MMO in the gas of a thumper?

[beanoil]

quote:" Has anyone ever used MMO in their gas on a thumper? I read somewhere that a kawasaki rep recommended it for the kx250f because people were having problems with their valves breaking. I'm getting my new bike this week so I was wondering if I should try it. "
What year? If it is an '04, there is little to do to fix valve issues with that year. Kibblewhite makes a SS valve kit, seats, springs, and hardened buckets, but my experience shows that the cams wear quickly with the hardened buckets, so even if the valve issue itself is fixed, you are still in the top end for something. Regular maintenance of the sump screen is critical in any case, as the top end WILL starve for lube when it starts getting covered. Personally, I feel that oil choice is critical in KX's, as oils with a lot of solids tend to clog the screen quicker. I had no trouble with MX4T, but had screen issues with Motorex Synt. Could be my bad luck, YMMV.
Some of the valve issues were addressed in '05, with a seat change, and cooling issues are covered with larger rads. The trans got a different third gear, as the '04's had issues with trans lockups and shattered gears.
To answer directly, MMO is not going to help the valves in a KX, nor will leaded fuel. Leaded fuel MAY extend the life of the valves marginally, but evidence exists on both sides of the fence- some have gone a long time on leaded, others have failed early, just like on unleaded, and vice versa. The only thing that will fix the valve problems in a KX is to buy a YZ.
Checkout www.thumpertalk.com for a board as professional and informative about thumpers as BITOG is about oil.

 

[Jaybird]

I think that the springs used is why most of the valve failures have occured. Once they sack out, trouble is close by.
IMO Kibblewhite is the best answer to the problem. Welll...second to changing your bike from that sickly green to a healthy blue!

Also, I think I saw a report on Motorex fluid and the virgin sample was very dirty from the bottle. That may have clogged up your screen...I doubt very seriously that anything in an add pack will.

 

[sunruh]

when my buddy rob split the cases on his 04rmz (i was standing next to the mechanic when it was done) there was a bunch of extra sealant that was clogging the screens and a few little pieces of metal as well. eventually he went through 6 valves in that motor (4 intake, 2 exhaust) in less than 1 year before he sold it.

 

[p-chem]

I did have a blue a bike (03 yz250f) and i have been on thumpertalk since 02. There is something about the feel and handling of yamahas that I dont like. I never did think that mmo would solve valve problems but i read something about it on tt. The 04 kxf/rmz 250 were horrible.

 

[KX 455]

I know the subject is about MMO,but I agree with Jaybird on the valve springs being the culprit for some of the valve failures. Why is it when we hear of valves tighten up or failure of a valve,I did not once, see someone posting a measurement of the spring.I know a spring tester is not in everyones garage, so I will leave testing the pressure alone. I believe keeping up on the springs or having a very good set will pay off.

 

[Mackelroy]

Has anyone ever used MMO in their gas on a thumper? I read somewhere that a kawasaki rep recommended it for the kx250f because people were having problems with their valves breaking. I'm getting my new bike this week so I was wondering if I should try it.
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I run a diluted leaded race fuel mix, super cleaning ability and real lead powder valve cushin.

If kawi rep says MMO is good for the valves to prevent breakage, I wonder if that because of the cleaning ability. Since a few grams of hard carbon might stress a 2 piece valve? other wise your guess is good as mine.

But as far as oil protecting valve seats, I think most oil people will say , if oil is on that side of the valve you have much bigger issues.

Never used MMO, but even diluted quanties of leaded race fuel really cleans well in addtion to lead powder formation.