Total Motorcycle Community Forums

Hello.
(First off I'm new to motorcycle maintenance and so have just about no knowledge of correct terminology of parts.)
I have a 1981 Honda CM400C. My chain is loose but I can't adjust the wheel back to tighten it up because the tightening bolts are already screwed in as far as they will go. My thought was to take a link out of the chain and bring the wheel forward to fit the shorter chain. Is this a stupid idea or does it make sense?

Bill Scanlon wrote:Hello.
(First off I'm new to motorcycle maintenance and so have just about no knowledge of correct terminology of parts.)
I have a 1981 Honda CM400C. My chain is loose but I can't adjust the wheel back to tighten it up because the tightening bolts are already screwed in as far as they will go. My thought was to take a link out of the chain and bring the wheel forward to fit the shorter chain. Is this a stupid idea or does it make sense?

If you can pinch and lift a link that's on the rear sprocket so that it rises about half the link's width then your chain is worn out and needs to be replaced. You should also look closely at the sprocket teeth (both front and rear) and see if they are worn and starting to 'hook.' Sprockets wear out too.

When I took a Navy base mc safety course way back in the last century there was a rider there who didn't even have any teeth on the rear sprocket! He couldn't keep the chain tight enough to make that work....

I tend to agree. A chain that's loose past the maximum potential of the adjustors probably has serious wear and needs to be replaced.

When the chain is wore that much I would go ahead and replace both sprockets and chain as a set.

Thanks. Sounds like the general consensus is new chain and sprockets. I was just hoping for an easier temporary fix that would get me through this season. Looks like I'm going to have to become more acquainted with motorcycle maintenance than I thought. I just ordered the Clymers manual and it's on its way in the mail.

As far as "fix-it" knowledge goes what I have is pretty minimal. I'm a high school physics teacher so I understand how things should work, but have never been too much of a gear-head. [I used to do brake work on my old truck in the 90s and some very minimal tune up work.]

Any general advice/tips on working on the bike? Are there any things (jack stand, torque wrench) other than a simple tool set that are essential? All I have is the basic household tool set.

You'll need a set of metric sockets, open and box ended wrenches, a couple of screwdrivers, and a set of chain tools. You may be able to find a chain with a master link, but maybe not. If your bike has a center stand you won't need jack stands. You should be able to get by with that.

Most important thing to know is that fasteners and parts are aluminum and cannot withstand the force you'd put on them if they were steel. SHORT ratchet wrench handles and tighten things so that you are sure you could turn it some more but don't.

Torque wrenches will help you learn the feel of things.

My first bike had some phillips fasteners which were prone to rounding out. An impact driver is how you deal with those. (you hit it with a hammer so that it simultaneously is forced into the slots and it turns.) I haven't used one in years but your bike is old enough you might need one.

Use the manual as closely as you can (sometimes they are too general or not quite for your exact model)

An 81 honda? Is that a JIS head and not Philips?

I bought a set and find less trouble with screws on my bike.

I've never heard of a JIS head. I had to look it up. I'm not sure if my bike has different screw heads or not.