I race with a polini 47mm rv cilinder the specs of the cilinder are very nice, quality of the polini nicaseal are superb.

porttimings;

exaust;

height; 24,4mm timing 180,1 degrees
(i always set the deck @ 0,5mm)

several deck heights ;
0,5 = 180,1
0,75= 181,44
1,0= 182,78
1,25= 184,11
1,5=185,44


blowdown= 30,56 wich means that the max power of the cilinder lays arround 10000 a 12000 rpm, untuned the cilinder wil rev up to arround 12,5 /13.000 rpm
powerband/revs/Hp depends on the exhaust youre using,

i'm using the cilinder on a puch maxi engine ( ) and it has arround 14/15 hp.

If you have the same exhaust as me on that picture, don't use it, because this one has a small diameter (i thought 28mm)
mine had an AM6 engine, i've never had this exhaust on 70cc's, but i did have a Zen exhaust on my 70cc, it would go up to 140km/h...

The standard Exhaust is a AF1 Futura Exhaust by the way

I meant create gallery on the gallery section makes things a lot easier
and im rather curious about how your af1 looks, you said it has the original colors, i'm an original color fan especially of the replica...

edit; my gallery (af1 replica) : http://www.apriliaforum.nl/viewtopic.php?t=9216&start=0

I will try and get some pictures on then if it lets me in the gallery section. as it basically looks like yours but with a number four on the back, different frame and clocks. Well i have to use that exhaust which is a shame as i don't have any others or the money at the moment. Thanks for the info again.

no problem i'm looking forward to your gallery

the exhaust is the only problem stopping you from going really really really fast according to your current setup... no need rushing things, exhausts can be bought every single day (except sundays )

Yeah the cylinders are good, mine does look almost exactly the same as yours and is a 47mm bore, but might not have the polini writing near the reed valve. as for port timings and blow down etc, i don't know much about this, sounds like you have opened the exhaust port? also this may sound stupid but could you explain what the deck height is,and blowdown?
Thaks for the help.

Itakura, i have created a gallery now in the gallery section,there are a few pictures but i have some others i will add later. There is an arrow end can on the exhaust this makes no difference in performance just makes a lot of noise and sounds quite loud and crackly.

i'll try to explain in my rubbish english . Deck Height is the space between the piston dome and the combustion chamber, at top dead center (TDC).

blowdown; the amount of TIME between the exhaust and transfer port openings
( http://www.muller.net/mullermachine/docs/blowdown.html )

Not very important if your not planning to tune the cylinder, but it comes in handy if you want to know the specs of a cilinder, and with that specs you can ask someone over here if its a good cilinder or not, and how it performs.

he probably means in the gallery section, but i just noticed you've did it already! succes with the aprilia

Thanks for the help i now know what they mean, how do you measure the deck height and blowdown? because the specs you have on your cylinder seems to get you good power and revs and i just wanted to see if i could do something like that.

just measure it with a calliper rule!

read some stuff on the internet about tuning or get a book about 2 stroke tuning,

http://www.amazon.com/Two-Stroke-Perfor ... 1859606199

ok thanks.

hey i've seen the images in your gallery, the moped rules!! there aren't that many sintesi's in this good of a condition... the exhaust is a slow exhaust, this is probably (like i mentioned before) the only thing holding your revs down

grtz.

Thanks for the comment on the bike, i prefer that colour of that style of af1. I think you're probably right about the exhaust, i took the exhaust off today and measured 28mm on the part that goes in the cylinder but it is a tight fit and a 32mm exhaust wouldn't fit the cylinder. so how would i fit a 32mm as i thought all performance/fast exhausts for rs50's were 28mm or had adaptors? Thanks for the help.

28mm is just fine, that would'nt stop the revving. the problem is the expansion.

try to find a gianelli or a yasuni exhaust

ok i'll keep looking for a cheap one or possibly try to make my own, or get someone who knows how to. Also racekees on your polini cylinder like mine what revs could you get with the standard ignition as you have hpi 2004 don't you?Thanks for the help.