OzVMX Forum
Marque Remarks => Spaniards (Bultaco, Ossa, Montesa etc) => Topic started by: evo550 on October 28, 2008, 07:06:08 pm
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Does anyone know if phantom gp2's ran a stepped or straight big end pin, I've just picked up a complete crank from the states, which the seller told me it came out of a #460 motor, but the pin is stepped, I thought they where straight.....and i don't mean hetrosexual.
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Everything I find says the Non-Stepped pin is for 74 and later Phantoms. Sounds like it might be an early model crank.
:(
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Thanks Red,
Do you know if the stepped crank fits the Gp2 motors? Was it from a stiletto?
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Evo,
I'm w Red. I'm not 100% sure about Ossa cranks, but what I recall is that the stepped-pin cranks were used on all Ossas prior to the 74 Phantom. W that engine they went to larger/stronger crank wheels/halves & unstepped crankpin w larger holes in crank-halves but same rod, if I remember correctly. (Bruce Rennie in Vic would know for sure.)
I'd ask the chap to measure the dia & width of the crank-halves & compare it to yr cases. I think I may have the dimensions of the larger crank here somewhere if you want me to check.
It is possible Ossa reverted to the smaller/lighter crank for the GP2 for quicker revving/response, but I have my doubts cos the bigger crank was said to be considerably stronger & I would have tho't the smaller/lighter crank would have compromised reliability w the power of the GP2.
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Yeah,
Just spoke with Phil Young, he said It's not a phantom crank and even if it fits, don't fit it, I'd only be asking for trouble.
So after about 6 months and about $500 I have a crank that is of no good to me even as a boat anchour (to light)
F$%#King arse wipe !!!
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Yeh Evo,
I checked part nos last night & same crank & pin in all phantoms
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Well that worked out better the expected, the seller has refunded me the money and I get to keep the crank.
I paid for it about 6 months ago when our dollar was almost equal to the U.S., he refunded me the full amount in U.S. dollars last night and I'm about $50 australian up because of shitty exchange rate now.
;D ;D
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Now does anyone have a Phantom crank i can borrow................for a f#$%king long time. ;) ;)
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Hell, Evo I need one too. did you try Keith Lynas at Ossa Planet? I have a Phantom which belonged to my father-he left it to me when he died in 1992. Not much there now -a roller parts are damn high and not that easy to find. Good side seems other than the trans they are durable bikes.
http://www.ossaplanet.com/
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MJ,
Yeah, I have tried Keith Lynas and Alex snoop, prices are comparable both want about $450 u.s. for a rebuilt crank, unfortunatly that is with an exchange crank, and that's where the deal falls over, I have a genuine gp2 crank, but the thread on the flywheel side is snapped off.
I am considering the option of having the pin holes enlarged on the second crank to fit a straight pin.
Do you think I'm playing with fire?
Option three would be to try the "High performance" stepped rod kit that Keith Lynas has advertised on the ossa planet web site.
What to do, these bloody Phantoms are a nightmare.
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evo
post some pics off the crank and what you want done and ill ask keith stacker to have a look at it ,they make all sorts of stuff there
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Here is the crank with broken thread, can I drill into taper and tap thread and hold magneto with bolt instead of nut?
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better pic
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The good crank with stepped pin, can the crank halves be bored out to suit straight pin?
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do both cranks have the same diamensions and is the only difference the pins amd why cant you use the good crank(which is not broken)
ive sent those pic to him but they are small if you can email me larger ones it might give him a better look
[email protected]
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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.
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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.
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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?
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this is what stackers say
can fix both cranks or make stepped pin to suit
----- Original Message -----
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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.
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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.
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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?
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Don't press it unless you have a jig or you will destory it.