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Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 6:12 pm
by jfw

I'm assuming that this is not the case, especially as I'm sure over the years I've changed the piston, on my 2003 Bullet 500 Kickstart model. But I thought I'd best ask before I start experimenting with my bike.


I want to actually add a small magnet into the inside of the crown of my piston. I'm sure the piston is probably not a magnetic material, probably being an alloy, so I'll probably have to glue the magnet in place. You might think that that is stupidest idea that you've ever heard, and you might just be right. But have to have a tinker. I'm hoping the combination of crank and piston aren't balanced so I can just glue in a magnet but if it is balanced I'll have to get somebody else to do that.


Anyhow if anybody knows the answer to that question I'd love to hear it.

Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 6:24 pm
by PO51UHD
Ok, I'll ask the question before anyone else does:



Why???!!!



Stephen

Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 7:41 pm
by jfw

I'm toying with the idea of seeing if I can generate engine timing using the magnet. I'm not thinking of replacing the current mechanical system but seeing if I could put something in parallel. As much in a learning exercise as anything else. The idea would be that if the magnet was on the inside of the piston then a coil of wire around the outside of the cylinder would have a current induced in it as the piston moved.


The sine wave produced would only be the first step, if it's even produced. If it is produced the wave would have to be fed into a small micro-controller to fire the spark plug, At the correct position in the sine wave.


It's just an idea I'm toying with. Be interesting if I could theoretically replace the whole timing side gears, unlikely but interesting.

Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 7:51 pm
by Bullet Whisperer
If you glue a magnet to the underside of your piston, it will come off in no time and probably cause lots of damage and the you will not be short of stuff to 'tinker with' !! A better bet would be to magnetise a piston ring, or the gudgeon pin, then at least you will be mechanically safe to try your theories out. Regards, Paul.

Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 7:53 pm
by Dennis C
First think how fast a piston travels, then think how fast it changes direction, now think what will happen when the magnet comes adrift, then think how does the coil sense the magnet through all that iron."you might think this is the stupidest idea you ever heard" if not then it is pretty darned close.

Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 8:03 pm
by scotty
Why not fit a boyer ign system cheap enough no alterations fit it timeit with strobe light on marks you made on rotorstator assy set and forget, take you 30 mins and all done cheaper than a engine rebuild

Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 9:08 pm
by Tim NZ
You could always get the gudgeon pin magnetised?




Otherwise, why not try lots of sellotape, or nailing the magnet?


Is the crank shaft/piston combination balanced?

Posted: Sat Aug 20, 2016 10:38 pm
by Adrian
Have you considered converting the engine to semi-diesel operation with hot bulb ignition? I'm sure you could adapt something like this:







A.

Is the crank shaft/piston combination balanced?

Posted: Sun Aug 21, 2016 7:16 am
by nigelphoto
jfw – the problem as I see it is that because mg=cosine h(v2) –53 to the nth degree, where v is velocity, mg is a penguin shaped fridge magnet and h is the angle of Uranus to Mars, then the field of proton neutrons will cause millions of shards of flying moonbeams to disnitegrate the torgon drive. . . . . . Don't do it mate, if you want to experiment then apply to the BBC to go on the next Bake Off series.

Is the crank shaft/piston combination balanced?

Posted: Sun Aug 21, 2016 7:56 am
by ChrisD
Jfw
Yes, the Bullets crank+piston etc are balanced – most 500 singles are balanced to a 60-65% balance factor. Egli quoted the factory as using a 66% factor for the late 90’s Bullet 500 but after tests reckoned 63% was better (and 62% for a 535cc) - such precision! But if the engine is out of balance by even just an ounce or two (~30-60grammes) you will have a very rough engine. And I learned to my cost that damage will result from that.
ChrisD