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Pandemic Panhead Project: Part 3 Tuning

It was a lesson in Frustration on Several Fronts

by Bandit with photos by Wrench
1/4/2021


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I’ve built a number of bikes and maybe I was just lucky. With the Pandemic not so lucky. Trouble getting it started in Sturgis, so we brought it home and sent the Morris Magneto back to Deadwood Custom Cycles for a check-over.



When I got it back, I retimed the engine, adjusted the carb and kicked. It finally popped. I had all the elements in place, but I wanted to know more. I called Lee Clemens, the owner of Departure Bike Works for over 40 years. Throughout his tenure he built anything and everything, so I asked him for some of his precious time.

First we talked about magnetos. I was instructed to set the points at .016 by Flathead Fern’s son at the swap meet and Lee confirmed it.

(Sidebar: Fern’s son warned about a new bad condenser mag guys were running with a Chevy logo stamped in the side. They are a cheap Chinese product and won’t last. Beware.)

Lee added something. He gets hard-starting old Sportsters on a regular basis. He removes the point plate carefully and with a Scotch brite pad cleans the magnet plates and armature of any rust. They fire right up.

Jason Mook at Deadwood Custom Cycles told me that mags can lose their magnetic charge, and that makes sense, if a magneto sits around in the wrong position for an extended period of time. He also said the charge can be reenergized in a few minutes by spinning the amateur.



Okay, I checked the marks on the flywheels to make sure the slot was 35 degrees before top dead center on the front cylinder, but Lee warned that finding TDC and backing down to the timing slot was not the way to go because of gear lash. You want the flywheels to come up to the slot, not back down to it.

The advanced mark should show up with the front piston 7/16 of an inch before TDC. Make sure to use something that won’t break off in the cylinder. I’ll bet JIMS has a special tool.

Lee suggested taking a scribe and marking the case and the mag, so you can mess with it and see where you made a change. Counter-clockwise is advanced.
Lee suggested taking a scribe and marking the case and the mag, so you can mess with it and see where you made a change. Counter-clockwise is advanced.



Lee also suggested timing the locked-down mag slightly retarded. Don’t want to break a leg. I use an ohm meter on distributors to set the points to just beginning to open. Lee suggested the cellophane wrapper off a pack of smokes. He wants the thin material to just drag out from the points where you lock it down.



It’s interesting. We never set up a mag to be retarded or advanced. I don’t know of any magneto mounting plate that allows retarded and advanced positions, but I bet there is one. We will get more into that, when we discuss the Dicey Knucklehead.


Lee called for four turns. Don't forget open the choke first.
Lee called for four turns. Don't forget open the choke first.



Regarding the carb, this has a M-35 Linkert rebuilt by Mike Egan, 20 years ago with next to no mileage and hopefully no Ethanol fuel. Lee suggested 4 turns out on the low range jet. Linkerts don’t have accelerator pumps, so jerking on the throttle doesn’t do anything. You need to use the choke.

I used a nut behind the kill tab to ground the mag for priming.
I used a nut behind the kill tab to ground the mag for priming.



He suggested no ignition and kicking it four times with the choke closed and the throttle open to pull fuel into the cylinders without any spark. Then opening the choke slightly and the throttle at quarter open and kicking.

In the foreground is the intake pushrod for timing. We were forced to remove the clip on the exhaust tube to get the mag in and out.
In the foreground is the intake pushrod for timing. We were forced to remove the clip on the exhaust tube to get the mag in and out.



I started to check everything again. Lee also confirmed that to find the timing mark easily take the front intake pushrod all the way up, and as it starts to close, start looking into the hole for the slot. Just after the valve closes the slot will appear. In this case the wheels contained a round indent at top dead center for the front cylinder.

Okay, we timed it again. Still wouldn’t start. Took the float bowl off and cleaned all the jets. Here’s where we started to learn more about Linkerts. We got it to deliver fuel and pop out through the carb on each kick. Lee said it was too advanced. We adjusted and kicked some more.

The mag had to be removed to lift the plate and stem and turn the gear. We ran into a problem removing it and almost freaked. We turned the engine over slightly and it behaved itself.
The mag had to be removed to lift the plate and stem and turn the gear. We ran into a problem removing it and almost freaked. We turned the engine over slightly and it behaved itself.



Magnetos are so cool in some respects but positioning them and clearance can have issues. Maybe that’s why they don’t have retard and advance plates. There’s not enough room for them to turn.

Lee said the copper float bowls in Linkerts were bullshit and to replace it. The adjustment must be perfect at ¼-inch from the edge of the float casting to the float bowl ring. He also said the float needle must hold air for 10 seconds or the float will flood the carb.



If you wash the cylinders down with fuel, it will destroy a set of rings in a hot flash. He also mentioned a small stapled book about Linkerts. I will try to find one. The Linkert carb bible.

The next day we discussed oil tanks, venting and external vents. When I kicked the Pandemic the rubber oil cap popped out. There is a feed line to the oil pump and a return line, no problem right. Then there is a vent line from the cam chest to the oil tank, but that doesn’t mean the oil cap needs to be vented like a gas cap.

But there is a way for your engine not to have enough venting. On the good doctor’s Panhead, his crankcase vents out a cavity in the case to a fitting aimed into the inner primary to oil the primary chain when the pistons are headed down inside the cylinders. Blocking that line in anyway slows the piston travel down and creates pressure in the engine.
 
 
 Later engines had a vent off the case behind the oil pump. There is a solution for this line. “It should be at least a foot long and not contain any goofy filter at the end,” said Lee. There’s a pulse of air being released. If the line is too short and you’re riding on dusty roads, it can suck dirt into the engine. A 1-foot line should be fed to the ground, the primary chain or the rear chain.

Okay, I asked Kent Weeks of Lucky Devil Metalworks about oil tanks and he brought up a couple of items to check. He wants me to check the compression and the valves again. If compression is weak or the top end leaking, that can add addition pressure in the cam case that can push into breather and into the oil bag. It can also be caused if Evo head breathers aren’t doing their job.

We also discussed starting fresh engines and how the drive gear on the circuit breaker lines up with the intermediate gear in the cam case. If there’s slop there the timing will change. Kent said he ran into two recent examples in his shop, Lucky Devil Metalworks in Houston. One was a Pan and the other an early Shovelhead. One would run one day and not the next, because the timing shifted so much.

Get this, he wanted to take the Pan for a test ride. It was on his lift, so he climbed up and kicked it. It kicked back and launched him into the air. He came down and his knee took the brunt against a fishtip exhaust pipe tearing the flesh as he fell. Then his lower back got tweaked against unforgiving concrete on the slick deck.

That’s not all. The open shop door revealed folks outside, but no one seemed to notice, so he crawled over, slid the door shut and lay back down on the concrete in abject pain. After a while he struggled to a couch. Then the phone rang. It was one of the girls in the complex office. “Can you come over,” she said frightened. “This badass is coming and threatening me.”

“I need a break,” Kent said. “Can you handle it?”

A minute later she called back. “I’m really concerned.”

This time Kent explained what went down and how he peeled the skin away from his kneecap. “Please,” she uttered.

“Okay,” Kent said. “I’ll come over, but if he acts up there’s nothing I can do but to shoot him. If you’re alright with that I’m coming.”

Kent hobbled to the office armed and sat in the corner. Not long after he arrived the door opened and Billy badass stumbled in using crutches. His leg was badly bandaged. Seems someone else just shot him.

Meanwhile back at the Pandemic in Wilmington, California, we removed the magneto and put it in a vice and spun the bastard with a machined Allen wrench chunk. It fired like a champ. We installed, timed it and still nothing.



I had prepared for an alternate contingency and found a used classic auto-advance mag from Flathead Fern. He checked it out and installed points and a condenser. I was concerned about my ’46 Knuck. It wasn’t starting and held another Morris Magneto. It was a monster with a retard unit attached for easy firing. You don’t need to kick these units hard, just nice and easy.



I took the S&S Shorty off and it was a mess. I cleaned the jets, the accelerator pump, checked the float and it started to work. I added a new foam filter from a shop vac to the Fantasy in Iron air cleaner and it worked like a champ with the help of the Redhead.

If you take the drain plug of the bottom of the S&S Shorty and it looks like this, you've got a problem.
If you take the drain plug of the bottom of the S&S Shorty and it looks like this, you've got a problem.





I put it back together and corrected the mounting some, replace the fuel filter and turned on the gas.



Fuel ran everywhere, so I shut it off and fixed the leaky accelerator pump cap.


There are two tiny O-rings (blue), two ball bearings and one tiny spring that fit into this accelerator pump cap, with the diaphragm and the return spring. It's tricky, but not bad to put back together. Just don't fuck up like I did.
There are two tiny O-rings (blue), two ball bearings and one tiny spring that fit into this accelerator pump cap, with the diaphragm and the return spring. It's tricky, but not bad to put back together. Just don't fuck up like I did.





I didn’t touch the mag and it fired to life immediately. Dave from Morris Mags and I installed that mag in the mid-’90s. It’s never been touched. Amazing.


All these puppies had to be soaked in something like paint thinner, cleaned and blown out.
All these puppies had to be soaked in something like paint thinner, cleaned and blown out.






Got to say, the S&S was a breeze to remove, repair and re-install.
 




So, when it came to the Pandemic we wondered which way to turn. I spent some change on two auto-advance circuit breakers, one new re-pop from Twin Power. It was cool but the base was wrong, but workable.



I installed a coil on the Pandemic and made up another set of sparkplug wires. I fashioned an old, modified bracket for the coil around my funky wiring system. I also had to add an ignition switch, wire the coil and buy and install a small battery.





I soldered the battery cable for a solid connection.
I soldered the battery cable for a solid connection.



I put it all together and timed the bike. It fired on the first kick. Every time after that when attempting to fire the bike, it hit on the first kick, after choking the carb. Amazing.



So, other than the oil breathing issue, this bike is ready for a test ride.
 
--Bandit 

Sources: 
 
S&S
 
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Departure Bike Works
 
Click for action from Departure Bike Works.
Click for action from Departure Bike Works.


 
Lucky Devil Metal Works
 
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Deadwood Custom Cycles
 
Click for Action.
Click for Action.

 
Twin Power
 
 
Click for action.
Click for action.

 
JIM's Machine 
 
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