Front Cam chain guide rebuild

[Jconnon]

So the front cam chain guides have been out of stock on the internet for awhile now and mine just starting breaking up. I have a run I need to go on next week. What the hell am I supposed to do? Had a friend that shipped me a use done ASAP but when I got it, it was in worse shape than mine! So, I have no choice but to try this. I'm going to attempt to completely reface one of the guides and just do a small repair on the other. In both cases I have decided to go with JB Weld as the material of choice. It's the strongest epoxy I can buy off the shelf and withstands temps up to 600 degrees.
Here is what I've done so far. Let me know your thoughts and I'll update this thread with the rest of the experience.

Wasn't hard to pull the plastic off. There was oil underneath the plastic!

Drilling holes for the epoxy to have a better grip

Clamped between two pieces of wood to allow buildup of the sides

Filed down a scrap piece of metal to form the groove
Figured I'd use this to scrape the channel to shape before the epoxy sets up

Epoxy poured in

Also epoxied the other guide that was just missing some of the plastic on the edge. The chain had started grinding into the aluminum shoulder.

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[gggGary]

IF you are planning on using the JB weld as the wear surface I don't think that's a good idea. The chain is going to lathe it off and spread that stuff through out the engine. Go buy a new Yamaha guide
256-12231-01-00 $60 from powersports.net.

 

[Jconnon]

Let both epoxy jobs sit overnight under a heat lamp to cure up real well. Initial testing this afternoon doesn't look too promising. Not sure if I didn't mix it well enough or what, but the epoxy grinds off very easy into dust. gggGary is right, I'm afraid the cam chain would eat away this epoxy for lunch.

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[jd750ace]

I was thinking of riveting in a chunk of Nylon 66, or, if I can find it nylon 4.6. It has to be a self-lubricating type of wear surface that has high shore hardness and high temp resistance (400 degrees worth should work fine), but enough lubricity to let the chain slide without eating up either part. Here's some discussion among material engineers on the subject (one of my favorite sites for researching this stuff)

http://www.eng-tips.com/viewthread.cfm?qid=292501

 

[Jconnon]

I've decided to use the guide that just had a little grind wear on one edge. I patched it with epoxy and filed it to shape. I also used super glue on any pieces of the remaining plastic that showed signs of cracking or lifting. This fix will have to do for the run thats coming up this week and likely the rest of this season. I'll buy a proper guide and install this winter.

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[weekendrider]

That fix may work for the life of the motor.

 

[drummin777]

Mikes just got the guides in stock. I just ordered mine. $32