Aftermarket cranks

[Tor R]

I'll check around. I know getting a 3120 crank stroked is around $500

im interested to know what you figure out Mike.
I guess the prices I got was simply to swap the con rod bearing.

 

[bikemike]

Send your crank to Bill Bune Enterprises in Anoka mn. they can build up the crank with better bearings and balance internal parts too.

 

[mdavlee]

Send your crank to Bill Bune Enterprises in Anoka mn. they can build up the crank with better bearings and balance internal parts too.

Thanks. Monday I'll give them a ring.

 

[Iron.and.bark]

Does anyone know if the pins are straight or tapered?

Mostly straight, 084 is tapered though. Blindingly obvious though because the taper is aggressive.

If the bottom end gets to hot, you change the temper of the crank pin. Why it should be swapped aswell.

Google alphacrankreconditioning.pdf
(Without spaces). Old doc, but has good info and good jigs to copy.

 

[Iron.and.bark]

I'll check around. I know getting a 3120 crank stroked is around $500

Ment to ask. You know what conrod you are putting in?

 

[mdavlee]

Ment to ask. You know what conrod you are putting in?

I don't know what rod they use. Used to guys were using 084 rods.

 

[Iron.and.bark]

I don't know what rod they use. Used to guys were using 084 rods.

That what I used. Still don't have that saw all together yet.

Thought you might have been going for a shorter conrod rather than longer.

 

[mdavlee]

That what I used. Still don't have that saw all together yet.

Thought you might have been going for a shorter conrod rather than longer.

I haven't done mine yet. Still unsure if I will. I may go 62mm first if I ever get it put back together.

 

[Iron.and.bark]

I haven't done mine yet. Still unsure if I will. I may go 62mm first if I ever get it put back together.

I am with you there. Spent to much on mine and still isn't back together. Also been a lazy bastard and not sent mastermind my carb off it to mod.

Ment to be my go to milling saw, but loving my 166 to much and with an echo cs 1201 on the horizon just haven't been pushing it.

 

[mdavlee]

I am with you there. Spent to much on mine and still isn't back together. Also been a lazy bastard and not sent mastermind my carb off it to mod.

Ment to be my go to milling saw, but loving my 166 to much and with an echo cs 1201 on the horizon just haven't been pushing it.

If I do mine it will be for a play saw. Hard to put all that into something to run 5 times a year for 3 cuts.

 

[Tor R]

They are not so difficult to press apart.



We manage to split one 550 crank with just using the vice.
When the con rod bearing is blown so bad as this one the rest of the crank is just to toss, cross bolt & con rod is ruined.
I do have a few more promising cranks then this, gone sacrifice one and see if it look more promising.

 

[Iron.and.bark]

They are not so difficult to press apart.

View attachment 40889

We manage to split one 550 crank with just using the vice.
When the con rod bearing is blown so bad as this one the rest of the crank is just to toss, cross bolt & con rod is ruined.
I do have a few more promising cranks then this, gone sacrifice one and see if it look more promising.

That conrod is definitely toast, look at those beautiful colours

 

[Tor R]

Lol ya, they can take a bit heat but not so much!
They for sure used all the seconds they could get out of the 550, poor saw!

 

[Wagnerwerks]

They are not so difficult to press apart. We manage to split one 550 crank with just using the vice.
When the con rod bearing is blown so bad as this one the rest of the crank is just to toss, cross bolt & con rod is ruined.
I do have a few more promising cranks then this, gone sacrifice one and see if it look more promising.

There ya go. Just be careful when pressing apart. Keep everything straight or it can mess up the webs. I screwed one up pressing it apart. It went back together ok, but was really hard to tune. In the end I used another crank and redid it.

 

[junkman]

How do you align the halfs perfect putting back together ?

 

[wcorey]

Google alphacrankreconditioning.pdf
(Without spaces). Old doc, but has good info and good jigs to copy.

Useful document, had a difficult time finding a good link though, this one works at the moment.

http://www.saltmine.org.uk/pdfs/alphacrankreconditioning.pdf

 

[wcorey]

How do you align the halfs perfect putting back together ?

Vblocks, dial indicator and a big lead hammer...
I find there's a lot less beating on it if you press the pin in part way, line things up, then press together the rest of the way, recheck.

 

[Wagnerwerks]

Yeah.... Be sure to mic everything before you start too. I use a copper hammer from HF. Watch some videos on YouTube. There's one of this South America dude doing honda cranks. Talk about beatnik. It's kinda wild.

 

[Nitroman]

I'll check around. I know getting a 3120 crank stroked is around $500

He-heh...he said "stroked", he-heh hehehehe...

 

[cus_deluxe]

Guys i know that are into racing snowmobiles send their stuff to midwest crankshaft in WI. Ive heard the guy jeff can be sort of surly, but a wealth of info on cranks.