348 Polarity Of The Flywheel Magnets

[mudyman]

Hi all

has any one heard of the magnets in the flywheel being affected "changing the polarity" after getting knocked about ?

I read that somewhere and had a very tight flywheel that got some knocks when getting it off. Now with new points and condenser theres no LT spark. The wirering is okay no short to earth etc. ? There was a LT spark before but weak and no HT spark then either.

[feetupfun]

what's an LT spark?

[mudyman]

with the low tension wire disconnected at the HT coil and rubbing it on the frame it should give a blue spark where it touches the frame (when cranking the engine).

[0007]

Magnets won't change polarity with impact but if you smack a magnet a weird thing can happen, you can knock the magnetism out of it

You never hit a flywheel directly with a hammer or drop it on the floor, unfortunately you are looking at the only thing on the bike you cannot test

I have never heard of the test you mention, but it sounds subjective at best, if you don't have a peak voltage number to look for on your meter then it doesn't mean anything

If you have a meter you need to test to see if the points are opening and closing

Also see what resistance the plug cap has, should be 10,000 ohms

I bet you have a points or condenser problem, what was the problem before you swapped the points?

[moleman]

has any one heard of the magnets in the flywheel being affected "changing the polarity" after getting knocked about ?

if you hit or drop the flywheel and break a magnet, each broken piece will each have a N and S , so yes you can change the polarity , i.e if you have 6 magnets round the flywheel you will have 6 N and 6 S (start and end of each magnet) if you break one you will have 2 extra poles in a short space

you may not know you have done this

[triple_x]

If your colleague or you have had to knock a flywheel off then you need help.

The flywheel has a thread in the middle to which you insert a puller, simply grip the outside diameter of the flywheel (tool required) and tighten centre bolt to brake the taper.

If you have not got the tools then get them!

Compared with the effort without they are worth every penny. Contact Bultacouk I did and it really makes life easy.

Sorry to be blunt but correct tools make life easy.

Further if you want a diagram of the wiring they can provide it.

Good luck and

Kind regards

Martin

Edited April 7, 2013 by triple_x

[stillers1965]

Make sure your wires going to the points aren't on the wrong side of the insulators, could be grounding out.

[feetupfun]

with the low tension wire disconnected at the HT coil and rubbing it on the frame it should give a blue spark where it touches the frame (when cranking the engine).

I use a multimeter for this and watch for a voltage spike in the LT wire

[mudyman]

Thanks for the replys and tips, I hope to get back to it on Saturday.

I never had a flywheel that was so hard to get off before, usualy they come off after lightly tightening and giving it a tap on the shaft.

By the first try after lightly tightening and tapping the shaft again and again it saw the threads on the In motion puller go. The next attempt with a new puller (after the normal try) and after warming the flywheel a bit saw the thread on the bolt go. The next try with again a new puller was where I started getting impatient and the flywheel got a few heavy knocks (I know you shouldn´t get angry) I then gave up for the day and got hold of an impact gun with 600 nm and big compressor. At last it came off.

When I think of it I had trouble getting the nut off so probably it had been overtightend by the last owner.