Reversed Cylinders

Is it possible to run a RD cylinder reversed like this?

The "ram air" effect you could get by doing a scoop out in the cold incoming air would be huge. 
 Keep in mind. Engines are air pumps..........The more air in, the more air out.
                                                    That  = more power. 

I am doing a reversed cylinder, liquid cooled Kawasaki H2 750 triple for one of my street bikes, long term project. Only thing I see that could be better on the Yamaha engine shown, would be CASE REEDS, not cylinder reeds. That's the way I am doing the Kawasaki H2. 

hhhmmmm, interesting, didnt know the ports didnt line up, hadnt thought about the heat from the exhaust on the cylinders either. I will have to do some more research. I def. dont want an epoxy job  bottom end on my bike, for a number of reasons as well.

HOw are you changing the thrust load?

Originally posted by yellowandfast HOw are you changing the thrust load?

 

Actually, in normal cylinders the cocking of the piston puts the skirt into the intake port.
This is why you really shouldn't widen a 400 port beyond the stock 40 mm width.
.
Yamaha turned the cylinders around just for this reason, the intake port size was limiting power once they went to reed valves.
.
With the cylinders reversed, the piston tends to cock towards the exhaust side, and of course the piston skirt is down past the bottom of the exhaust port by then. An ideal situation.
.
The problems are:
1) Carb angle, which can be mostly fixed by turning the boots upside down.

2) The pipes are short, less than 900 mm or even shorter. This is good if you are going to run 200 degrees exhaust duration and let the motor redline at 11K or more. The problem is the 400 crank is resonant at 10,500 RPM and life above that is very short(the crank wheels spread).

3) It is hard to fit carbs and aircleaners and still clear the front tire. A 17" rim and tire may help.

4) The cooling problem mentioned above, it is good to have the exhaust side and the headers right up front in the breeze.

5) The carbs are still going to be bathed in road grit, rain and any dirt you ride through.

I have seen pictures of RD350's and RZ's with reversed cylinders, and I'm sure that people have reversed 400 cylinders.
As I said before the "ram Air" effect is very small, this does seem counter-intuitive, but I have seen measurements done on modern superbikes that show less than a hundred Ten millibars at 60 MPH.
.
And installing a "Funnel" on the intakes does not increase the pressure (I don't know why, at first glance I thought it would) but I have read several places that it does not.
If anyone knows why a scoop or "funnel" gives no gain, I would like an explanation.
.

Dunno how this is not that much of a concern on the normal cylinder orientation but this caused them to go back from reverse cylinders.

Actually Yamaha went to case reeds and then the V-Twin.
I heard the biggest problem was the pipes and the mono-shock being in the same place, and also regulation of pipe temperature was harder with the pipes hidden up under the seat.
.
But, it has been done before. I am just not sure it is worth the effort. IMO

Dave

Edit: Corrected pressure number

"Thrust loading"is NOT a problem. Neither is exhaust port heat from the reversed cylinders, as we have success from things like RZ500, YZR500, Suzuki RD500, Honda v4 road racing engines, etc. Even Yamaha built an inline 500 engine for road racing that had two of the four cylinders conventional, aimed exhaust to the front, and the two others reversed, exhaust out the tail section. That half reversed engine ended up World Champion, so, no issues.

Hurley Wilvert and I built a single cylinder R5 years ago, that used one TZ750 cylinder, pipe and carb, street riddeen single cylinder bike, as a test bed. Total loss lighting, TZ ignition. We had NO problems running the TZ750 cylinder both conventional, AND later, reversed, with case mods.

Originally posted by torqu3e There is another thing that one needs to take into consideration. This was the reason that Yamaha went back from the reverse cylinders on the TZ series of road racers. There were issues that the crank spinning forward on the reverse cylinders causes the piston to hit and rock at BDC on the intake side, causing significant damage to skirt and cylinder lining. Dunno how this is not that much of a concern on the normal cylinder orientation but this caused them to go back from reverse cylinders.

I think the opposite is true.  Starting with The H model through the A model reverse cylinder motors (U W and A, 1988, 1989 and 1990 models were the 3 years of of the reverse cylinder motors) all had cranks that rotated backwards due to the water pump / primary drive jack shaft.  the N (1985) and newer had case reeds and for the most part had no intake port.  Thrust load is an issue with the intake side for motors with intake ports positioned in the cylinder.  The TZ500 and TZ750 inline motors all turned backwards, this placed the thrust load on the exhast side of the cylinder during the power stroke.  They have much better piston live than the pre-H model (1981) TZs as compared to the TZ250/350.  

Originally posted by BigBird The RZ motor in the picture has also been shortened (sorry if someone has already pointed this out) I believe it is modified to fit in a modern TZ delta box frame.