yz450f rebuild question


8 replies to this topic
  • YZ450F4

Posted January 30, 2011 - 05:24 PM

#1

Hey guys im fixing to put my yz450f back together and i read somewhere that your not supposed to put oil on the rings when assembling...can anyone help me out? i heard they will not set right? thanks for the help

  • brentn

Posted January 30, 2011 - 06:10 PM

#2

Install dry, don't lube the cylinder at all!

  • grayracer513

Posted January 30, 2011 - 07:37 PM

#3

I never put a top end together dry. I don't slop everything up, either, but I will not ever build a top end dry.

I put a drop of oil in each ring groove and rotate the ring several times, then align them correctly. A drop on each skirt, spread evenly over the surface, and a couple drops of oil rubbed over the whole surface of the bore.

Not one of my engines have failed to seat the rings, either.

But, there will be endless dispute over this topic, so do whatever....

  • YZ450F4

Posted January 30, 2011 - 07:55 PM

#4

well in the past on all the other motors we have built we put the oil to it pretty good while putting it together but since i heard that i didnt know if you were not supposed to on this certain motor. so it would be fine to put it together like we would in the past?(putting a good amount of oil on the rings/skirt)

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  • brentn

Posted January 30, 2011 - 07:55 PM

#5

I thought I read that rings should not be lubed here;
http://www.mototuneu..._in_secrets.htm

But I cannot find that reference. I know I have heard that you should not use oil on this forum by reputable people, maybe in the engineering section...
Not to sure, gotta get up at 5 so I'll have to do some searching tomorrow.

  • YZ450F4

Posted January 30, 2011 - 08:09 PM

#6

that link says to ride it under a load too when breaking it in

  • grayracer513

Posted January 30, 2011 - 08:37 PM

#7

well in the past on all the other motors we have built we put the oil to it pretty good while putting it together but since i heard that i didnt know if you were not supposed to on this certain motor. so it would be fine to put it together like we would in the past?(putting a good amount of oil on the rings/skirt)

It's not good practice to get carried away with a lot of oil. Use some, but do so sparingly.

I thought I read that rings should not be lubed here;
http://www.mototuneu..._in_secrets.htm

But I cannot find that reference. I know I have heard that you should not use oil on this forum by reputable people, maybe in the engineering section...
Not to sure, gotta get up at 5 so I'll have to do some searching tomorrow.

You'll find all kinds of really good, reputable, smart, experienced people who insist that dry building is the only way it should be done. But that will change neither my opinion, nor alter the results I have always gotten by lubing the top end the way I do on assembly. Ron Hamp, incidentally, uses a dry moly specialty lube on his, um, rather successful engines.

When starting the engine with a small amount of oil on the compression rings, the oil lasts perhaps all of 10 seconds before it is washed away by the fuel, which then takes over the lube duties. OTOH, When starting an engine dry, the second ring is without any lubrication for long enough that there is, IMO, a real potential for damage, and no real difference in terms of getting the rings to seat.

  • tpars121

Posted January 31, 2011 - 04:55 AM

#8

Good thread with opinions from Ron Hamp and Eddie Sisneros

http://www.thumperta...ght=marvel hamp

  • grayracer513

Posted January 31, 2011 - 08:12 AM

#9

Note post number twelve, by Ron Hamp.

Understand that my idea of oiling the rings and bore is not to liberally apply it, but to use very little and wipe it over the whole surface. If the bore is prepped correctly, smearing light engine oil or ATF in the cylinder and then wiping it "dry" with a rag will leave enough oil in place to prevent startup problems.





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