View Full Version : 1974 XL 125 Custom build, Cam chain too long.

08-13-2018, 2:01 PM
Hello Friends,

This is my first chop cult post ever so im stoked to hear everyone's input on this fantastic issue im having.

A few months ago my buddy decided to dump an sl and xl 100 into my front lawn. both with seized engines. Long story short, I smashed two into one, ground out the crank case to fit a 125 cylinder and put a 125 crankshaft in. So I got a new head with my cylinder as well but its from an 80's series xl125 not a 70's "its not as tall".

My issue is that my cam chain is two long, I popped out two links to match the cam chain length of the 80's xl which is 98 links aposed to 100 links....TOO SHORT!! So im conflicted on whether or not i buy and 80's series chain? or come up with something very custom. Im not worried about timing as the gear ratios been the same between all years.

Any input or suggestions would be wonderful, and yes its still loose the the cam tensioner maxed out.

08-13-2018, 4:23 PM
Thicker or double base gasket might do the job. You could shim the barrel to case joint (evenly) to check. I'd mic the shim thickness for reference. You might use feeler gage leaves for a known thickness or combination thereof.

How far off is it minus ONE link instead of two?

End result should of course permit further tensioner travel as chain wears.

08-13-2018, 5:08 PM
Modify the cam chain tensioner..Is it a sprocket or a wear pad/shoe?The later would be the easiest to modify using a thicker pad/shoe

08-13-2018, 6:10 PM
Pics wouldn't hurt.

08-14-2018, 9:24 AM

08-14-2018, 4:14 PM
I'm not seeing a lot of swinging room for tensioner extension to use.

I would leave the chain as it is now, raise the cylinder until the chain tension is well in its proper range, and note the height between case deck and cylinder base.

If what you need is thicker than a thick gasket you could cut a "stroker plate" out of aluminum and put a gasket on either side. Stroker plates have fallen out of fashion but they were once common on Harley strokers before the aftermarket rendered them unnecessary. That will reduce compression which may or may not matter depending on thickness.

08-15-2018, 2:15 PM
ya if you notice i had both a auto tensioner and manual, I went with the manual as i think the auto tensioner was for the SL case I had not the XL. Not particularly fond of messing with the compression but may consider it as a last resort, ordered a 98 link chain off a 80's model, we will see if that works. I will post back with details for anyone who may try this build in the future.