new HUNT magneto fitting question

[reverb]

...hello, in my pre unit the magneto is just a plug and play fitting but in this unit the tapered shaft of the mounting plate seems that does not fit properly...the tapered part of the shaft measures 7/16 and the camshaft hole before the threads measure the same.
From the edge of the threads of the cam to the edge of the timing cover measures the same as the mounting plate race to the edge of the shaft ¿? BUT when I put the plate does not fit to the timing cover. I have a gap of 5.5mm. How s that?
Is for the camshaft pin there?


This is my first time with a unit engine and magnetos.

Thanks

[Tony the torch]

On a unit Triumph cam cover the Hunt mag mounting plate often needs to be clearanced a bit up around the 11:00 position to fit into the cam cover.

Just keep sanding off material until it finally fits flat in the cam cover and the screw holes line up.

[reverb]

...hello Tony, so in other thread I just read from Vintagespeed "the cam on my '70 TR6 motor has a nipple in the bottom of the taper, which prevented the EI tapered rotor from seating fully.

i had to file off a little of the bottom of the taper so it would seat fully before touching the little nipple in the bottom of the cam."


---May be I would push that nipple up, somehow? I tried to screw in the mounting plate but no luck with that nipple.

Also, not sure what part I need to keeping sanding?

All these hassles because Hunt doe not have any precise instructions for their products.
And pretty bad communication for an expensive product.

[Tony the torch]

that "little nipple in the bottom of the cam" .....take a sharp punch hit it with a hammer as so to shear it off.

then typically you need to sand off some of the mount plate up in the upper left side to get it to seat flat on the cam cover.

[reverb]

...incredible that no one mention that when fitting these mags...the 650 s and 750s camshafts that I have seen have this nipple.
What s exactly the purpose?
Is to prevent that something enter inside the cam or is to enhance the rotation of a given piece?
Could be better if I cut the shaft to fit in the nipple to have a tighter seating?

Also, if I whack it down then the surface there could not be perfect to seat the shaft...again, nobody mention anything about it or to have a shaft seating problem due to finish with a not so perfect cut...

[Tony the torch]

that little pin is used to time the stock ignition.

you change one thing...you change many things.

.

[reverb]

...so if for some reason I decide to put an electronic ignition. It should go with that pin or is not necessary?

Thanks

[richbob]

The pin is a location point
Smash it off then maybe mark its location with a little centre punch or file mark
Tapers are meant to secure all not the pin
( or grind a slot in your mag ?)


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[reverb]

...yes, I mentioned to do a slot in the shaft...but I am not sure about it.
Location for what?

[richbob]

Location for what was there originally


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[Tony the torch]

Originally Posted by reverb

...so if for some reason I decide to put an electronic ignition. It should go with that pin or is not necessary?

Thanks

it's not necessary for a Hunt mag or an electronic ignition....only the stock points ignition.

if you try to file a slot in the Hunt taper drive you will play hell ever getting it timed correctly.

just punch it out and forget it was ever there.

you'll be fine

[reverb]

...will do soon. Thank you fellas.

[reverb]

...I did it, still I have that gap but may be is solved putting a shorter allen screw...
The screw is 1 1/4.

-Anyway, the Hunt instructions say that for safety is better to drill and tapping engine with 1/4 x 20.
Where should be that?

[Tony the torch]

the 1/4-20 repair is only necessary, after you fuck up the existing threads.

[reverb]

...the gap remains but may be is in this way? I tested different screw lengths.
The plate is not touching the timing cover and all is fully adjusted with the 3 screws.

I shoot these photos showing it. Please click and enlarge to have a better look.
I think the water could enter in this way.

Thanks

[Tony the torch]

that's where I was telling you that you need to grind off some aluminum from the mount where it interferes with the bumped out part of the cam comer....

ok imagine it is a clock face... 12 o'clock is the top.

now...grind the inside edge of that mount starting from about the 7 o'clock position all the way up to the 11 o'clock position. If you look carefully under the mount you will see the mount hits the cam cover right there closest to the "patent plate"

that's why the mount won't fit all the a way in....almost every other Hunt on a Triumph cam cover is the same shit.

grind it and be done with it.

[reverb]

...as mentioned the plate does not touch the cover in that part besides the patent plate.

Or could touch in this inside edge? that by the way protrude more between 12 o clock and 6 o clock.

[reverb]

...may be the bearing is not in the right place?
I feel that the taper does not go on its own because right now like in the photos the plate does not touch anything (still unsure about that edge)

I measured from the taper (edge to the cam threads) to the edge of the timing cover hole and is 4,5cm and the measurement of the shaft and the part of the plate that goes inside the timing cover is 4,6 or so.

[Tony the torch]

whatever, wherever they don't fit..they never do. they all need to be ground down or it will not ever be fully seated in the hole.


lay down on the floor and up look under it !... look closely.... you will see where it is hitting right there near the patent plate.....grind it there at an angle so it will go further down into the hole.

it's not rocket science so put down the calipers, you can't measure where it's hitting. just use your eyes.

[reverb]

...hey Tony, I am not stubborn but I checked by eye and with a LED light and the inside edge of the outer race does not touch the cover...YET; will be touching if the shaft goes forward, but I can rotate the plate and does not hit in the cover.