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When to replace camshafts and buckets/lifters?

737 Views 6 Replies 3 Participants Last post by  SparkyMJ
Hey folks, wanted some weigh in.

Working on my project K4 750, and it's got about 40k+ miles. It had pretty worn camshaft lobes, so I replaced the camshafts with used ones that were in better shape than my set. The wear looked like scratches/scuffing on the lobe tips, no chunks missing or anything that crazy, but enough I thought that replacing with used better ones would help it last longer. Haven't run the engine at all yet since replacement, due to other parts being worked on.

Anyhow, I've never opened up a bike engine that had lifters/buckets with any tangible wear. Sometimes they have visible wear patterns, but absolutely nothing you could feel with a fingernail, pick, or anything. The camshafts on this bike in particular as I mentioned had some pitting on the tips of certain lobes.

I guess the pitting on the lobe tips didn't cause tangible wear on the lifter/buckets. The pitting was very mild, but enough to me that I would like to try and not run those. The lifters looked absolutely flat, uniform, and good, with one exception, and it had a circular wear pattern on the head of the bucket, but again nothing I could feel in any capacity.

Question is, if you never run a stock motor out of oil or abusing the engine or anything like that, when or how would camshafts and lifters wear enough to warrant actual replacement?

Are lifters harder materials, and hopefully would result in only camshaft lobe wear, and not both? What level of wear is unacceptable for lifters?

What do you guys think?
Thanks in advance.
1 - 1 of 7 Posts
If you have uneven wear or light scoring on the lobes that you can actually feel sometimes you can smooth them out using a stone, then polishing. It's important to keep everything on the same plane. Think of this as increasing the surface area of contact. Yes you will be removing a few tenths or more but it may be the lesser of evils.

Often stuff like this starts during long periods of storage with temperature changes. Inside a motor you have a micro climate with condensation forming acidic water droplets that hang off certain areas and attack metallic components by etching into the surface. This is what may have caused the pitting you see.

The only way to prevent this is regular oil changes, storage at a constant temperature and possibly adding a moisture absorption device or packet. Starting the motor or at least turning it over often will circulate oil and preserve your precious motor components.
1 - 1 of 7 Posts
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