how much muscle on flywheel puller?

P

podfish

Member

May 14, 2007

28

0

• Oct 14, 2008

• #1

I'm starting to pull the flywheel so I can replace the stator coils on an 86 KDX 200. There's a bit of sign of corrosion on the outer flywheel (it's not shiny, a lot of the outer rotor has a dull whitish layer on it). A long time ago when pulling a flywheel off a Honda I found out too late that I was missing the trick, so I want to avoid it here! On the Honda, the puller screwed into the flywheel hub and you turned the center screw in till it pulled. No matter how hard I turned it, even with a breaker bar, it wouldn't budge. At least until I unscrewed the puller - at which point the rotor fell off in my hand. The tension of the puller kept it from coming loose, but not till I'd damaged the end of the crankshaft! So I want to avoid that here.
I'm using a steering-wheel puller (center hole for the puller rod, 120' spaced slots for the screws that hold it to the flywheel). This seems to work fine on the KDX since there are three tapped holes on the rotor. But when I torque it pretty hard, it doesn't budge. So any advice? Should I just muscle up till it comes loose or should it respond to gentler nudges? As I type, I've left it sitting with some penetrating oil to soak around the crank, but I don't know if that'll help much.

 

splatt

Resident mental case

~SPONSOR~

Dec 1, 2001

908

16

• Oct 14, 2008

• #2

Get some good penetrating oil and let it soak in and it may need to be heated a bit to get it to move.

Steve

 

P

podfish

Member

May 14, 2007

28

0

• Oct 14, 2008

• Thread starter
• #3

splatt said:

Get some good penetrating oil and let it soak in and it may need to be heated a bit to get it to move.

Steve

Click to expand...

I hate to heat something magnetic like a magneto rotor...

 

whenfoxforks-ruled

Old MX Racer

~SPONSOR~

Oct 19, 2006

8,129

2

Merrillville,Indiana

• Oct 15, 2008

• #4

There are no threads inside the rotor to accept the standard rotor tool? The improper tool will NEVER work properly, NEVER! It will damage the crank end at best, as you found out.

 

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podfish

Member

May 14, 2007

28

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• Oct 15, 2008

• Thread starter
• #5

whenfoxforks-ruled said:

There are no threads inside the rotor to accept the standard rotor tool? The improper tool will NEVER work properly, NEVER! It will damage the crank end at best, as you found out.

Click to expand...

On a bike this old it's not easy to get the manufacturer's tools. It looks like it's designed to work with a tool very similar to the steering wheel puller, although the shop-manual's photos show a big chunk of steel instead of a triangular plate.
The rotor has three equally spaced threaded holes, halfway between the center and the rim. The end of the crankshaft has a hole in it that's also threaded for the bolt that holds the rotor on. The hub of the rotor isn't threaded like many bikes that I've seen, though.

 

L

lemmy

Member

Jul 24, 2008

139

0

• Oct 15, 2008

• #6

Will this work?

http://www.repairmanual.com/items/17/10456

 

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podfish

Member

May 14, 2007

28

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• Oct 15, 2008

• Thread starter
• #7

lemmy said:

Will this work?

http://www.repairmanual.com/items/17/10456

Click to expand...

nope. That's the kind I trashed my Honda with :)
The KDX C series doesn't have threads in the hub to match the outer threads on the puller in that link.
It looks more like this one:

http://www.autozone.com/in_our_stores/loan_a_tool/pullers_specialized/harmonic_balancer.htm

 

D

dirt bike dave

Sponsoring Member

May 3, 2000

5,348

3

• Oct 15, 2008

• #8

I used a steering wheel puller to get the flywheel off my old '84 KDX when the stator failed. If I remember correctly, it took a fair amount of force before it popped off, to the point of bending the smaller bolts that were attaching the puller to the flywheel. When I say it popped, i mean it POPPED off.

And I did mine when the bike was about 6 years old. Yours is over 20 years old! It is probably pretty well rusted in place.

Soak it really good with penetrating oil. You can try tapping it with a rubber mallet when you start to torque the puller. Do not smash it sharply with a hammer as you can easily break the magnets off the inside the flywheel. Try to proctect the end of the crank as best you can by making sure you have as big a mating surface as possible between the bolt of your wheel puller and the crank end. If the steering wheel puller has a sharp point on the center bolt, you may want to grind it down.

No doubt the factory flywheel service tool is preferred to a steering wheel puller, but it is hard to justify hauling a 20+ year old bike to and from the shop and paying an hour of shop time.

 

H

Hoffies

Member

Feb 26, 2007

41

0

• Oct 16, 2008

• #9

Sometimes when you have really torqued puller to the point where you feel something is going to snap, leave all under torque and a light tap of the hammer on the bolt of the puller(on head of bolt in direction of flywheel) cracks it loose. Do not wack too hard as shock is not good for the magnets either)

 

whenfoxforks-ruled

Old MX Racer

~SPONSOR~

Oct 19, 2006

8,129

2

Merrillville,Indiana

• Oct 16, 2008

• #10

Make sure the puller you use has flats parallel to the rotor, where the bolts seat. Some have a slight radius and the bolts slide. Make sure the bolts are all the way in. When you think its got a lot of torque on it, hit the center of the puller sharply with hammer. That sucker may fly across the garage!

 

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podfish

Member

May 14, 2007

28

0

• Oct 16, 2008

• Thread starter
• #11

got it...

The mechanic at Cycle Pro in Santa Rosa pulled it for me (only charging $20) and he ended up using a much more massive chunk of metal than my puller, and applying way more force than I would have felt comfortable doing. That's the benefit of experience - I trusted his judgement more than mine on how much force was too much. It popped off with an extremely loud bang, too!
One downside of using non-factory tools: when I put the bolts in to the threaded holes in the rotor, I put them in a bit too far, so when the rotor turned, the end of the bolts contacted the stator coils and damaged them. Since the point of this job was to replace the coils, no harm was done - but that's a tip for anyone else doing this themselves! mark the puller bolts so you don't thread them in too far.
There's one other factor that I forgot, which limits or eliminates the problem of mashing the crank end. On the Honda, the crank end has outer threads like a bolt; that's what mushroomed. On the KDX, the taper extends to the end of the shaft and the hub is held on by a bolt, not a nut. So it's safe to use a LOT of force!

 

S

sr5bidder

Member

Oct 27, 2008

1,463

0

• Nov 3, 2008

• #12

podfish
look the flywheel over very good these things lose magnets and are very hard to find (flywheel) as precoution you can go to a hobby shop and purchase some hanger 9 6minute epoxy and mix it up and epoxy the ends of the magnet where they tapper back of course aft cleaning the suface with electrical contact cleaner.

If you don't want to finish the job you can send me your flywheel...have two bikes on the donor waiting list!!

 

B

bonitz

Member

Aug 20, 2008

69

0

• Nov 3, 2008

• #13

When i do this i leave the nut threaded on the end of the crank so its flush. It will help protect the end of the crank,I would have a 1/2"gap or so between the nut and the flywheel. Then put on the puller and tighten it little by little tapping around the whole magneto with a deadblow hammer or rubber mallet. These seems to be pretty effective.

 

G

glad2ride

Member

Jul 4, 2005

1,071

1

• Nov 11, 2008

• #14

bonitz, the end of the crank is not threaded. It is hollow and one puts a allen head bolt in it to use as something to press against instead of the end of tht cranksahaft.