[Warning] Yanmar 404cc Clone Issue

[snoopy]

My flywheel came loose today due to the key on the crank failing. The key had been spot welded on, not forged as it should have been, and the stresses of variable torque on it failed. My engine has done about 5000 miles.

Solution is to grind a second grove and insert a square kind of shaft like is done on the sprocket side. I modified an allen key (hardened). Should last unlike the crap original idea!

An essential mod for clone owners.

[forhire]

Your saying that on your clone rather than a key slot being milled into the crank it had a key spot welded to the crank?

Are you certain it didn't shear the key and you simply can't see where the slot originally was? Often the flywheel will smear the key leaving little evidence of the slot location. If you lightly pass a file over the taper it will bite into the soft key and skip over the hardened taper revealing the slots location. Dig out the key with a drift and install a new key.

Of course it sounds like you re-keyed it already.

[snoopy]

"Your saying that on your clone rather than a key slot being milled into the crank it had a key spot welded to the crank? "

That is correct. I couldn't believe it either. It's obviously done to save time/money in the clone factory, Yanmar do it properly.

[snoopy]

According to your picture,it is a tab on the right hand side taper (a slot is used on the left side). This little tab was spot welded in three places on mine.

[forhire]

That is correct. I couldn't believe it either. It's obviously done to save time/money in the clone factory, Yanmar do it properly.

I cannot imagine spot welding a key! I'm surprised it held as long as it did. What brand is your clone?

According to your picture,it is a tab on the right hand side taper (a slot is used on the left side). This little tab was spot welded in three places on mine.

I attached the diagram from the manual. Part number 10 is a 5x14 key. They really cut a corner if they weld on a tab instead

Here's a link to the manual: http://powr-quipsmallengineparts.com/im ... Manual.pdf

[snoopy]

I suppose it must make it easier pulling it out of the cast!

No idea on the brand or how to find out, it is a cheap clone with no identification marks.