ESE's works engine tuner

[dinamik2t]

Has anyone tried a relocated ring peg?
Frits once informed us that there is no problem when the ring opening passes above the boost port (up to a certain width though, which I don't remember - definately more than 15-16).

I had an old piston lying around and gave it a try. Old peg was positioned 11mm from IN center and protruded -0.6mm from the piston surface. I drilled a new hole -1.5mm- and my intention is to fit in a 1.6mm drill.
Do you think it will endure the forces of the ring and that it will stay in place?

Attachment 257698Attachment 257699


Also, Frits or Wob, you think that a radiused carb bellmouth like below (pic on the process) could have a positive effect?

Attachment 257697Attachment 257696

[wobbly]

Re that power graph from March 09 - run that engine on the track against the Aircooled of TeeZee and it would get smoked easily.
Apart from the new engine having 10% more power, it will spin to 12500,the other, lucky to spin to 10500.
On a sprint track the new engine would have say 3 more teeth on the back,this would destroy the other bike off corners and reach the same top speed way faster.
On a long track the extra 2000 rpm and power band width, means no contest at all.

The piston pin move - drilling down from the top was how Yamaha did it for years in the TZ engines.
They also drilled a short hole into the skirt, where the pin pushed thru, and bent the end inwards into the hole,making it impossible for the pin to fall out.

Shortening the carb bell may be a good move if the intake tract is already too long,but any sharp edge will create turbulence - even at the outer extremes.

[TZ350]

Hi Rick52

This is the piston we were talking about for TF/TS's, forged piston, 1mm rings and 14mm pin.

Use one ring keep the other for a spare. The piston skirt on these forged pistons can be cut back safely.

Attachment 257700Attachment 257701Attachment 257702

Ned Kelly got his one from Jawzys on Ebay for $82.48 plus $32.25 shipping. Jawzys seem to have a selection and are worth a look.

http://www.ebay.com/itm/Wiseco-Pisto...item335dc4d6b6

Wiseco 449M05600 449M05650 449M05700 449M05750 for Susuki 125 TS, TC DS replaces 449Pxx

[Haufen]

TZ, did you happen to test a bigger carb, say about 35mm on your engine? I know this is not allowed by the rules, but this way you could elaborate how much power you are down because of the rulebook. If it should turn out you have gotten pretty close with your current 24mm setup (which is my feeling), you could move on and concentrate on another area on your quest for a more powerful engine.

[TZ350]

TZ, did you happen to test a bigger carb, say about 35mm on your engine? I know this is not allowed by the rules, but this way you could elaborate how much power you are down because of the rulebook. If it should turn out you have gotten pretty close with your current 24mm setup (which is my feeling), you could move on and concentrate on another area on your quest for a more powerful engine.

Test a biger carb, that is a good idea and was also suggested to me by Speedpro and Kel. It is something I intend doing but its a bit harder to implement in practice as putting a much bigger carb on a small inlet port/tract may not tell us much, as the whole inlet system needs to be in balance.

EngMod2T tells me this is the area to concentrate on for now. The simulation software has given me the numbers for the complete engine (posted earler) but implimenting them in the real world of metal is a bit of a challange.

Attachment 257714 Attachment 257715 Attachment 257716

I have tried a 24/38 that flowed much more air on the flow bench than the 24/28 did, they both had the same outlet diameter. But when I tried the 24/38 on the dyno, it did not make any more power than the 24/28 suggesting the holdup is some place else and modeling with EngMod2T pointed to the size of the rotary valve inlet port itself.

Attachment 257717

Anyway the 24/38 was to long and is the reason I made the 33mm blue IE carb with the 24mm venturi placed at the back of the slide, any way that didn't work as well as the prototype taper bored OKO. Its been a lot of work but you have to go the extra mile to get anywhere.

I am making changes to the RV port and could re work the prototype 24mm OKO I bored and modified with glue in the bell mouth and bore it out further to 30mm. That would make an easy back to back test like you suggest with the new 24mm taper bored OKO as they are both 30mm inside diameter at the engine end, but it may only tell us that a taper bored 24 is nearly as good as a conventional 30.

Slapping on a bigger carb might be easy but its the complete inlet system that has to be changed for a meaningfull test .... a 34 is just to big at the engine end to be an easy thing to try properly.

Once I have sorted the inlet system, got my tripple port cylinder and Wobbly pipe on and working, my quest will not be more power although I am sure its there. But a wider power spread, at the moment its 4k ish but another k would make this a much more rideable bike on short tracks.

I would also like to make a new triple port cylinder liner, not for more power but power spread by reducing the exhaust port duration while still having the current ex port and blowdown time areas and improve the mechanical reliability by having a narrower main exhaust port, something around 65-68% of bore diameter to give the ring an easier time instead of the present 75%.

EngMod2T indicates the inlet system as a whole is the most fruitfull area for me to work on at the moment.

[2T Institute]

Has anyone tried a relocated ring peg?
Frits once informed us that there is no problem when the ring opening passes above the boost port (up to a certain width though, which I don't remember - definately more than 15-16).

I had an old piston lying around and gave it a try. Old peg was positioned 11mm from IN center and protruded -0.6mm from the piston surface. I drilled a new hole -1.5mm- and my intention is to fit in a 1.6mm drill.
Do you think it will endure the forces of the ring and that it will stay in place?

Try with a roll pin instead of a drill bit. There is one problem with moving the pin, that is getting the new peg in the hole. Many blood bilsters later I made a holder out of flat sheet that I could push a say 20mm long roll pin into, that allowed me to hammer it into the new hole. I would normaly go all the way through and hammer the pin flat and grind off excess inside the piston. I also made a height gauge off the old peg and carefully ground the outside down inside the ring groove to match the template.

[Rick 52]

Hi Rick52

This is the piston we were talking about for TF/TS's, forged piston, 1mm rings and 14mm pin.

Use one ring keep the other for a spare. The piston skirt on these forged pistons can be cut back safely.

Attachment 257700Attachment 257701Attachment 257702

Ned Kelly got his one from Jawzys on Ebay for $82.48 plus $32.25 shipping. Jawzys seem to have a selection and are worth a look.

http://www.ebay.com/itm/Wiseco-Pisto...item335dc4d6b6

Wiseco 449M05600 449M05650 449M05700 449M05750 for Susuki 125 TS, TC DS replaces 449Pxx

Cheers Teezee I will get 1 sorted early next week ..

[TZ350]

When I asked if the 180 in the bottom right corner of that dyno graph was the size of the motor the graph disappeared and was then re posted with that bit obscured and I have never figured out the discrepancy between the hand written date and the one printed on the graph.

Oh, yea, 28 P.S .....is the most I have ever seen out of an....AIR COOLED, DISC VALVED 125cc TWO STROKE....
Oh, the 28 P.S is with my own exhaust as well.....
I know alot about "DISC VALVED, 130CC TWO STROKES RUNNNING 24MM CARBS…

High hp air cool ed's have been around for a while ........ 28 hp claimed by SS90 ...... posted March 09

Attachment 257736

28 ps (DIN hp) with 20Nm (14.75 ft/lbs) torque and about 2.5K usable power spread.

Not everything you read on the net is true .......

That was back before I had cracked 20ps (20 DIN hp) myself, I think by claiming 28ps he was trying hard to make an impression …… if you read further on in the thread you will find the reality of his world was a bit different.

in almost 10 years of operating various Dyno's around the place, I have personally never seen more that 17 P.S and 14 N.M (at the rear wheel) on an air cooled disc valve two stroke, running a 24mm carb. I have probably done over 200 runs on that type of set up. (on various engines)

[speedpro]

Has anyone tried a relocated ring peg?
Frits once informed us that there is no problem when the ring opening passes above the boost port (up to a certain width though, which I don't remember - definately more than 15-16).

I've had ring pegs relocated by Pete Sale on Palmerston North. Always from the side never from the top. The difficulty with drilling from the top is making sure the pin isn't going to come out. As has been mentioned one method is to drill a horizontal hole that the new pin extends into and then it is bent inward making it impossible for it to come out.

My current engine has a KT100 piston with the ring peg at the rear directly over the middle of the boost port. There is so little ring free to do anything between the edge of the port and the ends of the ring that unless there is a huge force trying to rotate the ring it will just sit in the groove. If you have a problem the cause is something other than the location of the peg, say assymetrical port roof trying to spin the ring. This will cause problems for the ring peg no matter where it is.

[dmcca]

EngMod2T question...

For Wobbly, TZ, Dinamik or anyone else who can assist...

I mainly work on dirtbikes and im trying to model the air space trapped between the end of the carb bell mouth and the inside of the filter... basically the air available for the carb to suck on before it has to draw through the filter... I have today measured this volume on a KTM250exc at 2200cc (vol of the air boot and inside the filter)... and have entered this volume into engmod under the intake screen, as the volume of the air box before the carb...

My question is how do I model the entry to this 'air box' as the entry is basically the filter?? Obviously the filter offers a restriction but im not sure what equivalent size open 'pipe' would flow the same as the filter... im guessing 0.1-0.2 of the filter equivalent area?? So far I have simply entered the diameter of the filter as the entry.

To take things even further... this filter sits inside the main airbox under the seat... the volume of this is about 6000cc i think... and it has all sorts of holes and gaps that feed into it. Should i model the entry pipe above to reflect this larger volume of the main airbox... or just forget about it. Basically id really like to properly model the entire entry system, becuse up until now ive just done similar to TZ and modelled the carb with a correction factor and ignored the air box(es)

Hope this makes sense.

[dinamik2t]

Thanks for the contribution.
I've seen the blind hole on the side, in an old RS125 piston. If I remember correctly, the pin was tapered but not bent. I 'll look for the piston to confirm, because I might have just not noticed well -wouldn't be the first time..
Even if I followed this method, I think the drill bit wouldn't bend anyway.. Not trying to be stubborn, but wouldn't the tight/press fitment keep it in place?

Speedpro, your pegs are just press-fitted in a smaller hole?

I ordered a set of roll pins, as 2T suggested, so I might try that solution by the time I test the piston.

edit:
> Dmcca
I would love to help with your issue, but I 'd probably give you an inaccurate, or worse, faulty opinion.

I can think of a way to measure the fraction of X liquid that the filter permits. Place a container with no bottom over a delimited filter area and pour gasoline for, say, 30s. Then divide the amount passed with the amount pourred, in that period of time. Forgot to say, you need another container below, to collect the gasoline.
The fraction could then be used as the mult. factor, to calculate the "true" flow diameter.
Not sure whether such an equivalent is correct or the flow/volume/area variables function (verb) proportionately to make such an assumption.

Hope Wob or Tz can enlighten you.

[TZ350]

Some old TZ pistons and someone who may or maynot be Ago

Attachment 257747Attachment 257748Attachment 257749

To replicate the TZ pistons use Piano wire sharpened on the end for the pin, Piano wire can be bent so it stays in place.

[Frits Overmars]

Some old TZ pistons and someone who may or maynot be Ago

Yes, that is Agostini allright, though somehow I get the impression he has been photoshopped into that picture.

Attachment 257747Attachment 257748Attachment 257749

To replicate the TZ pistons use Piano wire sharpened on the end for the pin, Piano wire can be bent so it stays in place.

I think this is still the best way to fit the pin: from the top, with piano wire with a conical-ground tip, with a blind hole in the piston face below the groove to bend the pin.
My personal experience with roll pins: they're terrible detonation-raisers.

[2T Institute]

How do the roll pins make some deto Frits?

[Frits Overmars]

How do the roll pins make some deto Frits?

I don't know. It is hard to imagine that there could be enough end gases left in them to induce uncontrolled combustion. I am not even sure it was detonation, strictly speaking; maybe they caused premature ignition. But in any case quite a number of pistons were destroyed when Elko (the Austrian branch of Mahle at the time) switched from solid pins to roll pins for the Rotax 124 engine. It happened some 33 years ago but you don't forget things like that. If anybody wants to try roll pins: fine, keep me informed.