Old Cam Chain Inspection

Dental Mirror Cam Chain Inspection

With the use of a few household or easy to find tools you can tell the extent of the damage/wear of your cam chain.

Tools needed are Dental mirror Flexible flash light or any flash light and preferably a shaded area away from the sun. It just makes it easier to have total darkness.

Remove the right side engine inspection port. Remove the front inspection cover and rotate the engine to TL Then angle the dental mirror in the hole shining a flash light behind it till you get the right angle to view the cam chain tensioner. Remember everything is upside down since it's a reflection

This is a view of what you are looking for. You can see the slot showing below the bolt on the adjuster arm. Directly to the left of the spring. In this picture, when the slot is completely showing on the bottom, the cam chain has reached the end of its life and must be replaced as there is no more adjustment available.

You should get a view like this. This image is of a cam chain that is at the end of its life. There was maybe a millimeter of adjustment left.

The images below are around half life and may have up to 20,000 more miles. A timely follow up inspection will prove that.

Source

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Here's a diagram I made regarding the dental mirror check. I had a difficult time understanding that checking process until the rear cover was open. Hope this helps others.

Resized to 28% (was 1600 x 1077) - Click image to enlarge

Above diagram is of #5 and #15:

Resized to 30% (was 1500 x 751) - Click image to enlarge

Here is a post from Moto- Mucci on his bike's cam chain problem:

At the end of last riding season, I got the metal slappidy noises coming from the engine. Luckily when it happened I was on a neighborhood street and only rode it 2 blocks before shutting it down and getting it towed.

I've since acquired everything for the triple bypass and have spent the past couple days getting the engine out and opening it up to assess damages. Apparently 2 blocks can do much more carnage then I had thought. I guess when you think about it, if your shifting at 3k, and it takes you a minute or 2 to go 2 blocks, that's 3,000 - 6,000 times that chain is revolving against the bosses of the crank plate.

Here's the aftermath:

Resized to 78% (was 576 x 768) - Click image to enlarge

Resized to 78% (was 576 x 768) - Click image to enlarge

Resized to 78% (was 576 x 768) - Click image to enlarge

Resized to 78% (was 576 x 768) - Click image to enlarge

Resized to 78% (was 576 x 432) - Click image to enlarge

This was on an engine with 26k miles on it, that had the tensioner recall update done previously (3 dots on the casing). More information on the 1978 Cam Chain Recall Info '78 CX500 Std. | Moto-Mucci Blog

Inspecting the Auto Adjuster:

• • Here is a picture of a almost worn out cam chain with a auto adjuster. It wasn't making noise yet, but probably only had a few thousand miles left in it.

• • Now here is the same engine with a new cam chain installed:

• • Notice how the upper tip of the chain guide has moved from past the top guide in the worn out picture, to behind the top guide in the second picture. You may be able to see this with a mirror in the inspection hole, but I have not attempted it.