crank rebuild

Hi, I'm in the San Francisco Bay Area, anyone know where you can get a crankshaft rebuilt/reground/balanced? Thanks, Andy

First thing I'd do is call Raber's. I'm sure they can refer you to a reputable machinist.

Engine Dynamics in Petaluma. Owned by a Brit who knows Brit bikes. Simply a superb machinist. :!:


http://www.enginedynamics.com/

Thanks for the tip. Call Rabers always seems to be some default thing to do around here.

Do yourself a favour and strip the crank yourself and take a lgood look up the inside of the drive side lump. You will probably see that the factory shoved a drill up the centre to clean it out. Nothing wrong with that PROVIDING the sharp outer edge of the drill finishes in the area of the web and NOT directly beneath the big ends outer 90 thou stress REDUCING radius. The sharp edge of the drill leaves a stress raiser / the point at which it will break. The drawings show the correct positioning of the stress raiser in the position where it would do no harm. Unfortunately the workforce clearly knew bugger all about such subjects and it was easier and quicker not to follow the drawings especially when on piece work....and with a company having little or no quality control / inspection. i have had two cranks break at this point, one a 99 and the other an Atlas. When the 99 one failed I ASSUMED the big ends radiuses had been incorrectly ground but when the Atlas one later failed at the same point I engaged my brain and sent it to a friendly Senior Metalurgist with 20 years experience in the sateel industry to determine the cause. Within a day he phoned asking something like 'WHO WAS THE IDIOT WHO INTRODUCED THAT STRESS RAISER INTO YOUR CRANK ... YOUR CRANK SHOWS IT HAD BEEN PROGRESSIVELY FAILING OVER A PERIOD OF TIME BEFORE FINALLY LETTING GO'.
One friend who has for many years raced and won championships on Commandos and for nearly as long prepared Norton twins for road and race said as I told him about the stress raiser I thought I alone had found....'Oh dodnt you know about it...I thought you did...I have been removing them from peoples cranks for years...they break if you dont'. I sent a drawing showing the stress raiser positioning to Mr Hopwood for his comments and he replied 'IT LEAVES SOMETHING TO BE DESIRED IN TECHNIQUE' . Mr Hopwood and others of his generation such as Mr Hele etc were FAR more polite than I have ever been.
If the stress raiser is in the wrong position get the crank x rayed BEFORE spending money on it as it could well be on the way to failing big time and that could well cost you a set of cases, crank,barrels , rods, pistons and possibly a head. If it is not sahowing signs of failing find someone who can remove it and polish the inside of that crank half.
My money is on most people thinking either the crank was weak or that the crank grinder had not put the 90 thou stress raisers into the big end correctly.. as I did INITIALLY.
Not that many will learn from this of course..........but do I care???

Dont know what stress raisers are? Owning Nortons are a good way of learning....the clever souls at one time left a stress raiser when machining the top edge of the base flange of 750 barrels where the outer rear nuts sit and the barrel flange can fail more easily at this point....Alternatively go borrow from your local library Metals Handbook Vol 9.'Fractography and Atlas of Fractographs' and look at the pictures of failed lumps of metals and wonder how many died because of them. My friendly metalurgist recommended I take a look at the book..plus a few others...and telling me about Comet aircraft dropping out of the sky (destroying forever any British aircraft industry we could of had as the Worlds airlines went and bought the new Boeing 707s...) thanks to a stress raiser and early WW2 Liberty ships breaking in two thanks to stress raisers along with giving me a hour long lecture on the subject but as the General Electric Company were paying for the phone call to Gateshead did I care?? DEid I hell!! I even recieved an hours free lecture on welding EN16 cranks from a Gentleman at the UK Welding Institute one day when I visited them to enquire...... once I mentioned I worked for G.E.C. who had an account with them...... G.E.C had its uses......NOT many mind you which is why it no longer exists.........