Small bore stroker

[400exwhipper]

I really don't like the idea of the 440, however the idea of a 416 high comp stroker sounds good to me, but I can't seem to find a kit that I can choose the size of the piston there all 89mm, so does anyone know if it's possible to have a smaller bore with the stroker crank? And if so where can I buy it? Thanks

[Zakradu398]

Id be interested in this also because I had planned on just doing a 465 this winter but kinda want a little smaller.

[Wheelie]

Check out www.powroll.com. I've been running their setup for 6 years without any problems. Strong and reliable.

It's a 416 bore with a +4mm stroke.

[riotact]

Which crank did you go with Wheelie,the one with the tough rod or the combo?I've had my eye on the 440 stroker for two years now and since my suspension is finally done it's time t get into the motor.

[thebig450es]

Check out gt thunder

[drew416ex]

Yeah powroll is the best choice if you want to keep a small bore. You can keep the stock bore and send them your piston so they can machine it to clear the crank.

[thebig450es]

I like with mine i have the small bore of the 87mm/416cc but with a 7mm stroker that makes tons of tq proved by the DYNO. Plus i can also go bigger later....maybe 88mm bore with the 7 mm stroke.

[riotact]

Did you have to send your crank in and they do the stroke work on it like Powroll does? I like the idea of keeping the bore small and also going high compression.

[Zakradu398]

Did you need any trenching with a 7mil crank

[thebig450es]

I had Laz to the work, its been running stong now for a year and a half

[400exwhipper]

This sounds awesome but I have one big question, when you add those 4 or 7 millimeters to the stroke what happens to the compression, and do you have to change anything with the cam, or timing

[400exwhipper]

Bump

[NacsMXer]

Originally posted by Zakradu398
Did you need any trenching with a 7mil crank

Yes, lower cases need to be machined slightly for the longer throw of the rod.

[NacsMXer]

Originally posted by 400exwhipper
This sounds awesome but I have one big question, when you add those 4 or 7 millimeters to the stroke what happens to the compression, and do you have to change anything with the cam, or timing

GT Thunder's stroker kit uses a custom designed piston from JE. The wrist pin hole is relocated further up on the piston to compensate for the added stroke. The piston in my kit is 12.5:1 compression. There are no changes to the timing, although matching the right cam to your build is important just like any other build.

[Zakradu398]

Would it be an even race between a 4mil 440cc and stock stroke 440cc.. Advantages and cons to both?

[HondaRacing83]

Is it possible to have a pump gas stroker like a 4mill so you wouldnt have to touch the cases and still run on 93octane? Like say a lower compression piston like a 10: whatever with a 4mil crank would be what?

[Zakradu398]

Compression changes with piston or dome size. All the stroke does is add "travel" up and down to the piston. The hole for the wrist pin on the piston is moved further up on the piston itself 4 or 7mm so that the size of the chamber at TDC is still the same before, resulting in same compression. So as long as your piston is 11:1 or less your good on 93.

Also, from what I gathered here. You can run a 4 mil crank in untouched cases, but anything higher requires trenching(boring out the pocket the crank sits in)

[HondaRacing83]

reliability wise which is better an 11:1 stroker or 11:1 big bore stock stroke?

[Zakradu398]

11:1 stroker would be more reliable because of the added rod length. It puts less of a side load on the piston because the log rod has less of an angle when rotating.

[Zakradu398]

Originally posted by Zakradu398
11:1 stroker would be more reliable because of the added rod length. It puts less of a side load on the piston because the log rod has less of an angle when rotating.


Again, this is how I and the banshee community feels towards their strokers with long rods., so I assume it can apply here.

The shorter rod though has the tendency to rev faster. I'm gonna say the stroker is more torquey

[HondaRacing83]

how many cc will i be at with say stock bore, 11:1 4mil, 416 11:1 4mil crank, and 407 4mil crank? what will it be cost wise to go with a 4mil over a stock stroke big bore? which would i be better off with for xc riding and racing? im seriously considering this because im gonna need a rebuild soon. so the stroker crank doesnt bump the compression any?

[400exwhipper]

With the powroll kit they say you can just have your stock 400ex or any piston like machined to work, however compensation of the wrist pin 4mm higher in the pistion to keep true compression was no where to be found, I'm worried I'll end up with pre detination with all that added compression

[powerbomb400]

You get a longer stroke moving the wrist pin. It won't raise the compression but will give you more cc's. It will hold more air and fuel so when it does fire there will be a larger explosion to move the piston faster at the power stroke.

[Zakradu398]

Originally posted by 400exwhipper
With the powroll kit they say you can just have your stock 400ex or any piston like machined to work, however compensation of the wrist pin 4mm higher in the pistion to keep true compression was no where to be found, I'm worried I'll end up with pre detination with all that added compression Ya Not sure how the machining works.

[powerbomb400]

They move the mounting point of the rod on the crank. It allows for a longer stroke of the piston.

[400exwhipper]

Machining the case or the piston is the easy part lol, I can't figure any way that this crank won't bump compression.. Can someone explain this because they say you can use non stroker pistons with there kit

[HondaRacing83]

im confused what cc id be at with all that onnpump gas. sayyy stock bore 4mil, 407 4mil, 416 4mil?

[powerbomb400]

I'm going to guess and say that it will add 20cc. I see where people do a 440 bore then do the crank to stroke it to make a 460cc.

[HondaRacing83]

417,427,436,446 as in stock,407,416,426 haha those are pretty sweet displacement sizes