What modern(ish) kick start dirtbike has the toughest transmission?

xnewmanx
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xnewmanx
Edited Date/Time 9/13/2022 1:44pm
I’m in the process of designing an engine. Not my first stab at a project like this but typically I use a Harley 4 speed. For this build I would like to unitize the engine and trans. The engine will be a 2 stroke twin with rather large displacement. Hoping that you guys can chime in with: oh yea a “201X ______ was way overbuilt” or something like that. I want to use the Kickstarter assembly as well as trans gears, shift drum/forks and possibly clutch. Thanks in advance. Added some photos of my last build with a one off top end. All stainless. No chrome. Twin turbo.

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sandhills
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sandhills 9/11/2022 7:53am
9/11/2022 7:53am
Vins Motors in Italy is making two stroke twins, or are you really set on doing a one off?

Langen is using their twin.
xnewmanx
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xnewmanx 9/11/2022 8:03am
9/11/2022 8:03am
sandhills wrote:
Vins Motors in Italy is making two stroke twins, or are you really set on doing a one off?

Langen is using their twin.
Dead set on building my own. Lots of things I want to incorporate.
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Bearuno
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Bearuno 9/11/2022 8:19am
9/11/2022 8:19am Edited Date/Time 9/13/2022 8:25am
I'd think that you'd be best off doing a ' Non Unit ' engine. I really don't think you'll find any existing small 'Unit' engine that could take the HP and Torque you (I assume by your specs) are going for. Though, I guess you might be able to use a Superbike level gearbox, with either your crank case welded to it / your own full cases. But No, there's none of those with a Kick Start.

There are plenty of gearbox manufacturers , such as Nova, Quaife and others that do separate gearboxes, that are Motorcycle sized, , that could handle mega HP and Torque, and, I think some can be had with Kick Starters.

That you've put up a Chopper as pictures, sort of implies that you are not doing a small motorcycle.......

Thinking further, aren't there companies that make cases etc for 512cc / 585cc engines ( I'm guaranteed to be wrong on the capacities) for Banshees? That might be a source.
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Gravel
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Gravel 9/11/2022 8:48am
9/11/2022 8:48am Edited Date/Time 9/11/2022 9:02am
The 2014 ish KTM 500 exc might work. 6 speed, stout clutch at 55hp, kickstart and e-start.

This design ran from 12-16 IIRC, the last years (14-16) were the best. Don’t know what makes them best other than the con rod or if anything from the later years would benefit your plan.

You gotta post here when you’re done! That twin turbo is mind blowing!
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BobbyM
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BobbyM 9/11/2022 9:11am
9/11/2022 9:11am
Build yer own CV tranny. Should be easy for someone with your skill set. Good luck.
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Sprew
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Sprew 9/11/2022 10:09am
9/11/2022 10:09am
Not a Harley guy but appreciate your work. Pipes on the inside of the subframe. That is a lot of stainless work. 304?
FWYT
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FWYT 9/11/2022 10:14am
9/11/2022 10:14am
Just want to say that is some very badass work you have there! Keep it up!
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Gravel
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Gravel 9/11/2022 12:22pm
9/11/2022 12:22pm
suspensionguy wrote:
That’s a lot of chrome
It’s all stainless
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Richy
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Richy 9/11/2022 12:41pm
9/11/2022 12:41pm Edited Date/Time 9/11/2022 12:41pm
Nothing useful to add, just wanted to say that while that is 100% not my thing, massive props for the work and the detail in that thing, genuinely an awesome job 👍

Even the little vac hoses to the wastegate actuators are the right purple instead of the more commonly seen purple on most silicone hoses (like Samco), crazy attention to detail.
Munson'd
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Munson'd 9/11/2022 12:53pm
9/11/2022 12:53pm
I’ve followed you since the chopcult days. You’re a wizard and can’t wait to see what you have up your sleeve.
TeamGreen
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TeamGreen 9/11/2022 12:55pm
9/11/2022 12:55pm
The Honda XR650R has an excellent gear box.
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plowboy
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plowboy 9/11/2022 1:14pm
9/11/2022 1:14pm
You are the very definition of a "MAD MAN".Woohoo
Skerby
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Skerby 9/11/2022 1:14pm
9/11/2022 1:14pm
How are you gonna take the bottom end of a single cylinder engine and make it a twin??

That sounds downright impossible to me but I havent uhhh fabricated my own top ends before lol.
xnewmanx
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xnewmanx 9/11/2022 1:24pm
9/11/2022 1:24pm
Skerby wrote:
How are you gonna take the bottom end of a single cylinder engine and make it a twin?? That sounds downright impossible to me but I...
How are you gonna take the bottom end of a single cylinder engine and make it a twin??

That sounds downright impossible to me but I havent uhhh fabricated my own top ends before lol.
I’ll be making my own crankcase/crank etc
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BikePilot
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BikePilot 9/11/2022 7:33pm
9/11/2022 7:33pm
I think most big four stroke singe transmissions will hold up without a worry. A big lumpy four stroke single beats on its transmission way more than. A two stroke twin will. I would say any of the recent 450s or the old XR650R would survive most anything. The XR650R in particular is seriously over built. They last forever in harsh conditions and the gearboxes don't grenade even when running lots of road without a cush drive.
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xnewmanx
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xnewmanx 9/12/2022 11:12am
9/12/2022 11:12am Edited Date/Time 9/12/2022 11:40am
BikePilot wrote:
I think most big four stroke singe transmissions will hold up without a worry. A big lumpy four stroke single beats on its transmission way more...
I think most big four stroke singe transmissions will hold up without a worry. A big lumpy four stroke single beats on its transmission way more than. A two stroke twin will. I would say any of the recent 450s or the old XR650R would survive most anything. The XR650R in particular is seriously over built. They last forever in harsh conditions and the gearboxes don't grenade even when running lots of road without a cush drive.
I've dug into this a bit more and I just don't think there is going to be anything that will hold up. Does anyone here think an XR650R trans is going to be able to support 120 hp?

For those wondering, the build is going to be a dual crankshaft 1200cc "v twin" 2 stroke, so it has potential to make some serious ass.

Realistically I really might need to get into something way larger, I think I am going to buy a Baker 6 into 4 transmission and install the guts into my custom crankcase. Those things are tough as nails and parts are super available. Only gripe is that the input from the engine has to be outboard of output of the engine...

Only need to be able to kickstart one cylinder. Still a lots to figure out, though.


Thanks for the help on this.
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Munson'd
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Munson'd 9/12/2022 12:27pm
9/12/2022 12:27pm
You crazy bastard.

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Dirty Points 9/12/2022 12:31pm
9/12/2022 12:31pm Edited Date/Time 9/12/2022 12:50pm
BikePilot wrote:
I think most big four stroke singe transmissions will hold up without a worry. A big lumpy four stroke single beats on its transmission way more...
I think most big four stroke singe transmissions will hold up without a worry. A big lumpy four stroke single beats on its transmission way more than. A two stroke twin will. I would say any of the recent 450s or the old XR650R would survive most anything. The XR650R in particular is seriously over built. They last forever in harsh conditions and the gearboxes don't grenade even when running lots of road without a cush drive.
xnewmanx wrote:
I've dug into this a bit more and I just don't think there is going to be anything that will hold up. Does anyone here think...
I've dug into this a bit more and I just don't think there is going to be anything that will hold up. Does anyone here think an XR650R trans is going to be able to support 120 hp?

For those wondering, the build is going to be a dual crankshaft 1200cc "v twin" 2 stroke, so it has potential to make some serious ass.

Realistically I really might need to get into something way larger, I think I am going to buy a Baker 6 into 4 transmission and install the guts into my custom crankcase. Those things are tough as nails and parts are super available. Only gripe is that the input from the engine has to be outboard of output of the engine...

Only need to be able to kickstart one cylinder. Still a lots to figure out, though.


Thanks for the help on this.
Some of the boosted snow bikes are pushing up near or at that HP range on 450/500 bottom ends and transmissions, and that is a very high torque load application.

I don't know enough about them to know what additional beefing up they may have, if any.
xnewmanx
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xnewmanx 9/12/2022 1:05pm
9/12/2022 1:05pm
Dirty Points wrote:
Some of the boosted snow bikes are pushing up near or at that HP range on 450/500 bottom ends and transmissions, and that is a very...
Some of the boosted snow bikes are pushing up near or at that HP range on 450/500 bottom ends and transmissions, and that is a very high torque load application.

I don't know enough about them to know what additional beefing up they may have, if any.
That's interesting. I'll dig around a bit more. I'd MUCH rather use a lightweight dirtbike gearbox...
plowboy
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plowboy 9/12/2022 1:15pm
9/12/2022 1:15pm Edited Date/Time 9/12/2022 1:21pm
I'm not an engineer and couldn't dream of tackling your projects but would a hydrostatic drive work for this application?

Back in the day I worked for Ditch Witch. I worked on their big diesel machines. I converted military duece and half axles to hydrostatic drive. 50 mph on big balloon tires. I reckon that sort of drive could handle all the power you can throw at it. Like I said...an engineer I am not.
xnewmanx
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xnewmanx 9/12/2022 1:19pm
9/12/2022 1:19pm
plowboy wrote:
I'm not an engineer and couldn't dream of tackling your projects but would a hydrostatic drive work for this application? Back in the day I worked...
I'm not an engineer and couldn't dream of tackling your projects but would a hydrostatic drive work for this application?

Back in the day I worked for Ditch Witch. I worked on their big diesel machines. I converted military duece and half axles to hydrostatic drive. 50 mph on big balloon tires. I reckon that sort of drive could handle all the power you can throw at it. Like I said...an engineer I am not.
Possibly but a lot of what I do has a huge aestetic component and it's important to keep some things traditional, so having an actual standard gearbox is something that I'd like for no reason other than that's what I think it should be.
plowboy
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plowboy 9/12/2022 1:24pm
9/12/2022 1:24pm
xnewmanx wrote:
Possibly but a lot of what I do has a huge aestetic component and it's important to keep some things traditional, so having an actual standard...
Possibly but a lot of what I do has a huge aestetic component and it's important to keep some things traditional, so having an actual standard gearbox is something that I'd like for no reason other than that's what I think it should be.
GotchaWink
plowboy
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plowboy 9/12/2022 1:31pm
9/12/2022 1:31pm
There is a company that puts V8 engines in bikes. I believe their tranny's are propietary. Don't know any more than that. Boss Hoss. Blush
Skerby
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Skerby 9/13/2022 10:44am
9/13/2022 10:44am
plowboy wrote:
There is a company that puts V8 engines in bikes. I believe their tranny's are propietary. Don't know any more than that. Boss Hoss. Blush
Boss Hoss only has 1 gear.
SEEMEFIRST
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SEEMEFIRST 9/13/2022 11:43am
9/13/2022 11:43am
xnewmanx wrote:
I’m in the process of designing an engine. Not my first stab at a project like this but typically I use a Harley 4 speed. For...
I’m in the process of designing an engine. Not my first stab at a project like this but typically I use a Harley 4 speed. For this build I would like to unitize the engine and trans. The engine will be a 2 stroke twin with rather large displacement. Hoping that you guys can chime in with: oh yea a “201X ______ was way overbuilt” or something like that. I want to use the Kickstarter assembly as well as trans gears, shift drum/forks and possibly clutch. Thanks in advance. Added some photos of my last build with a one off top end. All stainless. No chrome. Twin turbo.

Man, that's insane!
Nice work!

You have spare spark plugs on board? Cool
plowboy
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plowboy 9/13/2022 11:51am
9/13/2022 11:51am
plowboy wrote:
There is a company that puts V8 engines in bikes. I believe their tranny's are propietary. Don't know any more than that. Boss Hoss. Blush
Skerby wrote:
Boss Hoss only has 1 gear.
Lol...I didn't know. Saw one briefly at the Tulsa fair years ago. They we're proud that their tranny could withstand a 302, 350, and even a 454.
Dave v3.0
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Dave v3.0 9/13/2022 12:48pm
9/13/2022 12:48pm
Most indestructible transmission ever was the 4 speed CZ. It also had a dry clutch that was basically indestructible.

Hey, you said "modern(ish)"Laughing
plowboy
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plowboy 9/13/2022 1:10pm
9/13/2022 1:10pm
Dave v3.0 wrote:
Most indestructible transmission ever was the 4 speed CZ. It also had a dry clutch that was basically indestructible.

Hey, you said "modern(ish)"Laughing
Lol...it had to be tough considering how hard you had to stomp on it to shift.Silly
Dave v3.0
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Dave v3.0 9/13/2022 1:14pm
9/13/2022 1:14pm
Dave v3.0 wrote:
Most indestructible transmission ever was the 4 speed CZ. It also had a dry clutch that was basically indestructible.

Hey, you said "modern(ish)"Laughing
plowboy wrote:
Lol...it had to be tough considering how hard you had to stomp on it to shift.Silly
The shifter was the only part on the bike that had 6 inches of travel.

But there are linkage kits to fix that today. Now you can have them shift like a Japanese bike and not risk hitting your chin with your knee.

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