ESE's works engine tuner

[wobbly]

The Cheetah cylinders from CPI have the Boyesen tunnel roof about 20mm down the B port rear wall.
But as Frits said, the dividing septum between the transfers is also dropped down to the same level, such that flow can equally access
both duct entries.

[peewee]

The Cheetah cylinders from CPI have the Boyesen tunnel roof about 20mm down the B port rear wall.
But as Frits said, the dividing septum between the transfers is also dropped down to the same level, such that flow can equally access
both duct entries.

ive seen those cylinders but doesn't that also shorten the transfer tunnels length and reduce the mixture enertia and kinetic energy ? I vaguely remember frits talking about this stuff in the pisa tower

[TZ350]

I vaguely remember frits talking about this stuff in the pisa tower

Page 1000 is your friend. It has links by Husaburg to Frits post about the leaning tower and lots of other great stuff.

http://www.kiwibiker.co.nz/forums/sh...tuner/page1000

And the post itself:- http://www.kiwibiker.co.nz/forums/sh...post1130452963

[philou]

get the same result with only 3 Port scavenging is more difficult

[peewee]

anybody relocate the ring pegs and weld the hole on top with success ? been practicing on old pistons and may give it a go. alittle more practice and I should have full confidence

[wobbly]

Yes the Cheetah cylinder has the port dividers well down from the duct/bore edge.
This was done years ago on TZ piston port cylinders, but only on the A port by dropping the bore wall down 15mm in relation
to the B port length that was left stock - it gave a good power increase.
But with the reeds and Boyesen ports in the back I think the flow around the entry to the ducts is more important than the effect of the
duct length.
Something that would be easily tested back to back, but not easy to reverse.

[wax]

Yes the Cheetah cylinder has the port dividers well down from the duct/bore edge.
This was done years ago on TZ piston port cylinders, but only on the A port by dropping the bore wall down 15mm in relation
to the B port length that was left stock - it gave a good power increase.
But with the reeds and Boyesen ports in the back I think the flow around the entry to the ducts is more important than the effect of the
duct length.
Something that would be easily tested back to back, but not easy to reverse.

This is something I plan on trying on my pjs cylinder for the vintage class jet ski.

[wax]

On another point I have a cool old school vintage class Jetski pipe and cylinder I would like to ask wobbly and Frits some questions on. I can do it in pm but I thought since we are all talking two stroke it may be interesting in here. Would anyone be upset if I posted some pics up in this thread

[peewee]

This is something I plan on trying on my pjs cylinder for the vintage class jet ski.

if you have a local dyno test facility you could find any performance difference by using epoxy. different angles and sizes or close the hole completely could all be tried

[RAW]

Interesting ? Frits, Jan, Wobbly your thoughts ?
http://citsengine.com.au/

[TZ350]

I thought since we are all talking two stroke it may be interesting in here. Would anyone be upset if I posted some pics up in this thread

Its all good. Not everyone races Buckets. Love seeing what others are up to with their own projects. Sharing ideas and questions about your own work that all of us to learn from is great.

[TZ350]

anybody relocate the ring pegs and weld the hole on top with success ?

Not us, my efforts ended in failure but plenty of people report they have managed it successfully, its worth a go.

[F5 Dave]

Safer to grind the old peg away. Mini cutoff wheel on a dremel and surgical care will nail it.

[wax]

This is a 550 vintage engine for a Jetski.
I have the rare twin dry pipes for the ski. These were the most powerful pipes they made god this engine, back in the day they had no ignition curve and simply ran a straight line. I have that fixed and am now running a zeeltronic ignition. They used to have a problem with seizing Pistons after a few laps if you even got that far. The engine should be pushing about 100-110 hp accordingly the data I have on them.
My question is the stinger on the pipe is only 22mm which seems to be not much for what's basically two 275cc cylinders producing between 50-55 hp. Assuming that's what it makes. What's your thoughts please. Is it possible to put larger stingers on the pipes with out effecting the rest of the pipe to much.
Thanks for your help.

[Frits Overmars]

Interesting ? Frits, Jan, Wobbly your thoughts ? http://citsengine.com.au/

I had a pleasant exchange of thoughts with CITS-inventor Basil van Rooyen (picture) last year. I think I did comment on the CITS engine before, didn't I?

The stinger on the pipe is only 22mm which seems to be not much for what's basically two 275cc cylinders producing between 50-55 hp...
Is it possible to put larger stingers on the pipes with out effecting the rest of the pipe to much.

It's not only possible; it's essential if you want to keep the engine alive. You may loose some overrev but you'll save some pistons and cylinders.
Here is that simple exhaust concept of mine once more (slightly revised). Amongst other things it will give you a guideline for the stinger diameter (D5 in the picture).



I just discovered https://www.hondarandd.jp
Registration is required and you must agree to not spreading the available information, but it may be worth while.