pin on crank for locating mechanical advance

On one of my project KZs, the PO had allowed water to get into the combustion chambers and the engine was frozen. The piston was frozen in the block. I got it off and have a new block/pistons coming (eBay) BUT, he had tried to turn the engine over using the nut on the end of the crank under the points cover. The pin on the end of the crank snapped. It is a hardened pin and difficult to drill. I have an endless supply of titanium nitride 1/8" bits (that would be the right size) and they won't dent the metal of the pin. My buddy Roy-b-boy-b had this happen and his "fix" was to heat the pin till it was glowing using a cutting torch and then hit it with oxygen. He claimed that he was told this would shatter the pin. I am scared to try this approach and would rather try drilling first. Is there a better bit that will cut into the hardened steel than titanium nitride (I buy these for my carb business)??? Before doing as Roy suggested, I would remove the crank and likely take it to a friend in a machine shop. Next part of the question, Roy suggested buying a "keeper pin". He told me that these pins had a split in them (I guess only part way) so they could be driven into a blind hole and be retained securely. I have never seen one. Any suggestions where one could be found?

ANYONE EVER FACE THIS PROBLEM?

I sure wish I could be of help, but I have to tell you..........................................................................I LOVE IT when YOU ask for help!:laugh:
I hope you get the problem resolved soon.
Jim

It would take a carbide bit or tool to try to cut it out. What you might try though is a slide hammer used for popping out small dents in car bodies. Basically if you have enough of the pin showing you weld a small rod to it and attach your slide hammer to the rod and knock it out. At some point Kaw started using a "roll pin" instead of the solid pin......mod

There is a method to electronically zap the pin and disintegrate it, but that's all I know about this method. Sorry:( It might be the only way to remove it. Ask your machine shops, George. If I think of the term or find a website I'll post again. Good luck.

Got it ! EDM machining
"Electrical Discharge Machining (EDM) is a process that uses electrical discharges from an electrode to erode an electrically conductive material.

It is very accurate from what I see on the web, and worth checking into.

And those pins you ask of, they are called roll pins, and also coiled rolled pins (for really fudged up holes). You can find them in Mcmaster Carr.

Post edited by: OKC_Kent, at: 2006/03/16 11:52

I think you will need a carbide drill bit, like they said before, if you try this use lots of cutting oil and go slow,
one other option might be to use a welder and spot the rod on the end of the pin, let it cool and try to pull it out

The pin seems to be 1/8"... It was snapped flush. I used to weld for a living (about 30 years ago) and can't imagine putting a tack weld on that thing. The PO did manage to start a nice pilot hole so I am hoping a new drill bit will allow me to drill it out. The next step would be the machine shop route which ain't all that big a deal... just have to pop out the engine, split the cases and drag the crank to a shop. I just didn't want to split the cases on this bike as the cam chain ain't bad and it will likely be the one of the two projects I end up selling.

WG, Could you forget trying to drill out the old pin and instead drill for a NEW pin, say 180 degrees rould from where the old pin is broken Then drill/form a new hole/slot in the advancer mechanism for the new pin location?

Haven't thought this ALL the way through yet but you might even be able to use the original slot and "swap" your Dyna wires to allow for the 180 degree move?

youd have to be pretty precise locating that hole,interesting idea though.goodluck,happy wrenching!

Wire,

Just a thought but you could 1) drill a new hole anywhere on the advancer then, line up the advancer where it should be, in line with the old broken pin, then drill through the new hole, into the plate that holds the pin.

Could even then tap a thread in the plate and use a bolt in stead of a pin?

if you know anybody with a body shop borrow a unispot welder it will weld a 1/8 inch copper nail to the end of it so you can pull it out with a slide hammer or use a cobalt bit with a low speed drill :sick:

BARNEYHYPHEN wrote:

Wire,

Just a thought but you could 1) drill a new hole anywhere on the advancer then, line up the advancer where it should be, in line with the old broken pin, then drill through the new hole, into the plate that holds the pin.

Could even then tap a thread in the plate and use a bolt in stead of a pin?

this sounds doable,now i just need someone to come along with a reason it wont work,and really screw up my day!:lol:

The pin is in the end of the crankshaft. I am kind of hesitant to move its location as any variance will effect timing and I will end up having to use a degree wheel to get timing back... I got a couple cobalt drill bits and a pin punch... we will see what happens! Thanks for all the great suggestions. Surprised someone else hasn't come across this issue.