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Discussion Starter · #1 ·
This is all on a 1977 Shovelhead with a Joe Hunt Horizontal mount magneto in a kick only no battery bike
completely fresh top end was just done, fresh valve job was done also
this motor ran great for years and was a 1 or 2 kick bike with the electronic ignition that was on it before I put the magneto on

I narrowed it down to what I think the problem is
I am getting what looks to be good spark with the mag off the bike and just turning it slowly with a ratchet wrench

when the mag is on the bike and I am kicking it however I am getting a dimmer more random and inconsistent spark

what would cause this ?

Im thinking this is the reason I cant get the bike to fire

this is a video of the spark with the mag off the bike and me just turning it over at a normal speed with a hex drive attachment on a ratchet wrench


so far I have gone over the pushrods about 20 times they are not too tight at all

the timing is set correctly
front intake pushrod on its way down (both front pushrods down) and when the timing mark (F with a line) comes into the center Im setting the magneto to the narrow lobe where the points are just breaking open (verified with my buzz box, which Ive used to time all my other magneto bikes)

clutch is set correctly it is not slipping

magneto has new Morris Condenser and Morris points ( I cleaned the new points after I took them out of the package)
points are gapped at .015

I have the correct Autolite spark plugs that I use in all my other magneto bikes (these are the ones Morris recommends)
spark plug gap set at .018 and I also tried them at .020
on my other bikes I run them at .018
I am using solid core spark plug wires which are also brand new

Air-
I do not have any intake leaks Ive checked it over about 10 times and reinstalled the intake over 3 times and keep checking and I dont have any leaks

Fuel-
the Super E carb is working just fine, I stripped it down quick and cleaned everything out on it
it was not really dirty or gunked up at all
I have a fresh tank of 93 octane fuel I put in there today
I cleaned the pingel petcock out also and the vent for the gas tank

also the bike is getting really good compression as well on the compression stroke

what am I missing here ?
and what is causing the spark not to be consistent and bright when the mag is installed on the bike vs it not being installed on the bike ?
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Discussion Starter · #3 ·
Was the magneto mounted horizontally when you were testing it?
yes i had it mounted in the same position it would sit on the bike
i just held it in my vice
 

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Grasping at straws here, so take it for what it's worth (probably nothing). When installed on the bike, is there any type of "side load" created by the drive gear(s)? What I'm getting at is perhaps a bad bushing or something along those lines.

If it sparks good off of the bike, what could possibly change when on the bike?
 

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I can't see anything in the video, but is the cap on it when you are getting spark OFF the bike? Then no spark when you install it on the bike with the cap on?

Sometimes you can pinch the wires with the cap. Also the small springs may not be getting on the right spot with the terminals on the cap. What type of cap are you using? Black or clear?

ALso what type of ground are you using? A wire or a kill strap? Make sure the insulators thru the mag are not damaged where the kill stud goes thru.

Sixball
 

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Discussion Starter · #7 ·
I can't see anything in the video, but is the cap on it when you are getting spark OFF the bike? Then no spark when you install it on the bike with the cap on?

Sometimes you can pinch the wires with the cap. Also the small springs may not be getting on the right spot with the terminals on the cap. What type of cap are you using? Black or clear?

ALso what type of ground are you using? A wire or a kill strap? Make sure the insulators thru the mag are not damaged where the kill stud goes thru.

Sixball
the video just show the blue sparks at the end of the plugs I did it in the dark so it was easier to see the spark

and yes I have the cap installed when I bench test it off the bike

I have checked to make sure I am getting good contact from the coil springs to the cap
the cap is brand new also
I thought about the insulators from the grounding post ( i had nothing hooked up to it)
so I removed the entire grounding post and wire out of the magneto just to eliminate that issue

and again bench tested it sparks great
back on the bike no spark most of the time then very randomly a low spark here and there
certainly not enough to fire up the bike

so Im really scratching my head on this one
Im gonna call Joe Hunt and see what they suggest

for now I tossed the electronic ignition back in since its too nice out to not ride
 

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Unrelated to this problem, did you confirm with hunt whether it was a '93+ cam cover? To my knowledge all their 70-92 covers come with the breather tube. And as I said, I'm not sure what if any other difference there is but I'd hate to see you do all this work only to run into oiling problems

Back to your current problem. I'm not sure how you are measuring the difference in spark on the bike and off. With kick only and trying to watch a set of plugs while holding them together or on the bike isnt easy, nor will it be as consistent as spinning the mag off the bike. I say all that to say, are u certain your spark is different on/off the bike?

If so I, other than some kind of grounding problem, or a physical reason the mag isn't spinning with the motor. And about the only likely reason I can think for that is the mag drive that bolts to the cam is missing the rollpin that holds it in place on the cam or its sheared, so your drive is slipping on the cam. Or your hex drive is rounded off or smaller than that of the mag (as I recall, morris uses a larger hex than hunt, so if someone adapted a morris .........)

Otherwise I think ur spark isn't really better or worse on/off bike; it just seems that way. In which case two things come to mind
-you got a deal on a used mag right? I always subscribe to the belief that no one removes a mag from a bike bc it worked too well? I.e. something is wrong with some part of the mag, in which case u may wanna send it to morris or hunt for some love.
-personal pref but id always go morris before hunt, but that doesn't help u now.

Lastly a few basics that you've likely read but not already mentioned;
-solid core wires
-real bakelite cap, not a tcme
-as a test if you have can't get a spark to jump a 1/4" gap (if you create one by crossing two screwdrivers stuck in your cap, or with two old plug wires) then something is causing spark to be weak
 

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When bench testing, are you spinning it clockwise or counterclockwise?

A horizontal mags point plate is different than a vertically mounted one, and direction of rotation makes a difference!

Be sure you have a model 2RHD (right handed) and not a model 2LHD (left handed) mag.
 
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