Yep I told you your answer makes more sense.
Thanks for the link.

 

But if you read the "Other answer", the guy says of all the equipment he's run in his life, he's never seen a chain tighten from heat. Well, except for Harleys!

 

I saw that and my experience is the same as his but I have never worked with a double chain before. I think that may make the difference.

 

The case expands (along with the engine and transmission), the centerlines of the two sprockets move farther apart.

The sprockets probably expand too, they get pretty warm, especially the clutch outer shell that has the primary chain sprocket mounted to it. When the chain gets hot, it will actually get longer, but it won`t grow as fast as the other parts in the equation.

Or it could be magic....

The Google description is junk science...

The chain itself does not get smaller when it gets hot, it gets larger, but the other parts in the equation grow at a greater rate than the chain.

 

When metal expands because it is heated up it expands from the center (source of heat) out in all directions.

For your theory to be correct the engine would have to expand forward and the transmission backward (to match the expansion of the primary case) which just doesn't make sense.

If the engine and transmission expand it would be from the center out and their respective sprockets would move (except for maybe out) in relation to the center of their respective sources.

 

The engine expands, the transmission expands, the primary case expands, the clutch shell and the compensator sprocket expand, the frame expands. The sprockets get farther apart.

But it doesn`t really matter, the main thing to know is that the chain has less slack in it when the powertrain is hot.

I work on machinery that gets very hot (jet engines), and I see the type of accommodations that must be made in the mechanical components to adapt to the great expansion rates of the machinery. Some engines have a floating mount to allow the engine to expand in diameter, some as much as one inch.

 

This sounds like a late night bar discussion.

 

Sounds good to me, see you guys at the bar, first one is on me.

 

I trained at Rolls-Royce Derby as an engineer. The expansion that occurs in jet engines and the designs required to accommodate it are quite remarkable. The engines themselves are held into the airframe by a mere handful of pins, even in a 747!

Dan has it, Texas. My earlier diplomatic reply was to skirt around confirming that I reckon the primary chaincase does indeed expand (along with everything else), with a nett effect of tightening the chain. That or there are dark and evil forces at work.....

 

That or there are dark and evil forces at work.....

yep thats it being the younger brother of a shovelhead what else can you expect --- johnjzjz