Kart Rods

[Kelly Wood]

ja.. ja ja.. GREAT!
but maybe (just maybe) a curved windshield is even nicer..
and easier like a visor or sunshade of a helmet for example.
View attachment 43916

'sid

Good idea.

 

[Kelly Wood]

Another mock up:

I figure with twin engines and a neat exhaust system tying it all together should look nice, and mean.

The fin, well, it then throws it all off for me so we're gonna "PUNT" and go get those rear fins I put on Brown Thunder and make 2 for the back of this one, one on each side, in the back on the rails.

See the pic, enjoy.

Time to find the garbage can now. The rest is pretty simple. I even have a gunners handle for this one.

That makes 5 actual machines, all unique.

Urban Defiance (functional)
The Sarge (functional
Moving Violation (unit 51) (all parts collected, ready to assemble)
Bonneville Spirit (all parts collected, ready to assemble)
and The Baronesse (most collected, need 2 matching techumseh's and a dual sprocket clutch.

 

[machinist@large]

So, question of the day... How would you run 2 5HP's, INLINE, powering the rear live axle only?

Yes please in line engines!

I already love the idea...
I'd move em a bit inward though more onto the passenger seat so to say.

Anyways.. connecting.. hmmm
clutches.. dual sprocket clutches to be precise, and a chain (with guard please and a tensioner)

Or do you want to get nasty with this one?
then right angle gears and a turning shaft
http://maedler.de/product/1643/1619/273/2511/kegelradsaetze-aus-stahl-spiralverzahnt-uebersetzung-11
(a simple rubber band on said shaft could then 'power' your 6 barrel minigun )

'sid

I like the dual sprocket clutch idea; my personal idea was to use a common JS mounted between/ below the engines; each engine uses it's own mounting plate, so you would just slide each one as needed to achieve correct chain tension, and you would still only have to deal with one chain to the rear axle. You would also have some options as to how you would like to package the engines; as long as all shafts are parallel side to side, they can be almost anywhere you like in the fore/aft/ height above ground layout.

The same applies for the clutch(s) that 'Sid listed; the only concern I have with one engine or the other driving both clutches. Will they have bushing problem? IDK....

Just put 12 inline engines on it...

I think Kelly is looking for a design that doesn't need a NASCAR pit crew to operate....

Pat

 

[Kelly Wood]

the only concern I have with one engine or the other driving both clutches. Will they have bushing problem? IDK....

We're gonna find out...

 

[Doc Sprocket]

Jeez, K- you just keep setting that bar higher and higher! I love the photochop mockup pic. Pure dynamite!

With the two engines- I personally would be really inclined to lock them together (no clutches) and then run a common clutch off a jackshaft. Why?

Because with the engines locked together, you can set the timing of the power strokes on both engines. Bearing in mind that a four stroke fires every 720° of crank rotation, you can time them to both go at the same time, or alternate revolutions. You can even time them to fire 180° off on the same revolution, then delay for the next 540°... Each different way they could be timed, would alter the way the whole thing sounds, possibly rather dramatically. There's no way I could refuse the temptation to try that!

 

[machinist@large]

Jeez, K- you just keep setting that bar higher and higher! I love the photochop mockup pic. Pure dynamite!

With the two engines- I personally would be really inclined to lock them together (no clutches) and then run a common clutch off a jackshaft. Why?

Because with the engines locked together, you can set the timing of the power strokes on both engines. Bearing in mind that a four stroke fires every 720° of crank rotation, you can time them to both go at the same time, or alternate revolutions. You can even time them to fire 180° off on the same revolution, then delay for the next 540°... Each different way they could be timed, would alter the way the whole thing sounds, possibly rather dramatically. There's no way I could refuse the temptation to try that!

Max coolness? Most likely. Max complexity? "THE NEW WINNA......"

The easiest question I can think of is also one of the biggest; Kelly said he's looking for a matching pair of Tecumseh's, in the 5HP range. I personally have never seen one that small with electric start, which suggests to me he might want to have the disconnect feature of dual clutches. It means you can start them one at a time without having a dead one turning it into a giant .

The next question I have is how do you actually synchronize two separate engines when they are chained together? Someone's probably figured it out, but I haven't seen or heard about it, or how they did it. This is something that needs to be addressed.

From what I've read, in twin engine piston powered aircraft, where the engines are usually synced in cruse, they use a system that matches the RPM of the slave engine to the one set up as the master using a mechanism that selectively "misses" the slave engine by pulling the spark in the magneto for that engine to sync it to the master. I'm guessing that the slave engine is set to turn a couple of hundred RPM faster than the master to make that work. This description has been an educated guess on my part...

When tying two engines together ridgedly, you'll also need to balance things like caurburation as well. That is doable, but most folks don't have a calibrated carb sync gauge set. I've got a four cylinder set (four cylinders= four gauges, with all the necessary fittings to hook them up [the ones I'm referring to are vacuum actuated]). The set I have cost over $200.00 US when I bought them ~ 20 years ago. I have no clue what they cost today; I do think that many DYI'ers might choke at what they might cost today, and I know that I've never loaned mine out. If you want to borrow, the Snap On Tools rule starts to come into play, and to get me to help you with them, you had better be an actual friend......

Pat

 

[Doc Sprocket]

Pat- your thoughts are good, but far too complex for the simple thing this really is. Two very archaic engines chained together. Carb balancing is entirely unnecessary.

 

[Kelly Wood]

Jeez, K- you just keep setting that bar higher and higher! I love the photochop mockup pic. Pure dynamite!

With the two engines- I personally would be really inclined to lock them together (no clutches) and then run a common clutch off a jackshaft. Why?

Because with the engines locked together, you can set the timing of the power strokes on both engines. Bearing in mind that a four stroke fires every 720° of crank rotation, you can time them to both go at the same time, or alternate revolutions. You can even time them to fire 180° off on the same revolution, then delay for the next 540°... Each different way they could be timed, would alter the way the whole thing sounds, possibly rather dramatically. There's no way I could refuse the temptation to try that!

Makes sense. See my next reply.

 

[itsid]

Bearing in mind that a four stroke fires every 720° of crank rotation, you can time them to both go at the same time, or alternate revolutions. You can even time them to fire 180° off on the same revolution, then delay for the next 540°... Each different way they could be timed, would alter the way the whole thing sounds, possibly rather dramatically. There's no way I could refuse the temptation to try that!

Oh and a shared muffler... brabble
Nice idea, but starting them would requie a one way clutch on at least one of the engines

And although I think it'd be nice to have the engines synced, I don't think it's actually crucial to make the clutch setup work properly.
Think about it this way.. if one engine revs faster, it applies the majority of power to the axle, which means the other engine needs less power to rev up,
And as soon as both clutches are fully engaged, they run at the very same rpm anyways.

True, I would synchronise them as good as I can before tying them together, but I wouldn't actually make it a science

'sid

 

[Doc Sprocket]

but starting them would requie a one way clutch on at least one of the engines

No it wouldn't. It would merely require less effort.

And although I think it'd be nice to have the engines synced, I don't think it's actually crucial to make the clutch setup work properly.
Think about it this way.. if one engine revs faster, it applies the majority of power to the axle, which means the other engine needs less power to rev up,
And as soon as both clutches are fully engaged, they run at the very same rpm anyways.

I assume you mean carb synchronization, not the stroke synch I was referring to earlier.

 

[machinist@large]

Pat- your thoughts are good, but far too complex for the simple thing this really is. Two very archaic engines chained together. Carb balancing is entirely unnecessary.

Sorry Chris, it's just that you were amplifying the problems as challenges; what had me go into depth was the "....lock them together (no clutches)....." part.....

Two engines, with clutches? I've never done it, but I think 'Sid's thought might be spot on....

Pat

 

[Kelly Wood]

Ok... so in the Bat Cave I'm chatting with your friend & mine, Doc Sprocket.

His idea had me thinking but I'm not sure what he meant so I got clarification.

Doc Sprocket says:
Hard gears on output shafts down to a jackshaft with 2 sprockets. So, 2 chains here. On the jackshaft, the clutch and chain to the rear axle. Good idea.

Positives:
1. Only one clutch to deal with
2. Timing could be achieved with variations of sound. Nice.
3. Use of ANY clutch and Teeth I like would achieve very high speeds.

Negatives:
1. If one engine dies, the remaining engine has to work harder turning the dead engine.
2. Starting one means starting the 2nd one as well.
3. Three chains.


What I was going to do: (Sid's idea)
Dual gear clutch. Clutch with dual gears goes on the back engine. Then a normal clutch on the front engine. The engines hook together with one chain, then one goes to the axle from the rear engine. If rear engine dies, it would act like a jackshaft and still function. Same with the reverse.

Positives:
1. Only 2 chains.
2. Reasonably simple
3. If one engine dies, everything would continue to roll smoothly with no excess power draw on the running engine (other than the weight of the dead engine it's moving around rather than turning over)

Negatives:
1. Unknown how the two engines would "fight" each other... and where it would occur. (personally, I'm hoping to see a fight)
2. 2 Clutches needed, one of them being a dual sprocket clutch and they only appear to come in 13t configurations


Anyone else wanna take a stab at this?

 

[Doc Sprocket]

The engine's "fight" isn't likely to be at all dramatic. They'll regulate each other, no issue really. Dual engines on a kart, is NOT a new idea by any stretch. Many have done it with excellent success over decades.

Alex's idea is likely the more practical one. Sometimes I sacrifice pure practicality in favour of "oh man, is THAT cool!".

With regards to one engine dragging the other down (if one dies) is really a non-issue. How often will THAT happen, if the engines are in decent condition? Speaking for myself, no problem- no concern.

 

[itsid]

I assume you mean carb synchronization, not the stroke synch I was referring to earlier.

carb and rpm/throttlepos. (thus ignition up to a point) but not stroke like in your idea no

What I was going to do: (Sid's idea)
Negatives:
1. Unknown how the two engines would "fight" each other... and where it would occur. (personally, I'm hoping to see a fight)
2. 2 Clutches needed, one of them being a dual sprocket clutch and they only appear to come in 13t configurations

As I mentioned earlier, I think as long as they're at least very close to run the same rpm, they wouldn't fight but synchronise themselves as soon as both clutches are fully engaged.
Most likely at least one will not provide it's full potential powerwise... but is that really important?

'sid

 

[Doc Sprocket]

at least one will not provide it's full potential powerwise... but is that really important?

'sid

Not at all- and kind of alludes to a previous comment I had made about putting together two archaic engines. They aren't highly tuneable performers. The carbs especially, are about as basic as they can be, and yet still actually function. In fact, actually trying to synchronize them might be futile if not entirely impossible. If these engines we're each fitted with say, a Mikuni slide carb, then it would be a lot more feasible, and MIGHT actually benefit from the exercise. Maybe.

 

[Poboy kartman]

Ok- Am I missing something here? With the engines linked- how can you not start both engines unless one has a kill switch on? Yet it seems like the opposite has been posted.

 

[Kelly Wood]

Continuing on:

Beer 2.

While I said Tecumseh's, I had to find out if it would work. Knowing the back part of this frame is a split version of its former self, this meant the wheels would be closer to the engine on the original mount if I leave it there, and I try to if possible.

With a kart rod, it's not really about re-inventing it... it's about seeing what you can do with what you have.

So I sat a tec on the mount... and guess what? There's not enough room for the rear wheel. It'll hit the shroud/pull cord attachment. The Tec is 10 inches from the inner motor mount hole to the outer edge of the shroud/pull starter.

The Briggs is 8. Also, length wise, the tec is almost 10 in in length (visually from the top) and once again, the briggs is 8... and we need the room here to cram them together.

So sitting in place (balanced on all kinds of stuff) we have another step in the mock up. I have 2 briggs 5hp flatties and with an extra updraft carb, I could make this work rather well. We'll plop a bullet tank in the middle of both feeding the updraft carbs and I think it could work. Then we'll run the exhaust around it and together in the back.

There's enough clearance for the chain to go engine-to-engine above the bar, so good there too.

Does anyone know if OLD briggs shrouds fit the newer ones? I really want more rounded (on top) ones for this.

The motors must sit in-line and be where they are, right on the bar, or the front one's gonna be close enough to me to cause issue... so there they will go.

Onward.

Oh yes, seen in the picture holding it all up, on my dirty living room floor... is an actual empty can of spam... and a flashlight... and a big ole screwdriver.

 

[Kelly Wood]

Ok- Am I missing something here? With the engines linked- how can you not start both engines unless one has a kill switch on? Yet it seems like the opposite has been posted.

If linked directly, yes, they'd have to start at the same time. I'll most likely be using dual clutches, one of them is a dual gear. Thus, you can start either individually. if one dies, the other clutch will just spin and cause no issue. Correct?

 

[Poboy kartman]

In a word- yes. And obviously the dual clutch on the rear (drive) engine.

 

[Kelly Wood]

Last update:

I think I've got a 2nd updraft carb, now to make these briggs look older. How? Older shrouds. Anyone anywhere have anything laying around? THey're 5HP stock blocks and any shroud with a rounded top will work here. the older the better.

Nite!