Magneto tachometer cable problem
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
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From: Houston Texas
Yes, I would hope you can rotate it one tooth and that will allow the mag case to be parallel with the timing cover.
My recollection is that even with that, the tach cable was a tight fit because of the angle of the cable coming off the case and pointing toward the engine. But it should all work after you get the case better aligned.
pg
My recollection is that even with that, the tach cable was a tight fit because of the angle of the cable coming off the case and pointing toward the engine. But it should all work after you get the case better aligned.
pg
Cruiser
Joined: Feb 2008
Posts: 118
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From: Athens, GA
I had similar problems with magneto alignment. Morris Magneto set me up with a new gear that was drilled about a 1/2 tooth from what I had. Solved my alignment problem. They told me the drive gears are drilled randomly, so they weren't surprised with the alignment issue.
Cruiser
Joined: Oct 2008
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Well, I guess this is a "Pinion" question, The only Sportster that I had with a "mag" was a fuel drag bike based on a "67" XLCH engine. Not quite sure which part I owned ( kind of like two guys owning a horse), I built the engine and did the mechanical and my friend did the other stuff like tuning/ fuel mix, etc. We used a set of rollers that you could put a car on one side and the cycle on the other to start it, so it was turning 1500-2000 when you lit it off. I was looking @ your exploded view of the Mag and see no advance mechanism, did I "miss the boat" or does that mean that until they put the mechanical retard on the Mag you would be trying to start one with 45 degrees initial timing? Just never thought about that before. What was the compression ratio on the early sportsters?
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
Well, I guess this is a "Pinion" question, The only Sportster that I had with a "mag" was a fuel drag bike based on a "67" XLCH engine. Not quite sure which part I owned ( kind of like two guys owning a horse), I built the engine and did the mechanical and my friend did the other stuff like tuning/ fuel mix, etc. We used a set of rollers that you could put a car on one side and the cycle on the other to start it, so it was turning 1500-2000 when you lit it off. I was looking @ your exploded view of the Mag and see no advance mechanism, did I "miss the boat" or does that mean that until they put the mechanical retard on the Mag you would be trying to start one with 45 degrees initial timing? Just never thought about that before. What was the compression ratio on the early sportsters?
The magnetos had a fixed mount up through 1964. In 1965 onward the magneto was a movable mount with a left hand handlebar twist grip. Many people with the movable mount turned it into a fixed mount however. In my opinion it was really never of any great benefit.
The movable mount is the 'Y shaped' lever in the parts breakdown. (item #63)
The lever connects to a cable from the left hand twist grip. The 'advance' takes place when you turn the twist grip and the cable moves the magneto around in a clockwise/counterclockwise direction.
This moves the points foot inside to another location pertaining to the ignition cam. That is....It advances and retards the spark timing depending on which direction you twist the grip.
A 1957 Sportster (XL) had a 7.5:1 compression ratio.
When the XLCH came out in 1958 both the XLCH and the XLH both had 9:1 compression ratio. This held all the way through the 1974 models and probably beyond, although I cannot say for sure if a 1984 ironhead still had a 9:1 comp ratio or not because I am not that educated on these newer models.
pg
Last edited by piniongear; Feb 8, 2010 at 02:26 PM.
Cruiser
Joined: Feb 2008
Posts: 118
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From: Athens, GA
I think the gear and a new drive pin were around $25 - $30.
Last edited by GA Ironhead; Feb 14, 2010 at 05:51 AM. Reason: Found my receipt. Changed cost.
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Joined: May 2008
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From: Madison WI
Lots of time has passed since I posted, sorry for that..been busy. I heard that the magneto gear drives were manufacturered to low tolerances back in the 60's and the pin hole that holds the gear to the shaft in the magnetos was not placed consistantly at the factory when they were made. To this day they are still inconsistant. Sometimes putting a new gear will help...sometimes not. It is the luck of the draw. Is this true?
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Cruiser
Joined: Feb 2008
Posts: 118
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From: Athens, GA
That's what the folks at Morris Mag told me. They sent me a gear that was drilled about a 1/2 tooth off from the one I had, based on a picture I sent them after I had sent in my rotor. Solved my mag body position issues, which were similar to yours. If they know what your gear looks like, it's no longer luck of the draw.
Last edited by GA Ironhead; Mar 20, 2010 at 09:06 PM.
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