is 2.68 and the 6dgy29-69 is 2.69, so I believe my caliper when it tells me the blue needle from the CR250 kit is 2.65, which is too rich on the needle, but the tapers could actually be leaner than OEM.

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As I noted above, I transposed the estimated red and blue diameters and they are now corrected above :thumbsup:. The fact that they could be reasonably approximated in the JD Spreadsheet using DDK and DDL needles was stated to me in an e-mail from James, so I'll put the caliper on them tonight. If the blue is 2.65 mm, that would be an extremely small diameter in my experience...

HOLD ON! .....

Do NOT try to compare the Keihin carburetor needles' diameters to the Mikuni needles. The needles are not the same design, and the diameters are different and tapers and located at different heights relative to the needle clip positions.

The JDJetting spreadsheet is used for Keihin needles, not Mikuni. Referencing an L1 dimension has no relevance to Mikuni carburetor needles.

The CR125R jet kit needles made for the Mikuni TMX carb can have a smaller diameter than stock in some cases and still run cleaner, because the tapers are located to run leaner at low speeds without compromising the mid-range.

The kit for the CR125 has a pilot jet, 2 needles, and 4 main jets. The combination will stop plug fouling in the CR125's. I can guarantee that statement, or we'll refund your money if you're not satisfied. I went through weeks of iterations to find a balance between plug fouling and crisp jetting. You could wear out the carb screws making changes if you don't have the right parts, ... and I fouled many plugs to get there too.

Thanks,

James

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Do NOT try to compare the Keihin carburetor needles' diameters to the Mikuni needles. The needles are not the same design, and the diameters are different and tapers and located at different heights relative to the needle clip positions.

This is the reason for the disclaimer from above...

(at least they are for PWK's).

Point below says it all.

If you'd like a good chance of riding without changing plugs, I'd go with the JD kit...

And I do mean get the entire kit :thumbsup:.

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ok i got the jetting kit, im using the red needle on the 4th from top clip position, #35 pilot, #420 main, air screw 1 3/4 turns out...the bike runs much better

but when i go from idle to wide open throttle it bogs, i still have white smoke and oil coming out of the exhaust...im wondering if its just burning off all the gunk from before?

the only after market part i have installed is v-force 3 reeds.

Bigtymer, this is interesting... I have an '07 CR125 on wich i installed a JD kit+Rad Valve. I used the red needle in the 3rd position, with the recomended 420 main. When i was riding in a higher gear, with low rpm, and instantly opened the throttle full open, i had a huge bog! I thought it was running too lean, so i went to the Blue needle, with the clip in 3rd position... Same result! I think the problem is that the main jet is too big... because they advise to go 1 or 2 sizes down on the main with an aftermarked reed. I'm waiting on some better weather, and will try the red needle in 3rd, with the 410 main (or even lower). Hopefully this will help!

Let me know if you have some improvements with your jetting!

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I went to the blue needle on the second from top clip position and the bogging stopped completely. I havent really had a chance to ride my bike since I installed the blue needle, but I road it down the street and I couldnt get it to bog even if I tried now.

I'll probably be going down on the main jet too (from 420 to 410) because I'm about to put on a pro circuit works pipe and r304 shorty silencer.

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I had that exact same problem with my 06 i bought leftover 5 months ago. I switched to a 410 main and a 37.5 pilot with the main on the second clip position. MInd you i was riding this bike in the winter which just shows how crappy the stock jetting is. So far i have run the same sparkplug the past 5 hours and its a nice cocoa brown color when i check it.

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Bigtymer, i installed the blue needle in 2nd from top position, and my bog increased. What actually makes sense, because the red needle in 4th should be richer in mid than the blue needle in 2nd.

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here's what JD told me earlier about RED vs. BLUE ... "The clip position is not an absolute comparison in optional needles, as the Red needle is bigger down it's entire length and NEEDS a lower clip position to match Blue #2 in the mid-throttle." ... if that helps ...

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well this might sound stupid, but make sure the spark plug connector is on all the way, i checked my spark plug after i installed the blue needle and i realized mine wasnt pushed down all the way

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That wouldn't affect any of the lean issues... It sparks, or it doesn't!

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ideas on jetting for pismo beach, ca? im at 410 main, stock pilot blue needle middle clip.

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Im at my wits end with the fouling problem on my 05 CR 125. The bike runs fine with a BR8EG plug, but when running the stock plug (BR9EG) it will fowl in minutes.

Ive altered the jetting today gone to a 410 main and 50 pilot after looking round the net and also needle clip is in position 2. I just need to know what the air idle screw should be set at and the mixture screw?. I am right in guessing that the idle screw is closest to the throttle slide valve and the mixture screw is the furthest right of the carb as Im getting a lot of oil out the exhaust.

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Im at my wits end with the fouling problem on my 05 CR 125. The bike runs fine with a BR8EG plug, but when running the stock plug (BR9EG) it will fowl in minutes.

Ive altered the jetting today gone to a 410 main and 50 pilot after looking round the net and also needle clip is in position 2. I just need to know what the air idle screw should be set at and the mixture screw?. I am right in guessing that the idle screw is closest to the throttle slide valve and the mixture screw is the furthest right of the carb as Im getting a lot of oil out the exhaust.

Given what I've seen on the 'net, you should be running closer to a 35-40 pilot.

JayC

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Given what I've seen on the 'net, you should be running closer to a 35-40 pilot.

JayC

I actually do have a 40 pilot, but read that everyone was going down from a 55 to 50 and 430 to 410 main and 2nd clip on the needle. I had a 390 main and a 40 pilot and it was still fouling plugs, So thought I would try what everyone suggested, looks like i may have to go back to my 40 pilot. Out of interest how many turns out should the mixture screw be

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Guys, I'm from Melbourne, Australia and have been following your forum with great interest. I have a 2007 Honda CR250R and would foul plugs all the time after one hour of riding. I tried many suggested changes... I also had my local Honda dealer (recommended by Honda Australia), but to no result!!... I kept fouling plugs and at $16 a pop, it was expsenive to ride the bloody thing!!!. then i came across an article by Matt (mcdirtclod posted on 01-03-2008, 04:39 AM), I sent Matt with my set-up details (jets, spark plug, fuel mix, etc.)and he replied with the suggested changes and "BINGO"... problem solved!! the bike runs great...with less "spooge" and no loss of power. Well done Matt!!!

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Steve70 - glad it all worked out and great to see your bike running like it was meant to. Curious about your dealer - not sure i would go back to a guy who can't fix my bike and sells me $16 spark plugs ... keep an eye on your plug, monitor spooge production and twist the grip on the right side of the handlebar. Happy to help - that's why we're all here. Good luck!

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Steve70 - glad it all worked out and great to see your bike running like it was meant to. Curious about your dealer - not sure i would go back to a guy who can't fix my bike and sells me $16 spark plugs ... keep an eye on your plug, monitor spooge production and twist the grip on the right side of the handlebar. Happy to help - that's why we're all here. Good luck!

Matt- the $16 plugs are the NKG indium...all motor bike parts are expensive in Australia. Last week, I bought a pair of Honda decals from "flu" in the USA and even taking the postage into account, it still came out 1/2 the cost than buying in Australia... our dollar against the USD is good value at the moment. Once again, thanks for the advise!!

Regards

Steve

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Steve70 - glad it all worked out and great to see your bike running like it was meant to. Curious about your dealer - not sure i would go back to a guy who can't fix my bike and sells me $16 spark plugs ... keep an eye on your plug, monitor spooge production and twist the grip on the right side of the handlebar. Happy to help - that's why we're all here. Good luck!

Your suggestion being the JD needle? What's your take on swapping to the '03 or '04 stock or rag recommended needles (2.69-2.71mm diameter)?

JayC

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First, the 250s don't seem nearly as finicky as the 125s. Closer to sea level, the stock needle seems to work OK.

Here's what worked for Steve70 ... "32.5 pilot should be the ticket for near sea level. Put the needle clip in the second groove from the top. Air screw should be 1 and 3/4 turns out to start with. 420 sounds about right for the main jet at your elevation. Lastly, go ahead and switch to a BR8ES plug. It's a little hotter and will tend to run cleaner at trail riding speeds. If you still have problems, you'll need to switch to a leaner needle. The red needle in the JD Jet Kit is the real ticket. Oh, I've been riding Honda 2-strokes since 1973 and have always used Bel-Ray or Pro Honda pre-mix at 32:1. I've NEVER had an engine failure. In fact, one of my kids is still riding a 1985 CR125 that's only on it's second piston!!"

Remember, the 32.5 pilot is what comes in the JD kit. My brother-in-law's CR250 was a "once and done" jetting exercise, while we've been wearing out the screws on our 125 carbs ...

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First, the 250s don't seem nearly as finicky as the 125s. Closer to sea level, the stock needle seems to work OK.

Here's what worked for Steve70 ... "32.5 pilot should be the ticket for near sea level. Put the needle clip in the second groove from the top. Air screw should be 1 and 3/4 turns out to start with. 420 sounds about right for the main jet at your elevation. Lastly, go ahead and switch to a BR8ES plug. It's a little hotter and will tend to run cleaner at trail riding speeds. If you still have problems, you'll need to switch to a leaner needle. The red needle in the JD Jet Kit is the real ticket. Oh, I've been riding Honda 2-strokes since 1973 and have always used Bel-Ray or Pro Honda pre-mix at 32:1. I've NEVER had an engine failure. In fact, one of my kids is still riding a 1985 CR125 that's only on it's second piston!!"

Remember, the 32.5 pilot is what comes in the JD kit. My brother-in-law's CR250 was a "once and done" jetting exercise, while we've been wearing out the screws on our 125 carbs ...

hi matt whats the difference in a br8es and br8eg, which is the best to use in my cr 250

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