82 KZ440 LTD Rod Knock Sound

Hey all,

Attached here is something that I hope will help a few others in diagnosing thier bikes if they have a bad internal ticking in thier engine.

This is what was found.

This crank shaft is out of round because there was found to be no crankshaft journal bearing for the right side.

This is the sound it makes.

That is about 3/16" of play in the right side connecting rod on the crankshaft.

There was initial thoughts of a loose cam chain or of a loose starter clutch but both of those have been eliminated since disassembling the engine.

Hope this helps!

The bearing shells were gone? What happened to the? Did someone "rebuild" the engine and forget to install the bearing shells?

Ed,

I go into more detail in my build page as the bike has apparent history that I'm discovering over time as I work on it. I had no cause for concern when I bought it. Sounded great! Just purred! No clanking. Didn't even get 100km on the bike and then came a loud ticking noise more noticeable on the right. The only slight trace is a very very small amount of metal shavings that came up on the oil after. But it's like it didn't have a bearing shell as you are calling it because I can't find the rest of it!

Bearing shells will still be attached to your con rod big ends. They are soft metal and the idea being they take the wear rather than the hardened steel crank. Different thickness inserts (identified by different colour paint marks) can be used to compensate for wear, using plastiguage clearance markers.

Cranks, cases and conrods are all individually measured and marked in size 3 ranges, shell bearings then fitted to make up the right clearance.

Selective assembly allows manufactureres to work to precise tolerances but also fast production allowing for wear in tooling.

i would fix it, no big deal.

Jbosh wrote: Hey all,

Attached here is something that I hope will help a few others in diagnosing thier bikes if they have a bad internal ticking in thier engine.

This is what was found.

Attachment image-2-3-4-5.jpeg not found

This crank shaft is out of round because there was found to be no crankshaft journal bearing for the right side.

This is the sound it makes.

Attachment trim.8EF95743-C059-415F-879E-045C21B84024.MOV not found

That is about 3/16" of play in the right side connecting rod on the crankshaft.

There was initial thoughts of a loose cam chain or of a loose starter clutch but both of those have been eliminated since disassembling the engine.

Hope this helps!

Crank is toast. DUH :blink:
Steve

swest wrote: Crank is toast. DUH :blink:
Steve

Looks pretty bad for sure as arrow shows in image below. I wonder if the journal could be turned and oversized bearings used to compensate for the smaller diameter? Ed

I guess it could be done. Seems they made slight differences with the 400's over the years. If no used crank is available, it would be the only way. Would it be worth it?
Steve

I had it happen on my 1977 kz400; for me the cheapest way out was to buy an entire used bike, take the crank and rods out, and throw away the rest.

So I seriously doubt it's economically viable to repair a crank like the one under discussion on a machine with very low value. like an '82 KZ440.
Of course it can be done; most likely there's too much wear for an available undersized bearing so the crank would be welded to add metal, then reground. It's done all the time for high value engines, but as you can imagine, it's not a really cheap procedure.

650ed wrote:

swest wrote: Crank is toast. DUH :blink:
Steve

Looks pretty bad for sure as arrow shows in image below. I wonder if the journal could be turned and oversized bearings used to compensate for the smaller diameter? Ed
]

Machine shops weld journals all the time, it is not a big deal. About $100. I am talking about real machine shops not bike shops.
Find out bearing sizes, and measure journal. I use digital measuring caliper, $30 from HomeDepot. People usually use micrometers.
Bearings can be +.25mm and +.5mm.
Find out specs for the crank and deduct .5mm

mark in Portugal wrote: I had it happen on my 1977 kz400; for me the cheapest way out was to buy an entire used bike, take the crank and rods out, and throw away the rest.

So I seriously doubt it's economically viable to repair a crank like the one under discussion on a machine with very low value. like an '82 KZ440.
Of course it can be done; most likely there's too much wear for an available undersized bearing so the crank would be welded to add metal, then reground. It's done all the time for high value engines, but as you can imagine, it's not a really cheap procedure.

Use to be done all the time in the day. I'd be concerned about what else has been munged up. :dry:
Steve