kymco build looking for 60+ cruising

[spider82]

with a 50 mm kit i dont wanna over rev and i want to keep the engine temp down to keep from seizing what would the best way to do so be? im thinking put max gear sets in and keep speed from hitting max. id like it to top about 70 or better but cruise reliably for fairly long distance at 60 i go on 25 miles trips on a reg basis most of it str8 away and no stops no lights few small hills and one big hill live in the country at the edge of a small town

[Wheelman-111]

Greetings:

Quoth Spider:

with a 50 mm kit i dont wanna over rev and i want to keep the engine temp down to keep from seizing what would the best way to do so be?

The best way to keep a 50mm kit from seizing is to set it aside and install a Malossi or Polini 47mm kit. Many have had good luck with Asian-made 50 and 51mm cylinders, but I have not. Despite the larger displacement, their performance is typically even with the Italians or a little slower, but with FAR inferior reliability. Sometimes cheap costs more.
"Cruising" at 60 is more than even the best kits can summon without a great deal of extra go-slightly-faster goodies such as manifolds, exhausts and carbs, plus a lot of trial-and-error fine-tuning. Topping out at 70+ is much harder than it looks.

[LMH]

I agree with wheels. Theres a difference between topping out and cruising, to maintain 60 will require a lot of gas and rebuilds. Its not impossible but go to the kymcoforum and look up the member "zombie". Hes on a quest to do the same, well more like cruise at 70+, but he has over 3k invested in R&D.

[spider82]

i signed up for that forum but i have been waiting to be cleared for membership for over a week.i already know im gonna have to go with larger carb as well as larger exhaust. also going with biggest gear ratio i can find. wanted to go with 47 mm but saw that 47mm replacement parts are a bit of a pain 50 mm parts are common enough.also found a 50 mm kit for about1/3 the price that a good 47 will cost me. even if i have to buy a new piston and rings to go with im only paying half the cost of the 47mm kit. from what i have found stock kymcos will go close to 50 after derestricting cdi and variator. im going to go with larger drive faced performance variator. im also planning on going to go with a larger carb. someone on here offered to sell a 19mm carb with intake previously ported to a 72cc kit. havent heard from them since they made the offer however. open to suggestions on the exhaust

[spider82]

cruising at 70 should be fairly easily done i would think 500 max the 120 cc kit for 280 and the carb kit for 150 on ebay. after that get a pipe and gears and should do the trick

[LMH]

You should be ready for boring out your case if youre going stroker. Strokers may not be the best idea for everyday riding, also I wouldnt use the 19mm for a 120cc kit, 19mm is maxed out at 72cc in my opinion, I would recommend a 28mm carb for the 120 kit along with a CT black manifold.
I decided to go ahead and set up the 50mm kit, spent a couple more hours porting and honing and measuring the block and cylinder. After much debate I left the jug a little low to help he compression and squish. With 2 gaskets I got 2.46mm of squish, with one i got 1.23 mm, compression was only 110 ish with 2 base gaskets, 125 with only one. But of course the roll off from the piston dome to edge to exhaust port is well above 1 mm and transfers are not completely open at BDC.
Monday when my neighbors machine shop is open I will bring the jug down there and shave 1.5-2mm off the top of the cylinder and raise the jug at the base. Its clearly for a stroker, but lets see where this goes. This is a spare engine I had laying around so if it goes boom at least it was fun.
Im going to start with a 45 pilot, maybe go to 48 or 50, and 140 main to start. run it rich till break in is over.
Before you buy that 50mm kit ask if its for a stroker or not.

[spider82]

well i havent found a machine shop that can mill my cylinder for me here. how much does your guy charge for milling? i am not planning on going with the stroker right now. im trying to keep bike down to a price that i can afford.one you get that milled down let me know what it sits at. i def dont want the piston going above ports at bdc i want them all the way open. founf someone online whos ruima 47 was shredding variators like to know if its possible and how likely

[Downsouthdio]

Shredding variators?

[spider82]

yea said the torque was shredding them he was finding bits of metal all over tranny even roller weights were getting shredded

[fastplastic]

was not a proper install on the var. or rollers.... u can use the same var. on a 130cc without it shredding anything, something was done wrong.....

[LMH]

The variators work on any torque engine for sure, improper installation is the reason for malfunction.
I ended up moving down to a 130 main, and a 48 pilot with a 24mm OKO, uni open filter, extremely ported block and CT, using a PG V8 exhaust to finish. Almost impossible to keep the front wheel down and its only using half throttle, and still rich as *. After tonight it should be finished with the break in.
Ah ya, also I used 2.75mm of gaskets, and shaved 1.5mm off the top of the cylinder on the lathe. If you dont have access to a lathe or machine shop, use an upside down(turned on its back) belt sander after you measure and mark 1mm,2mm,3mm on the top of the cylinder, just make sure to clean it up after and make it really smooth on top for the machined area is necessary to seal the head.

[sleeperscoot]

Think about it, if the kymco zx was so popular don't you think it would be a better build than the elite-s the head and exhaust are interchangable but thats it!

[LMH]

Think about it, you have no clue what youre talking about. 99% of a AF18 zx engine is a AF16.

[JJ Joseph]

ruima kit any good?

I've been running a Ruima 50mm BBK for Kymco on my Honda Dio for about 2 years now. Some minor surgery is needed on the shroud to adapt to the Kymco jug, and you have to search out a 28mm exhaust pipe to replace the stock 24mm Dio job, but otherwise it's a good quality unit. Lots of low-end torque!