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Fredda

What eats my rocker?

9 posts in this topic

Have a XR600 with new cam (HotCam) but saw that the valve lash become bigger all the time. But only on one valve/rocker. So I put away the top head cover and saw that the rocker been "eaten" up. I didn´t change the rockers when I changed cam (said it wasn´t nessesary). What could have caused the dammage? So I won't destroy the new I should install..

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Not enough assembly lube during the initial break in. If the rockers are not properly lubricated, they will begin to gall. Once Galling starts, you can't stop it. It will destroy the weaker of the two parts, in your case, the rocker.

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In my opinion, You should always install new rocker arms with a new camshaft...

They are wear mated items .. :)

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Maybe oil pressure, or oil flow to that rocker or valve spring compressed length wrong (a high lift cam can compresses the spring enough to cause excess pressure on rocker ,make sure when the valve is compltely open you can still depress it more by hand beyond what the lobe can move it, assuming there's no auto decompressor issue. That's my 2 cents

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Maybe oil pressure, or oil flow to that rocker or valve spring compressed length wrong (a high lift cam can compresses the spring enough to cause excess pressure on rocker ,make sure when the valve is compltely open you can still depress it more by hand beyond what the lobe can move it, assuming there's no auto decompressor issue. That's my 2 cents

Could maybe be the oilpressure but there have been no other problem with the other valves. The cam only have a different duration (opening earlier/closes later) but the same "lifting".

No auto decomp to worry about...

Thanx

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Honda would probably say its because the two parts aren't compatible, (hardness-wise) ... and, they might be right ..

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Is it the exhaust? ? The decompession side?

Exhaust - yes, decomp no. The left side...

Probably they would say something like that.

The manufactur of the cam said it wouldn't be no problem with stock rocker/stock engine.

I guess after reading some posible reason that it's probably a combination of to little grease in the instalation and that the rocker was used when the new cam was maunted.

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My NX650 had just worn out the same lobe, and follower. I think it was due to low oil pressure. I checked the seal on the inside of the clutch cover (seals the end of the crank) and it had blown. This seal is easily missed, and its vital to maintain oil pressure to the big end (since the oil is pumped down the crank centre) and the top end.

Of course , running in the motor in those few early miles would also be vital, this was difficult on my race engine.

Worth checking before running the motor again. Im just in the process of getting my hotcam and followers welded and ground.

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