TOPIC:

Air filter is a set of K&Ns...rc2222 or something like that. Been about 4 years since I got them so I don't remember exactly.

I did torque the head down to spec initially...and checked it maybe the 3rd time I ran the bike afterwards...but not in the last 500 miles. My guess is on my 'hauling ass' ride they loosened and when I pulled off at the exit that was it. No more sustained rpms, no more compression.

I will do a test now, that would be a good data point.

Well, all is not well my forum friends....

The bike running for a second on starting fluid was a trojan horse.

To recap: All head bolts were loose - I tightened them to 30 ft/lb each. The bike then ran on a squirt of starting fluid, then ran on a squirt of gas from my gas bladder. Then I had to go home.

Today, I put the valve cover back on (running for 10 sec without a valve cover gets oil EVERYWHERE) after checking valve clearances. All were within or very close to spec.

Tried to start it on the gas bladder again and nothing. Zilch. Measured compression on 1 & 4 - 1 was 50 or so, 4 was 30 or so which is what they were previously.

Wondering if the head gasket is compromised as some have suggested. Also, starting to doubt my Harbor Freight compression tester. I should test it on my Dodge truck.

Extremely bummed after the false glimmer of hope the other day but life goes on....

The head gasket may have valleys in it now. Pull the head and see.
Steve

A leak-down test should help diagnose where the compression within the combustion chamber is being lost.

A leak-down test injects air pressure through the spark plug hole to pressurize the combustion chamber.

Can perform a poor-man's leak-down test by introducing compressed air into a spark plug hole and listening to where it escapes from the combustion clamber. This may be done at TDC or any other cam positions where both valves are fully closed. Top dead center (TDC) is when the piston is at its highest position. An easy way to tell TDC is by alignment of the T mark with the case mark when viewed through the timing window.

May introduce a spurt of compressed air by using a rubber cone-tip blow gun (rubber air nozzle) held into the spark plug hole. And of course keep holding it in position to keep air from coming back out the spark plug hole while listening for escaping air at other places. The air compressor should not be running while listening because the noise will likely drown out any sound of escaping air. Or just use a portable compressed air tank.

Air heard escaping from exhaust port indicates exhaust valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from carb intake indicates intake valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from crankcase breather indicates loss of compression past rings into crankcase (perhaps worn piston rings or cylinders).

Air heard escaping from head gasket area indicates loss of compression past head gasket (perhaps due to a blown head gasket).

A leaking valve may sometimes be resolved by adjusting the clearance to within specs.

A leaking head gasket may sometimes be resolved by torquing the head fasteners when the engine is stone cold (such as after sitting overnight).

Good Fortune!

OK, morning update. After I posted that last post I had about 6 beers and went back to the shop. Fiddled with the timing a bit and the bike fired right up.

Put the timing light on and dialed it in...I hadnt checked the timing since the top end was re-done...it had been quite some time in fact.

So as of now it starts easily and runs well - started it cold, hot, kickstart, etc. a few times over the last 12 hours.

Will keep everyone posted. I guess the loose head / slightly off time was the issue

A leak down test would be a good idea even now that it is running, just to make sure I don't have any issues. The exhaust valve clearances are (all 4) are 0.0015 - which is a bit tighter than spec (0.002-0.004)

They should be at least .002, .004 would be better. The compression may come up after use.
Steve

Agreed...Time to bust out the shims. Now that I have established the bike runs again time to do maintenance like clearances and carb tuning.

Well, bike is back running and in working order. Adjusted the valve clearances, re-balanced carbs and verified ignition timing and buttoned it back up. So this thread can be filed under the 'solved' section!
Thanks for input from everyone.

Awesome I love the bike and was sick to see it die......... have you checked the comp again after all this ..... have checked my head bolts at 100 and 600 miles and after reading this I will at 1,500 too.

Ha! Yea good thing to check! Honestly no I did not bust out the compression tester. I am somewhat skeptical of its accuracy. Not one of my better HF purchases. I will at some point just for kicks.
And boy, the valvetrain is definitely a bit more chattery after loosening up the exhaust clearances to the loose side of spec...
I also need to tighten the 2 hex head bolts on the right/left outside of the head. Forgot to do that. Only rode the thing home from work (where my bike workshop corner is) so far.