What is the meaning of this?!

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Sounds like you're just as crazy as me.

In some circles I am renowned, but not for my sanity.

Maybe I can talk You out of it .......

You have, but not permanently. I've bookmarked that post and will come back later. Thanks!

 

What is the meaning of this?!

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Shortbus is mocking me,
and I could care less ...........
He'll get tired of it eventually.
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Shortbus is mocking me,
and I could care less ...........
He'll get tired of it eventually.

Ok I see that now, but what is the meaning of this then?

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It's just an old habit of mine that keeps me from having to type at the very bottom of the page.
I like to be able to type my text in roughly the middle of the screen,
especially if it's a long Post.

Being able to see more text helps when checking Sentence-Structure, and insuring that
the text is easy to read and comprehend so that the reader is not having to work so hard at
deciphering and reconstructing the text into something understandable.

It really bugs me to read a Post where virtually no punctuation is used,
so that's another thing that I scrupulously try to implement when posting.
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The two bottles might work but don't know if the carbs you have have the ports for the tubing. The Uni-syn fits on the carb intake.

If you look closely at the carbs in that video you can see the equalization tubes in some of the views.

You might want to reconsider the removal of those springs in the carbs. If they seem to be too strong either cut down the length or get weaker springs. The springs help the blade move in the carb, and not cock and stick.

I looked at a site this afternoon that sells hot rod stuff for the clone type engines like the Predators. Not sure but think the Vtwin is a Kawasaki clone, the singe cylinder ones are Honda clones. Any way I know you went with dual carbs but they had a different way of using the Mikuni carb, and that is what I would have done, but made my own in the shop. It is an adapter that bolts to the original manifold and then uses a single Mikuni, would be a lot less troubles. Here's the link - https://www.performance670.com/product-detail/mikuni-carb-adapter

I started using the semi colon thing to make me look smart too.
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The two bottles might work but don't know if the carbs you have have the ports for the tubing. The Uni-syn fits on the carb intake.

If you look closely at the carbs in that video you can see the equalization tubes in some of the views.

Yeah, these carbs don't have any port for such purpose. I would have to drill & tap my intakes which I'm not afraid to do because I'm the one who made them. And which I would have to do anyway to port them together as you suggested. I was kinda planning on it anyway.

You might want to reconsider the removal of those springs in the carbs. If they seem to be too strong either cut down the length or get weaker springs. The springs help the blade move in the carb, and not cock and stick.

I am considering everything I know enough to consider, and reconsidering it perpetuity as I go along. I will try without springs and see what happens. I'm not throwing anything away. If I need to put the springs back in I can, but the slides never cocked or stuck as I was molesting them last night.

I looked at a site this afternoon that sells hot rod stuff for the clone type engines like the Predators. Not sure but think the Vtwin is a Kawasaki clone, the singe cylinder ones are Honda clones.

I believe this one is a clone of the no-longer-produced Honda GX670.

Any way I know you went with dual carbs but they had a different way of using the Mikuni carb, and that is what I would have done, but made my own in the shop. It is an adapter that bolts to the original manifold and then uses a single Mikuni, would be a lot less troubles. Here's the link - https://www.performance670.com/product-detail/mikuni-carb-adapter

Yeah I'm with you on that one, I should have gone for the single carb. If this little experiment of mine fails in ways I can't foresee, I have that to fall back on.

I started using the semi colon thing to make me look smart too.
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I must admit, it's working. When I picture you now, I see a full size bus with no more than 3 window lickers.

 

Is this project the same one you had a while ago with controlling the variable speed pulley?

The problem, I from my experience see, is using a governor at all. Governors are great on things like lawn mowers, garden equipment or things like that, where you set the trotttle and go. The governor then keeps it at that RPM under most loads conditions.

But your talking about a UTV/buggy, they like motorcycles or snowmobiles or other things don't have or need a set RPM. They need the driver/operator to have control of the motor speed. Even the minibikes I've built using mower type motors, the first thing I do is disconnect the governor. This is to give the engine control to who ever is operating it.

If I was doing this and wanted to limit available RPMs from the motor I'd put a stopper in the Mikuni slide, around the spring. Doing this you would then experiment to find the length of this stopper(like a short piece of tubing) to not allow RPMs to go above a set limit.

When these Mikunis are new they won't have much "stiction" in the movements. But after a time the lubrication will get washed off and they will not move as well.

Like in the other thread about limiting the variable speed pulley, I'm not trying to force you into doing it my way, just giving advice from years of working with this stuff and solving problems the fastest and easiest way.

If the semi colons worked, how about this?
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Is this project the same one you had a while ago with controlling the variable speed pulley?

I thought I remembered discussing this on the forum before, but you just confirmed it.
Yes, if it sounds familiar, it's the same one; I haven't done anything similar.
I also have plans for experimenting with the CVT/Variator/Variable speed pulley.
The buggy has sat dormant for a long time, probably since you last heard about it.

The problem, I from my experience see, is using a governor at all. Governors are great on things like lawn mowers, garden equipment or things like that, where you set the trotttle and go. The governor then keeps it at that RPM under most loads conditions.

But your talking about a UTV/buggy, they like motorcycles or snowmobiles or other things don't have or need a set RPM. They need the driver/operator to have control of the motor speed. Even the minibikes I've built using mower type motors, the first thing I do is disconnect the governor. This is to give the engine control to who ever is operating it.

Ok, you have my attention. I have watched a lot of videos about modifying this engine, and like you, the first thing most people do is disconnect the governor. If I were the only intended operator I would do the same. At most, I would put a tach on it with a red light and manually not explode it. But my kids will be operating it too, and I don't trust them to manually not explode it.

During the times that it ran properly with the old carb, the engine was running with the governor just fine. Throttle response was quick, I did not see any issue.

If I was doing this and wanted to limit available RPMs from the motor I'd put a stopper in the Mikuni slide, around the spring. Doing this you would then experiment to find the length of this stopper(like a short piece of tubing) to not allow RPMs to go above a set limit.

In my mind, that would be like putting a brick under the gas pedal. Yeah, it would be effective at preventing RPM from going above a certain point but it would be more of a power limit than an RPM limit. It would crawl up hills like an old dog and probably couldn't pull a trailer anymore. Am I wrong? I'm fine with being wrong, just say I am and I'll give it a try.

What I want (what I think I want) is a true rev limiter that allows full throttle under high load but precludes full throttle under light load, such that RPM never exceeds a certain value. Which is what I believe the factory governor does, and in my experience (with this specific engine at least) does a decent job of it. So I don't understand why everyone is so bent on bypassing it. That's not a jab but an invitation to expound on the why behind [your suggestion] and [everyone else's actions].

When these Mikunis are new they won't have much "stiction" in the movements. But after a time the lubrication will get washed off and they will not move as well.

Ok, you obviously know what you're talking about so I'll take your word for it. I'll try and find a lighter spring and/or some way to assist overcoming it so that the throttle action can be "balanced" and easy like a butterfly valve. Before I removed the spring my idea was to counteract with another spring externally, but the problem with that is that springs force increases with compressed length. The external spring would be decreasing force as the internal spring is increasing force and vice versa. Rev0 of my twisting rod idea had a chonch-shell-shaped "pulley" with a spring wrapped around, so that the torque applied by the tension spring would increase as it collapsed, rather than decrease. I can explore that further.

Like in the other thread about limiting the variable speed pulley, I'm not trying to force you into doing it my way, just giving advice from years of working with this stuff and solving problems the fastest and easiest way.

Understood, and appreciated. Likewise, I'm not trying to argue with you or challenge your experience (which I freely admit is much greater than my own) but I see value in having these discussions because I learn from them. So, thank you.

If the semi colons worked, how about this?
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No, no. That makes you look less confident. When I checked your bus at the end of this post the number of window lickers had doubled.

 

In my mind, that would be like putting a brick under the gas pedal. Yeah, it would be effective at preventing RPM from going above a certain point but it would be more of a power limit than an RPM limit. It would crawl up hills like an old dog and probably couldn't pull a trailer anymore. Am I wrong? I'm fine with being wrong, just say I am and I'll give it a try.

What I want (what I think I want) is a true rev limiter

A rev limiter is what the tube/stop in the carb slide does, only allows a certain RPM. Many small motors use the same bore and stroke with different HP levels. The old days they used a different compression /head to change the HP. Now it's done by how far the throttle can be opened. That way one engine can be sold as different HPs. A shorter throttle link is cheaper than a new assembly line.

Dynamometers measure torque and convert that to HP by how fast the RPM is on the pull. That is why both torque and HP lines on the graph cross at 5252RPM, no matter how powerful the engine is.

I think you misunderstanding how a small engine governor works. They don't slow a motor down, but do speed it up. You set a speed and when a higher load tries to slow down the engine the governor opens the throttle to keep it at the speed setting.

You could make something that you could control though. If this has a throttle pedal put a shaft collar on it. then a bracket with a arm that can be flipped/swung out of the way when you drive it. With the arm in one position full throttle is available, swing the arm down it stops against the shaft collar limiting RPMs.

 

A Governor allows the Engine to generate it's maximum rated Torque,
until a specific RPM is reached, at which point,
Torque is reduced to prevent over-speeding the Engine.
Over-Speeding the Engine will eventually break one or both Connecting-Rods.

With a travel limiter set on the Throttle,
Torque will be severely limited at all times,
therefore, a Throttle-Limiter will also limit acceleration.
With a Throttle-Limiter,
the Engine may still be able to achieve dangerous RPM levels
when there is no Load on the Engine.

High-RPM, combined with no-Load,
places much more stress on the Connecting-Rods than High-RPM under full-Load.

If a Rod is going to break,
it will break right AFTER You take your foot off the Throttle.

An Ignition-Cut Rev-Limiter is extremely hard on an Engine,
and would be a bad idea if the goal is protecting the
Engine from damage caused by excessive RPM.

A Governor, or, heavy-Ignition-Timing-Retard,
are the best methods for protecting the Engine against damage caused by excessive RPM,
and neither will have any negative effect on maximum-acceleration.

Another bonus of a Micro-Squirt-Computer is that
a simple switch to Ground can command it to "swap-Ignition-Advance-Tables",
with the secondary Ignition-Advance-Table adjusted for a lower Rev-Limit-RPM.

And, an additional "Fun-Fact",
is that the Micro-Squirt can be tuned to create
a "Crackle-Pop-Snap-Crackle-Pop-Snap" Exhaust-Sound
when letting up on the Throttle from High-RPM.
It makes the Engine sound like a gen-yoo-wine Race-Car,
and will shoot-flames out of a "Straight-Pipe" Exhaust.

It doesn't hurt anything, unless You have a very restrictive Muffler,
which might get blown-open along the seams after a while.
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A Governor allows the Engine to generate it's maximum rated Torque,
until a specific RPM is reached, at which point,
Torque is reduced to prevent over-speeding the Engine.

You need to read up about small engine governors.. They don't slow down the engine but do speed it up when it gets overloaded. Unless the load is so high it stalls the engine.

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You might need to do the same: https://en.wikipedia.org/wiki/Governor_(device)

"Small engines .... are equipped with a governor to limit fuel to the engine to a maximum safe speed when unloaded and to maintain a relatively constant speed despite changes in loading"

I'll believe the people that actually make the engines. https://www.briggsandstratton.com/eu/en_gb/support/faqs/browse/governor-system.html

Or actually read what is in your link. From your Wiki link -
"Small engines
Small engines, used to power lawn mowers, portable generators, and lawn and garden tractors, are equipped with a governor to limit fuel to the engine to a maximum safe speed when unloaded and to maintain a relatively constant speed despite changes in loading"

We are talking small engine governors here , not truck speed control governors.

Seems like both you and lqc read the only site out on the net that actually gets it wrong. Briggs, Kohler and all other places say what I'm saying. Here's a link to the one you guys agree with - https://www.small-engines.com/govtheory

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If a Rod is going to break,
it will break right AFTER You take your foot off the Throttle.

Not the usual way it happens. Usually a rod breaks when the engine is being revved up, not then it's off throttle.

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A pertinent short clip outlining the conditions that cause Rod failure .........

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Full Video ...........

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When Riga moped factory still was existing, then models Delta and Stella had electronic limiter. Simply ignition box worked by means of triac (no, thar was thyristor) and that thyristor had inherrently so slow opening/closing timing that max speed was exactly 40 km per hour. No way how to hack except to produce own spark making circuit - then it was able for 65 per hour. Later they applied a cetrain RC circuit to slow it down more, and when RC was eliminated, that moped was able for 60 per hour. Many youngsters was got their infavor end after such extirpation procedure. ... Thus, try to slow by ignition system.

 

A pertinent short clip outlining the conditions that cause Rod failure .........

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Full Video ...........

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I must have missed it. Where time wise in either of those videos does it say rods fail when you slow the RPM down after they were running at a higher RPM? Please give the time in either video, I like learning.

Your original quote in that regard -

If a Rod is going to break,
it will break right AFTER You take your foot off the Throttle.

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You might need to do the same: https://en.wikipedia.org/wiki/Governor_(device)

"Small engines .... are equipped with a governor to limit fuel to the engine to a maximum safe speed when unloaded and to maintain a relatively constant speed despite changes in loading"

Apology accepted JHT.

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I meant precisely what I wrote .........
But maybe I should have been more explicit, and said,
the exact "instant" that the Throttle is closed.

I said nothing about the Engine "slowing-down".

There is actually a more severe condition than this,
and that is, "Down-Shifting" in a manual-transmission car, to slow the car down.
Under this condition, there is a continuous Vacuum on top of the Piston,
which stretches the Rod at high RPMs.

Either condition can seriously increase the Tensional-Forces acting on the Connecting-Rod.
These conditions substantially reduce the maximum safe RPM that the Rod can withstand.

The only other things beside excessive-RPM at Light-Loads,
that can cause Rod failure are ...............

1) Lack of Oil for the Bearings,
2) Severely over-heating the Engine, or,
3) Heavy-Detonation ...............
caused by overheating, or,
poor-Fuel-quality, or,
excessive-Ignition-Advance, or,
a combination of all 3, or,
4) Adding Intake-Boost-Pressure or Nitrous-Oxide-Injection.

This is not new information,
I've known about this phenomenon for around ~50-years,
way back when I used to build race-engines, ( and win races ), and
a set of "Pink-Rods" ( forged-Rods ) were the hot-setup for high-RPM Chevy-Engines.

My first, and last, "Thrown-Rod" was in a Briggs & Stratton 3-hp Go-Kart when I was around ~15.
Since then, I've watched many other people destroy perfectly good Engines.

I've studied every page, in every issue,
of Hot-Rod, and Car-Craft Magazines, from about ~1968 to ~1992, ( and occasionally a few others ),
and every Book ever written by Smokey-Yunick, Jim-McFarland, David-Vizard,
and and 4 or 5 other famous authors and innovators in the Hot-Rod and Racing fields.

All Connecting-Rods, in every Piston-Engine,
still follow all of the same principles and rules.
Some designs just do it better than others.

The key to understanding Connecting-Rod failures comes with
studying the varying Cylinder-Pressures inside an Engine,
and how those pressures can create both tremendous compression-loads on the Rod,
and, how they can exacerbate the incredibly high inertial-forces which are
trying to tear the Piston off of the end of the Connecting-Rod.
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there is a continuous Vacuum on top of the Piston,
which stretches the Rod at high RPMs

What?
First, vacuum vs atmospheric conditions are only a difference of 14.7 psi for complete vacuum. Less in real life situations. Stretching steel with vacuum is in need of a citation. Please post one.

Second, how does an engine create a "continuous vacuum"? Valves are controlled by the cam shaft and the cam shaft is directly linked to the crank shaft. There is no way to keep valves closed continuously - especially not closed with vacuum. What removes the air/combustion products from the cylinder?

ny vacuum in an engine is from a Venturi effect or the draw of air on the intake port as the cylinder goes down. Which creates a mild vacuum at best.