1964 FLH Spark Plugs Fouling

[Iacovos]

Hello everyone
We had been working on a second 64FLH (not the one we rebuild the carb and changed manifold seals - which is working great).
on this second FLH we did timing, new plugs and reset the carb as per manual.
The bike would run ok however if you tried to open the throttle quickly it would hesitate/cut-out.
After three runs the spark plugs fouled (see pics)
How can i back track and fix this?
Where to start?
Facts are:
1) Carb was rebuilt 2-3 years ago
2) In a box given with the bike i have found a spare brass float (so probably carb was rebuilt with brass float)
3) Have not performed vacuum leak and not sure if manifold seals where replaced at the time the carb was rebuilt
4) on couple of occasions i found some gas leak from carb (believe from small hole)
5) Both plugs appear to “blacked out” the same (see pics)

The idea is to pull off the carb and do a rebuilt and change the float if brass

also change the manifold and carb intake seals

Anything else i could be missing?

Thanks a lot

[tomfiii]

You need to finish adjusting carb. maybe lean out idle and set to best running, then adjust high speed.

[T. Cotten]

When you swap out the manifold seals, Jack,

I suggest using viton seals (such as from JAMES Gaskets) and bubble-testing while you tighten the clamps in order to avoid over-tightening.

....Cotten

[1939wl]

Hello lacovos.
Are you running the stock dual point timer? Careful attention needs to be adhered to when setting point gap (Front cam, rear cam on timer) and setting timing.
The intake seals available just get destroyed with the modern gasoline which may use at least 10% Ethanol. If using non-ethanol premium grade service life is longer but not near as well as when the engine was built in 1964, and we could buy "good gas". I have ridden a Pan since 1972, and find now that I routinely change my intake seals every Spring, and I always run non-ethanol premium in my bike. I built the motor with less cam, and less compression as well. Just a couple ideas. Intake seals used to last 10 years or more, but not with todays pump gas.
Hope that may help.

[1939wl]

My post went out at the same time as Cotten's.............totally agree with him. Viton seals are the only way to go and bubble testing should always be done.
Using a good quality clamp as well.

[T. Cotten]

It ain't just the ethanol, 1939wl!

There are uncountable Federally allowed additives, (https://www.epa.gov/fuels-registrati...-under-part-79), such as Intake Valve Deposit inhibitors ( 'mandated' IVDs, which are why its now futile to read plugs for 'color'), antifoams, injector cleaners, etc., which are all probably corrosive or digestive, and ethanol just makes those worse.

If you start mixing pump fuels, particularly traveling to different regions, there is a synergistic effect that can make it eat just about anything. So its best to pick a fuel and stick with it.

....Cotten

[Iacovos]

Thanks for all the replies everyone

1939wl - correct the bike is running stock dual points which had been set as per manual.
This is very interesting on what you say on the increased frequency of changing the intake manifold seals! Completely agree that modern gas is causing a number of problems on the old bikes. Will definitely go for manifold seals.

Cotten - so should gas additive be used? My Knucklehead which was restored I know that the valves had been done to accept the “newer type” gas like unleaded, but not on the Panhead.
I know the manifold seals you are talking about from James as we have used them on the other 64. They are great!

Last but not least - bubble test - i think there was a link somewhere on the procedure in the forum right?

[T. Cotten]

Modern USA fuels, Jack,

Cause many "rubbers" to expand, and eventually fail:

P4ORING1.jpg
ORING.jpg

Viton resists far, far better.

Its been decades for me, but the traditional "unleaded" kit just meant nitrided valve stems, guide seals, soft castiron guides, and often-disastrous hardened seat replacement (Knucks are already 'hard'),

I doubt the effectiveness of any out-of-a-bottle additive, except to lighten your wallet.

A simple discussion of bubble-testing can be found at http://virtualindian.org/11techleaktest.html; A constant, regulated air supply is critical.

....Cotten

[Iacovos]

Thanks Cotten

Wow that seal has really swollen!!

Understood on the additives and agree completely

Will revert with updates -

Need to do a number of things on this 64 namely

Wiring - couple of bypasses and non correct wiring used on places. Best bet is complete rewire

Correct repop parts with oem

Manifold and Carb rebuilt / seal

THANK YOU FOR YOUR INPUT

[dukekleman]

Lacovos,

Your spark plugs indicate that the fuel calibration needs to be dialed down, not that your leaking ambient atmospheric air...

I would verify proper spark quality (KV output) and then dial back the fuel delivery.

Do you have OEM hydraulic valve train yet or has someone reverted it backwards to solid lifter?

Duke

[T. Cotten]

...Your spark plugs indicate that the fuel calibration needs to be dialed down, not that your leaking ambient atmospheric air...
Duke

Just what if, Duke,..

An air leak required the needles to be fat, fouling the plugs, because it wouldn't run any other way?

Once Jack puts in a decent float and snugs up the clamps just right, then the plugs should not be an issue.

I don't remember KV output in any of my manuals, but then they didn't seem aware of bubble-testing either. (Except for an oilpump note in the "Panhead Manual" compilation, page 304 or so.) It was probably first documented on papyrus by Heron of Alexandria.

...Cotten

[dukekleman]

Cotton,

The float, if working incorrectly, could dialed down the fuel calibration as I stated.
Tightening the clamps, if they are leaking, would do the opposite.

Yes, I have not read an older service manual where the technical writer has published the kilo- volts.

We have come along way with tooling, method's and procedures. Even from the 80's when I started service Shovelheads and the new Evolution series.

A lot has changed over the years indeed and the adaptability of modern tooling and methods has been a positive thing.
I know these things from what is coming down the pipeline
(Future technology) and from where we've been.

I truly feel blessed to have grown up in shops servicing Flatties, Knuckles, Pans, Evo's, Twin Cams and M8's.

The older ones have always been a passion and a challenge to improve upon.

Apologies for getting a little off track,

Duke Kleman

[T. Cotten]

I guess if the float is "working incorrectly", Duke,

All bets are off, and any correction by the needles would be only a band-aid; Tightening the clamps can go either way as well.

An air leak producing sooted plugs is easy to illustrate:
Consider the most common situation where only one plug is sooted; The motor demands to be tuned for its weaker cylinder, thus the one with a leak will burn cleaner, and the sealed cylinder will be naturally too rich.

In this case, many variables must be considered, and we hope they come out in the wash with a proper float and sealed manifold.

....Cotten
PS: Another bubble-testing note specific to Pans, Jack,..

Unless you are a true believer that the pans have never been removed, it is always prudent to squirt snooping soap upon both cover screws directly over the intake ports, as it can be maddening when they have been abused; I even encountered one that was welded back up but still leaked:
panpoke.jpg

[Iacovos]

Lacovos,

Your spark plugs indicate that the fuel calibration needs to be dialed down, not that your leaking ambient atmospheric air...

I would verify proper spark quality (KV output) and then dial back the fuel delivery.

Do you have OEM hydraulic valve train yet or has someone reverted it backwards to solid lifter?

Duke

Thank you dukekleman

Th bike is running hydraulic lifters (i believe correct after 52-53 for the OHV engine?)

Since i will be getting into sorting a bunch of other things (wiring and replacing repop parts, speedo needs attention also) and the fuel tanks will be off the bike, would be worth getting into that carb as well, replace and adjusting float. Then of course resetting and correctly dialing in the carb.

Also will be worth changing those manifold seals

[Iacovos]

I guess if the float is "working incorrectly", Duke,

All bets are off, and any correction by the needles would be only a band-aid; Tightening the clamps can go either way as well.

An air leak producing sooted plugs is easy to illustrate:
Consider the most common situation where only one plug is sooted; The motor demands to be tuned for its weaker cylinder, thus the one with a leak will burn cleaner, and the sealed cylinder will be naturally too rich.

In this case, many variables must be considered, and we hope they come out in the wash with a proper float and sealed manifold.

....Cotten
PS: Another bubble-testing note specific to Pans, Jack,..

Unless you are a true believer that the pans have never been removed, it is always prudent to squirt snooping soap upon both cover screws directly over the intake ports, as it can be maddening when they have been abused; I even encountered one that was welded back up but still leaked:
panpoke.jpg

Thank you Cotten for mentioning another area to do a bubble test
i am sure the Pans were off as i know the piston rings were changed when the bikes were re-commissioned back in the 80’s

Jack