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06 450 exc Crapping out big time on top.

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It does rev up. But once I get close to the top it starts crapping.

Well I found a brand new pulser coil on fleabay for $40. And I'm going to pick up a plug cap this week so thats where I'm starting.

After that will be the CDI then the coil since the coil seems to be the rarest failure.

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We had this exact same problem on two of our 2008 XCR-W 450's. The bike will start, idle, and rev up to about 1/2 - 3/4 throttle (under load) and then pop, back fire and loose power in all gears above 1/2 throttle. We had this problem through the Baja 250, 500 and 1000. Had to "short shift" the bike to a higher gear to keep the RMP's low in order to go faster... very frustrating when racing!

--The fix was a faulty CDI box. We called the KTM dealer and gave the VIN number from the bike and they sent out a new CDI box and new Iridium spark plug. Put the NEW CDI on bike 1 and it fixed the problem. Then move the NEW CDI to the second bike and it also fixed the problem.

New Spark Plug - LKAR8AI-9

75039093-000

Hope this helps....

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Maybe I missed this but did you check the connector that connects to the wire on the top of the carb? I've had this wire come disconnected on the bike on rides before.

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We had this exact same problem on two of our 2008 XCR-W 450's. The bike will start, idle, and rev up to about 1/2 - 3/4 throttle (under load) and then pop, back fire and loose power in all gears above 1/2 throttle. We had this problem through the Baja 250, 500 and 1000. Had to "short shift" the bike to a higher gear to keep the RMP's low in order to go faster... very frustrating when racing!

--The fix was a faulty CDI box. We called the KTM dealer and gave the VIN number from the bike and they sent out a new CDI box and new Iridium spark plug. Put the NEW CDI on bike 1 and it fixed the problem. Then move the NEW CDI to the second bike and it also fixed the problem.

New Spark Plug - LKAR8AI-9

75039093-000

Hope this helps....

EXACTLY!!!!!!

I'm buying a CDI now that I heard your claim. I know my CDI is different than yours but was it some kind of warranty issue? Did they replace it for free? I know my CDI has a superceeded part number. I'll give them a call tomorrow and see what they say about replacement.

I'm also looking to replace it with a 525sx CDI because I have heard, through searches on here, that the 525sx has a more aggresive spark curve, like the 450sx, but still has a lower rev limiter......and my bike needing the lower rev limit because the 450exc motors cant handle the 450sx rpms.......does this sound right? good idea/bad idea?

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I believe it was a warranty issue. Yes, they sent us a new CDI for free. All I can suggest is you call your dealer and see what they can do for you. Best of luck... Dealers are hit or miss when it comes to warranty stuff. :banghead:

I don't have any suggestions about your 525. I haven't worked on one yet.

Keep us up to date on what your results are!

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I believe it was a warranty issue. Yes, they sent us a new CDI for free. All I can suggest is you call your dealer and see what they can do for you. Best of luck... Dealers are hit or miss when it comes to warranty stuff. :banghead:

I don't have any suggestions about your 525. I haven't worked on one yet.

Keep us up to date on what your results are!

Well mine is an '06 and I didnt get the extended warranty so no go on that.

The warranties are usually 30 days or up to 1 year.

And....I have a 450 exc and wanted to try the 525sx CDI because I have heard that it gives you are more aggressive spark curve with more bottom end snap and still has the lower rev limiter.

Anyways....thats what I got on order....$230. But I can return it if it turns out that the CDI isnt the problem.

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I know this is a long shot idea, but it happened to me on another bike.

Do you happen to use tank foam? You know the stuff that goes inside to keep it from sloshing around? I liked the stuff, but it actually breaks down over time and somehow a bunch of it got past the tank and clogged up my fuel line on the brass fitting that goes into the carb.

Here was the test:

Ride it wide open down a fast road, when it craps out and dies on you immediately turn off the gas. The pull off the 17mm nut under the carb and it if doesn't have fuel or not much fuel, then you have a clog somewhere...

Sounds like you are sure it's electronic at this point, but if you have time and are waiting for parts anyhow.

I also had same kinda problem on another bike and it was just jetting terribly lean, so just go up on the main and pilot 1 step and ride it again can't hurt just to kill time while your waiting for parts?

Good luck and report what happens either way!:banghead:

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Its all rejetted and ran perfectly fine for the past 3.5 years.....then bam.

We'll see.... the CDI comes in this week and I'll test it out.

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Well I jut got my pulser coil in the mail today and its looking like I may not need it.

I'm heading to Malcolm Smith's to pick up my CDI.

I'm gonna test it out tonight I'll keep you all posted.

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Well... was it the CDI?

I say either it was and now he's out enjoy a big ride!?

...or it wasn't and he's still cursing in the garage!?

:ride:

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Well........I was going to go pick up the CDI but I had another errand to run before and they closed an hour earlier than I thought. But today is the day!!! For sure.

I'll pop on here around 9 with the verdict.

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Now I'm starting to feel like a douche. I got held up at work and didnt have time to pick up the CDI. But its Friday and I'm outta the office at 5......then I'm heading straight to pick it up. Hopefully it works cause I got riding plans for tomorrow.

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Now I'm starting to feel like a douche. I got held up at work and didnt have time to pick up the CDI. But its Friday and I'm outta the office at 5......then I'm heading straight to pick it up. Hopefully it works cause I got riding plans for tomorrow.

Don't you know... all Bike Shops close at 4:59pm on Fridays :ride:

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HA.....it took me almost 2 hours sitting in traffic to make it to Malcolms....but I made it............aaaaannnnnnddddddd

IT WORKED!!!!!!

Thanks for the heads up mrstein......I guess we can chalk this up on the list for the guys that say....oh I've never heard of a CDI going bad.

I'm going to play in the dirt tomorrow.

THANKS!!!!

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That's good news!!!!! Post up again after your ride to confirm it was your CDI. Ours would run OK for a short bit.. but after 10 miles or so the problem would occur agan. The new CDI was our final fix.

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Ran great all day yesterday. Ready for my race next weekend.

And my old CDI is not crushed or anything.

Maybe water or something got in the plug and arced something. Who knows.

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