My Valves are at .13mm and .15mm!!!!

[Boatguy]

So I have a pretty big question here.


First time looking at doing the valve adjustment. I have about 5500 miles on the bike or so right now.

My intake valve is at .15mm and my exhaust valve is at .13mm!!!

This is straight from the factory.

So what do I do? This thing has been running fine the whole time. Everything I read tells me that these valves tighten up overtime and that’s why you have to adjust them. However, mine are much looser than the spec.

Do I just leave them? Or do I tighten them down?

[Boatguy]

I kind of knew doing this was going to be a waste of time since it runs so well. But to be this far out of spec is kind of strange. How should I proceed?

[JerryHawk250]

Did you check them while it was cold or hot? It makes a difference. Valves should be adjust while engine is cold like after sitting over night.

[Boatguy]

Damn. I was hoping somebody would see this right away.

I’m Right in the middle of the project. And I can’t leave the bike apart. I have to put it back together. It’s just sitting out there at TDC looking like a backroad development thread. LOL

I guess I’ll give it another hour and hope somebody has an opinion. Because I have no idea what to do here. It seems to make sense to leave well enough alone. But it is so far out of spec that I worry.

[Boatguy]

Originally Posted by JerryHawk250

Did you check them while it was cold or hot? It makes a difference. Valves should be adjust while engine is cold like after sitting over night.

Thank God you showed up, Jerry.

Yes. I checked them cold. It hasn’t been run in days actually.

[JerryHawk250]

Originally Posted by Boatguy

Thank God you showed up, Jerry.

Yes. I checked them cold. It hasn’t been run in days actually.

Personally I would adjust them to the factory specs. whatever they are. I know it's different specs. than the Hawk.

[Boatguy]

Originally Posted by JerryHawk250

Personally I would adjust them to the factory specs. whatever they are. I know it's different specs. than the Hawk.

OK. I’m going to take your advice because you know a heck of a lot more than I do about this.

The accepted values on this forum are currently .06mm intake and .06mm exhaust for this bike. There have been a lot of different opinions, the manual says tighter values, but somebody talked directly to American Lifan and got .06mm across the board.

That’s why I’m so shocked. They are more than twice as loose.

Thank you so much for the timely advice. I’m in your debt. Nothing like having the motorcycle completely apart in a place where you can’t keep it apart and then running into a problem.

[Boatguy]

Also, I started to adjust the intake valve and there is play in the rocker arm.

It moves a lot more than .06mm. The far end of it seems to move over where the rod goes to the camshaft or whatever.

The exhaust valve does not have this issue.

Now I’m more concerned about how to adjust this because I’m not sure if I should adjust it. I’m not sure if I should adjust it for the position where it is higher on the cam side and lower on the valve side or where it is higher on the valve side and lower on the cam side . The rocker arm has play.

[Boatguy]

Here’s a link to the loose rocker arm.

Is this normal??

The intake is the one that is very loose. The exhaust is not really loose at all.

https://youtube.com/shorts/4wuBkzB5U1E?feature=share

[Boatguy]

And for more clarity, here I am at TDC.

[Boatguy]

I got to that mark by watching the intake valve depress and open, then close, then it jumps ahead of tiny bit, then you can keep rotating it around to the mark that I lined up. Also, looking in the spark plug hole, I can see the piston right there at the top.

[Boatguy]

So how do you adjust a valve clearance when the rocker arm doesn’t stay stationary?

[JerryHawk250]

Make sure you are on the compression stroke. There should be no pressure on the rockers at that point.

[JerryHawk250]

Originally Posted by Boatguy

Here’s a link to the loose rocker arm.

Is this normal??

The intake is the one that is very loose. The exhaust is not really loose at all.

https://youtube.com/shorts/4wuBkzB5U1E?feature=share

Definitely too loose.

[TominMO]

REVISED POST

I use inches, so .006" = .15mm.
From inches to mm, you multiply by 25.4 (I use 25 even).
From mm to inches, you multiply by .03937008 (I just use .04). Or divide by 25.

My intake is .004"/.10mm. Slightly loose I admit.

My exhaust is .007"/.175mm. That's a little loose for sure, but it gives plenty of margin for expansion. Exhaust valves always get hotter, so the valve stem expands more and closes the gap more.

I'd say to tighten up the intake to .06mm, exhaust to .08mm. I prefer just a hair looser, in case I goof up a little. Better too loose than too tight.

Just checked my Clymer Manual model #M315, for Honda 100cc - 350cc OHC singles, 1969 - 1982.
https://www.amazon.com/Clymer-Public...ps%2C99&sr=8-1
On page 52, Table 8, Tune-up Specifications, it lists these specs:
Intake (all models): .05mm/.002"
Exhaust (100 and 125cc): .05mm/.002"
Exhaust (175 - 350cc): .08mm/.003"
So even though these are pushrod bikes, not OHC, I think the numbers should stay the same. Might tighten mine up a bit.....