ESE's works engine tuner

[husaberg]

don't know what size the pins are but maybe can use the ktm118 rods. its still collecting dust in the corner of the garage but I put some 118rods and Suzuki thrust washers on my banshee. fit like a glove . cant remember the wristpin but I think its Suzuki also, been a while since I been to that corner of the garage

KTM200SX-EXC ’98-16
Ø Small End (A) 20.00mm
Ø Big End (B) 28.00mm
Center to Center (C)118.00mm
Width Small End (D)15.90mm
Width Big End (E 15.90mm
Total Length (F) 151.40mm
Eye to Eye Center (G) 94.00mm
Ø Big End Pin (H) 22.00mm
Length Big End Pin (I) 55.00mm
Washers 22 x 37 x 1.0mm
Remarks Barreled Rod

RD250 + RD350 Air Cooled -360-
Ø Small End (A) 20.00mm
Ø Big End (B) 28.00mm
Center to Center (C)110.00mm
Width Small End (D)16.00mm
Width Big End (E)16.00mm
Total Length (F) 141.50mm
Eye to Eye Center (G)86.mm
Ø Big End Pin (H) 22.00mm
Length Big End Pin (I) 50.75mm
Washers 22 x 37 x 1.0mm

RD400 ’76-79 -1A1/2T2-
Ø Small End (A)20.00mm
Ø Big End (B)28.00mm
Center to Center (C)115.00mm
Width Small End (D)16.00mm
Width Big End (E)16.00mm
Total Length (F) 147.00mm
Eye to Eye Center (G) 91.00mm
Ø Big End Pin (H) 22.00mm
Length Big End Pin (I) 51.00mm
Washers 22 x 37 x 1.0mm

The TZ350 - 3G3 with six transfer ports is very happy with much fatter pipes - perfect on a sidecar setup.
It has little to do with the case volume, and everything to do with the transfers ability to control the scavenging streams at BDC when the diffuser is sucking like hell on the Ex port.
The 6 port configuration has much better ducts, and the smaller individual ports have way better ability to keep the in flowing streams coherent.
You are right though, the volume is too small, but thats easily fixed by utilizing RD400 cases.
If you are really keen then use the 3G3 casting and weld on reed boxes, making it like a Kenny Roberts OW of the period.
This then allows another couple of boost ports up the back.
The very best setup though in this case would be a G - 250 cylinder bored to 64,the reeds welded on and the cylinder turned around.
If you then use waisted studs, the inlet port width can be huge, and you can also add Aux Ex ports.
A killer engine, that is as we speak, being built to go into a LSR streamliner.

I fully understand how close the bore centers are now on a RD250-350-400
I have one appart, talk about cramped, so the 6 port makes sense.
I can see why yamaha did it as they wanted to keep it slim,rocking couple etc. but odd they never chose to offset the transfers like a T500/GT750 or a works H2R.

Small case volume is likely why the H2R's went better with the std road porkchopped flywheels than the full circle ones they tried.

[Norman]

Hey Norman,
may you show us some colored section views through the exhaust ports? I would like to see the speeds in the exhaust - specialy in the auxilaries.

I have an idea what might have been the problem on those exhausts of the early Aprilia / Rotax cylinders. The exhausts of the latest cylinders are looking quite different.

Thank you (and your colleague) for this very informative work!
Kindest Regards
Tim

Here are a few more pictures showing the velocities in the exhaust. It should give a picture but i keep in mind that I have been told that the calculation grid (mesh) still could do with some refinements and more refinements still. I have also been told (yes I tried to push a little) that doing a fully dynamic cycle, possibly with combustion and everything is quite complicated and I think we would have needed more 2-stroke knowledge. Unfortunately, we have to work with others things during working hours for a while now...

[peewee]

husa my memory isnt great so ill have to take a look why i used the suzuki thrust washers and small end bearing. maybe the banshee rods are different than what you listed ? ill have a look tomorow. oh ya, between the +4 stroke and the 118 rod, i had to trench the cases also

[DaisyB]

That's not a serious question, is it Daisy? Because if it was, I would need to know about a hundred things regarding your engine before I could give a more or less accurate estimation.
Just pick a value between 350 and 550 m/sec, build a pipe, see where the rpm of maximum power is, and if it is not where you want it to be, adapt your picked value accordingly. If your first pipe isn't already in the ball park, your second one should be. It's not that difficult.

Thanks Frits, sorry just meant should I be looking at couple of percent off or 50, trying to avoid building to many pipes!

[husaberg]

husa my memory isnt great so ill have to take a look why i used the suzuki thrust washers and small end bearing. maybe the banshee rods are different than what you listed ? ill have a look tomorow. oh ya, between the +4 stroke and the 118 rod, i had to trench the cases also

The Pro X cattledog listed the bearing type as well lots to choose from.

[guyhockley]

The TZ350 - 3G3 with six transfer ports is very happy with much fatter pipes - perfect on a sidecar setup.
It has little to do with the case volume, and everything to do with the transfers ability to control the scavenging streams at BDC when the diffuser is sucking like hell on the Ex port.
The 6 port configuration has much better ducts, and the smaller individual ports have way better ability to keep the in flowing streams coherent.
You are right though, the volume is too small, but thats easily fixed by utilizing RD400 cases.
If you are really keen then use the 3G3 casting and weld on reed boxes, making it like a Kenny Roberts OW of the period.
This then allows another couple of boost ports up the back.
The very best setup though in this case would be a G - 250 cylinder bored to 64,the reeds welded on and the cylinder turned around.
If you then use waisted studs, the inlet port width can be huge, and you can also add Aux Ex ports.
A killer engine, that is as we speak, being built to go into a LSR streamliner.

Bit of a fuzzy picture, sorry, I had to extract it from a pdf that was too big.
Just thought it made an interesting comparison, old school to now.
Not sure why they confused things by mixing in the RD...

[husaberg]

Bit of a fuzzy picture, sorry, I had to extract it from a pdf that was too big.
Just thought it made an interesting comparison, old school to now.
Not sure why they confused things by mixing in the RD...

[G Jones]

Bit of a fuzzy picture, sorry, I had to extract it from a pdf that was too big.
Just thought it made an interesting comparison, old school to now.
Not sure why they confused things by mixing in the RD...

Do you have the original PDF still ?
(Are you any relation to Austin Hockley ?)

[guyhockley]

Do you have the original PDF still ?
(Are you any relation to Austin Hockley ?)

Yes and not as far as I know.
Hopefully this should get you it...
https://www.dropbox.com/s/u8oldz4urrg7oqc/Eckerold%27s%20portmap%20-%20Motorrad%20Classic.pdf?dl=0

[G Jones]

Yes and not as far as I know.
Hopefully this should get you it...
https://www.dropbox.com/s/u8oldz4urr...assic.pdf?dl=0

Many Thanks ! - just in case you didn't know - Austin Hockley was a good runner in (mostly) 125 class back in the days of the Yamaha 125 twins...

[guyhockley]

Many Thanks ! - just in case you didn't know - Austin Hockley was a good runner in (mostly) 125 class back in the days of the Yamaha 125 twins...

Yeah, I remember him. Used to be Granby's rider at one point?
I also think I remember you and/or your brother posting on the TZ forum a bit worried because your TZ350 had dynoed in the 60s and your competitors were all claiming much bigger numbers from Banshee based engines.
You then had a pretty good season as I recall!

[G Jones]

Yeah, I remember him. Used to be Granby's rider at one point?
I also think I remember you and/or your brother posting on the TZ forum a bit worried because your TZ350 had dynoed in the 60s and your competitors were all claiming much bigger numbers from Banshee based engines.
You then had a pretty good season as I recall!

Yes - Austin did ride the Granby bike - and a few others I guess - pretty sure Clive Horton too...
Must be a namesake of mine - although I have spent some time on the TZ forum - I've not dyno'd my bike - something I think we'll have to do with any pipe changes - we've also some plans to try some different carbs at some point - although - not a lot of places to race the thing any more...
As for Banshee bigger numbers - was never convinced...water under bridge now...

[seattle smitty]

Smitty, nowadays I wouldn't attach too much value to the details of a 500 cc four-cylinder two-stroke racing engine that produces 75 hp on petrol.
And I would not advocate the use of iron sleeves in any case.

I was using the old Konig sleeve as a starting point to explain an idea. But whatever.

[guyhockley]

snip
The very best setup though in this case would be a G - 250 cylinder bored to 64
snip

Does this only apply to the Gs? I have TZ 250 and 350 cylinders, D and E, and I'm sure the 250 has more room between water jacket and outer barrel, they're in a different place to me at the moment so I can't check. I looked before and wondered if the 250 could take going out to the 59-60 range for a squarish 350.
OTOH just found this and looks very much like an underbored 350...
http://www.ebay.co.uk/itm/YAMAHA-CYL...3D262005385275

[wobbly]

The 250G cylinder has much more modern transfer ports and ducts than anything previously.
Thus you could do the mods as per the Eckerold cylinder but using waisted studs allows the inlet to go even wider ( with a bridge of course ) allowing two extra boost ports
and you then dont have to add an Exhaust bridge as going 3 port is easy.
Turning the cylinder around is also easy and this makes the pipe headers straight, and then the inlet becomes dead straight onto the reed blocks with the carbs sitting horizontally.
The 350 period engine going into the LSR streamliner is as above, but uses a Banshee 58mm crank/115 rods with 61.5 Kawasaki pistons, making it a not so big overbore and close to square.