Thanks Bogie,

I want to break it in properly, but I am afraid with the time I have available, it may take all summer. As you know, our riding season is short...

Plug looks fine to me. Slightly rich during breaking is a good idea.

I don't even need choke to start in these hot temps. Perfect in my opinion.

Valve lash was checked a couple times. The factory timing appeared to be off.

I thought it was very clear that the engine failure was a direct result of the rocker arm adjustment lock nut coming loose after you adjusted the valves.

Is there any way to check/adjust timing on these bikes?

My spidey/flame senses tell me you're trying to be funny at my expense. Stop.



I'm about to buy one of these things and I want to know as much as possible before I pull the trigger. I apologize for asking stupid questions...actually, no, I don't.

No, I wasn't trying to be funny. That really happened.

No stupid questions. You should change the oil before starting. Check the valve lash if you feel comfortable doing so or have someone else do it. Otherwise the engine does come with a one year warranty.

Freddie is right. OP told us about the valve adjustment session not going well.

Be ready with the right tools and procedure when you receive the bike. Now this is posted in the Templar resource guide (post #22). I use an offset 10mm wrench to tighten the lock nut. It is a flathead screwdriver (small one) for the tappet adjustment. 0.001" to 0.002" on the intake side. Maybe slightly more on the exhaust side. I have found the 1/8th turn from snug is about 0.0015" on mine. That's where I set both.

So, yes, my initial thought was the locknut coming off, but that happened while running for a very short time and it seemed to run fine (only sitting still and running) after that was resolved. The intake valve was in adjustment the whole time, as far as I can tell. The locknut that came off was on the exhaust valve. The valve that was compromised was the intake valve. I do also think the initial noise that I heard and thought was the valves being too loose was actually the piston hitting the intake valve.

As I got into it, the top cam chain gear was clearly not set to TDC when the crank was at TDC. I can't see any way to adjust timing on this motor, only the ability to have it correct or not.

I do not claim to be an expert at this and am only relaying what I experienced in real time. Not trying to confuse or piss anyone off.

It is all very new to me and I hope to figure it all out.

All I know is I have the valves adjusted on the rebuild just as I did on the old one. This time it is very quiet and seems to be running just fine. Time and miles will tell.

I will stand corrected from my last post.

The lock nut was absolutely off during the failure. I had replaced it after the fact to try to get it to run.

My earlier post was written with the two grandkids talking at me and I wasn't recollecting accurately.

At this point I have no idea what the actual cause of the failure was, but am open to suggestions.

Sorry for being even more confusing....

I suppose it doesn't really matter what caused the failure. The important thing is that you fixed it and can enjoy the new bike. Where did you find torque values for the head or did you guesstimate? It's hard to find any spec's for these bikes other than generic values based on fastener sizes.

any more than 30ft pounds on head bolts or anything else on these bikes is overdoing it.

a multi cylinder liquid cooled engine might be a bit tighter...

I couldn't find any specs for this motor. I had a '74 Yamaha SR 500 I turned into a little barhopper several years ago. The spec for that was 27.5 ftlbs for the head bolts, so I ran with that.

That seems reasonable. I've rebuilt quite a few 2 strokes without a torque wrench and never had a problem. Good luck with the rebuilt engine.

It sounds like the timing chain may have been off. There would be really no way to set clearances if that was the case. But this is unusual. The ZS172 has proven to be a good engine for most folks.

FYI, the valve train on my X has been very good, easy to set clearances, and the engine runs really good. Its the 5speed version that originally came on the X (ZS 172FMM-3A). I did buy the X with the 6speed when it showed up last year, and it was equally good. I stuck with the original carb on both, just rejet it. But I just didn't need two bikes. I kept the 5speed because I ride 90 percent off road and it was easier to sell the newer 6speed.

If I were to do this all over again, I'd probably buy the 6speed X for the KKE adjustable suspension. The counterbalanced engine is definitely smoother, but that's not important for my off road riding.

I did add a tooth on the front (14T). But when I replaced the chain, I got a 51T rear sprocket to slow it down a bit for tight quarters off road. It doesn't go fast on the road, but it's great on the trails!