Hard ti Kick Panhead

[billpedalino]

In all the years I've been doing this, I've come across a problem that, at least for now, has me stupmed (but still working on it), I just completed my '53 FLE and it runs wonderfully - for the five minutes that I've run it. The reason for the short run-time is that it's quite hard to kick. Realizing this, I decided that its not right and started investigating. Before going further, please allow me to state that I've built many Harley motors and own, and have owned multiple old bikes for over 50 years. So yes, I do know what it feels like to kick a 74 or 61.
So, at this point, the bike is up on the lift with its cylinder heads removed and has gone through sequential and rigorous investigations in trying to isolate the problem. In doing so, I've eliminated the most obvious possibilities and note the following findings:
Stroke was confirmed as stock 3-31/32"
Cylinders are stock Length 5.535"
Piston crown distances were compared to stock 74 pistons and are a match in height - they're NOT high-compression.
Cylinder head depth (compared to 2 other stock heads) is stock at 1.850 (gasket surface to combustion chamber crown). They haven't been milled.
Compression is 114 psi, which is consistent with the above findings.
Outer Valve springs were checked at 1" compressed length with a reading of 187 lbs. Coil bind >0.075" after valve is fully open.
Rocker arms are OEM.
Valve seats are new (Head Hog, may Bob Sullivan R.I.P.) and valve penetration is back to new/stock.
Cam is new, Andrews 'J' which I always use, although I haven't checked it yet with a degree wheel - but it runs so well that I doubt this is an issue.
Given the above, and given the normal compression readings, I'm baffled as to why I really have to stand on the kicker to start this thing. Also note that I'm using the newer kicker gears (1959 P/N), but the normal kicking pressure difference between the two is far less than I'm experiencing.
Any suggestions?
Thanks for enduring the above!
Bill Pedalino

[Rubone]

Hi Bill,
Too much ring pressure, lands machined deep enough in the pistons?
Flywheel end play, washer shifted?
Gearbox issue, bushing binding etc?

[FNG1]

Maybe remove the cam case cover. Look at the cam endplay and bushing clearance. Hope this helps

[T. Cotten]

Good suggestions Folks,..

But wouldn't Bill have felt them with the plugs removed?

....Cotten

[billpedalino]

Hi Bill,
Too much ring pressure, lands machined deep enough in the pistons?
Flywheel end play, washer shifted?
Gearbox issue, bushing binding etc?

Thanks Robbie - you can always be counted on for intelligent responses!
And thanks to you Cotton and FNG for equally observant thoughts....
I must admit, I wouldn't have thought of ring-to-wall pressure! But I don't think that's the problem. I had also removed the front cylinder to check the ring gaps, although I didn't even imagine checking the ring depth in the piston. But I did compress the rings tight to the piston diameter in the ring compressor and then backed it off a bit before sliding the cylinder back over the piston, so I do know that there is distance between the compressed rings that the back of the ring lands.
Also, when both heads and the front cylinder were off, I also removed the cam cover to check that I didn't have a senior moment and install the cam a tooth-out. I was able to move the flywheels left and right, so the 0.012" (+/-) end play that I originally set is still there. You are astute in cautioning against a flywheel washer slipping off of its locator pin, but apparently this hasn't happened.
To be a little more descriptive, with both heads removed the motor turns over very easily when cranking the kicker by hand. Using the rear head only as a test, with the head and push rods installed (at 4 turns into the bleed hydraulic lifters) the motor still turns over very easy by hand. It's not until the spark plug is installed that the cranking pressure increases. Yet, the compression chamber pressure is only 115 psi...!!
Very strange.....
HAPPY INDEPENDENCE DAY TO ALL!!

[dukekleman]

Quote: "Using the rear head only as a test, with the head and push rods installed (at 4 turns into the bleed hydraulic lifters) the motor still turns over very easy by hand. It's not until the spark plug is installed that the cranking pressure increases"

This rules out my thoughts of idler gear issues (tight end play) and thoughts of generator issues causing binding resistances.

[billpedalino]

Quote: "Using the rear head only as a test, with the head and push rods installed (at 4 turns into the bleed hydraulic lifters) the motor still turns over very easy by hand. It's not until the spark plug is installed that the cranking pressure increases"

This rules out my thoughts of idler gear issues (tight end play) and thoughts of generator issues causing binding resistances.

I wish you were right! Unfortunately no....

[dukekleman]

Bill,
Any discoveries on this issue?

[billpedalino]

Gentlemen,
I've read a report of an instance where an Andrews cam was purchased with the camshaft improperly indexed onto the drive gear. So I purchased another J Cam thinking that, if the cam is improperly indexed toward the advanced position, this would significantly increase the compression pressure. It's now installed and the bike will be off the lift in a couple of weeks. I'll give it the kick-test then. But quite frankly, I'm still skeptical.

[vph-d]

I once installed a Sifton 468S cam that had the gear pressed on in the wrong place. As I remember, the bike was easy to kick, but I think these cams were known for that, but ran poorly.
vph-d

[billpedalino]

Gentlemen,
I've read a report of an instance where an Andrews cam was purchased with the camshaft improperly indexed onto the drive gear. So I purchased another J Cam thinking that, if the cam is improperly indexed toward the advanced position, this would significantly increase the compression pressure. It's now installed and the bike will be off the lift in a couple of weeks. I'll give it the kick-test then. But quite frankly, I'm still skeptical.

Good day all,
Well, the cam was changed and the high compression problem still exists. I'm now thinking that when Head Hog (R.I.P.) replaced the valve seats, he milled a significant amount of material from the gasket surface, thereby reducing the combustion camber volumes. I previously measured the distance from the gasket surface to the crown of the chamber using a caliper, to compare with another head. However, I don't have faith in the accuracy of my measurements.
We used to measure actual combustion chamber volume by 'CC-ing' the chambers using colored alcohol which I should do to accurately measure these volumes. I'll start looking for the graduated cylinders that I'll need. If I can arrive at accurate measured volumes, I have other heads that I can compare these measurements to.
I would be interested to know if anyone knows the standard panhead chamber volume. Hopefully, my volumes have been significantly reduced and all I have to do is make some aluminum stroker plates to install beneath the cylinders.
The bike will be up on my lift in the late Fall, so we'll see where it goes then and I'll report back.