Hi all, i know i have probably said this before but anyway, i have an aprilia af1sintesi replica 1992,engine is an rv6 minarelli, it has a polini 70cc aluminium big bore kit and a 19mm carb with a 74 main jet,is this the right jet for running this setup as it doesn't feel set up properly? there is basically a weak power band and not much power from the kit. also i have 15/40 gearing ,only changed the front sprocket. rear is standard same as the rs50 extrema. i can only pull max 9000rpm in any gear and just 9000rpm in top gear at about 100/105 kmp/h about 65mph it tops out at(clocked by two cars). just wondered how i can get it to rev up to atleast 11,000/12,000 rpm like other 70's as it doesn't even go to the 10,000 red line
i have thought it is my exhaust holding the engine back as it is standard but de-restricted but it sounds like it will blow up at 9,000rpm.

Any help on how to make the bike quicker, rev more and have more power through the revs would be appreciated. Thanks.

it's far too small, i'd put in size 120 and see how it runs with it.

if you put in a larger main-jet, it will automatically produce more rpm's if it's properly tuned

well i had about the same problem with my engine, untill i bought a top performances ignition unit. the bike made alot more revs tot about 13.000 while with the original one i couldnt get higher than about 10.000 revs in 1st till 3rd gear

also in the last gear (4th) it wouldn't get higher than about 8000 revs, while the new ignition easely made 13.000

maybe you have the same problem?

this is the part i mean
http://www.opvoeren.nl/shop/onderdelen_res.asp?Merk=Aprilia&Type=AF1&Afk=af1&Srt=onts&Srtn=Ontsteking

Top Performance bobine/CDI unit
Race Cdi unit €36.50

Thanks for the help, great info, i will buy some new jets then(Thanks itakura for the jet size)
cypher, i did change the ignition(put a different cdi on) and it still only makes 8000-9000 rpm in top gear(last gear) but perhaps the top performance cdi will be different/perform better. also i have still got the standard/original exhaust on,maybe this is limiting my revs?

also cypher what main jet did you have in your carb? and what make of exhaust do you have on your af1? Finally because i have the rv6 engine,the crankshaft is heavier than the rv4 so this could be something to do with my problem. And i have looked at the link showing your af1 and saying the setup, i notice you have a polini cylinder kit 80cc, mine looks the same but is only a 70cc(47mm diameter piston/barrel). i didn't know they did an 80cc as i have only seen 70cc ones.

Thanks again for the help.