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Re: Cheapo crankshaft pinion tool

Submitted by leslie,peter_howard on Thu, 10/03/2011
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Heavy Twins

The Dominator twin engine, including the Commando, is a very easy unit to strip down usually only requiring a standard 3 leg puller for the camshaft sprocket but a Special Puller for the crankshaft, that is quite expensive at around £36.

I have stripped down about 6 Dominator engines including a Commando and have used the following improvised tool(s) to remove the half time pinion.

You will require two or three M6 Roofing bolts around 100mm long or similar.

Grind down the head flat so that the screw driver slot has just about disappeared, this gives about the right thickness of the lever âfootâ

Slightly bend them at around 25-300mm from the head approx 15 degrees, and that is it, you have made the tools.

How to use;

1) First you should try just two of them as usually that is sufficient to shift the pinion but see further details ant the end.

2) Slip the head under the gap below the pinion and with a bolt in each hand, pull equally and radially outwards as to lever the pinion. You will find that with very little effort the pinion will start to move off the crankshaft end. With a little bit more resetting, the pinion can be coaxed of the remaining distance.

3) IF the pinion is very stubborn you may require all three bolts, but the third one will probably need the head slightly more reduced by grinding as the crankcase face, sometimes, is slightly higher and makes it a touch more difficult to get the bolt in the right position. Oh yes, you will also need to loan a willing third hand.

I have used this method every time, and yes looking back if I had known I would be taking down Norton engines as many times as I have maybe it would have made sense to buy the tool. The only thing I would say is that it has always been an effortless, quick job using this method so the tool seems a bit superfluous.

Anyway. It may be of some use to someone who is stuck without the special tool.

Regards

Les H.

Attachments P1070137S.JPG

Submitted by leslie,peter_howard on Thu, 10/03/2011

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Many thanks Chris for your approval and suggestion. I would very happy to send them, orsome better ones,to Ian fo the Roadholder mag. However, it would be nice to hear from others who endeavour to try this method and get their feedback and approval to see if it worked for them as easily as it always does for me. Thiscould save some embarrassment all round, and the article shown with confidence.

I would just like to point out that the bend position is at 25-30mm not 300mm of course. Using a bench grinder, and then a vice to bend them, eachbolt can bemodified in lessthan 2 minutes each.

On my current engine, a 1953 Model 7, I found the lower crankcase face surrounding the pinion is raised slightly so, asI said earlier, the bolt head of the third one (IF needed) might need slightly more grinding away to access the slot,but it will be obvious as to how much. Icannot recall if the later engines were like this. I have never owned a Norton single butI imagine the set up is similar and therefore this method would also apply...verification required.

The bestsposition of the pinion to use the tools is when thereis one gap behind the pinion at 6 o'clock and the other two at 10 to 10 and 10 past 10 positions. Usually the upper two are the only ones required. I should have taken the photos before I dismantled the engine. I would also like to repeat that the proper tool is best, but if you don't have one, this little improvisation can help out a treat.

Les

Submitted by lionel_yexley on Sat, 12/03/2011

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Hi Les - on the face of it you seem to have a simple puller - unless you're saying that you lever the bolts against the alloy crankcase to remove the pinion! That is definitely NOT to be recommended, no matter how many times you have down it successfully!

Better to buy a piece of bar at a jumble and make up a puller with a bolt that screws down onto the crankshaft end. A simple matter of drilling the bar and tapping it to suit the bolt of your choice. (I'd go for 3/8") The roofbolts or carriagebolts canfit througha hole each side, similar to a small sprocket puller. The holes can be at fixed centres to suit the diameter of the pinion and just held on the "crossbar" with normal nuts - one each side of the bar. Slacken the outer nut to loosen the bolts so that they can fit each side of the pinion then tighten them agains their backnuts.

The pukka pinion puller is a meaty piece of kit as the pinions should be a really tight fit - make it worse if you're levering against the crankcase!

Cheers, Lionel

Submitted by leslie,peter_howard on Sun, 13/03/2011

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Hi Lionel. Yes,you do lever against the crankcase, but as the levers are only about 4" long and you are using 2 or three, just with finger tip pressure the forceis very low, I can promise you. In fact I have always found thatthe pinion is an easy fit on the parallel shaft. Use penetrating oil first on the shaft by the way. The piniondoes not have to be tight as the end nut and woodruff key do all the load carrying. I can honestly say that removing the pinion like thisdoes not even leave a tiny mark on the crankcase, the force required is quite slight. It is easy to theorise and imagine that masses of force and damage are taking place and if it was I would not have suggested it. It is only when you try it you will be surprised how easy the pinion starts to move and once it moves even a tiny bit it is easy to remove it by lots of other ways which are obvious when you are there with it.

There is another, more conventionalway you can use the modified bolts however.

Firstly make up the modified bolts but don't bend them. Then using all three of them, slip the ends under all three position below the pinion, then slip over a pre adjusted Jubille clip that is just the right diameter to hold the three bolts against the the pinion so they cannot slip sideways off the the pinion. Then you are in a position to either find the body of a small 3 legged puller or make a plate etc. to take the three bolts and thenfit nuts to the top of the bolts to stop them pulling through. You then have a puller that will work in a normal way, but the legs will not splay out because they are held by the Jubilee against the sides of the pinion. You can alsoaccess the clip to tighten for added security too.

Why have I personally not gone to that second method? Simply because the first one always works for me with no trouble, but if things were very tight I would do it the second way or at worst, get the right tool at £36...ouch!

Best regards

Les

Submitted by phil_hannam on Mon, 28/03/2011

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Les

I think that this is a really smart idea thatyou have proved actuallyworks.

Please do send in the photos and description to Roadholder. It is the kind of item the Tech Section loves to have in it.

I broke my mate's pinion extractor, last year,when trying to dismantle the bottom end of a Model 7. The pinion was firmally rusted in place and led to the extractor losing a foot before finally winning the day.

I bought him an expensivereplacement (arm and 2 legs) but he won't lend it to me now for obvious reasons.

This year, when working on another engine,I spent ages grinding down some old extractor legs to do the extraction job.

Your idea seems far simpler and a lot cheaper.

Onesuggestion I would like to add. I always heat the pinion using a blow torch until it isreally hot. (water sizzling temp). This usually helps to loosen it on the shaft, unless it is a model 7 crankshaft that has lived in the back of a garden for 40 years.

 


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