Stroking a stock crank

[te4250]

I was going to re-pin my stock crank to a 4-6mm stroker. I had seen somewhere that some of the earlier stroker cranks up to 6mm were re-pinned stock cranks. Anyone done this, anyone still doing this? I pressed apart a blown stock crank last night. Looks like you could probably get away with 5mm adding a sleeve to completely remove the old crank pin hole, or barely 8mm with no sleeve and weld the pin after assembly. This is with 26mm pins for small pin kawi rods.

I am curious if anyone has seen one of these stroked stock cranks, did they press a sleeve in or leave some of the old pin hole, weld up some material before cutting new pin hole, or maybe make a little eyelet to press in between old pin hole and new pin?

On a side note does anyone know if someone still makes long rod 5mm stroker cranks? It sounded like the hpe setups worked pretty well before he stopped making them. I could possibly machine crank webs for people out to 5mm strokers for 133 rods but I have little interest in assembling cranks lol.

 

[Storbeck]

I always wondered if a guy could slightly shorten a Kawasaki crank and stick it in a Yamaha for a dirt cheap 6mm stroker. Someday when I have both motors apart at the same time I'll set the cranks side by side... And probably see some problem that explains why nobody does it lol

 

[yamanube]

I was going to re-pin my stock crank to a 4-6mm stroker. I had seen somewhere that some of the earlier stroker cranks up to 6mm were re-pinned stock cranks. Anyone done this, anyone still doing this? I pressed apart a blown stock crank last night. Looks like you could probably get away with 5mm adding a sleeve to completely remove the old crank pin hole, or barely 8mm with no sleeve and weld the pin after assembly. This is with 26mm pins for small pin kawi rods.

I am curious if anyone has seen one of these stroked stock cranks, did they press a sleeve in or leave some of the old pin hole, weld up some material before cutting new pin hole, or maybe make a little eyelet to press in between old pin hole and new pin?

On a side note does anyone know if someone still makes long rod 5mm stroker cranks? It sounded like the hpe setups worked pretty well before he stopped making them. I could possibly machine crank webs for people out to 5mm strokers for 133 rods but I have little interest in assembling cranks lol.

I have a damaged 4 or 5 mil modded stocker. The flywheel snout was damaged by a loose flywheel. It will need the front web and snout replaced. It might answer your questions and offer a cheap project if you can do the work yourself. PM me if you'd be interested in it.

 

[DylanS]

I was going to re-pin my stock crank to a 4-6mm stroker. I had seen somewhere that some of the earlier stroker cranks up to 6mm were re-pinned stock cranks. Anyone done this, anyone still doing this? I pressed apart a blown stock crank last night. Looks like you could probably get away with 5mm adding a sleeve to completely remove the old crank pin hole, or barely 8mm with no sleeve and weld the pin after assembly. This is with 26mm pins for small pin kawi rods.

I am curious if anyone has seen one of these stroked stock cranks, did they press a sleeve in or leave some of the old pin hole, weld up some material before cutting new pin hole, or maybe make a little eyelet to press in between old pin hole and new pin?

On a side note does anyone know if someone still makes long rod 5mm stroker cranks? It sounded like the hpe setups worked pretty well before he stopped making them. I could possibly machine crank webs for people out to 5mm strokers for 133 rods but I have little interest in assembling cranks lol.

I’m running a stock gp800 crank with a 5mil stroke on it from crank works and a balance in my 1050cc. 2 seasons in and so far no slop or issues. I don’t ride nearly as much as some other guys on here that probably have their strokers remanned every season. I can send you pictures of how they move the pins if you’d like. Pretty sure they just machine/make an offset pin, or so I think I remember being told. I remember for a lightening service, balancing, and +3mm stroke on a gp800 my bill came to about 1200. I’m sure you could find a cheaper AM crank unless you’re making your own!

 

[te4250]

Yamanube is hooking me up with his stroked stocker so I can see how its done, Based on the pictures it looks like they just welded the hole up a bit before re-boring it but I'll check it out when I get the crank. I have been thinking about building a gp800 motor in general as well, TBH it seems like less work compared to making the stroker crank, epoxying, porting and trenching the cases, boring, sleeving and porting the cylinder, making a cylinder spacer, cutting custom domes, etc etc.

You have that stroker crank in a 66e motor with 90mm pistons or what?

 

[DylanS]

Yamanube is hooking me up with his stroked stocker so I can see how its done, Based on the pictures it looks like they just welded the hole up a bit before re-boring it but I'll check it out when I get the crank. I have been thinking about building a gp800 motor in general as well, TBH it seems like less work compared to making the stroker crank, epoxying, porting and trenching the cases, boring, sleeving and porting the cylinder, making a cylinder spacer, cutting custom domes, etc etc.

You have that stroker crank in a 66e motor with 90mm pistons or what?

If I recall early gen stroked cranks were welded and moved, the newer ones are entirely new pins that have been milled to be offset so they didn’t have to sacrifice web structure/strength.
I have 89mm pistons and a 5mm stroke. The only thing to watch out with gp800 motors is the extreme scarcity of parts. And ironing out low end bog. IMO it’s not even worth it unless you can get hands on a TL system or WDK’s custom ZEEL ignition. You’d also need a manifold and pipe from Jeff or at the least a mani and a pfp chamber. My motor hits incredibly hard and so does my uncles, but they are a massive pain in the ass. If you ever do decide to get into the motors I have years of info on dialing them in and I have a few parts lying around. Would be happy to help, 66e guys are a dying race!

 

[yamanube]

The 66E has a 10mm longer stroke than the 62T to start, it's an all around better engine but aftermarket support is basically non existent. Having had multiple 66E standups, I'd still pick a 62T platform, unless you just like to experiment with homebrew stuff and can find an engine cheap.

 

[te4250]

I'm hoping to go pick up a complete gp800 in canada for like $380 usd in the next couple days, I was planning on making intake and exhaust manifolds as well as upright mounts. Yeah nikasil, powervalve and 10mm longer stroke sounded good to me. I also read the cases and transfer ports can flow a lot more without porting.
As far as ignition goes, has anyone used gp1300 throttle bodies and ran the 66e fuel injected with a cheap standalone like a speeduino or megasquirt, then run some coils off that?
Dylan are those 89mm pistons from a cr500 or something else?

 

[Storbeck]

I'm hoping to go pick up a complete gp800 in canada for like $380 usd in the next couple days, I was planning on making intake and exhaust manifolds as well as upright mounts. Yeah nikasil, powervalve and 10mm longer stroke sounded good to me. I also read the cases and transfer ports can flow a lot more without porting.
As far as ignition goes, has anyone used gp1300 throttle bodies and ran the 66e fuel injected with a cheap standalone like a speeduino or megasquirt, then run some coils off that?
Dylan are those 89mm pistons from a cr500 or something else?

Selfishly, I want you to do that pretty bad, and post a lot of info about it.

 

[DylanS]

I'm hoping to go pick up a complete gp800 in canada for like $380 usd in the next couple days, I was planning on making intake and exhaust manifolds as well as upright mounts. Yeah nikasil, powervalve and 10mm longer stroke sounded good to me. I also read the cases and transfer ports can flow a lot more without porting.
As far as ignition goes, has anyone used gp1300 throttle bodies and ran the 66e fuel injected with a cheap standalone like a speeduino or megasquirt, then run some coils off that?
Dylan are those 89mm pistons from a cr500 or something else?

The pistons are custom order from weisco. 87mm is about as high as they go without special order. Stock stroke at 87 is a 927. I personally run Ed from full spec’s custom manifolds and reed cages/three stage reeds for my motor. And I think we just bought the last set! I do have a set of Jeff’s early intake manis and m16 single stage reeds laying around. I also have several complete used MSD systems for the 800. Jeff has manifolds/pipes and a new ignition he swears is the bees knees (I’ll be testing compared to total loss this summer) for around 1000 with a gp800 ignition core and flywheel. He just takes a while to get parts back from since he’s a busy guy. You’ll also NEED either custom bed plates or Jeff’s custom lower case half. You can run up to 5mm stroke without trenching these cases too. If you do end up going into these motors PM me and I’ll happily help you source parts and let you know how we get ours to scream.

 

[Storbeck]

I've always wondered why people don't just mount them at an angle like they are stock. Then you could use a much simpler/shorter straight intake manifold, and even the stock exhaust manifold looks like it is pretty good and you could just make a chamber. *looks....so I'm basing this on mostly ignorance*

Maybe it just doesn't physically fit in a small hull that way?

 

[DylanS]

I've always wondered why people don't just mount them at an angle like they are stock. Then you could use a much simpler/shorter straight intake manifold, and even the stock exhaust manifold looks like it is pretty good and you could just make a chamber. *looks....so I'm basing this on mostly ignorance*

Maybe it just doesn't physically fit in a small hull that way?

I’d have to look at my old bed plates but I think it is possible to run them at an angle. As far as stock exhaust manifold, it’s junk and doesn’t fit anyways. The first generation WDK cast manifolds arent the best and they’re heavy but they’re what was around at the time. The stock horizontal intake manifolds are no good either and if I recall do not fit in a Stand up. At one point a buddy of mine actually had a stock stroke and bore/ported cases 800 with a WDK mani and a custom drop chamber pipe he welded up. Thing ran like it was pissed for what it was. IMO without a Total loss or demagneted flywheel they’re sluggish out of the hole and hit very hard mid. Complete different beast with a system though.

 

[te4250]

The pistons are custom order from weisco. 87mm is about as high as they go without special order. Stock stroke at 87 is a 927. I personally run Ed from full spec’s custom manifolds and reed cages/three stage reeds for my motor. And I think we just bought the last set! I do have a set of Jeff’s early intake manis and m16 single stage reeds laying around. I also have several complete used MSD systems for the 800. Jeff has manifolds/pipes and a new ignition he swears is the bees knees (I’ll be testing compared to total loss this summer) for around 1000 with a gp800 ignition core and flywheel. He just takes a while to get parts back from since he’s a busy guy. You’ll also NEED either custom bed plates or Jeff’s custom lower case half. You can run up to 5mm stroke without trenching these cases too. If you do end up going into these motors PM me and I’ll happily help you source parts and let you know how we get ours to scream.

I already had pmed you about the cast intakes lol. And yeah I thought the 87 mm pistons for the 927 were just 1mm over kx500 pistons with the wrist pin hole bored out from 19 to 22mm? So I figured your 89s might be std bore cr500 With the same thing done.

I've always wondered why people don't just mount them at an angle like they are stock. Then you could use a much simpler/shorter straight intake manifold, and even the stock exhaust manifold looks like it is pretty good and you could just make a chamber. *looks....so I'm basing this on mostly ignorance*

Maybe it just doesn't physically fit in a small hull that way?

When I get my hands on a motor I’ll find out why everyone goes upright I guess lol or maybe keeping it angled is the way to go, we’ll see. I did want to get my hands on a stock exhaust to see if you could Make a chamber and keep the stock manifold, I still have never even seen a 66e in person though so I’m pretty in the dark lol.

 

[Quinc]

I'm hoping to go pick up a complete gp800 in canada for like $380 usd in the next couple days, I was planning on making intake and exhaust manifolds as well as upright mounts. Yeah nikasil, powervalve and 10mm longer stroke sounded good to me. I also read the cases and transfer ports can flow a lot more without porting.
As far as ignition goes, has anyone used gp1300 throttle bodies and ran the 66e fuel injected with a cheap standalone like a speeduino or megasquirt, then run some coils off that?
Dylan are those 89mm pistons from a cr500 or something else?

https://www.waterdawgkustomz.com/gp800bb.php

 

[CARBONX2]

20yrs ago I used to make pipes that fit to the stock manifold on the WB800, the skis pulled hard off the bottom. Be careful on skimming the stock head, didn't take much before head would flex between bolts and leak water into cylinder.

 

[DylanS]

I already had pmed you about the cast intakes lol. And yeah I thought the 87 mm pistons for the 927 were just 1mm over kx500 pistons with the wrist pin hole bored out from 19 to 22mm? So I figured your 89s might be std bore cr500 With the same thing done.


When I get my hands on a motor I’ll find out why everyone goes upright I guess lol or maybe keeping it angled is the way to go, we’ll see. I did want to get my hands on a stock exhaust to see if you could Make a chamber and keep the stock manifold, I still have never even seen a 66e in person though so I’m pretty in the dark lol.

Oh haha that’s right I forgot about that, I got all sorts of dumb stuff like that laying around. If you’re any good at machining it won’t be hard to make your own though!

 

[DylanS]

I've always wondered why people don't just mount them at an angle like they are stock. Then you could use a much simpler/shorter straight intake manifold, and even the stock exhaust manifold looks like it is pretty good and you could just make a chamber. *looks....so I'm basing this on mostly ignorance*

Maybe it just doesn't physically fit in a small hull that way?

Just looked at the plates
Unless you have one of Jeff’s hulls the stock bedplates aren’t going to fit unfortunately. I know a guy that has a set of cases and plates if you’d ever want them. Also, Jeff’s cases allow you to adjust your timing and use a the TL system.

 

[te4250]

So I got Yamanube's crank, finally got around to checking it out, looks like they just welded up the bottom of the hole a bit before re-boring it further out. Simple enough. Turns out Yamanube's was a 4mm stroker. I might make a stroker front web to match and put it in something, or just weld up the damaged taper section and turn it, about the same work either way.

 

[yamanube]

Glad it was of use to you, thanks for the update.

 

[te4250]

Got around to doing a bit of work on that crank, also I realized they pressed in a sleeve and welded it, didn't just build the whole thing up with weld