Loose chain remedy

[The_big_dill]

Hi all,

First off i would like to thank N4MWD and Motofool for the continued assistance on this forum, I really found your continued help appreciated, you guys rock!

I wanted to post this thread to give feedback as well as my discoveries in dealing with a loose cam chain.

Diagnosing:

- Clicking/tapping/ticking at the rate of the bike revolutions at the head of the engine, on the outside of cylinder #2.

- Clicking/tapping/ticking becomes louder as engine warms up.

- Valve adjustment to spec does not eliminate the noise.

This is what a loose cam chain looks like:

Solution:

Replace what is not allowing the chain to hold tension:

- Stretched Cam chain ---> replace chain
- Worn guides ---> replace guides
- Seized/rough motion of CCT ---> clean/lube CCT as well as leverage mechanism OR replace CCT if damaged.

Remedy:

In my situation, it appeared to be a stretched Cam chain, replacing required a full rebuild, i did discover a temporary remedy to keep the bike running for the remainder of the season. Although this may not work for you, it is worth a try.

When i adjusted my valves, i set it to the outer clearance specs from the service manual. This resulted in a louder slapping sound, meaning a more loose chain. I then re-adjusted the valves to the lower spec and the sound dumbed down and now i don't cringe my teeth every time i ride.

My thought process leads me to understand that when you have a tighter clearance, the cam lobes contact the rockers more "often" or press harder ultimately creating more tension in the chain and that fractional clearance makes a big difference.

Nevertheless, replacing whatever is not going well should be done eventually. If a loose chain is left unattended for too long, chances of the chain slipping a tooth and offsetting your timing increases, this is detrimental to the engine and will most likely break many critical components of its operation.

Cheers!

[FvnnyL3tt3r1ng]

Interesting.

[crazymadbastard]

How many miles on your ride?

[The_big_dill]

Originally Posted by crazymadbastard

How many miles on your ride?

~ 43,000 on a 1987 model, i am the 15th owner and i have noticed multiple half assed repairs all over this bike, which leads me to believe that this bike was neglected pretty badly.

[Motofool]

Originally Posted by The_big_dill

..........My thought process leads me to understand that when you have a tighter clearance, the cam lobes contact the rockers more "often" or press harder ultimately creating more tension in the chain and that fractional clearance makes a big difference...........

You are very welcome, Phil

Yours is a really good tip !!!

[The_big_dill]

Originally Posted by Motofool

You are very welcome, Phil

Yours is a really good tip !!!

The important bit is that it works very well, i think thats how the previous owners kept the chain from smacking so much. When i checked the clearances initially, they were way too tight.

Does anyone here have a picture of how a cam chain guide should look like? preferably the upper one.

Also, i think this thread should be adjusted to "Loose Cam chain remedy" to avoid confusion.

[bruce71198]

This one? Even though the center has a groove in it this one has little ware.

[bruce71198]

Also, loose valve adjustment causes a rattle as the cam lobe takes up the clearance between the lobe/rocker/valve tip. The slack you show in your pic. is typical.

[The_big_dill]

Originally Posted by bruce71198

Also, loose valve adjustment causes a rattle as the cam lobe takes up the clearance between the lobe/rocker/valve tip. The slack you show in your pic. is typical.

My cam chain guide looks a lot like the one you showed in your picture (same condition)

The service manual says that it is too much slack, and the sound of slapping chain is loud.

[n4mwd]

You are welcome Phil.

There was another guy here that posted that he ground off just enough of the crank sprocket cam chain guard (which is molded into the case) to allow the cam chain to slip through. I have no idea if this is a good way to do it or not, but it seemed like a nice solution that didn't require splitting the engine.

[The_big_dill]

Originally Posted by n4mwd

You are welcome Phil.

There was another guy here that posted that he ground off just enough of the crank sprocket cam chain guard (which is molded into the case) to allow the cam chain to slip through. I have no idea if this is a good way to do it or not, but it seemed like a nice solution that didn't require splitting the engine.

I saw that thread and what concerns me the most is where the remnants of the guide shavings go. Furthermore, there is a reason that guide is there in the first place.
Thanks for the suggestion though.
Posted via Mobile Device

[n4mwd]

Originally Posted by The_big_dill

I saw that thread and what concerns me the most is where the remnants of the guide shavings go. Furthermore, there is a reason that guide is there in the first place.
Thanks for the suggestion though.
Posted via Mobile Device

I haven't really looked at it enough to say whether its a good idea or a bad idea, but any dust from grinding that made it into the engine would be filtered out by the filter. But another thing is that usually when your cam chain is stretched, its time to open it up anyway.