Any Idea What This Is???

[Mastermind]

Something like this I'm thinking.....

 

[CR888]

wasabi pea stand?

 

[boxygen]

How is the force applied? Is this assembly just put into a shop press? How much force is required to put one together? I've never had one in my hand.

 

[Mastermind]

Yep, I just use a small shop press. Nuttin fancy.

 

[Stihl 041S]

To align crank halves a soft aluminum plate.
Drop.
Check.
Drop.
Check.

 

[lone wolf]

How about a Lathe to true the cranks?

 

[tree monkey]

Something like this I'm thinking.....

nope, centers on the ends

 

[Stihl 041S]

nope, centers on the ends

Yup. And don't have to be perfectly aligned.

 

[big t double]

Just subbing in and getting this one back up top. Most interesting thread here in weeks.opcorn:

 

[Mastermind]

I just wanted to see how close I could get these by using a jig. Not good enough to press and run, but a hell of a lot better than just "eyeballing" it.

 

[wcorey]

I press the pin in just part way first, easier the move the halves around and get things lined up before pressing it in all the way.
Then the fun with the lead hammer begins...

That stand looks more like something used for balancing, much like for doing a bike wheel.
There is a 'balance factor' (noted as a percentage, like 65%) that can be applied to alter the point in rpm where the least vibration occurs.
Would be more of a pain to do on one piece con rods, would need to be pressed together/apart twice.
Some math is used to figure out the relative reciprocating weight of the piston and rod, then an appropriate two piece 'donut' of that
weight is put on the pin and material added/subtracted from the counter weights to achieve desired balance.
Been a very long time since I've done any of that stuff.

 

[67L36Driver]

The workshop that did a go-cart crankshaft for me fixed the runout by mounting the crank in a lathe at one end and then checking the runout with a dial indicator at the other end. They marked the high spot and then used two soft blow hammers to tap the crank around until it ran true.

Yup, lathe + dial indicator + brass hammer. You can't really tell if you got it aligned properly untill you put it in the crankcase and spin it by hand. Spin freely = good to go.

My first m'cycle, a Ducati 350 single, had a pressed together crank w/roller bearing setup just like some saws.

Wonderful tinker toy. Shaft driven OHC with mouse trap valve springs. Itilian electric system was crap.

 

[wcorey]

My first m'cycle, a Ducati 350 single, had a pressed together crank w/roller bearing setup just like some saws

Recently I put new rollers in a 450 (desmo) Ducati crank, the originals had worn down only a bit but just enough to make me nervous.
Using not much more than the motor, rear wheel and bits of the frame from a '70 r/t to build a somewhat modernized road race type setup.
Getting pretty close to completion, though one of those long term projects that gets done in bursts of progress with lots of time in between.

That's a big reason I like saws, can build one in a day and for less than the cost of one Ducati part, lol...

 

[redoakneck]

Nice! If you got some time, shoot a vid of it in action. I thought the only solution was a new/used crank.

Dude, if thats yer idea idea of action I need to take you downtown some summer night, sheesh, action, LMAO

Just bustin yer chops my man,

Pete

 

[towingace]

crank press

I was gonna say that but I woulda been cheatin' cuz I already saw it on SH.

 

[splitpost]

I was gonna say that but I woulda been cheatin' cuz I already saw it on SH.

To be honest its the first time i seen one since the early 90's ,i borrowed one to rebuild my yz125H crank

 

[jar944]

Anyone have any measurements of different saw con rods/bearings/pins? It seems like the only feasable way to "cheaply" rebuild a saw crank where AM does not exist is to find a complete china crank for a different saw and cannibalize the rod pin and bearing from it.

 

[Gypo Logger]

Is it a ported 3120 jug?

 

[CJ1]

A shop towel?




with a little metal on it.
CJ

 

[olyman]

It still has some runout.......now I gotta build a proper truing stand.

just a que...how to tell, when the journals are where they are, phased to a one another?? and if they aren't pressed together perfect, for zero runout,, wont straightening them proper, make the journal real loose??? just que........ not being wise at all, as this is something I have thought about...also, you could have, the crank halves, perfectly phased to each other,,and have the crank pin off just a bit?????