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Cam Bearing Failure

13 posts in this topic

Head.jpg

Not sure If my photos posted ?

45hrs

The intake cam bearing surfaces are badly galled and will need to be repaired and from what I have read Engine Dynamics is the place to go so I will call them today. Couple other questions I have hopefully you guys can help.

Why did this gall ??

Probably should replace the cam as well ?

Any chance of the buckets and valves still being good ?

Kibblewhite seems to be good stuff do they not make a complete kit (springs,retainers,valves,seals, locks)

Stock Yamaha valve seals the best choice ?

Thanks

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I would say that the intake cam bolts was over torque.

If that was not the case then a plugged up oil passage.

The exhaust looks ok from the photo, exept for what looks like a little chaffing on the top of the left valve bucket. That could have been caused by floating partials from the intake cam problems.

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This is the first time the cover has been has been off so I better check for a plugged oil line.

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So your saying since the bike was new, the valves and cams have not been out untill now?

In that case, did you put your oil filter in backwards?

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So your saying since the bike was new, the valves and cams have not been out untill now?

In that case, did you put your oil filter in backwards?

You can only do that if you use an aftermarket oil filter cover.

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Oil Filter was not in backwards as I have the stock cover. Yes this is the first time the valve cover has been off.

I talked to Engine Dynamics I told him the year of the bike and he knew right away it was the intake side so that leads me to believe it is fairly common. He contributes to to tight of a tolerance.

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The exhaust looks ok from the photo, exept for what looks like a little chaffing on the top of the left valve bucket.
My left exhaust bucket looks the same and I think I've seen it before. Looks like the bucket is spinning. Don't know why it's only the left exhaust, though.

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My left exhaust bucket looks the same and I think I've seen it before. Looks like the bucket is spinning. Don't know why it's only the left exhaust, though.

The buckets are supposed to spin.

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and is also the decompressor bucket
Not on a YZ450. There is no manual decomp lever on that engine. The left side is the one where the auto decomp operates.

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Update:

I sent the head to Engine Dynamics to have the cam bore fixed, I sent the entire head loaded. I got the head back on Thursday went to install yesterday checked the valve clearance all looked good. I removed both cams to inspect the repaired journal looked pretty good not brand new but good. I wanted to document the shims that were currently in the head, the two buckets that are next to the journal that was repaired were stuck in the head I had to use a pliers to get them out after two hours of polishing and scraping the buckets fit like the rest not really sure what the deal is ? If they forgot or don't check the buckets ? not sure why they wouldn't ? I am a little disappointed at this point with that part, otherwise they were great to deal with I will give them a call tomorrow and see what their thoughts are.

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