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Kuda
Posts: 348
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Here's a weird one...

#1

Post by Kuda » Mon Sep 17, 2007 10:00 pm

So I'm still trying to figure out why my '49 FL is such a pain to start when it's hot. Sometimes. Cold, it starts right up and runs great. But if it's been fully warmed up, then shut off and sits for about 10 minutes, it can be a real monster. Like last weekend. But this time I noticed something weird: about every other kick, it would cycle over what felt like two full revolutions before I got a compression cycle. Not every time, but like every other, or maybe every 3-4 kicks. Not a half cycle, but at least one full cycle, maybe 1 1/2. And when it finally started, after about 5 straight minutes of kicking, it wouldn't idle, and backfired pretty bad when it got below like 2000 rpms. Now I'm starting to wonder if maybe a valve is hanging up? It's a basically stock '49 FL, but with 8.5 -1 pistons, FLH cam, solid lifters, a Morris G-5 magneto, and a CV carb (with a 3/8" phenolic spacer). 90% of the time it starts and runs great, but when it's warm and doesn't start right up, it's a a real monster. Any thoughts?

-Kuda



captainharley
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Weird One....

#2

Post by captainharley » Mon Sep 17, 2007 10:54 pm

Maybe it is flooding out real bad, washing oil off rings and drowning out the plugs? And when it does start running the plugs are fouled out causing missing and backfiring?!?!???? When it is warm/hot do you even "touch"
the throttle? I always tried to grab the handle bar just in front of the throttle so I would not accidently twist it when jumping up and down.

AMF/Ride Safe

FlatHeadSix
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#3

Post by FlatHeadSix » Mon Sep 17, 2007 11:35 pm

Kuda,

My 49 FL does the exact same thing and it drives me nuts! I don't like riding it on short hops, I only take it somewhere when I'm sure it will sit for a while before I have to start it again.

Mine is totally stock; 6 volt, M74 Linkert, etc. with the exception of solid push rods which I installed last winter. Before I went to solids it still had the original "oil-can" hydraulic push rods which were not opening the valves until they filled up with oil and built up enough pressure to bring the valves off the seats. That problem was even more annoying because after a few kicks it would build up so much compression in the cylinders you couldn't kick it over with both feet jumping on the pedal.

After installing the solid push rods it immediately started behaving exactly as your description. After a few "normal" kicks it will kick through a few strokes just like you had the spark plugs out, practically zero compression. I've readjusted the push rods a bunch of times, trying different methods but then it goes right back to the same behavior. The push rods are aluminum, the best results seem to be setting them so tight you can barely turn them.

So, my guess is the problem is in the valve train somewhere. I'm going to tear it down this winter and put in a cam designed to run solids, new lifters and a set of decent solid push rods.

If somebody else has a "quick fix" I'd sure like to hear it, I'll try anything.

It ain't no fun if it don't run!

mike

Panacea
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#4

Post by Panacea » Tue Sep 18, 2007 12:09 am

Kuda, I had that same problem with my 51. What I did to correct the problem was to get the timeing right on the money, mine was a bit late, and the cv can't be too rich. I'm useing a 45 pilot with a 85 main and she starts great now. Check the enrichener cable to see if it is fully inserted into the elbo, otherwise you'll have the choke on constant. And it goes without saying, start with an intake pressure test (Cotten). And a few words of encouragement to the old girl might help as well! Mike

Cotten
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#5

Post by Cotten » Tue Sep 18, 2007 1:54 am

Assuming there are zero vacuum leaks, and timing is dead-on...

The first thing I would suspect for hard hot starts would be that the solid adjustors are loose.
A quick drop of the covers will tell if the pushrods are sloppy when hot.

....Cotten

Kuda
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Re: Weird One....

#6

Post by Kuda » Tue Sep 18, 2007 1:05 pm

[quote="captainharley"]Maybe it is flooding out real bad, washing oil off rings and drowning out the plugs? And when it does start running the plugs are fouled out causing missing and backfiring?!?!???? When it is warm/hot do you even "touch" the throttle? I always tried to grab the handle bar just in front of the throttle so I would not accidently twist it when jumping up and down.[quote/]

Not flooding, for sure. In fact, the ONLY way it'll start is by flipping the throttle a couple of times, then having it open about 1/4. One or two kicks, it'll pop and start to catch, then a couple of flips, 1/4, and again. Eventually, it'll catch. If I don't open the throttle at all, I can kick all day and get nothing...

-Kuda

Kuda
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#7

Post by Kuda » Tue Sep 18, 2007 1:09 pm

Panacea wrote:Kuda, I had that same problem with my 51. What I did to correct the problem was to get the timeing right on the money, mine was a bit late, and the cv can't be too rich. I'm useing a 45 pilot with a 85 main and she starts great now. Check the enrichener cable to see if it is fully inserted into the elbo, otherwise you'll have the choke on constant. And it goes without saying, start with an intake pressure test (Cotten). And a few words of encouragement to the old girl might help as well! Mike
I was using a 45 and a 185, went up to a 46 and a 190. I'll drop back to the smaller sizes and see how that does. One of the reasons I went up a size was the idle mixture didn't do anything at idle, and pinging on long uphills. The intake tested fine up to 12 psi. I'll double check the enrichner, but I'm fairly sure it's OK. Can't hurt to double check. As for encouragement, I can't honestly say that I'm always encouraging. In fact, I've developed a whole new set of profanities when it was 114 and she wouldn't kick in MT...

-Kuda

Kuda
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#8

Post by Kuda » Tue Sep 18, 2007 1:16 pm

Cotten wrote:Assuming there are zero vacuum leaks, and timing is dead-on...

The first thing I would suspect for hard hot starts would be that the solid adjustors are loose.
A quick drop of the covers will tell if the pushrods are sloppy when hot.
Timing is always a crap shoot with that thing. I love the simplicity of the G-5, but since it can't be static timed, the strob is the only way to go. And I've had horrible luck with that. Even using a time sert (rubber tube that supposed to brush against the flywheel), it shoots so much oil out of the timing hole that the gun gets blocked up pretty quick. Plus, the timing mark jumps all over the place, popping in and out of the hole. Since I can't run a tach, I'm just guessing I'm over 2,500 when I run the light...

As for the pushrods, I'm still using the aluminum pushrods as I haven't been able to find any steel replacements. Tried ordering a set but when they showed up they were for '54 and up. (Still have 'em if anyone wants to trade for early model steels.) I adjust 'em so they're barely fingerable when cold, using two oily fingers. I was thinking maybe they were too tight, lifting the valves off the heads and bleeding off compression. But as you said, that's an easy thing to check, so I'll check that too this weekend...

-Kuda

fourthgear
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#9

Post by fourthgear » Tue Sep 18, 2007 3:53 pm

Have you done a compression test and leak down test ?Check travel on push rods while you got the covers down.
I don't have any problems with the alloy push rods ,if adj. correctly.

Panacea
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#10

Post by Panacea » Tue Sep 18, 2007 10:48 pm

Kuda, try this method for timeing, put the advanced timing mark in the center of the timing hole,(front cyl. comp stroke) then turn the auto-advance lobe clockwise till it stops and hold it there with a small screwdriver, with a buzzer or test light hooked up to the points, turn the timer counterclockwise till the buzzer just stops. Lock the base in this position and re-check. If you have one of those hall effect systems I'm not sure how to read the signal other than just useing the little light on the thing, but that should work fine also. I'm sure you know how to set timeing, I just wanted to share the part about turning the lobe manually to full advance. I tried useing a timeing lite with a plastic plug in the timeing hole, but with stroker wheels the plug won't reach close enough to see the mark. Another way to tell if your CV jetting is close is this, after starting up the motor when cold, how long must you wait before pushing the enrichener fully back in? if you can do it right away that tells me the pilot is too big. It should take at least a couple minutes to warm up enough to run on it's own. Nuff said! Mike

Panacea
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#11

Post by Panacea » Tue Sep 18, 2007 10:57 pm

Kuda, I forgot to add, if you are opening the throttle 1/4 turn when starting that screws up the enrichener circuit, try a squirt or two from the throttle pump then two kicks key off, key on, one or two kicks and she should fire right up. After it's warm just one kick no throttle no choke. Mike

Kuda
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#12

Post by Kuda » Wed Sep 19, 2007 1:32 pm

Panacea wrote:Kuda, try this method for timeing<snip>,

Another way to tell if your CV jetting is close is this, after starting up the motor when cold, how long must you wait before pushing the enrichener fully back in? if you can do it right away that tells me the pilot is too big. It should take at least a couple minutes to warm up enough to run on it's own. Nuff said! Mike
Great stuff, but unfortunately I'm running a Morris G-5 magneto, which uses an inductive coupler to create a hotter spark. Works great, I can "kick" it over with my hand, but because it "snaps" around when it fires, the unit can't be static timed at all. Plus, the advance must be built into the base, 'cause I can't seem to see any way to manually advance it.

As for the enrichner, it definately will NOT run for at least 2-4 minutes without the enrichner, but I can't tell if it's the added idle speed or richer mixture that's causing that...

-Kuda

Ohio-Rider
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#13

Post by Ohio-Rider » Wed Sep 19, 2007 2:36 pm

Kuda... I am also one of the panhead owners that have been trying to figure out why they act this way when hot. With mine, if I shut it down while hot and go to restart it immediately it will start right back up. But if I let it set for as little as ten minutes I'll be a kicking for a while.

I'm using an S&S "E" with mine. I have found that while hot if I go to start it when hot and use the procedure as when cold except I hold the throttle open about 1/2 way, it seems to help.

This same topic has been discussed many times over without anyone coming up with a sure fire method of starting a hot panhead. I believe the guy who figures it out will become the hero of many of us.

VT

#14

Post by VT » Wed Sep 19, 2007 3:50 pm

After installing the solid push rods it immediately started behaving exactly as your description. After a few "normal" kicks it will kick through a few strokes just like you had the spark plugs out, practically zero compression.
Focusing on this particular abnormality, my 59FL used to do the same thing. Sometimes I would be able to kick the motor over repeatedly and have no compression. Years later, I removed the heads and found that Old Lakeside Bill had built my motor using a '49 rocker arm in a bearing block that allowed the rocker to bind and stay open. Even with this condition though, I guess eventually the rocker arm would get released and drop back down. I still got a lot of miles on the heads before I decided the heads needing re-manufacturing.
Static timing is important to make sure you have it dialed in spot-on, as someone already suggested. If you start having trouble getting the single lamp bulb to light (or to go out, depending on if you have your test light grounded or not), then look for worn timer shaft bushings (2). Worn bushings are rare, but enough slop will allow the shaft to move laterally and drive you crazy. You can see what it did to me....don' t let it happen to you.

fourthgear
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#15

Post by fourthgear » Wed Sep 19, 2007 8:21 pm

Also, the Circuit breaker ( distributor,Magneto etc. )drive gear could be worn or shaft end play may not be to spec's..Vintagetwin makes a good point about the rocker arms , even if a little stiff , could make the valve timing a little slow and can effect starting.
I wish I could help you with the Mag. timing , but I have never ran or worked on one , they may give great performance ,but all my Bro's that used them always were bitching about how hard they were to start and it could have all been a timing thing.

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