its raining in so cal, so id like to view ported cylinders to cheer myself up, 10x bonus points for stock slow cylinders. ill start. its a pug 103 w a bunch of extra crap carved in, rips but have a high rpm stutter.
rusted on og two coil.
no that one dont rip, damn picts too small, this one. cant find it double damn.
Thanks for posting this. I literally have no experience with porting, but I'm starting to experiment. It will be good to get some ideas. This should be a very informative and educational thread.
> Seth B Wrote:
> Thanks for posting this. I literally have no experience with porting,
> but I'm starting to experiment. It will be good to get some ideas. This
> should be a very informative and educational thread.
Here is some more I found from MST performance of the same ajh
Adding that third transfer I’d be worried about the cylinder lining and that thin bridge it creates and the thin piston skirts possibly cracking
Yea that skirt is gonna blow. I would do this to a 50cc ajh though, now that is a really fun cylinder that stays really cool.
> Adam Smith Wrote:
> Posted these the other day
> MST performance adding in the third transfer on a puch e50 engine with a
> Athena ajh cylinder
Nice work, those transfers look very clean.
well the op title says success and failures so here's a failure
not on a moped but a 64mm bore
auxiliary exhaust ports that went within a whisker of the stud holes
long time ago and since then ive learned how to get a smooth finish
instead of the "beaver porting" my pals nicknamed it.
it revved to high heaven but coughed and misfired at 7k
wouldn't pull through so you had to keep it 7k and above.
horrible to ride.
Did you know that aux port bikes cough like that if theyre too rich? I've see that every time I start my 50cc hobbit before it warms up.
I've done lots of aux ex port cutting and they love lean needles. The scavenging is so good and they pull charge so hard that if you use a standard needle it'll often be mega rich.
That being said, your main ex looks way too big, very snaggable
the picture actually lies, not as wide as it looked
I did the old 60% of the bore width and used the dunno what its called shape - loaf of bread? so that most of the ex port area was above the transfers
the sides were divergent easing the rings gently out and back in
vertical sides as you know just allow it to plop out and in = snagsville.
and oval ex ports most of the area blow transfer opening calls for a good bit of pipe assist
then I just went wider and wider until I hit 70% with no problems
I was just playing. I tried flat roofed transfers = no difference then to get them angled again I had to raise them and matched the exhaust height so it revved too high for the big heavy old crank
it was just fun -learning by mistakes
same road different/(better) pipe and porting only revved to 8-9 ish (analogue tacho no worky)
in the end I got it going 120mph and 100 sat upright and could play and embarrass the litre hypersports guys on the right road thanks to an enthusiastic riding style that belies my old codgerism
aplologies for bragging
i am in awe of you guys and your achievements with so little to work with and i am now inspired to have a go
just need one more beer......
That's a great sounding bike
hopefully the puch will sound better . . . .
I need to get in the Aux port game!
That bike sounds great!
That choppy shit on top was just a very overdone version of ring land porting.
Are you saying that window was on the ex side? Pretty stupid if so.
The Skirt was shortened about 7mm and there is a Piece Missing on the Intake side, the Exhaustside has a Window and the Holes for the Boostports are in the Normal position on the Intake side, just both are connected.
There is zero reason to window the exhaust. Just blowing out mix.
There are no boost ports in that cyl.
There is a Boostport, have you ever seen a Supermaxi Cylinder?
Just to clarify, i dont know who modified that piston, i haven't done it, it came with the Bike. (edited)
Oh so the window faces the intake not the ex to feed those boosts.
Ah, i think we are talking around each other:
This is the Intake side, the Window rounded with Red is the Window for the stock Boost Port, The Green Circles show how it would have looked stock and not connected:
And this is the Exhaust side of the Piston, as i said, the Piston skirt is already shortened 7mm compared to a Stock Piston, and that window is at least 7mm High:
Where we come from we call both of those "Kolbenfenster" wich means "Piston Window" and we normaly do the second style on the Intake side if we don't want to port our cylinders. Mostly because it's easier to go back to stock if you only have a modded piston and don't need to find a Stock cylinder again.
Ya I just didn't know supermaxi had the piston port boosts over the intake. Makes sense now
Question is still Up, how fast did it go? Stock E50 Supermaxi with that Piston and a Biturbo,Stock 10mm Carb and Stock 13:47 Gearing!
It doesn't matter how fast it went
well, i would say it does, because even if it didn't have any Power, it hit 55, (34mph), it reved to high heaven, nearly 10'000 RPM, with a 10mm Carb and an Exhaust diameter of 19mm.
34mph is nothing to boast about frankly.. My 40cc goped does 34mph. I ride my bicycle at 34mph.
I eat babies at 34mph
Shure about that? obviously you could get a lot out of that Cylinder, even unported, but it's still quite a lot for what it was.
please stick to mopeds please.
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