We're at it again - I'm building another bike, and this time i want to show what a mean 50cc should be like.. It's gonna be a Piaggio Zip, which i happen to have hanging around in spares after the engine got slapped onto one of my Typhoons, so thats sorted. Now comes the funny part, picking the parts.. It's gonna be a race-only machine, so i don't really care about things like economy, reliability (Altho, i don't want to change parts every round) and all that silly nonsense. I've already got the feeding side of it (24mm Keihin, Hebo reeds), the crank (Athena Racing crank @ Stage6 tefloncaged bearings), and im thinking of using my TopPerformances Nardo Rep. for it too (Unless i find a cheap Evo 50cc exhaust or similar), so that leaves the cylinder... I'm looking at the Polini Evo 50cc kit (LC), the Malossi MHR Team 50cc (LC), Manston 50cc (LC), Stage6 Alu 50cc (LC and AC) and an Airsal T6 (AC). What to choose? After the cylinder comes the clutch - Stage6 Torque Control R/T w/ a Stage6 WingBell (Again R/T), or a Malossi Delta with the bell too (I'm leaning towards the Delta because of good experience). And then we're down to the ignition side - I'm thinking Italkit (Maybe pair it up with a Malossi DigiTronic module), MVT Inner-Rotor or a Stage6? Or should i go the "cheap" way, and get a TopPerformances not (i don't know the english name for it, sorry) that shifts the ignition by 6mm towards the top, and the rest of the ignition left as stock? And that was about it - I'm aiming for double figures here, so what would you pick of it?
cant go wrong with an evo ive always found afterall the t6 does take alot of work (i have a 70 ali on my bike and yes it took alot of cutting to even get the piston on my crank, the ports were all over the place and the outside of the exhaust port needed filling so i could actually get it to a nice shape) team ive never used and the stage 6 ali 50 i thought was aimed at semi performance (not really looked at cylinders for close to a year now) im a polini lover tho tbh. pipe wisew i found the c16 works ok with 50 kits, the timings need to be spot on and the bottom end is prittymuch useless but if its a race bike then crank bearing life and narrow powerbands are just somthing to deal with LOL or you can grab the polini 50 wich is made for the kit, altho ive found the polini pipes to be a little under timmed for the kits there desighned for (more endurance tune than all out power) the ignition wont really be an issue tbh unless your going for silly rpm in wich case id go for the italkit/hpi teamed wiht the tunebox cdi (expensive choice but it';s SO nice to use/setup) everyone on the planet seems to love the delta clutch and slag off the 2g but im a REAL big fan of the 2g.. delta's i find a bastard to setup, altho they have weights and many spring options/tentions the stiffest springs with no weights still didnt quite reach takeoff rpm i was aiming for last time i used one so it got scrapped for a 2g, wich took me 5 mins to setup and is still working to this day. # at the end of the day im sure you already have some idea of what you want to do/use, as far as cylinders go its all up in the air as quite frankly any port map of the same layout can be applied to any barrel (i have an over port evo map on my t6 for instance) the piston is the main thing to worry about as the rest can be filled and ground to any shape and size you want.. the head is also a considderation unless your going to make one/have one made/use one from another kit (no cylinder head is ever good for sprint/race setups, simply because after you raise the durations to a powert hungry level you loose all compression and cant compensate as you narrow the squish too far) be it a remachined head or what i prefer, a full custom 2 peice head.. cant beat press in press out inserts for heads, once you have the water jacket made up the heads take all of 5 mins to make in any shape you want. but ye im going off course a little hear.. this is just what id do, you may go completly the other way and have good results. thats thew good thing aboiut tunning afterall. combining parts as you choose then spending weeks MAKING them work together good luck and dont forget to put a build project up :hello:
The Polini 2g clutch is not an option - i've cracked/bent two (Both with my ProRace engine), and im not the only one (They need to be strengthened, they have a weak spot apparently. ) I think i'm going for the Polini cylinder tho - I belive it's just for Minarelli the portmap looks dissapointing. I think i'm going overboard and getting the Stage6 Torque control, but it's still floating in the back of my mind, to just get a cheap Delta (Or copy of it, they work charms too). Exhaust wise - Well, it might be the C16 that will take me high, and since i can get that at a 10% discount, why not Gotta love being a powershopper :grin:
ye everyone i speak to about polini 2g's slag them off/say they bend and they do if you dont get em right.. need to be 0.1mm accurate to remain straihgt, its not a weak spot, its poor setup but ye, was waiting for that responce anyway. LOL the delta i just couldent get to rev (even with the stiffest springs and removing the weights completly) but ye. get a project up already!!
I'll be getting all my W-I-P's up one of these days, but it's not much fun taking pics when its raining cats and dogs... I haven't had the problems with setting up the Delta, so it might be a human error with your setup of it? I'm currently running the blue springs, total stretch and weights replaced with locking nuts on the ProRace Typhoon, and its running great. Evo 50cc LC, C16, Delta, 24mm S6 R/T carb., Athena "evo" crank and a good flow optimizing - ought to get me to around 13bhp if setup correctly, nay? Now comes the funny thing - To gear it up a notch, or to leave the stock gearing?
2 times... delta, heaviest springs, tentioned to max, weights removed and it still engages at 7000rpm.... were 3 of us fucking about on several ocasions.. deffo not human error.. worked fine on anything below 15bhp then threw one at a ported evo and irt REALLY didnt wanna rev. stock clutch wiht blue springs was better LMAO but ye, depending on what stock gear set your running you may not need one. being a 50 it will be a struggle to get up to higher speeds irespective of hp as torque is the lkimiting factor of gearing. the stock's should be good all round altho if your on a big track (long straights) it may be worth a 12% increase.. thought you were gonnan run overrange transmission ether way? this is usually good for an extra 10mph top end (pushing 70mph if you have ebnough power and dont mind revving the thing) i do REGULARLY top out the stock gearing on mny typhoon tho (ported airsal t6 kit) nad its not fun feeling the clutch hit 40,000+rpm LOL try it and see is the only responce i can give you. like i said its down to what track your riding more than anything as if everyone has theres geard up for the track your all gonna be that bit slower off the line.
I'll be leaving the stock gearing, and i don't intend to aim for top speed just yet, since most of our karting tracks are too small for "heavy" gearings/mostly made for technique instead, so if anything, i might get a lower gearing when looking at the things objectively. I might run an OR kit on it some time in the future if needed, but atm i can't find any OR tranny that supports my wallet. And tough luck with the Delta's - i haven't had them, but who knows, i might get it in the future.
