Annoying clatter from 1650
 

My 1650 makes a loud clattering noise that you would swear was a rod about to come flying out through the hood. But the engine runs perfectly at wot, will pull my brinley plow and just recently pushed 10 yds of topsoil all over my yard. Doesn't run hot, doesn't use oil, etc. I've looked everywhere I can see for some sign of interference but can't see anything hitting. The clatter follows rpm so it's either in the engine or it's the engine shaking enough to hit something. Any ideas? Has anyone else had this problem? Tia
Dave

It isn't any engine tin that is loose is it?

How are the ISO mounts? Can you wiggle the engine around in the frame?

Drive shaft possible warped? My 1050 can make some noise from time to time because I need to replace the drive shaft, its got a slight warp in it.

Before I did anything to my 1450 was smooth wide open only.
So far I've reduced noise by:
replacing iso mounts/cradle mod
bending/fastening upper grill/headlight screen
welding cracked muffler
bolting engines tins together properly
putting rubber edging on the hood
adjusted idle lower

Now, just off idle it still bounces a bit and rattles the hood a little. At idle and mid on up it runs smooth. Smooth being relative, its a big single cylinder, its going to move around, key is to have move quietly.

Bill

The cap/dipstick on my 1200 was loose and made the same noise.

My old 1450 had a missing mm iso on th rear along with a tweeked driveshaft and it was horrible. Replaced the shaft and the little bushing on the fk ywheel side and it helped a lot

piston slap. drain some oil and look for metallic (aluminum) in the oil.

It doesn't sound tinny, and I've laid under the darn thing with the engine running and can't see anything moving or touching. The engine does shake a bit but then that's more or less normal isn't it. I plan on taking a harder look at the iso mounts and I'm going to take that aluminum muffler box apart to check that out.
Piston slap, man I hope it isn't that. But with a piston that loose in the bore wouldn't it be burning oil? All good things to look at. I'll probably end up pulling the engine. The driveshaft seems to be a new one, looks like stainless and is very snug fitting. The rag joints look good, too. Thanks again everyone.

But with a piston that loose in the bore wouldn't it be burning oil?


No. Rings could be well seated, and still get piston slap. Usually that will improve when up to operating temp, has been my experience in a couple of cars.