ESE's works engine tuner

[philou]

for 3 transfert ports scavenging, this document K11B engine, indicates hooks transfers



I have a lot of testing to do and cylinder sacrificed

[peewee]

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

welding it sucessfully shouldnt be the problem for me. ive been practicing on old pistons and ill do some more practice until my confidence is alittle higher. what im wondering is how 3-4 seconds of heat affects the integrity. ive heard it was common to weld on pistons in the old days but im sure they were made of different alloys

[jasonu]

welding it sucessfully shouldnt be the problem for me. ive been practicing on old pistons and ill do some more practice until my confidence is alittle higher. what im wondering is how 3-4 seconds of heat affects the integrity. ive heard it was common to weld on pistons in the old days but im sure they were made of different alloys

Why not use a thin cutting disk and grind the pin flush with the bottom of the ring groove?

[wax]

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?
Attachment 323062

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).
Attachment 323061


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.

Thanks Frits for your comment and that link.
I believe some one did the math on your exhaust concept and made a page where mere mortals could put in the figures and get information out the other side.
Does anyone know the link to that I used to have it many moons ago
Cheers

[Frits Overmars]

Thanks Frits for your comment and that link. I believe some one did the math on your exhaust concept and made a page where mere mortals could put in the figures and get information out the other side. Does anyone know the link to that I used to have it many moons ago

Several people built EXCEL-files around my exhaust concept but I'm not too happy about it.
1: There is hardly any math involved; it doesn't get more complicated than just a square root.
Any pocket calculator can do that, so why complicate things with an Excel-file?
2: In spite of the simplicity of my concept, some geniuses managed to build errors into these Excel-files.
3: If I were to change a default value, these Excel-files would still be around with superseded values.

[wobbly]

The 22mm stingers are stupid small.
We have 250MX engines making 50 Hp and they all use 26mm.
The 2 into 1 Y collector should be over twice the exit area of the two stingers, and I can see that it has been set up to use
an rpm switch driving a solenoid that dumps water into this to vary the back pressure.
Having the back pressure too low increases the bottom end power dramatically to get off the line, then the pipes are choked down to normal pressure
by using jets to control water flow into the Y exit - works very well.

[wax]

The 22mm stingers are stupid small.
We have 250MX engines making 50 Hp and they all use 26mm.
The 2 into 1 Y collector should be over twice the exit area of the two stingers, and I can see that it has been set up to use
an rpm switch driving a solenoid that dumps water into this to vary the back pressure.
Having the back pressure too low increases the bottom end power dramatically to get off the line, then the pipes are choked down to normal pressure
by using jets to control water flow into the Y exit - works very well.

Thanks wobbly and frits.
Ok well maybe i will turn up some 28 mm stinger ( do you think i should go bigger } on the lathe and use the water injection controller i have to dump in water to increase the back pressure, Thats pretty easy to do. I will try and measure the length of the pipes tonight if i get a chance to actually work out their tuned length tacking my port timing in to consideration it will help me when i select a prop for the ski.
Frits I will see if i can work out the details tonight on your calculation and see what it comes back with. time to get into some math huh

[peewee]

Why not use a thin cutting disk and grind the pin flush with the bottom of the ring groove?

yes ill have to grind down the existing pins flush with the groove bottom but for the new pin ill drill one hole from the top down then weld the hole shut and both rings will use the same pin. this method will only require one hole/pin and the fit between pin/hole wont need to be quite as precise. as long as the pin is about the same size as the hole i should be good

the other method of drilling two new holes into the ring grooves will require a precise press fit of .003" from what wiseco told me. this is beyond the capabilities of my available tools or knowledge. besides i have no idea where to get these pins. for the top down method i can probly use most any standard 1/16" steel pin from local hardware store.

ive had pins relocated before but the old codger retired so im on my own now

[trevor amos]

In the past I have used the parallel shank of a metric twist drill, the material quality is assured and drills are available in tiny diameter increments and, they wont break the bank!

cheers, Trevor

[TZ350]

I think Yamaha used Piano wire in their TZ pistons. Where the pin is inserted down from the top and secured by bending the end over inside the small blind relief hole drilled into the side.

[Frits Overmars]

I think Yamaha used Piano wire in their TZ pistons.

Yamaha would, wouldn't they? After all they're a musical instruments manufacturer.
Piano wire or guitar string is excellent stuff, available in all diameters (1/16" is way too thick, peewee) and one length of string will keep you covered for years.

Where the pin is inserted down from the top and secured by bending the end over inside the small blind relief hole drilled into the side.

I do not recomment Yamahas method of bending the pin over inside the hole drilled below the ring groove. Bending will cause plastic deformation of the piston material with according loss of fit. Closing the top of the pin hole by welding is a better method.

[husaberg]

welding it sucessfully shouldnt be the problem for me. ive been practicing on old pistons and ill do some more practice until my confidence is alittle higher. what im wondering is how 3-4 seconds of heat affects the integrity. ive heard it was common to weld on pistons in the old days but im sure they were made of different alloys

I have used a piston with a welded ring land repair before it was used as a replacement was unavailable.
It will destort not a problem with the ring land even if only a few seconds, you can limit the distorting by preheating the piston but be careful.
Burt Munro once used a rather large rivet to repair a piston his this sidekicks Velocette piston it melted again, but in their haste to get the bike ready for the Cust GP they forgot to richen the lean mixture that actually caused the initial melted piston.

[Tim Ey]

I would not close the hole with a TIG Welder - instead I would let the remaining hole above the pin get filled by laser welding. Normally it is expensive as hell, but if you talk to the guy who is working at the machine...

[jonny quest]

Or just peen the hole

[casal-fan]

Citation:
"Will this float your boat peewee? https://transmoto.com.au/ktms-two-st...ampaign=buffer
Attachment 322629 Attachment 322630 Attachment 322631 Attachment 322632"

Interesting, but if I´m not wrong KTMs spanish rivals, GasGas, designed an engine blok encorporating a counterbalancer, already in 2003, wich perhaps (seems to be some doubt here) also was used on a 2wheel motorcycle?
It was defo used on the 300cc quad, because I have one of these engines coming from Spain as I write here.
Encouraged by Wobblys build of the KTM250 superkart engine, and the fascination for simplicity, one cyl. one carb. one reed, etc, thought a project revolving on using a 300cc single cylinder conter balanced engine for a track/race motorcycle would be interesting.
Would like to take the oportunity and the lead, to ask for your opinions on something I´ve been meditating a bit on though...
In the article Frits so kindly posted a link to, many exemples of increased reliability are shown. In one of mine preliminary studies regarding the engine I would like to "build", focus was directed to the stress levels imposed on crankshaft components (focus mostly on big and little end bearing). The 300cc engine in question, at 9750 rpm (expected max. power rpm) will put about 15% more load on crankshaft components then f.exe. a CR250 engine tuned for superkart racing at turning 10500 rpm.
Since my knowledge on metalurgics is none, this troubled me a bit. Stress levels could be reduced by lowering rpm, but then power would probably also suffer...
But even more then that, a counter balanced engine, will perhaps put more stress on crankshaft bearings because of the more "unbalanced" crankshaft alone? This troubles me a bit...
Was hoping KTM had written something about this when I saw Frits' link, but nothing, so if somebody has an insightful word about this, please shear, as many times errors can be avoided just by someone saying something.