rebuildable crank?

[Nightbiker07]

ok, i have a stroker crank for my 84 250R.
the problem is that the crankshaft pin has been welded into place.
i am wondering, is this possibly rebuildable and then usable?
or is it just junk, and i have to accept that?
i mean...a 300 big bore stroker.......DAMN thats alot a power!

i cant find a stroker crank for a 84 anywhere, nor even ANY mention of one ever being made, leading me to believe that this was fabricated, at least partly.

also, why would the crank out of an 85 not fit into an 84 case and be usable?
this crank looks somewhat like a crank out of a 85, because it is ROUND, instead of Tirangular like a stock.

[Dirtcrasher]

I can't say if the 85 crank has the same journal diameters and width or that the shoulders are in the right spot. I can't see why the welds can't be ground down, pin pressed out and it should all go back together.

I don't think they throw them away??

[ATC-Eric]

Worse comes to worse, If they cant press, grind, or drill your problems away, get yourself a used crank. Send both units to a reputable machine guy, and have them drill some new wholes on the new crank.

[Nightbiker07]

thats the thing. the crank that had been modified is NOT a stock crank. its a different shape than the stock, and i cant find even a reference to a production stroker crank for this, leading me to believe that it was fabricated, at least to some degree.

and i thought about grinding the TIG welds out, BUT. would that throw the balance on the crank way outa whack?

[Yamahondaman]

naaa .. theres not enough weld to do that ... Trinity welds theres after they rebuild Cranks ... just grind and re-build ... the weld is GOOD if you use Nitrous !!

[ATC-Eric]

THROW up a pic, someone here can identify it.

[Nightbiker07]

ill throw a pic when i get access to a camera

also, there are 2 tig welds on the pin on each side.....quite a bit of grinding.

suggest a dremel to dig as little weld out as possible? what is suggested here?

the crank had other welds on it, other than on the pin. not sure what there for(possibly balancing?) it needs to go to a machine shop for sure to get worked on.

[kuotown]

I had to have the crank shaft on my jet-ski rebuilt just a few weeks ago. The original part was almost a grand and I wasn't going to spend that so I took it to a good machine shop and had the jacked up part ground down, built back up and then turned down to the stock size again. All of that was just over 120 bucks and it works perfectly again. I don't know how long it will work of course, but it works perfectly right now. It is a 2 stroke crank too so maybe yours can be re-worked as well? It wouldn't hurt to at least have it looked at by a good machine shop. Good luck!

[Nightbiker07]

was it a regular machine shop, or a machine shop that specializes in doing engine components?

[kuotown]

In my experience only machine shops that specialize in engine components can get the crank balanced correctly, but not all machine shops will add metal to a crank if it needs to have it added. You may have to take it to one shop that will add metal in an appropriate manner and then to another engine based machine shop to get the crank turned appropriately depending on what they are comfortable doing. Make sure that you see examples of the shops work and that the shop is dirty. That may seem weird, but in my experience shops that stay extremely busy are the great shops and they don't seem to have time to keep the shop clean. That's my experience, but of course that's not always the case... :beer

[Nightbiker07]

that is to true. dirty shops are usually the good shops.

[jeffatc250r]

I have an extra crank sitting on my shelf from a water pumper. If you have metric vernier calipers measure the shaft dia, overall width etc. etc.... we will compare.

[Nightbiker07]

ok. i will measure it out when i get the crank back, and find my caliper.
i will measure: shaft dimensions, overall length of assembly, length of right side shaft, and left side shaft.
also, the width and height of the big part of the crank (not sure what its called)