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super_dave438

Help!!! 07 wr450

16 posts in this topic

I have a 2007 WR450, it has had all the mods done ( before I bought it ) it is very low hours ridden. I have been having the problem of it cutting out most of the time, tried to jet it but still would do the same. I found out the automatic compression release was sticking on, so I took the spring off and ran really good for one day ( I planned on replacing all parts when I got back from riding in the mountains ) , the next day I changed the air cleaner, checked the plug to make sure the jetting was good and filled it with gas, I took off and went about 100 feet and it started cutting out again only worse this time, I can only go half throttle ( sometimes it run perfect ) and if I would hit a dip it would almost die. I acts like it is hitting the "REV" limiter at half throttle, I took the carb off cleaned it and found nothing in it. Any idea's what could be wrong?

Thanks,

David

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I have a 2007 WR450, it has had all the mods done ( before I bought it ) it is very low hours ridden. I have been having the problem of it cutting out most of the time, tried to jet it but still would do the same. I found out the automatic compression release was sticking on, so I took the spring off and ran really good for one day ( I planned on replacing all parts when I got back from riding in the mountains ) , the next day I changed the air cleaner, checked the plug to make sure the jetting was good and filled it with gas, I took off and went about 100 feet and it started cutting out again only worse this time, I can only go half throttle ( sometimes it run perfect ) and if I would hit a dip it would almost die. I acts like it is hitting the "REV" limiter at half throttle, I took the carb off cleaned it and found nothing in it. Any idea's what could be wrong?

Thanks,

David

Could you be more specific about 'all the mods'?

- Jetting specs?

- Have you changed the plug? You can't tell by looking if it's good.

- Plug wire cap connection?

- Coil ground wire?

- Battery terminals tight?

- Hot start cap leaking?

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Starter jet 65

Pilot 45

Mian jet 158

I have check all you said except the hot start cap I will check it tonight after work, also tried 2 brand new plugs just in case one was bad. All the mods that was done is all of the California emissions was taken off. The gray wire was cut, the air induction system was taken off, has a FMF power core 4 pipe, also has FMF jet kit. Thanks for any input .....I am pulling out what little hair I have left..

Thanks,

David

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I'm having the same problem. 2009 WR450 bought with mods done. Ran great for a year until I broke my leg. Sat for 3 months and now has this cut out under load on the mid & top end.

Things I've tried:

1. Cleaned the carb 2 time myself

2. rejetted with same problem, so went back to how it was before. cleaned it again (3rd time)

3. New plug

4. New stator

5. new coil

6. tried to disconect the TPS with no change

7. Checked valves. They where spot on.

Anyone have a CDI I could try in SoCal? I'm ready to part this thing out :smirk:

Edited by DrewRanch

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Starter jet 65

Pilot 45

Mian jet 158

I have check all you said except the hot start cap I will check it tonight after work, also tried 2 brand new plugs just in case one was bad. All the mods that was done is all of the California emissions was taken off. The gray wire was cut, the air induction system was taken off, has a FMF power core 4 pipe, also has FMF jet kit. Thanks for any input .....I am pulling out what little hair I have left..

Thanks,

David

Not your problem, but 45 sounds too big for the pilot. I run either a 40 or 42 depending on temps and elevation. Follow the procedure in the sticky and you will probably find you need to go down a size.

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I have a 2007 WR450, it has had all the mods done ( before I bought it ) it is very low hours ridden. I have been having the problem of it cutting out most of the time, tried to jet it but still would do the same. I found out the automatic compression release was sticking on, so I took the spring off and ran really good for one day ( I planned on replacing all parts when I got back from riding in the mountains ) , the next day I changed the air cleaner, checked the plug to make sure the jetting was good and filled it with gas, I took off and went about 100 feet and it started cutting out again only worse this time, I can only go half throttle ( sometimes it run perfect ) and if I would hit a dip it would almost die. I acts like it is hitting the "REV" limiter at half throttle, I took the carb off cleaned it and found nothing in it. Any idea's what could be wrong?

Thanks,

David

Did it just start doing this? Did you change anything? It's been really hot out, does it happen worse when it's hot outside? I had a similar problem that wound up being the ignition coil, but that is expensive to just try.

If it was running fine and now it's not, that's not jetting.

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- If it runs fine on the stand, all rpms, it is most likely not jetting.

- If it runs fine on the ground until a certain rpm, it is most likely the CDI.

- If it runs fine on the ground, until a certain load, it is most likely, a harness or ground issue, and maybe still the CDI.

I would pull apart every connector, and de-corrode and di-electric grease them all, including the grounds and CDI molex plugs.

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I checked the boot and its good, I did unhook the TPS and now I have full throttle and is strong no cutting out, but now in the midrange it will burble and cut out, any thoughts??

David

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Ok plugged it back in and its still the same, better but midrange still cuts out just like before I unplugged the TPS!!! I GIVE UP!!!

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Ok plugged it back in and its still the same, better but midrange still cuts out just like before I unplugged the TPS!!! I GIVE UP!!!

The Throttle position sensor tells the CDI how to map ignition based on throttle position and rpm.

If you unplug the TPS and it gets better at acceleration, you have a bad CDI.

If it just gets better at constant throttle steadiness, this is a normal symptom of the stock CDI, and cannot be fixed without a aftermarket ignition.

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Well this one even stumped the "Tech's" at our local Yamaha dealership..... they could NOT find anything wrong, they went from "carb" problem to "stator/CDI" problem. SO...... I once again took it on myself and found the problem ( by luck )....... Just a FYI to all.... next time you change your needle setting to make DAMN sure you get the spring back in that goes between the needle and cap!!! " Shade tree mechanic error"!!! Now about the automatic compression release, they had no explanation for the malfunction on it either. I took it all apart cleaned it and so far it is working PERFECT ( I will keep my fingers crossed )!!! I want to thank for all the input on what could be wrong....

David

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Well this one even stumped the "Tech's" at our local Yamaha dealership..... they could NOT find anything wrong, they went from "carb" problem to "stator/CDI" problem. SO...... I once again took it on myself and found the problem ( by luck )....... Just a FYI to all.... next time you change your needle setting to make DAMN sure you get the spring back in that goes between the needle and cap!!! " Shade tree mechanic error"!!! Now about the automatic compression release, they had no explanation for the malfunction on it either. I took it all apart cleaned it and so far it is working PERFECT ( I will keep my fingers crossed )!!! I want to thank for all the input on what could be wrong....

David

:smirk::bonk::p:bonk::(:bonk::lol:

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Well so much for working "PERFECT" now its back to mid range cutting out, I have the FMF jet kit that was put in it ( before I got it ) I found out it does have the FMF needle but the stock jets, I heard you HAVE TO HAVE THE FMF JETS in order for the needle to work right. It still cuts out "HARSH" in mid range, almost like you are pushing the kill switch randemly, I guess I will order the FMF kit so I have the right jets if that don't work guess I will change the Stator and see what happens if not ITS GOING TO UP FOR SALE!!!

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I gave up along with the Dealer, I bought a 09 KLX450R man what a bike it is, don't have the punch my WR had but atleast it runs and runs GOOD!!!

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