1990 Zephyr 550 Project

Just the cap bolt that threads in at the end of the tensioner? That’s happened to me before. The original tensioner is… not great. 

If you can track one down, get the later model tensioner. I know I’ve posted about it somewhere else here on the forum, might take me a little while to find the post and part number for you. But it’s a way better tensioner that is much more intuitive to use. People will tell you to get a manual one, but you’ll end up having to adjust that, well, manually, and with the tight space behind the engine on these bikes it’s a huge pain in the #$$. 

Edit: here’s the thread:  www.kzrider.com/forum/2-engine/621445-ea...changeability#910178
it looks like I never followed up on it, but I ended up getting the later model superseded part and it works great. The best part is that when you are checking timing you don’t pull the whole thing out, just the spring. So it stays where it was, without the risk of it expanding further, and after you check timing, you put your cam cover back on, reinstall the spring, and you’re good to go. 

But also if you decide that a manual tensioner is what you’d prefer, I have one that’s yours for the cost of shipping. 

Yes, it was just the cap bolt that stripped out.  Thanks for the information about the tensioner, I went ahead and ordered the updated/later part. I did a leak down test(glad I did), cylinder #3 exhaust valve is slightly bent.  I pulled the head and have a new valve on order. 

I've had a manual tensioner on a KLX250SF back in the day, it was more of an annoyance than anything. I like the set it and forget it of automatic tensioners. 

Here are pictures of the scoring on the camshafts.