1975 850 Commando pinion removal tool issue

p400 said:
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I notice a distinct difference in the end profile of the MCA P158 as compared to "new" pullers.
The MCA P158 does appear too blunt.

These "new" pullers have been tapered down as Greg suggest, but they lack the arc modification .

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There is no arc modification required! You just have to get the three legs to catch between the pinion and sealing washer and the "triangle" washer provides the space to do that.
 
1975 850 Commando pinion removal tool issue

Maybe this will help. Just a little grinding on the outer edge was all I needed.
 
Here is what I find for jaw profile on the new pullers.

Deets55 I notice the jaws you show are "arc modified", does your puller have any stampings to identify?

20221211_ThreeJawCorners.jpg


20221211_PinionNortonMK3.jpg


I think scar marks are visible in the triangle washer where the current new tool is attempting to grab.

Greg if you get a chance please post a photo of the tool you use for Norton pinions.
 
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Airhead BMW advice for same situation says toast up the gear until it turns blue , then pull .
Much easier . Anyone considering this Idea ?
 
P400,
I’ll take a look tomorrow for a brand name on the tool.
The issue I found was that the back end of the tool would hit the edge of the case counter bore and would not allow the teeth of the puller under the gear.
As mentioned the puller goes where the flat parts of the triangle washer are.
 
The ideal shape for the jaw ends for a Norton pinion would match the tiny sliver of gear exposed for pulling.
The need to also fit a Triumph must be leading to a compromised shape of the jaw.


PinionToolJawNortonIdeal3.jpg
 
It's very difficult to get pictures that are helpful. After several tries, I got one. I have two MCA P158 pullers. The one in the picture came as part of a parts buyout and is unmodified. The two were made at different times - the part number stamps are different sizes and the other one does not have the un-needed "radius modification" that this one has. The washer in the picture is 0.111" thick. The parts that hook the gear are 0.115' thick. This puller will not work unless at least 0.004" is taken off the bottom. I've ground the one I use down to 0.100" (approximately). I also ground off part of the outside but I don't remember if that was for a Commando or something else. The Triumph/BSA similar puller I have barely works on Norton after I modified it a lot.

1975 850 Commando pinion removal tool issue
 
My problem was the outside diameter of the tool was too big to fit into the recess in the case so I ground the outer part down a bit until it fit. Looks similar to photo Deets posted. There's plenty of material there, it's not going to compromise the strength of the tool. Had no choice, either grind it or leave the pinion on.
 
I needed a puller, reading all this concerned me.
I looked around at the photos and bought one off E-Bay from 'bsanut' AKA Eurojamb..
Everything I have purchased from this vender has been 'Top Shelf'..
This was no exception. Worked a treat...
1975 850 Commando pinion removal tool issue1975 850 Commando pinion removal tool issue1975 850 Commando pinion removal tool issue1975 850 Commando pinion removal tool issue

Here's a link..
www.ebay.com

Norton 3-JAW Crank Pinion Gear Puller Tool 650 750 850 crankshaft Atlas Commando | eBay

Tool jaws are specially double-ground and should fit nearly all but the closest crankcases, unlike other tools on the market. A lovely tool, CNC-machined and black oxide coated.
www.ebay.com
 
I almost hate to ask, but is the screw turned out far enough? Only asking because a friend had the same issue, and the extractor screw wasn't loosen enough. My tool works on both Triumph and Norton, but it is ancient.
 
Rooted out both pullers i have. The black finished one dates from the 1980's. The silver one i got for a tenner at Rufforth
Both have flats on the jaws. Both a good fit.





 
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