Phantom crank pin.

[Lozza]

You cannot 'bore' out crank pin bores. They must be either EDM wire cut or jig ground, anyone who says anything else is bullshitting.Your broken taper could easily be machined from EN36a/b, heat treated and ground to final size. When your new crank pin bore is being cut, another hole could be cut for the new taper to be fitted.Husky's have a similar thing with there cranks. That would cost much less than $450US plus shipping.

[firko]

Evo....It may be worth looking into welding a new threaded section to the old crank. We've done it in the past to Husky and other cranks that have suffered the 'left hand thread/rattle gun' butchery. The nut merely holds the flywheel on so if it's welded properly you won't have any problems as long as you remember which direction the thread goes and don't over tighten it. Another method is to drill and tap a bolt into the end of the crank. All of the methods work well enough to allow you to use the original flywheels and if you can't find a crank pin, have one made.

[JC]

That's one option, but I'd have tho't yr (Evo555) own suggestion of drilling the end of the shaft on a lathe, then tapping it & using a bolt to secure the flywheel would be much easier & worth investigating. Thats been done before for similar failieres & many jap bikes secure their flywheel that way. It wouldn't be left hand thread but I would think loctite would suffice.

Or you could look for a super pioneer crank. I believe they used the 'big crank' from 75 on & as far as I'm aware it's the same rod/crank/pin as in the phantoms. I tried to check part nos but the vintagedirtbike.com site is now completely different (& useless)

The stronger rod that Lynas sells (with or without steeped pin) requires maching of the flywheels to take the wider big-end brg.

BTW what's the width & dia of the stepped-pin crank?

[paul]

this is what stackers say
can fix both cranks or make stepped pin to suit
----- Original Message -----

[nmauto]

have you pressed apart the crank in the last picture? as it looks like a strait pin crank, need a picture from a side view.
Does any one have gp2 parts or bike for sale?
all the best Nigel Munday.

[OSSA PHANTOM]

 The stepped pin is used in SDR , MAR etc. phantom pins are straight. My suggestion is to have the crankshaft repaired by stubbing a new threaded snout the flywheel side and then install the Yamaha rod
modification done to the crank. I don't recommend using a stock rod. Don't even try drilling and tapping a bolt into the crank to hold the flywheel on. The good crank with the stepped pin also requires a cush drive so it won't work in a phantom engine.

[evo550]

Have managed to get a correct crank, but needs rebuilding and finding a 35 ton press in Brissy isn't easy.
Those pins are seriously tight.
Still got your gp3 Nigel?

[OSSA PHANTOM]

 Don't press it unless you have a jig or you will destory it.