cylinder kits can be a lot of fun, but they are also no guarantee of instant rip roaring performance. at the same time, they’re not guaranteed to be unreliable, either. if you want a faster bike, here’s some things you should know:

1. get a pipe, too!
the exhaust is one of the most important factors in twostroke tuning. this is not to say that you should build an engine to suit an exhaust, but that you should definitely budget money to spend on a suitable pipe! a leo vinci ain’t going to make you 20 hp, even if it’s hung on a full reedvalve malossi motor.
having a kickass cylinder and carb will not help you if yr exhaust can’t get rid of all that burnt gas. when my expansion chamber was being fixed and the stock exhaust was re-installed, the cut crank and match ported malossi were dumping so much gas in there that the plug fouled in about 45 minutes. think of breathing in compressed oxygen, then having to exhale thru a virginia slim. for god’s sake, get a pipe.
here are some choices

2. decide what kind of power you want
the malossi kit is obviously the strongest, but it makes its power at high revs. if you want “streetable” midrange grunt, get a polini. the same goes for carb purchases – bigger carbs will mostly boost yr high-rev power, anyway.

3. resolve to treat it right
this means that you’ll not only break it in right and set the timing with a light, but that you’ll also buy all the parts it might need to really work right…. unless you want to buy clutch plates every 1000 mi, you’ll want stiff clutch springs…unless you want to replace yr tranny, you’ll re-shim it frequently… etc.

4. get used to buying more (and more, and more) stuff til y’r satisfied
the kit and the pipe alone won’t cut it. you’ll need things like a cut crank or fullcircle crank (if y’r using a reedvalve), new bearings if it needs em, new, stronger clutch springs and other things like a lighter flywheel if you have a revvy kit, or an upgear kit if you just want hwy. cruising. kits aren’t just bolt on items, and you have to know this going in… it’s the whole package that makes a bike fast. if you have ridden an all-out bike (that’s what made me want to tune), you will not be satisfied until you do all the modifications that bike had (unless its owner was a lousy mechanic). so resolve to spend money.
also important is finding someone who can do the porting for you if you don’t think you can do it yrself. believe me, it makes a big difference.

okay, sermon’s over. now let’s talk about some of the barrels:

for p200s

the malossi 210 has the best power/reliability reputation out there. it’s aluminum, with a nikasil bore (nickel and silicon coating), so it stays cool . just bolting it on is good for 14 hp, according to s.i.p., and with match porting expect much more. this kit is compatible with the stock carb and oil injection, but they recommend a cut crank. mazzuchelli makes some ‘ready-made,’ or a machine shop can cut yrs back for you. in addition, you must modify yr head – the supershop can do this for you, or you can buy an aftermarket central-plug head, which will also boost yr power a little. with a reed and a radical carb, you can make as much as 20 hp.

note: the malossi kits from germany come with pistons that can be further modified to gain performance. the ‘windows’ near the crown and next to the wristpin can be cut out further, and s.i.p. marks these areas for you. figure on doing so while y’r match porting yr cases.

the polini 208 is pretty powerful — bolt-on, @ 17 horse. however, since it’s cast-iron like a stock barrel, it is more seize-prone than the pinasco or malossi. part of this can be alleviated by having the barrel honed or bored over slightly, keeping the original piston. in addition, it goes without saying that you have to time this kit with a light and be careful jetting it in. this kit has much more midrange thump than a malossi. like the malossi, it does not come with a head. i’ve seen some in scootering that are claiming 24-27 hp on the dyno. so figure more like 18-20hp, max. and it’s cheap!! @ about 100 to 120 bucks.

saint louis tuners recently told me a good option for reliability is to put a malossi piston in a polini, tho this will require a small overbore and match porting of skirt to transfers, etc. whether this saves you any money over just buying a malossi depends on how cheap you can get yr machinist to do the modifications, i suppose. now that i have the bike with this setup, i can tell you it hauls ass AND it’s possible to rebore it if it seizes.

the pinasco 213 is not something i know a whole helluva lot about. it’s aluminum, like a malossi, w/ a nikasil bore. unlike the malossi, it uses only one transfer from case (i think)and makes good power. legendary power, actually, since no one i know has one and all the stories are thus ‘legends.’ ha ha ha.
it’s supposed to be great for touring…. and you can do a twin-carb setup for it!
i don’t know, if you have something to add, email me using the button below.

for p125s

the malossi 166 is not really a kit i know a lot about. but here’s what jake thought about it: the 7 transfers beat out the pinasco’s 5, and it’s also light and nikasilled to take punishment. why don’t i let him speak in his own words here…

“BUT if you are a cast iron road bastard, the Malossi is for you!!! POWER and maybe because of it, SEX too! heh heh heh…”

the polini 177 is a common choice for 125s and 150s, and will even shoehorn itself onto older bikes as well. it takes carbs between 24 and 28 mil easily, and as usual will work best with either a reed or a cut crank. cost-wise, pretty effective. you will probably want an upgear kit unless you just like to drag.

the pinasco 177 is, according to the sage advice of scott spaeth from hardluck sc in st. louis, much better than a crappy ol polini. truthfully, the fact that its aluminum and nikasil means it’s probably more durable. it’s also more expensive. jake points out, however, that it’s cheaper than the malossi and it comes with an alu. head. so there are lots of benefits.

for smallframes

the polini 133 is much more popular here than in the 200 cc class, and ppl i know have used them with pretty good reliability results. i have no idea what the horsepower gain is, but it’s pretty fat versus a stock bike. paired with a race crank (you must get one) and a 19 or 24 mil carb, you can expect between 60 and 70 mph out of the bike, but the main gain will be quickness. that, and wheelies.

the malossi 136 is a full-race screamer. this kit needs a reed to really work out right, and a huge honkin carb may be fit to match. i know ppl are running around out there w/ 28 mil flatslides!! a good pipe for either this or the polini can be found on the pipe page. hey, if you go with the reed option, you can also run the reeds into the cylinder (instead of into the case) so the carb sticks out the body. baddddd assssss.

of course, the alleged pinnacle of smallframe tuning is the zirri mr2000 . this is sort of a tuning system more than it is a simple kit; zirri recommends you buy their manifold, cylinder, crank, and exhaust if you want results. i have never known anyone who had one, but let’s just look at ‘the facts’:

– 6-petal reedblock into the cylinder (note: you will have to block up yr old inlet) with carb stickin out the engine door (yeah baby).
– huuuuge transfers (7, i think)
– bombproof fullcircle crank
– funky p2-style pipe
– new head

now let’s look at what s.i.p. has to say (if ever there was a funnier translation into english, i don’t know it):
“all those suzuki-malossi tin-can conversion heroes can eat yr dust — and their hearts out”. nuff said, then.

3 thoughts on “What about cylinder kits?

  1. XXX says:

    what happen if use full circle crank but not replace the carb(original vespa carb) and do not using reed valve???


  2. Lee says:

    Hay, I have just rebuilt my engine using the malossi 136 but dint go with the reed valve. I used sips recommended options regarding full circle crank but have keeping with the original 19/19 carb, up sizing the jet as sip said to a 90.
    I cannot get the motor to run.i have a good spark and the timing is set at the factory marks until I can stobe it.
    I feel that there is fuel starvation???



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