Problems with attachments solved: viewtopic.php?f=7&t=17433

Crankshaft sprocket

Post Reply
Panchop
Posts: 1
Joined: Mon Jul 16, 2007 2:42 pm

Crankshaft sprocket

#1

Post by Panchop » Sun Oct 12, 2003 8:35 pm

Description: The crank sprocket is on tighter than dicks hatband

Trying to pull the motor out of a 50 Pan. Got the top end out, however the crank sprocket is on tighter than dicks hatband. The manual I have doesn't mention that it is a press fit, so what the hell am I doing wrong? Do I need a puller and if so what kind. Any help would be appreciated.
Thanx



weezeo
Posts: 117
Joined: Wed Mar 24, 2004 8:47 am
Location: South Florida

Re: Crankshaft sprocket

#2

Post by weezeo » Sun Oct 12, 2003 11:23 pm

1950 had a tapered shaft as opposedto a splined mainshaft. I believe it changed in 1954. You will need some type of 3 legged puller after you get the nut off, is that the problem the nut or nut is off, Then a puller for sprocket. Not sure what name of puller is. Good Luck don't damage the crank shaft.

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Crankshaft sprocket

#3

Post by Cotten » Mon Oct 13, 2003 12:34 am

Believe it or not, the tapered sprockets were meant to be loosened by smacking them with a soft hammer or a brass drift. Shocking them distorts the metal momentarily enough to release it. Unfortunately, it could also knock your flywheel out of true!

Fortunately, you are facing a total rebuild anyway.

VintageTwin
Panhead Register Member
Posts: 707
Joined: Mon Aug 16, 2010 7:18 pm
Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Crankshaft sprocket

#4

Post by VintageTwin » Mon Oct 13, 2003 12:43 am

Try the two-jaw puller available at Pep Boys (aka. Mannie, Moe & Jack's) They usually stock two pullers, one smaller than the other. , mfg. by Performance Tools - Kent, Washington- The big puller part number is W139 or the smaller version # W140. Either will work on the '36-54 tapered shaft.

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Crankshaft sprocket

#5

Post by Cotten » Mon Oct 13, 2003 2:02 am

Geez Kirk, do you really thing that putting puller jaws upon sprocket teeth is a good idea?

Here's a half-way compromise:

Put the puller on and torque it up firmly, and then smack its drive screw sharply. That might be the gentlest way to release the taper without damaging teeth or the flywheel true-ing.

VintageTwin
Panhead Register Member
Posts: 707
Joined: Mon Aug 16, 2010 7:18 pm
Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Crankshaft sprocket

#6

Post by VintageTwin » Tue Oct 14, 2003 2:26 pm

Sounds good. Grease the threads on the puller shaft, make sure the innermost taper of the sprocket shaft doesn't take a direct hit. The pullers I named have a small blunt point on them, that will not touch the bottom of the shaft taper. An undamaged taper is needed when truing the flywheels. I have to ask Stett about this tapered motor sprocket pulling. He always has the last word with anything I print. If he gives me the OK on our compromise method I will come back and say so. It's got to be right.

VintageTwin
Panhead Register Member
Posts: 707
Joined: Mon Aug 16, 2010 7:18 pm
Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Crankshaft sprocket

#7

Post by VintageTwin » Sat Oct 18, 2003 2:03 am

I talked to Stett about using the tension on a two jaw puller with the '36-54 motor sprocket and then giving the puller shaft end a rap with a brass hammer to free up the sprocket. He said that was OK, but that we should use a brass center-locating adaptor between the puller shaft tip and the crankshaft. This brass locator was essentially a disc with a tit on the crankshaft side and a dimple on back for the puller shaft tip to register in. That otherwise the puller shaft tip sometimes wants to "walk" off the end of the crankshaft. He said "Flanders" use to sell them, or "Pat's Tool", or "MSC", or "Grainger" carried them. I looked in Grainger and the MSC catalog, but couldn't find one listed.

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Crankshaft sprocket

#8

Post by Cotten » Sat Oct 18, 2003 2:38 am

Just cut one on a lathe.

Or why not just stick a penny between your puller and the shaft.

I just tap on the dammn sprocket with a brass hammer and be done with it.

57stroker
Posts: 84
Joined: Thu Apr 08, 2004 2:21 pm
Location: Burley Idaho

Re: Crankshaft sprocket

#9

Post by 57stroker » Sat Oct 18, 2003 10:41 am

If the crankshaft has a small tapered hole drilled in the end of it (and it should have), be sure not to bugger up the hole. This hole was put in when the shaft was built and everything else on the shaft was created around it. (It's real name is the center drill mark.) It will be needed to true the flywheels again. It can be fixed if it gets screwed up, but the machinist will cuss you (and probably charge you extra for his efforts!) Just do as Cotton suggested and use a penny between the puller and the end of the shaft. Tighten the puller down with an end wrench (not an air gun) and smack the puller bolt with a hammer. It will probably need a pretty good whack to get the two apart. One really good hit is probably better than several small taps. Good Luck!

Post Reply

Return to “Sprockets”