A reason to follow service intervals for RMZ & KXF 250 owners

faceplantin

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Apr 24, 2006
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Rich, how are the '06's doing? Has Kawi corrected most of these design flaws? I'm a novice non racer with 30 hours on my '04 and I'm gearing up to install Kibblewhite SS valves, springs, buckets and Wiesco piston. I wasn't going to split the cases yet. Is there anything else I should do?

Eric
 

Rich Rohrich

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faceplantin said:
Rich, how are the '06's doing? Has Kawi corrected most of these design flaws?

Unfortunately, no they haven't.

faceplantin said:
I'm a novice non racer with 30 hours on my '04 and I'm gearing up to install Kibblewhite SS valves, springs, buckets and Wiesco piston. I wasn't going to split the cases yet. Is there anything else I should do?

Eric

The oil pump screens really should be cleaned but that requires splitting the cases.
 

faceplantin

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Apr 24, 2006
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The oil pump screens really should be cleaned but that requires splitting the cases.[/QUOTE]



Good point, I'll do it. That will give me an excuse to check the shift forks and drum.
Thanks
 

Rich Rohrich

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If you plan on keeping the bike for a while it's worth putting in main bearings and a crank while you have it apart. The RMZ/KXF main bearings are a loose fit in the cases and tend to walk around. This causes strange wear on the bearings and the crank. The 2004 cranks had some problems with cracks forming near the big end pin area, so replacing that original crank with a new spec version is cheap insurance in the long run.
 

Rich Rohrich

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faceplantin said:
Will current aftermarket bearings have a tighter fit?


Nope. Unless you have a 5 axis Haas CNC in your garage and can install bearings from a Yamaha or a Honda, you are pretty much stuck with the built in design issues.
 

JWW

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Rich Rohrich said:
Wes - I'll try and put together a list of stuff for the various bikes. Good idea. :cool:

I searched but came up empty handed. Did a maintenance by hour list ever come out?
 

Rich Rohrich

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I decided against doing it. Too many want to argue the point and I have no interest in doing that.
 
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Pete Payne

MX-Tech Suspension Agent
Nov 3, 2000
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You should be able to bore the cases on a Bridgeport. You could even make a steel insert . I had to do this years ago on a LT500 . Man , them things were hard on the cases.
 

charlie5ive

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May 31, 2009
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I just wanted to say I joined this site about 2 hrs. ago ran across it while researching a friends RMZ choke cable it was frozen like you mentioned .How does the cable or choke valve come out there appears to be a seat in the choke valve bore for the cable nut does the valve clear? Thanks you guys have already been helpful. Charlie5ive
 

Jasle

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Nov 27, 2001
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How about Green Loc-tite? The original design of the Green loctite was to fill the space between bearings and the outside on some paper making equipment. I've used it successfully on pounded out cases...Just make sure you use heat when you want to remove them.
 

peterhively

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Nov 15, 2009
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Hi all, I have an 04 RMZ 250 set up for off road and it is really fun to ride, perfect for the trails at my local riding area.

I've read about all the problems with the bike, but was hoping with good maintenance and mellow trail riding it would last. Sadly, no.

The stock left intake valve started losing clearance early on, so in the interest of longevity I installed Kibblewhite SS valves, springs, and retainers, along with a good valve job. At the same time I put in new piston, rings, and cam chain.

I keep the air filter clean, change the oil and filter every couple of rides as well as checking the valve clearances.

Clearances stayed put for about 30 hours, then the left intake started closing up again. I've reshimmed a few times but now having gone from a 285 to a 265 obviously it needs to come apart again. Not sure yet if it is the valve, the seat, or both.

I've searched on this topic and read about how the 05 and 06 heads have better seats, can anyone confim this? Also I read that the 06 Kawasaki head is the best, again can anyone confirm this? A quick search found the 05 Suzuki head for about $354, and the 06 Kawi head for $425.

I know about the oil groove in the later heads but so far I have had no trouble with the intake cam seizing, the cam and the journals look great.

I've also read a lot about the overheating. I have the stock 04 rads and cap, and run normal coolant and water with water wetter. I added a coolant recovery bottle and very rarely does the thing get hot enough to spit even a little coolant into the bottle, so I don't know if it is really getting too hot.

Finally, if I could get the top end to last, what about the bottom end? I read what Rich said about the main bearings, ugh. If my cases aren't worn out yet, and I replace the crank and main bearings, can I expect some decent life out of this thing?

I'd love to go buy a WR250F but that is not in the budget anytime soon.

Thanks,

Peter
 

_JOE_

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30 hours and Kibblewhites started to tighten up? Wow....

I would guess you're getting some dirt in there. Is the airbox seal good?
 

peterhively

Member
Nov 15, 2009
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I think so, but I will re-check it, thanks.

I had the airbox out when I replaced the valves, I was planning to re-seal it but the stock seal appeared to be very good so I didn't take it apart. I run a stock filter with no-toil oil and use a pc racing airbox seal. Last time I checked there was no dirt in the boot.

Why is it only the left intake?

Thanks,

Peter
 
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