Cylinder 2 won't run, valve issue?

I checked everything on cylinder 2 so far, the thing still won't run. Carb is clean, getting fuel, and is not clogged, plug is getting nice fat blue spark. I checked the valve clearance on the exhaust valve of number 2, and i COULDN'T even fit a .002" feeler gauge in it. Could this be the problem? I've checked everything else.

Thanks,

-Erik

yes that is a problem, if you dont have any clearance then you dont have any compression.
get the valves adjusted to the proper spec, and run a compression test.

Don't run it until that valve has clearance. valves run super hot and transfer heat to the head when they close. If the valve doesn't close, two things happen:

1) It can't transfer heat to the metal head

2) Hot gasses blow by since it's still partly open.

That can burn the valve and the valve seat pretty quick and then your head is gone.

What is the spec for exhaust and intake?

Thanks,

-Erik

cuds wrote:

What is the spec for exhaust and intake?

Thanks,

-Erik

On mine it's .002 - .004" on both. On some engines, they run the exhaust a shade wider than the intake (I've seen exhaust specs as high as .006" max)

I think if you stay around .003 - .004" you can't go wrong.

I fired the motor up today open header (no muffler). I put my hand where it came out, and sure enough I felt wetness. That is telling me it's fuel. So, I'm goin to guess that this is another clue as to the exhaust valve no closing all the way.

you can run the valves any were betwen .003 to .008 and you will be fine mabe the valve is burnt frome running it this way

I'm going to teat into it tomorrow. I'm going to switch around the shims from cylinder two and see what I can get. Right now, I'm big on the intake a small on the exhaust. I'll post up any questions I have.

Thanks,

-Erik

I got into it last night. I re-shimmed the intake and exhaust valves, and both are in clearance. I started it up, and what do you know, all 4 cylinders are firing! :banana dance:



BUTTT, now I have a carb problem. As soon as I put gas in, it goes straight out carb #3, which is usually a sign of a stuck float or some sort. I'm going to be working on it all night tonight....hopefully.

It's also running rough, maybe I got the timing off when putting it back together. Is there a way that it would start, even if I was one tooth off? T

Thanks,

-Erik

cuds wrote:

... It's also running rough, maybe I got the timing off when putting it back together. Is there a way that it would start, even if I was one tooth off?....

Here's help regarding the floatbowl overflow --

link 1

link 2

As to the cams --
Typically, over-bucket shims are removed and replaced with the only camshaft involvement being that the camshafts are turned to the correct positon for measuring the clearance at each valve between cam and shim. And without any loosening of the camshaft, and without any changes to location of cam-chain links on the sprockets.

Am thinking the running rough is due to some other reason besides the cam-chain. Maybe carb-synch, pilot adustment, ignition timing, or some other area, needs attention.

Good Luck!

AHhh, AT LAST!


Fires up and runs on all 4. I wish I could be exciting, but I have a loud ticking coming from 2, sounds like the exhaust valve. Any ideas as to what to check? It has run for approximately 1 minute, then I shut it off, just in cast it is a valve hitting the piston...although I doubt it.

Thanks,

-Erik



I'm getting closer, one step at a time!

Possibly an exhaust gasket leaking or valve clearance too large.

Good Luck!