190cc Honda swapped 125 Pit bike Manual

karl

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Totally not clickbait.

Dumb idea, use blade stop clutch from a honda hrx217 hxa style push mower as a cheap 3d motorsport style manual clutch :p

Honda Roto-Stop® Blade Brake Clutch
Allows you to start & stop blades with the engine still running
Step away from the mower without having to restart the engine

And preform mad wheelies and peels???

Took a junk gcv190 OHC vertical shaft with a bent crank, and swapped the crank from a motor that pushed a valve guide.

Then removed pesky things like the governor, dipstick, and oil slinger gear. Drilled and tapped a level and drain plug, trimmed the shroud, and good to send horizontal. 6 whole horses of power. Sprocket will be welded to an old blade.
 

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mckutzy

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wow ...Definatly havent heard of this type of machine before.... cool...
Youll need to give lots of info to us on this type of clutch, when you are trying to mate this to the engine.... I like this Idea alot.....
 

karl

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wow ...Definatly havent heard of this type of machine before.... cool...
Youll need to give lots of info to us on this type of clutch, when you are trying to mate this to the engine.... I like this Idea alot.....

Thanks bud, I used a vertical shaft push mower engine that came with the blade clutch from honda. The engine/clutch may be pieced together from several mowers, but It is assembled as honda would. Not counting what I did to make it run horizontal.

The crank is stepped to fit the clutch, so the clutch would not be very easy to put on a different engine. Hopefully tonight I will get the motor mounted to the frame.

Ohhhhhdeariemeeeeee.......:(
Who needs life insurance anyways??:roflol:

Nahhh, she'll be tame for the standard of my creations at least.
 

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JTSpeedDemon

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I wonder, if t’s stepped inside, how hard would it be to take a lathe to the bore to adapt it for a std 3/4 crankshaft?? Definitely following this build, curious to see how long it holds up.
 

mckutzy

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Its bigger than 3/4".... so for 1" shaft maybe...

I just realized... this is a cone clutch......Interesting...
 

karl

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I wonder, if t’s stepped inside, how hard would it be to take a lathe to the bore to adapt it for a std 3/4 crankshaft?? Definitely following this build, curious to see how long it holds up.

Yeah the crank is around 7/8 diameter, but if you had a lathe, sleeve adapter could be made.
The clutch's typically outlive the mower, I have never changed a friction disk out.
The only failures I see, is if the mower sits somewhere damp, the bottom bearing can get crusty.
Should be more reliable than a SS clutch.

Its bigger than 3/4".... so for 1" shaft maybe...

I just realized... this is a cone clutch......Interesting...

Yeah, the friction plate thingy is really thick. Has some material.
I will play with the spring tension and see how smooth I can get it to engage.
 

karl

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Slapped a carb on for a test, and its miinntt. Did not even crack the bowl.
 
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karl

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Jackshaft is done, need to pick up some pan head m10x1.25 bolts to make the clutch sprocket actually work.

Should be ready to send soon.

The neighbors have a few pit bikes they hoon on, occasionally we will drag race.

Both my monster motos beat them, but I want to beat them on a pit bike,
I think If I win with a push mower powertrain, id be pretty funny.

Since the motor is bone stock,

10t clutch, 14t JS in, 10t out, 39t rear sprocket, for a 5.46 to 1 gear ratio.

16in tire, good for 31mph at 3600, and 44mph at 5000 rpm. Plenty.

So hopefully the extra torque, and inertia of clutch dump with the flywheel spinning 5k,
she will be sufficient.
 

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karl

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To fit the theme, I welded a bracket to use the original fuel tank, and chunk of shroud that I cut off the rear (or bottom)

Plus I think it looks cool, all shrouded and such.

As being a budget project, The total is up to $23 for this build. I only had to buy a stick of angle iron, and a 14t #40 weld on sprocket.
Plus the bolts.
 

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karl

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I just realized... this is a cone clutch......Interesting...

Surprisingly, its smooth. Really smooth. Too smooth.

At least with the current gear ratio, Its slips a bit much.

I have some things to try with the clutch, to make it grab a bit better.
I have doubts about mad clutch dumps tho. Not a total fail.

And a throttle control (I just set a tad above idle for the test runs) , kill switch, pegs, and chain guard might be needed.

Its still a fun bike to putt around on, worth the effort in my opinion.
 
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karl

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Well if anyone is interested, I got the clutch working just right, after some tweaking.

The gear ratio is too tall, a SS max torque style would be burning,

but with this clutch, it slips just right, smooth, and when you let it out all the way it grabs tight,
and works just like a professional motorcycle or car clutch. After 20min of riding, and plenty of slipping,
you can hold your hand on it, does not get hot. Should last a long time.

After a sprocket change, it should rip quite nice.

That's all

 

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karl

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Wow... this is pretty darn cool...... Holy cow... that goes pretty fast aswell....

Thanks, Its a blast to rip around the yard.
After changing the JS input from 14t to 16t, it should
be less sluggish on takeoff.

that's awesome! have you done a speed run?

Yeah it goes about 35mph flat out (edit it does indeed break 40) . Not too bad for an old push mower. Thanks.

I have taken it on 4 mile plus round trips, and she solid. Great cruising ratio. I fabricobbled an air filter adapter, as nothing else would fit.
To be honest Ive had more fun on it than my billet hipo rigs lately. It gets some weird looks too.
 

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