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davecampbell

$$ouch$$

15 posts in this topic

I had a head repaired at Engine Dynamics and an hour into the first ride the same problem (cam seizing) re-occurred. Tore the motor back down and sent the head back to have it redone. The gal in their office calls when it's done and we discussed shipping methods and costs and settled on two-day for $50. All this time I am assuming that the re-work on the exhaust cam lobes is a warranty item. When my card bill arrived and I saw the $238 bill I called and all I got was excuses on why they had to do more than last time and why it is all our fault that it failed. Mike made it clear that he never works for free! The way we left it is that he is keeping all of my money unless he has a change of heart at which point he will call back:banghead:

I'm not holding my breath on that one! Who else does this type of head repair? I have heard that someone on the east coast does these also.

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Did you measure the cam journal clearance when you assembled the engine? As long as the clearance was correct then it isn't really their fault that it seized again. That would mean that it either wasn't getting oil or it wasn't torqued properly, neither of which would be an issue with their work.

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Did you measure the cam journal clearance when you assembled the engine? As long as the clearance was correct then it isn't really their fault that it seized again. That would mean that it either wasn't getting oil or it wasn't torqued properly, neither of which would be an issue with their work.

They measured the clearance when the did the repairs and we torqued it to their recommendations. I have at this point gone so far as to split the cases and have found no problem with the oil system. I doesn't mean there isn't one but I can't find it. The intake cam journal still looked OK when we tore it down.

I don't think there is the possibility that a definitive determination can be made about the cause at this point we have expended an awful amount of effort to do so. I sure don't claim to be the master mechanic and I know that Mike is a pro at what he does. As good as someone is there is always the possibility of an error. It could actually be that errors were committed on both sides. I am really not upset with the work they have done but I was definitely blindsided by the card charge. I could come a bit closer to understanding if they assumed that the original quote for the repair applied to the second time around since it appeared to be an identical problem, but not only was I charged that but also more for additional work they saw that needed to be done. I seems like I should have at least been consulted about the additional work and at the very least made aware of the total before it was placed on my card! In their defense ,on the second repair, they were working very quickly to get us back together before the start of our racing season. On the second go around they completed the job the SAME DAY they received the head. They actually received, repaired, and re-shipped all on the same day. That was impressive!

why is the cam seizing repeatedly?

Great question. I wish I had the answer to that!

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Have you replaced the oil pump? Cleaned the oil screen/s?

Yes on both.

I'm finding pieces of yamabond in it and think I may have gotten the wrong stuff. I have Yamabond 4, it says semi-drying but it seems to harden into something the consistency of silicone! I'm thinking maybe a piece lodged somewhere important and restricted oil flow enough to at least contribute to the problem if not cause it totally.

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The correct Yamabond is Yamabond #1215 (Threebond® #1215), Yamaha PN 90890-85505

Does that stay softer than the yamabond 4? This is the second motor we have assembled with this tube of sealant!!

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Wow Dave this is a good story. I just heard about Engine Dynamics this week and had a 2004 Suzuki head do the same thing. I sent it up there yesterday.

Your head was off a Yamaha? Did the galling happend on the head and the cap? Mike at ED says it's from people not torquing to cam caps right. He also says that the Yamaha has much tighter cam clearance then the Honda.

I guess he can recut the cap but I don't think ha can cut the head. That would change the cam height.

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He can cut the head, but most times it's not necessary to remove very much on that side because the load is born by the caps, so that's where the greatest damage occurs. When it's required the head can be built up.

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Mine was damaged on both sides both times. I imagine that it will take a bit smaller shims this time around.

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Mike does great work. The damage would need to be significant to perform a build up. He skims the mounting surface of the cap and line bores the journal. This effectively lowers the centerline of the cam which requires a shim adjustment.

He does the head. You are responsible for oil delivery. Did you rework the head and put it pack into service without assigning a cause for the failure?

Sounds like you are on to a probable cause with the yamabond.

Good Luck

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I did find a piece of Yamabond in one of the oil galleys. As grayracer posted the book calls for Yamabond 1215 which my Yamaha says they have never heard of. The yamaha shop here uses the semi-hardening yamabond 4 which is what we used. So we used it again. We used it sparingly though. I really hope that is not the cause because this is the second motor I have done out of this tube of yamabond! I split the cases and triple checked everything as well as re-cleaning all of the parts because Mike found grit on the head and I found metallic particles in the oil filter. I installed a new oil pump and a new scavage pump and then reassembled the motor without a timing chain so that we could rotate it well without the cams in place. We then kicked it over until we had oil coming to the cams and then installed the cams. The exhaust cam that was repaired took a lot of shimming but I think a couple shims or a couple of valves got switched because one valve went up several sizes and another went down almost as much. The motor started and seemed to run fine but it did that last time as well. It is raining here this morning but when that breaks we will take it out for another trial run.

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