 Motorized Bicycle Incremental Chain Tensioning, Chain Management
HI well, I thought sure that I had written this here, but in case not, here goes.
Other than a true spring-loaded guide, which some I knew in the past had made, the best tension roller LIFTING the chain is NONE.
This is how it came to be that I invented the aluminum T-Shirt.
Remember that when you move the engine forward the chain slack reduction is twice the distance of the movement of the engine. One full link-set is one inch, therefore the MAX that you would ever need to move your engine would be 1/2 inch. Additionally, good is good enuf, and there is no need for perfect, which, actually does not exist.
Now, take your rear sliding motor mount, make a pattern on a piece of extruded aluminum strap, not to exceed the width of the mount or it can hang up in the chain.
Originally I drilled the holes, and slid them on the studs in-between the rear motor mount and the engine case. AFTER pulling the engine in and out several times it occurred to me that when I aligned the front-end on my 55 Chevy, that the shims had a tab-handle, and did not require removing the bolts, just loosen, pry open, slip in and re tighten.
This is where we are now, your shims look like t-shirts, and the "arms" of the t-shirt lay on top of the 2 studs, with the body of the shirt hanging down, full-length to space the engine evenly, and rock-solid.
Next installment, after you-all ask anything you like about this, I'll explain the other section of Chain Management, which we invented (Kevin "evil elvis" Waddle, and Meself), the Upstop Roller.
Mike | 
