more stroker quesions...

[WaveDemon]

Do stroker motors last as long as non stroker? I would think not.

Do they use shorter and thicker rods or special pistons or maybe a spacer above or below the cylinder?

What are the reason's to use the smaller stroker cranks?

When is Wax's stroker crank coming out?

Would a stroker 62t/61x give you more power than a non stroked Lamey?

what case mods are necessary if any?

can you offset turn a stock crank and use special bearing to make a cheap stroker?

 

[WaveDemon]

and....

where can you buy them new and at what cost?

 

[parrdaddy]

and....

where can you buy them new and at what cost?

Jr. Magoo's can build you one, cost depends on what you get :Banane01:

 

[Jr.]

Do stroker motors last as long as non stroker? I would think not.

Do they use shorter and thicker rods or special pistons or maybe a spacer above or below the cylinder?

What are the reason's to use the smaller stroker cranks?

When is Wax's stroker crank coming out?

Would a stroker 62t/61x give you more power than a non stroked Lamey?

what case mods are necessary if any?

can you offset turn a stock crank and use special bearing to make a cheap stroker?

Here is a little lessons in strokers for the Yamaha twin.................

Does a stroker last as long as a std stroke, The crank does but the pistons don't. The pistons are traveling Further & at a greater rate of speed than a std stroke, so the wear is greater.


Rods, 5& 6 mil strokers can use std rods that have been modified for clearance. RAD did offer special billett rods for their cranks, those are no longer avail.

The shorter strokes slow the piston speed down & make them last longer, they are better suited for the rec rider. Strokes also don't like substained high RPM use. the shorter stroke is better suited for that.

A stroked oem cyl compared to a std stroke Lamey? ?????? good question, many builders have great luck with oem cyls, but dollar for dollar invested with special machine work, the Lamey is the way to go in my opinion

The cases need to be clearanced to accept the additional swing of a stroked crank. average cost of that machining is $150

Can a std stroke crank use offsets, Yes!! Phil at crank works does it all the time. But the life span is shorter than a true stroker crank.

I build stroker motors all the time, I have a nice selection of cranks in stock & I will taylor build to your needs. please contact me for a personal quote


Strokers are a great way to increase power, but as with any modified motor, the price tag goes way up, as does your maintaince costs.
If you wanna play, fully expect to pay for that pleasure!!

ski ya, Paul

 

[Jr.]

Oh By the way, If you are going to the Riot Ride next week, I will have several there. Let me set you up with a test ride!!!

 

[steve802cc]

Do stroker motors last as long as non stroker? I would think not.
Depends on how you set them up. Any motor tweeked for high performance will not last as long as a stock one.

Do they use shorter and thicker rods or special pistons or maybe a spacer above or below the cylinder?
Most Yamaha strokers up to about 5mm can use the stock lenght rod. After 5mm the cranks use a longer rod (Kaw 750 often). A shorter rod causes to much side load after the fuel is ignited.

What are the reason's to use the smaller stroker cranks?
I've never really heard of anyone putting a shorter stroke crank in a jetski. Theoretically I think it is supposed to make a motor rev faster and higher.

When is Wax's stroker crank coming out?
Soon I hope

Would a stroker 62t/61x give you more power than a non stroked Lamey?
I'd always go for the Lamey myself. If you ever have the chance to compare the two side by side you'll know why I picked the Lamey. I have one of each in the garage maybe I'll take some side by side pics if I get a chance

what case mods are necessary if any?
Up to about 5mm on a Yamaha you don't have to do to much to the cases. Once you get up to 8mm and above I know you have to do extensive crankcase mods. Basically you have to clearance the cases for the bottom of the rods.

can you offset turn a stock crank and use special bearing to make a cheap stroker?
If your asking if you can make a stroker crank out of a stoke crank the answer is yes but it is a lot of work and costs a lot.
__________________

 

[wildman326]

Wow. Now that's a big can of worms.

Cheap? Like how much? I got one for $1000 and another for $600. Neither are what I really want. They aren't made for bottom end.

 

[steve802cc]

Paul,
We mus have been typing at the same time.
Later
STeve

 

[WaveDemon]

What are the reason's to use the smaller stroker cranks?
I've never really heard of anyone putting a shorter stroke crank in a jetski. Theoretically I think it is supposed to make a motor rev faster and higher.

I knew that question would come arcoss wrong. I ment 5mm vs 8mm

With a stock rod or even a longer rod you must be useing a special piston with a higher pin location. That must beat the hell out of the piston and rings. I've read somewhere that pistons with a shorter dist between the crown and pin don't disipate heat as well. maybe that isn't a problem with 2 strokes.

If I understand everything I've read a 5mm stroker is a pretty easy upgrade when building a motor at home.

 

[WaveDemon]

Wow. Now that's a big can of worms.

Cheap? Like how much? I got one for $1000 and another for $600. Neither are what I really want. They aren't made for bottom end.

are you saying the your stroker canks or motors aren't made for bottom end. I figured the longer stroke would only help bottom end.

 

[WaveDemon]

sometimes its hard for me to think about things in a 2 stroke state of mind rather than 4 stroke.

If the distance from the top of the stroke to the top of the exhaust port doesn't change then your power stroke isn't getting any longer. are you really gaining that much with a stroker crank? I guess you are compressing a little more air/fuel and a longer lever (crank throw) is easier to push. so maybe a little more torque?

 

[wildman326]

The cranks are suited for top or bottom end. The cylinders that came with the cranks were cut for racing, so they aren't designed to "pop off the bottom" as much as I'd like.

As you probably know for bottom end you port wider and for top end you port taller. They were both ported too tall to get a clean bottom end "hit".

All I'd need to get more pop is a different top end. Used, maybe $500? New, $1500 - $3000? Or more.

I really want to do it right and am looking for a 5mm powervalve lamey or wax-cylinder. I'd like to set it up flat-top . . . anyone wanna sell a top end like that let me know.

 

[steve802cc]

With a stock rod or even a longer rod you must be useing a special piston with a higher pin location.
Nope, not unless your building a flat top motor. I'm running stock type Pro-X pistons in my Lamey 5mm stroker motor. If you are using a stock cylinder you will either have to make a spacer plater or cut the domes to accept the extra stroke. This is not required with the Lamey cylinders since the are milled or decked to the proper height when you order them.

If the distance from the top of the stroke to the top of the exhaust port doesn't change then your power stroke isn't getting any longer.
This distance increases as soon as you add a stroker crank. For example in a 6mm stroker motor the piston will go 3mm higher and 3mm lower in the bore for a total of 6mm

are you really gaining that much with a stroker crank? I guess you are compressing a little more air/fuel and a longer lever (crank throw) is easier to push. so maybe a little more torque?
More torque is exactly what a stroker motor is supposed to do

 

[WaveDemon]

More stroke, same piston, same rod. Is there a spacer or something? why isn't the piston going through the head?

I understand that it will have some more torque. my queston really is how much? how noticable is it?

 

[wildman326]

Spacer plate or special domes recessed to take the extra stroke. It's quite noticeable.

 

[WaveDemon]

Spacer plate or special domes recessed to take the extra stroke. It's quite noticeable.

I"ll have to ride one in lanier...

 

[waxhead]

believe it or not i am talking with some other company about stroker cranks at the moment and hopefully they will be back to me soon with a price
the drawigs are all done but i just have to get it done for the right price
and also the right material for that price
but things are progressing i assure you that

 

[Idok]

i hear they use different piston return springs too....billet with a carbon fiber shell....pretty pricey :sneaky:

 

[Mile9c1]

More stroke, same piston, same rod. Is there a spacer or something? why isn't the piston going through the head?

Like Wildman said, some use recesses cut into the domes, some use spacer plates under the cylinder, and some use spacers on top. For example, this one uses a spacer plate on top of the cylinder: http://cgi.ebay.com/ebaymotors/ws/e...d=1,1&item=4639262793&sspagename=STRK:MESE:IT

(sorry for the shameless plug)


A stroker motor will make more torque than a stock stroke motor because the torque is simply force x distance and that distance is the stroke. Of course how well an engine runs depends on a hundred other vairables, but even Group-K who doesn't recommend strokers admits that they "leave harder"... which is great if you ask me :biggthumpup:

 

[madoyster]

A lot of good questions (and answers) in this thread. :Banane01: