1000cc two stroke

[FilthyLuka]

Transfer ports are more or less determined by your reed valves, and piston. Bear in mnd that the crank is going to be substantially bigger thana 125 cyclinder crank. Ditto main bearings.

I rather like the idea someone had of joining two CR500 crankcases.

Joining them left to right or back to front? Cause i suppose we could do the Neander crank trick. Not the two connecting rods but two cranks joined together by a gear on each crank, so they are effectively counter rotating... Although i can see how this could lead to problems in a smoker

Why a V-twin,other than fashion?

Work out how much this home built will cost.
Go and buy any sprotbike that will outperform it.
Spend the savings on whores and drugs.

Why a Vtwin? Because i dont want to have to cast a block to hold two sleeves and because every man and his mutt has a big bore parralel twin stroker.

Go and buy a sprotbike? A traction controlled, four stroke, wide tyred, steering dampened, easy to ride sprot bike that comes off the showroom floor? Id rather have my manic stroker

[FilthyLuka]

Really? So how do you manage the come down then?

Come down aint so bad, its the flash backs that get ya

[speedpro]

there was a story on a guy in kiwibiker mag a few years ago.
He used 3? rm250 motors from memory.
I remember he had to cast his own crankcase as the rm ones would not be upto the job. he had a way thicker casing.
Vibration was one of the main problems.
if you want to read it ill scan it and pm it to you if you like.

Jim Steadman, 75deg V3, 3x RM250s. Rumour has it that Dennis Charlott may be doing a few laps on it later in the year at a few chosen meetings.

[speedpro]

IIRC there was a Speedway midget (TQ?) back in the mid-eighties that was a V4 made from 4 YZ465 (may have been 490's) engines. I have the vague recollection that Graham Standring was the driver - or at least involved with the project... but it was a long time ago...

3x IT490s and 1X IT250. Bob Haldane had a hand in it and I thought Bill Buckley was involved as well. They played with firing intervals to see the effect on traction and on the driveline. The "big bang" version was evidently quite interesting.

Don't forget the V8 TZ1000 (4x TZ250s) with the water jackets cut off and fins welded on, in a midget. Big air scoops to the airbox and 8 expansion chambers. When it was in the powerband it flew.

[speedpro]

V2s are good on a 2 smoker especially on BIG ones. Plenty of room for the transfer ports which on a parallel twin would require the barrells to be spaced apart to allow room. The centre bearings can be recessed into the crank webs with the labyrnth seal between them making the whole crank a reasonable length. There would still be a version of the parallel twins rocking vibration but a balancer shaft could take care of a lot of that. Because of the intervals and the duration of the power strokes the clutch and gearbox will only have to ever handle the same peak torque loads as on a single, just that there will be two peaks per engine revolution, therefore a stock standard 500cc 2-stroke gearbox and clutch should be just fine.

Also it is wrong to assume that high primary compression is good. It isn't only the primary compression that "moves" the mixture up the transfers. Primarily it's the partial vacuum in the cylinder caused by the expansion chamber that draws the mixture up. In some cases raising the primary compression, by reducing the crankcase volume, reduces and restricts the amount that can be drawn up into the cylinder actually reducing peak power. Reed valves help here but it's better to have the volume already in the crankcases.

[speedpro]

Rumours are about of a V6 being made with 2 cranks and 6 125cc GP cylinders, either Yamaha TZ or Honda RS. 240hp shouldn't be hard at 14,000rpm. Not bad for a 750. finding somewhere to put the pipes will be the main challenge.

[Coyote]

can ya make me a sv2000s? V4? put two sv engines together?
maybe two tl1000r engines would be better?

Was wondering when someone would mention a V4. That would be great, but I'd much rather be interested in a 2 stroke, turbo'd and fuel injected 2 litre V4 made from 4 KX/CR cylinder heads.

Why a V-twin,other than fashion?
They make so much engineering sense - that's why Rotax don't make one.
The sensible layout for a two stroke twin is a parallel twin.
Ditto for a two stroke four it's a square four - RG's and RZ's were squares - anything with 2 crankshafts is a square.

Work out how much this home built will cost.
Go and buy any sprotbike that will outperform it.
Spend the savings on whores and drugs.

If a cylinder goes bang, you replace the one cylinder rather than the cylinder block. Makes sense when a lot of high performance 2 strokes tend to go bang often.

I agree with Ixion with the whores and drugs thing.

By the way, why does the fuel/oil have to pass through the crank? Has there ever been a wet sump 2 stroke that didn't burn oil?


I'm off to do some porting to my minimoto.

[FilthyLuka]

By the way, why does the fuel/oil have to pass through the crank? Has there ever been a wet sump 2 stroke that didn't burn oil?


I'm off to do some porting to my minimoto.

two stroke deisel? uses exhaust valves and a blower....

[xwhatsit]

If a cylinder goes bang, you replace the one cylinder rather than the cylinder block. Makes sense when a lot of high performance 2 strokes tend to go bang often.

No you don't, you just re-bore the cylinder that got damaged. Or, worst case, put a new liner in for the cylinder that got ferked. Not as though you've got camchains eating the chain tunnel down the side of the block or anything silly like that.

[Pixie]

Best you back away from this thread slowly, and quietly shut the door. You do not, and probably never will, understand. But that's ok, it takes all sorts to make the world go round

/edit: Oh, and the RZ500, it is a dual crank V4, not a square 4.

V engines only have one crank - it's a square four.
Do you even know what a square four is?

I probably owned more two strokes than you ever did, several before you were born,I look forward to their return and vanquish of the four stroke world and I recognise a pointless exercise when I see it

PS only an inadequate wanker red reps a post because they disagree with it paLuka

[Pixie]

Was wondering when someone would mention a V4. That would be great, but I'd much rather be interested in a 2 stroke, turbo'd and fuel injected 2 litre V4 made from 4 KX/CR cylinder heads.

If a cylinder goes bang, you replace the one cylinder rather than the cylinder block. Makes sense when a lot of high performance 2 strokes tend to go bang often.

I agree with Ixion with the whores and drugs thing.

By the way, why does the fuel/oil have to pass through the crank? Has there ever been a wet sump 2 stroke that didn't burn oil?


I'm off to do some porting to my minimoto.

Plenty of inline engines have separate cylinder: Deutz Fahr ,SAME

Wet sump two strokes?
stepped piston:

http://users.breathe.com/prhooper/opads.htm

Pivotal from Christchurch ( which is best described as dry sumped or no sumped )

http://www.pivotalengine.com/index.html

And supercharged are possible.

[diesel pig]

By the way, why does the fuel/oil have to pass through the crank? Has there ever been a wet sump 2 stroke that didn't burn oil?

Yeah there is, Detroit Diesels but with no crankcase compression they here big fuck off blowers to get the air into them which brings me to fun fact No 237 2 stroke Detroit Diesel blowers have been turned into superchargers on Top Fuel Dragsters for 50 years.

[speedpro]

V engines only have one crank - it's a square four.
Do you even know what a square four is?

I probably owned more two strokes than you ever did, several before you were born,I look forward to their return and vanquish of the four stroke world and I recognise a pointless exercise when I see it

PS only an inadequate wanker red reps a post because they disagree with it paLuka

Yamaha's 500/4 2-stroke is a V4, it even says so on the fairing. Pairs of bores are parallel but each pairs bores are set at an angle to the other pair making a V when viewed from the side. From "motorcycle.com" about the RZ500 - "Inspired by the YZR500 factory racer ridden by Roberts during the 1983 GP season, the twin-crank V4 was the closest thing to a Gran Prix bike (with lights) that you could get your hands on".

Suzuki's 500/4 is a square 4 with 2 cranks, obviously. A friend has turned one into a V4. It still has 2 cranks just the barrels are now in a similar configuration to the Yamaha 500. All 4 carbs are set in a line in the middle of the V.

The number of cranks has nothing to do with it. A V4 could have 1 crank, 2 cranks geared together and contrarotating, or 2 cranks with a jack-shaft between so both cranks rotate in the same direction.

[rudolph]

What about a DKW SPLIT SINGLE 2 stroke, one cylinder is the compresser, they say it is the loudist thing you have ever hird

[Pixie]

Yamaha's 500/4 2-stroke is a V4, it even says so on the fairing. Pairs of bores are parallel but each pairs bores are set at an angle to the other pair making a V when viewed from the side. From "motorcycle.com" about the RZ500 - "Inspired by the YZR500 factory racer ridden by Roberts during the 1983 GP season, the twin-crank V4 was the closest thing to a Gran Prix bike (with lights) that you could get your hands on".

Suzuki's 500/4 is a square 4 with 2 cranks, obviously. A friend has turned one into a V4. It still has 2 cranks just the barrels are now in a similar configuration to the Yamaha 500. All 4 carbs are set in a line in the middle of the V.

The number of cranks has nothing to do with it. A V4 could have 1 crank, 2 cranks geared together and contrarotating, or 2 cranks with a jack-shaft between so both cranks rotate in the same direction.

The Fact that it has 2 cranks precludes it from being a true V.
They could hardly write "Square four Crank Configuration With Non Parallel banks of Two Cylinders" on the fairing could they?

On a true V pairs of conrods share the same crank pin

Don't put your understanding of engineering in the hands of some ignorant motorcycle journalist.They still don't understand that an engine with a side to side crankshaft and four parallel cylinders is a transverse straight four and one with a fore and aft crankshaft and four parallel cylinders is an inline straight four
Don't try to teach your grandmother to suck eggs