What happened to the stroker "kits"

[mthomps]

Lpw and the maniac is all we have

 

[kevbo]

It would be hard to sell a +1 or +2 stroker even though it would be less work and probably run better than a +4 or +5 with a stock rod. It may be better to just improve B-pipe chambers and sell them with fuel tanks that allow for that. Few customers understand the fine details, size is a much easier sell.

 

[fastgtfairlane]

Lpw and the maniac is all we have

Newmiller machine is also every bit as dependable as Jetmaniac and lpw as well. Also had very good experience with Jeff seebold at competitive crankshaft. I'm not sure if Newmiller is still around or not but I delt with him on my kawi engines. Very knowledgeable guy and always picked up the phone when I called or returned the call.

 

[bored&stroked]

Newmiller is/was a machine shop though, not a sales company. Unless there was an entire aspect of him I didn't know about lol

 

[Storbeck]

It would be hard to sell a +1 or +2 stroker even though it would be less work and probably run better than a +4 or +5 with a stock rod. It may be better to just improve B-pipe chambers and sell them with fuel tanks that allow for that. Few customers understand the fine details, size is a much easier sell.

This is an interesting take, I like it when people question the popular opinion.

What is the reason why a 1 or 2mm stroker might run better than a 4 or 5? Obviously you'll have less displacement with the smaller increase in stroke, so the initial impression would be "bigger is better", For what reasons would it not?

 

[kevbo]

The little Yamahas are a compact design to begin with. Longer strokes start outgrowing the stock cylinder very fast. An aftermarket cylinder with longer rods can bring the engine back to more ideal configuration.

 

[WFO Speedracer]

This is an interesting take, I like it when people question the popular opinion.

What is the reason why a 1 or 2mm stroker might run better than a 4 or 5? Obviously you'll have less displacement with the smaller increase in stroke, so the initial impression would be "bigger is better", For what reasons would it not?

I would think the port timing woulod be the main issue with a 4 or 5 mil stroker, the aftermarket cylinders have a better port configuration.

 

[joeschuit]

When I swapped to a 5mm crank on my stock/ported cylinder, it raised my exhaust and transfer port timing about 3 degrees. The only way to do that was to use 133mm rods so I could space the cylinder up and poke the pistons out of the bore. So far I'm pleased with the performance. I also needed a crank rebuild so it was a good excuse to dabble in the stroker game. if you kept the 125mm rods the rod angle isn't great and you're stuck with machining the cylinder base to get the port timings close.

 

[Dustin]

I am rebuilding my ski for the first time and realize my cylinders are 62T and 73mm stroke (5mm stroker). Now I had a protec head on, but I want to put an ADA girdled head on. Looks like I need to machine my domes as the piston comes out a fair bit. As for port timing, I’m not experienced, so for the stroker what looks the best? The exhaust/transfer durations and blowdown times are in Blue. These are my port timing measurements with different base gaskets/shims (first row)

 

[Dustin]

I should mention I’m looking more for freestyle porting.

 

[yamanube]

Transfer volume (and design) is pretty trash on oem cylinders. Displacement hits a point of diminishing return regardless if it's through bore or stroke. That's why porting offers such a significant gain over any incremental displacement increases.

 

[Dustin]

Transfer volume (and design) is pretty trash on oem cylinders. Displacement hits a point of diminishing return regardless if it's through bore or stroke. That's why porting offers such a significant increase over any incremental displacement increases.

I actually used your porting template for the exhaust and intake. Thanks!