Tec H70 valve job

#1
Hi ya fellas, I dont post here much anymore, but I decided to get my little drag bike out and work on the engine. It had very weak compression and was hard to start last fall so I decided to investigate the reason why. I started with checking out the valve lash. I had none..... The valves were floating above the seats and very easy to spin. I researched online what the lash should be and everything I read said .008 on the intake and .012 on the exhaust.

So I decided to pull both the intake and exhaust valves and grind them down and then lap them in. I had the engine at TDC of course and I started with the Intake valve. I ground it down and took a little to much off of it. I ended up having .012 on both the intake and exhaust valves when all said and done. I then lapped them in and got a good pattern around the valve.

I got everything reassembled and pulled it over.. HOLY CRAP it has compression now!!! I thought I was going to dislocate my shoulder, I just wasnt ready for that compression it had. Well I guess now its time to start it and see how it runs. Within 3 pulls it popped right off, WOW! That never happened either. Last fall maybe within 20 pulls it might fire.

So its sitting there idling and I hear some damn noisy valve chatter. I just cringe that it was because I took to much off of that intake valve. Sooooooo, how much harm is this going to cause to my engine? I do have a H60 engine here and was wondering if those valves are the same? If not, I assume the only fix is to buy new valves and try it again? Or is it ok to run I just have to deal with the noise?
 
#2
That clearance should not cause a loud clatter, after it cools recheck the clearance and make sure it is not riding on the compression release or you may get a false reading
 
#3
That clearance should not cause a loud clatter, after it cools recheck the clearance and make sure it is not riding on the compression release or you may get a false reading
That is what I was thinking....I've been researching all afternoon and I think I found my problem.

I think I was on the intake stroke and not the compression stroke. Which would change everything. I have to open it back up tomorrow, and if I was... I took way to much off my valves.

If that was the case, I didnt see any new ones for sale in the OldMiniBikes store. So still wondering if the H60 valves will work or a place to buy them. Thanks again
 
#4
Went and pulled the head and breather plate over the valve springs. Yep I was on the intake stroke! Grrrrrrrrrrrrrr! On the compression stroke I what appears to be over 1/8" gap maybe more. I can imagine that is the noise I hear where the lifters slam into the valves. Well time to research finding some replacement valves.
 
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