has anyone run a cylinder upside down, sideways?

why? Just because u can. pictures?

Re: has anyone run a cylinder upside down, sideways?

Wesley Ambrosini /

In Australia all carbs intake from the bottom, exhaust on top... Something to do with hemispheres and gravity

Re: has anyone run a cylinder upside down, sideways?

Aaron Ward /

What if your run your head sideways to match the fins?!

Screenshot_20200623-162703.png

Re: has anyone run a cylinder upside down, sideways?

> Wesley Ambrosini Wrote:

> -------------------------------------------------------

> In Australia all carbs intake from the bottom, exhaust on top...

> Something to do with hemispheres and gravity

Ha . The exact same thing happens in the northern hemisphere and our northern gravity . ;)

Re: has anyone run a cylinder upside down, sideways?

I think if the carb was on the bottom, the engine would drool oil into the intake after running. Which would cause problems for people that don’t live in Australia.

Re: has anyone run a cylinder upside down, sideways?

Emil Kniemel /

Heads, yes. Cylinders...not yet.

Re: has anyone run a cylinder upside down, sideways?

Black Betty.......

The best one!

Re: has anyone run a cylinder upside down, sideways?

Eric beat me to it.

I have a dumb sachs project, it's right side up but I've got the intake cming out the bottom of the cases.

Also on Matt busaswoop's PA50-iii he ran the motor backwards, just switch the timing. not upside down but again a neat approach to getting the hobbit to mate up with a vespa rear pulley

Re: has anyone run a cylinder upside down, sideways?

Dirty30 Dillon /

Can't really run it sideways, without plugging the wristpin holes in the piston.

Re: has anyone run a cylinder upside down, sideways?

I've done it with the China bike engines. You gotta match the transfers and turn the piston around, but it works really well.

Also had a buddy with a triumph that did it. I think that was a pretty popular mod, to have the exhaust coming out the back.

You could do it on pretty much any two stroke. It's better if you have a vertical cylinder. Having the carb on the bottom of a horizontal engine would seem like it wouldn't flow right, and it'd be sucking up a lot of dirt, and one good speed bump would smash it.

Here's a motorized bike I reversed:

speedster004.jpg

And another:

glamourshot008.jpg

Re: has anyone run a cylinder upside down, sideways?

Terry dean ran the whole hobbit engine upside down, not just the top end.

Re: has anyone run a cylinder upside down, sideways?

^right, theres a lotta almosts but i dunno any who truly did it, well except bairds bicycles

Re: has anyone run a cylinder upside down, sideways?

Sx4 black betty ftw

Re: has anyone run a cylinder upside down, sideways?

There's this:

IMG_20200623_233002.jpg

Re: has anyone run a cylinder upside down, sideways?

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> Can't really run it sideways, without plugging the wristpin holes in the

> piston.

would this matter? once the exhaust is out n transfers open the wristpin its all below the rings. i need a visual. Forgot about the cutouts in a piston as well.

totally nuts to have a carb on the ground as well as the pipe on your leg.

Re: has anyone run a cylinder upside down, sideways?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

upside down cylinder would work just fine, as long as you remember to run the piston upside down too haha

your transfer ports are gonna be all goofed up, but that's a given, and can be fixed with some dremeling and adding material as needed

Re: has anyone run a cylinder upside down, sideways?

The pin would be open to the intake and exhaust ports. On some engines, that would blow the mixture straight through. Or blow it back out the intake during the exhaust stroke.

Or when open to the intake, it'd probably have a huge blow back, as the mixture would be forced into the hole?

Same with exhaust port. The return wave would blow right into the hole, and that can't be good.

I'm just guessing, but that sounds about right.

Plus you'd have to spin your rings so they don't hang up, and relocating a piston pin is no fun. I just did that on my Lazer. And I'm praying to the moped gods it doesn't come loose.

Re: has anyone run a cylinder upside down, sideways?

Dirty30 Dillon /

> pat splat Wrote:

> -------------------------------------------------------

> > Dirty30 Dillon Wrote:

>

> > -------------------------------------------------------

>

> > Can't really run it sideways, without plugging the wristpin holes in

> the

>

> > piston.

>

> would this matter? once the exhaust is out n transfers open the wristpin

> its all below the rings. i need a visual. Forgot about the cutouts in

> a piston as well.

>

> totally nuts to have a carb on the ground as well as the pipe on your

> leg.

Just a rough idea, but view the MK port map below

moped-army-9438d7634e855727809c33bec48f1a1f.jpg

With a ~10mm hole, you would have a portion of the stroke where the intake would flow straight out the exhaust, causing a complete loss of pumping pressure.

Also, carb on the ground isn't crazy. The Laura M48 motor has an underslung carb, as does the Vespino motor.

In a lot of ways, it makes sense to have your carb away from upward-rising heat. Keeps the fuel and air colder, so it's more efficient.

Re: has anyone run a cylinder upside down, sideways?

^i see, maybe case inducted easierr to flipp cylinder

Re: has anyone run a cylinder upside down, sideways?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

you'll still have the exhaust port to contend with

it's a lot more work than it's worth, unless it's one of those do-it-cos-you-can things, then by all means. i wanna see it rip!

Re: has anyone run a cylinder upside down, sideways?

I just thought of that in the shower. Case induction, flip the cylinder and piston.

Or get really crazy, use a non case induction cylinder, hog out the intake port to match exhaust, and run dual exhaust. one pipe on top and one on the bottom.

Re: has anyone run a cylinder upside down, sideways?

You guys must be talking a center pin location , front to back .

Aren't most 2 strokes made with a slightly offset pin ?

Or doesn't that matter ?

Re: has anyone run a cylinder upside down, sideways?

Dual exhaust?

That’s a thought I’ve never had. I imagine it has been tried and killed. Probably not the best use of cylinder real estate.

Re: has anyone run a cylinder upside down, sideways?

Dirty30 Dillon /

> Papa _ Wrote:

> -------------------------------------------------------

> Dual exhaust?

>

> That’s a thought I’ve never had. I imagine it has been tried and killed.

> Probably not the best use of cylinder real estate.

The Biggest issue with opposing exh ports would be getting a decent charge wash. On case inducted bikes the third eye and side transfers are meant to flow towards the exhaust to push hot, unspent fuel out the exhaust. If you redesigned the roof and shape of the side transfers you could get them to push this way, but that's basically just casting a new cylinder.

Re: has anyone run a cylinder upside down, sideways?

Re: has anyone run a cylinder upside down, sideways?

hah! that'd be siiick! it totally wouldnt work well if you just went ahead and did it but dual exhaust top and bottom is a super funny idea

Re: has anyone run a cylinder upside down, sideways?

Dan (high idle) Conway /

All classic vespa small frame models, 50, 90, 125, primavera, et3... they've all got the carb underneath the cylinder with an intake that snakes straight into the frame. Rotary valve crank. The good stuff.

Re: has anyone run a cylinder upside down, sideways?

I've wanted to run a cylinder sideways for so long, but it's a tricky to do right. And I'm lazy.

Re: has anyone run a cylinder upside down, sideways?

Sachs did a sideways cylinder from the factory. I rebuilt one a few years ago. They're wild little engines. Wrist pin rides over the exhaust.

Re: has anyone run a cylinder upside down, sideways?

Some pics of the parts engine here.

20200625_152500.jpg
20200625_152542.jpg

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