Joe Hunt magneto photos (2012)

jseng1 · Mar 2, 2012

willh said:
comnoz, Jim, Ken,

What would you charge for welding an early 750 rear timing section on an 850 MKIII case or other 850? Provided that the costumer furnished the to-be-modded case and donor case, for the mod.
Curious and assume others would like to know.

I think its better to just match the Atlas or early 750 case with the 850 drive side to get the rear mount magneto. It would be less work and no welding - minimal machining and maybe some hand work. Check crank end play. Then have someone mill off the deck so its flat. Flexible superblends help because perfect alignment is not necessary. I haven't checked everything but I've got some similar cases here that I've looked at and it seems do-able. But you must be very careful about using the correct timing cover with the right side case or an oil hole can be exposed and there will be no oil pressure.

willh · Mar 2, 2012

jseng1 said:
willh said:

comnoz, Jim, Ken,

What would you charge for welding an early 750 rear timing section on an 850 MKIII case or other 850? Provided that the costumer furnished the to-be-modded case and donor case, for the mod.
Curious and assume others would like to know.

Click to expand...

I think its better to just match the Atlas or early 750 case with the 850 drive side to get the rear mount magneto. It would be less work and no welding - minimal machining and maybe some hand work. Check crank end play. Then have someone mill off the deck so its flat. Flexible superblends help because perfect alignment is not necessary. I haven't checked everything but I've got some similar cases here that I've looked at and it seems do-able. But you must be very careful about using the correct timing cover with the right side case or an oil hole can be exposed and there will be no oil pressure.

Thanks for the wisdom.

I assume the difference in 850MKIII case regarding the wider crank is on the drive side so no difference in the bearing area of the timing side compared to early 750. If not, I guess I should have kept my old 750 crank.

Thanks again.

lcrken · Mar 2, 2012

willh said:
I assume the difference in 850MKIII case regarding the wider crank is on the drive side so no difference in the bearing area of the timing side compared to early 750. If not, I guess I should have kept my old 750 crank.

Thanks again.

Fraid not. The bearing bores in both case halves are wider apart to accomodate the wider crankshaft. When you fit an earlier crankshaft to the MKIII cases you have to fit spacers behind both the main bearings.

Ken

bwolfie · Mar 2, 2012

The MK3 crank and cases are .120" wider than the MK2 and earlier. I know because I modified a MK3 crankshaft to fit a MK2 crankcase.

willh · Mar 3, 2012

Back to welding...how much$?

jseng1 · Mar 3, 2012

willh said:
Back to welding...how much$?

Much easier to find a pre MK3 crank, match the 850 case to an Atlas case, and shim the drive side main bearing as necessary. .

willh · Mar 3, 2012

jseng1 said:
willh said:

Back to welding...how much$?

Click to expand...

Much easier to find a pre MK3 crank, match the 850 case to an Atlas case, and shim the drive side main bearing as necessary. .

Lighter weight crank as a bonus....wish I hadn't sold my Atlas crank....

willh · Dec 15, 2012

just curious, what mag is that? Forerunner to the ARD? Looks like a Karata top.

lcrken · Dec 15, 2012

Not something I've seen before, but it wouldn't be a Karata. They weren't in business yet at the time of the picture.

Ken

comnoz · Dec 15, 2012

willh said:
Back to welding...how much$?

I have welded up a few cases and re-machined for a Mag so I have the jigs. I recently finished a set of Maney cases. It takes about $400 to $450 labor weld in the needed material and machine it.

I tried to post some pictures but due to some kind of conflict between Mozzilla and Adobe my pictures will not upload. Jim

willh · Dec 15, 2012

comnoz said:
willh said:

Back to welding...how much$?

Click to expand...

I have welded up a few cases and re-machined for a Mag so I have the jigs. I recently finished a set of Maney cases. It takes about $400 to $450 labor weld in the needed material and machine it.

I tried to post some pictures but due to some kind of conflict between Mozzilla and Adobe my pictures will not upload. Jim

So no donor 750 cases be harmed?
Love to see your work, can you PM the photos to me and I'll put them up?
Thanks
Will

comnoz · Dec 15, 2012

Ok, I'll try this again.

lcrken · Dec 15, 2012

Very nice, Jim. Much neater than the conversions HPI did. He used to grind the corner of the mag instead of machining out the back of the cases to clear. You can see where he ground into the threads on this ARD mag for clearance.

Ken

willh · Sep 3, 2019

Bump. Anyone copied the ARD yet?

ashman · Sep 4, 2019

Not that I have heard but after 9 years on the side of my Norton my JH is still working as good as the day I put it on, haven't touch it and still firing up on the first kick every time, how many ignition systems work so well like the JH, I still have the same point in it and still has survived a few slides down the road in its first years on the bike, I haven't touched the timing every thing is the same as the day I put it on.

Ashley

Joe Hunt magneto photos (2012)

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