Broken cam chain = bent valve

[hannibal]

Time to buy an impact driver since that's what everyone suggests.

Edit: I'm gonna go ahead and ask the next logical question. How do you reattach the nut and torque it to spec (30 lb-ft)?? I guess that isn't a lot of torque so you can hold it with one hand while tightening with the other?

[chuck hahn]

Same way except I also wedge a hammer handle between the rear brake pedal and the frame to hold the rear brakes on for that added resistance.

[hannibal]

Thanks guys. I made some good progress last weekend. Got the cases split and doesn't seem to be any damage to the lower chain guide bucket. The last 3 or 4 links on the broken chain were folded back on itself, preventing the crank from turning more than a few degrees.

I'm out of town and forgot to save my shopping list to my phone so I can't order til I get home. A few questions on parts: is an OEM cam chain the way to go? Also, I'm considering replacing the guides. Front guide is reasonable but the rear guide (12810-45040) is listed at $350. This can't be right can it?

I'm not planning to replace any of the case seals on the crank, trans, or countershaft. I didn't have any leaks from here so I think I'll be good just reusing the seals.

Any thoughts? And thanks again. I never would have made it this far without this forum.

[jdion81]

I don't know if you got the head cleaned up yet, but I wanted to offer what I used to get the carbon off - paint stripper. I used the "premium" kind that will eat/burn your skin through rubber kitchen gloves. I brushed it on and it instantly started loosening the carbon. I let it sit over night and took a nylon brush to it to get it the rest of the way off.

As for the tensioner - I also needed a replacement, the original and the spare that I got with a donor engine had several lateral cracks. I too, almost passed out from the new cost of a tensioner guide. So, I have one on the way from eBay (under $40).

[hannibal]

I've been using simple green pro to clean. It's not strong enough for the piston tops or combustion chamber so I'll consider paint stripper.

In my mind, there's no way a piece of plastic can cost that much. Did you buy a new or used one on ebay?

[jdion81]

I got a used one. I did ask the seller if there were any cracks in it and they told me that there were not. We'll see what it looks like when it gets here.

Here's another one that I was looking at:
1980 Suzuki GS850 G Cam Chain Tensioner Guide Rail Slider Good Used 119314 http://r.ebay.com/ZRtgow

It looks like it cross references to fit the 77 750 also.

use part number 12810-45040 and then click on "Where used"

http://www.suzukipartshouse.com/oemparts/partsearch/suzuki

[hannibal]

Bought used guides on ebay. Both guides for $16. At that price, I can buy all of them and still be cheaper than new guides.

I got the cases apart and removed the broken chain. My plan was to put the cases beck together, turn the motor over, and clean the piston tops. I cannot get the cases back together. If the front closes up, I have a 3mm gap at the back. If I get the back half to close, I have a gap at the front. Got pretty frustrated and took a break. Any tips? And sorry for the stupid questions.

[chuck hahn]

Recheck that all the trans bearings are seated properly and the half circle retainer clips things are in right. Also see that the shifting forks are in the grooves on the shifting drum all the way and also into the gears as well.

[hannibal]

Thanks Chuck! One end of the driven shaft had moved and it wasn't sitting in the retainer clip.

The journey continues...