54 stroke long rod?

[Up north rider]

I was on CPI’s website looking at all the different cub configurations they make. I seen a few different setups with stock 54 millimeter stoke, but had a 115 long rod. 
some of the ones that I seen were:

65.0

54.0

115.0

358.37

 

68.0

54.0

115.0

392.22

72.0

54.0

115.0

439.72

The last is pretty interesting to me. A 440 super cub. I’ve never seen these setups. My brother has a 392, but it has stock 110 crank. How is it achieved. 

Edited January 13 by Up north rider

[locogato11283]

There's a million combinations. You just have to decide what you want and how much you want to spend.

[Up north rider]

I hear ya, but who makes a stock stroke crank with 115 rods? 

[SKEETER]

55 minutes ago, Up north rider said:

I hear ya, but who makes a stock stroke crank with 115 rods? 

Just about every single crank builder. 

[SKEETER]

However, in today's age stock stroke 115 rod motors aren't common.  Cost same to build a 4mm 

[trickedcarbine]

Most folks switch to a long rod on just about any build once the stock crank shits the bed. The theory is that the rod angle has less wear on the piston and the skirts stay together longer. Just takes a different piston combo. Just about every crank manufacturer has a 110 and 115 option, most opt for 115. 

[Up north rider]

On 1/16/2026 at 12:16 PM, SKEETER said:

However, in today's age stock stroke 115 rod motors aren't common.  Cost same to build a 4mm 

I completely understand. Why wouldn’t you just get a 4mil instead of a long rod stock crank for the same money. That’s exactly what I did. For my brother it made sense because he could just get a 392 top end without splitting the case or replacing the crank. However do some people just prefer factory stroke? Does a stock stroke just retain some quicker Revs? For instance the 440 cub vs a 472 cub. I appreciate the responses. I ask only because I find it interesting. Thanks 

[SKEETER]

Nobody wants a 110 rod on a motor making power,  period. 

[n2otoofast4u]

You are confusing rod length with stroke. 

To make a crank a "stroker" (more stroke that stock) the big end (End that attaches to crank) is relocated closer to the outside of the crank wheel so that it pushes it up farther and pulls it in farther are the crank rotates. 

The "long rod" in this case 110 to 115 in length the big end of the rod remains in the same location as stock so the rod itself doesn't move any farther up or down, it is just simply longer. To keep the piston where it needs to be (5mm lower) the wrist pin location in the piston is raised, which lowers the piston in the bore. Hence why you cannot use a stock piston on a long rod motor. (Well, you could, but that's another huge can of worms!) 

 

@ClaudeMachining fucks Eskimos, but he probably has a good diagram and probably active model of this. 

 

 

[ClaudeMachining]

3 hours ago, n2otoofast4u said:

You are confusing rod length with stroke. 

To make a crank a "stroker" (more stroke that stock) the big end (End that attaches to crank) is relocated closer to the outside of the crank wheel so that it pushes it up farther and pulls it in farther are the crank rotates. 

The "long rod" in this case 110 to 115 in length the big end of the rod remains in the same location as stock so the rod itself doesn't move any farther up or down, it is just simply longer. To keep the piston where it needs to be (5mm lower) the wrist pin location in the piston is raised, which lowers the piston in the bore. Hence why you cannot use a stock piston on a long rod motor. (Well, you could, but that's another huge can of worms!) 

 

@ClaudeMachining fucks Eskimos, but he probably has a good diagram and probably active model of this. 

 

 

Yes i do, but your explanation is pretty good.

I'll post somes pics for ya.