cam chain

Hi, I have adjusted cam chain as per manual and at tightest point have set at 1/8 inch free play ,at its loosest point it is 1/2 inch free play is this to much does chain need replaced.

Varying chain tension is an issue with cog and shaft run out, not the chain. To determine chain condition try to lift the links out of teeth valleys, ideally not able to but I get pension if 1/3 easy lift found. Chain tension has No Effect on this test.
Varying slack in chain will mess some with ignition timing, darn it. I"d be pensive to leave only 1/8" as least slack and aim more for 3/8". Wise to check some time when at full temp like primary chain. That may reveal how to set cold for your particular condition, which should run long time just fine, if not race quality hi rpm valve control. Two types cam chain solid or rolled link pins. Same say solid stronger while others say the rolled pin are more perfect round. So I've no preference and just take what shows up.

Well, if he adds another 1/4 inch slack at the tightest point, then would he not also be adding the same amount to the loosest point?

That would make his loosest a full 3/4 of an inch slack, and does this not seems to be VERY much too much slack?

Because of the somewhat significant variance in your findings, let's see what the real experts say for the next couple of days when they get a
chance to see your post!

BOY HOWDY I'd sure rather error on the too slack side than the too tight side, DAMHIK-!!!!!!!!!!! : (

Jerking timing is one thing jerking the snot out of cam shaft or oil pump snout is whole nother level of grief.

If the variation is due to the chain then yes it is shagged and needs replacing, but you need to ensure first that the variation is not due to the tension being moved from the top run to the bottom run by the valves being opened and closed by the camshaft, this will give you false readings.

Hi kommando ,adjusted chain as per manual by turning camshaft anticlockwise when measuring at various places,so sounds as though its had it ,was wodering about a new tensioner as well ,have you had any experience with the rubber pad ones that RGM are selling and is there any benefit from these

If you want to determine, quickly, if the chain is shot or the sprockets are out of round, mark the chain in the center of where it has it's bigest slack, then remove the sprockets, re-orient the chain and measure again, if the slack stays in the same place you have a chain issue if it moves you have a sprocket issue. Likely you have a pinch of both, but one will be more telling.

RS

My experience with cam chains has been that the difference in play between the tight and loose points is usually due to the sprockets not running particularly true. I've checked several stock cam sprockets and found them to be a fair bit out of round.

Ken

Ok, my sad findings also found shaft and/or shaft support off center with chain tension variation, Until of course links began to bind up. Familiar phenomena on my old zero turn mower with two tears of sprockets to reach tires.

Rubber and fancy spring loaded tensioners are now known as weak hazardous items. Best is well worn factory tensioner with the link grooves at full depth so the rollers glide across on hydraulic wave oil layer. Vendors have piles of em or likely one of your own.

The rubber lined tensioner is the better one but it will require a retension once its bedded in, the side plates have to wear 2 grooves in it until the rollers are touching the rubber before it reaches full usage. This doesn't take long and is much easier on the engine than the steel bits from the plain steel version.

Be careful here or you may spend a small fortune on stuff you don't need.

Your chain may be going tight because the valve springs are turning the cam forcing it tight. Check by turning the cam slightly anti clockwise and you may find the slack with return. It's at this point when you set the play.

Best of luck
Cash

lcrken said:

My experience with cam chains has been that the difference in play between the tight and loose points is usually due to the sprockets not running particularly true. I've checked several stock cam sprockets and found them to be a fair bit out of round.

Ken

Click to expand...

My experience as well, even with a brand new vernier cam sprocket chain tension was allover the place even with a new chain. Fitted the original cam sprocket back and made an offset woodruff key. Came upon the same issue on a friends bike that was also the cam sprocket. Good luck on your quest for a non eccentric one.
Regards