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My Yfz Needs Help...

585 Views 8 Replies 4 Participants Last post by  07YFZ450SE
I posted this issue before, but it still continues.

Got to ride today for the first time in a while, got my jetting PERFECT.

1-4 gear run awesome and pull hard..

once i shift into 5th, i would give it some throttle, and the power will just drop, then get power again, then drop...over and over when you keep the throttle pushed (nowhere near full, so its not the rev limiter).

Then after that happened i took it onto the road ( maybe 300 feet to my truck). And every gear sounded so bad, like KKKKRRRRRRRR type of sound from the motor.

Also, i got spanked today bad by an LTR that only had a cherry bomb and the cork removed from the pipe... dirt drag race, lost both a rolling start 2nd gear, and a dead stop taking off in 2nd.
He weights about 50-60lbs more than me... And not to sound cocky but i believe im a better rider.

So i dont know whats wrong with my quad, its always been reliable and powerful, but now it seems like theres always something going wrong.

Help meeeee.
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I have a lower end of a 04 right here that the customer was having the very same issues as you are describing, and we could only get it to act up for us by strapping it to the dyno and waiting until the motor was really heated. Everything checked out fine... head, and valves, and clearances...etc. We decided to rebuild it and his crank bearings and crank were showing some scoring and IMO was about to seize... and he was experiencing mild seizing.

I ope this is not from the 07 in your sig?
Yes this is my 07...

I change my oil often and use the yamalube from the dealer.

How much money we talking about here if it is what your saying?
Parts can be $470- $950

+ labor.

Lets hope it is something else.
If thats the case my quads gonna be sittin for a while, i dont got that kind of money right now.

And yeah, it is alot worse after hard riding, with the engine hot.
ugh. terse explanation sounds logical and reasonable. i hate to say it, but i think its time for a lower end. stroker and big bore while youre in there? i would when you get the money =)

no, but that does suck alot.
If you dont have the money get urself a service manual and do it urself u will still have to pay for parts but u will save on labor and shipping costs for shipping ur motor.
Even that is gonna take me a while.

Still got school going on, and truck payments/insurance, ect..

This sucksssssss :icon_frown:

Drained my oil today, and it was blackish but no metal shavings except for a few tiny tiny particles.

It shouldnt be black yet as i just changed it maybe 5 hours of ride time ago.. :wtf:
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