1979 xs400 - Cam Chain Tension Blade #2

[mixelpix]

Hi,
put some 600 miles on my 1979 xs400 sohc twin four stroke. About fifty miles from home i heard a crack from the engine and when I got home and opened her up, I saw that the cam chain tension blade (#2 - the blade at the rear of the motor with the auto tension adjuster on top of it.) I have two questions:

1) this engine has appx 22,000 on it. Any idea how long these blades usually can be expected to last?

2) I found a replacement (NOS), but it will be a little while before it arrives. The last days of sunny weather are upon us here in northern california. If I ride w/o the tensioner, how likely am I to snap the chain?

Thanks,
Patrick Kennedy

[mixelpix]

Just to clarify: when I opened up the cover I found that the blade had snapped apart. I have cleaned out the pieces and there doesn't appear to be any visual signs of damage.
Thanks Again!
-pdk

[srq68]

I wouldn't ride it without the tensioner. Any slack in the chain may be enough to jump one tooth on the cam, which means bent valves and damaged piston.

Then again, you have all winter to rebuild the top end if that happens...

Don't take a chance.

[mixelpix]

Thanks for the reply. Okay, I'll wait. . . I do, however, have a question about installation: I tried this once before on a identical motor and the tensioner got all chewed to hell. this is a new (to me) motor and everything appears to be in good working order. Other than rotating the cam when I am installing the blade and making sure the bottom fits snugly in place and properly setting the auto tensioner unit, any tips, advice or caveats to watch out for would be greatly appreciated. Thanks Again!

-Patrick