another "first kit" thread: 50cc k-star?

I have been reading the forums and wiki doing e50 kit research for a couple of hours (oops...) and the 70cc k-star seems real popular around here, but there's relatively little info about its little brother the 50cc. The general consensus seems to be that for a 70cc a better crank isn't optional, but still being a relative moped rookie I'm hesitant to mess with the bottom end. Can I slap on the 50cc Kstar with the hi comp head (and bigger carb + pipe) without having to change anything besides jetting? Will stock timing be OK, or will I need to retard it? Putting bigger carbs and exhausts on stock cylinders is pretty much the extent of my tuning experience, so go easy on me...

Re: another "first kit" thread: 50cc k-star?

***VANILLA BLUNDER*** /

you wont get much out of a 50 kit without a case match and all that., even then new crank or at least new bearings are a good idea. jump in headfirst and tear up your bottom end and get a 70 kit, you wont regret it.

Re: another "first kit" thread: 50cc k-star?

Thanks for the input. I figured I'd have to bite the bullet if I wanted real performance. But even if I could get the bike to do mid-high 30s I'd be happy. Not looking for a real ripper, just something that can keep up with city traffic. Would the treats/kstar kit at least give me that? The other thing is that I only have very basic tools and don't really want to invest in the tools needed to do a bottom end rebuild properly according to the wiki, while it seems like the top end rebuild is possible just using stuff I already have.

Re: another "first kit" thread: 50cc k-star?

Overpriced Parts /

Stock timing will blow most kits

Time to 16-17 degrees/mm on the flywheel

Full retard may not be enough without dremeling slots.

See my post on Lukus McWhorters post dear mother of god ..

Bla bla whatever he said

Re: another "first kit" thread: 50cc k-star?

Michael Dreamboat /

Ken, is there anything online for instructions on how to do this timing? I only saw a vague description in the wiki.

Re: another "first kit" thread: 50cc k-star?

im the dude with the moby, just got my hands clean from kitting it and i havent even started it yet. follow the wiki and its cake man jump on that 70cc kit

Re: another "first kit" thread: 50cc k-star?

Thing about 50 kits is that you get the most out of them by shooting for high rpms, which is exactly when you'd need a new roller bearing crank. High rpms melt the brass bushings in stock cranks.

In this case, if you really want more performance while still using the stock crank, a bigger kit is going to allow you to pull harder at the low rpms that are safest for brass bushings. Take Ken's advice about timing and also see if you can't search out some of his other posts about getting the most out of kitted e50's while maintaining reasonably low rpms. It's basically along the lines of: 70 kit with a modest carb paired to a circuit exhaust and geared tall. He does a better job of explaining it though.

Either way, if you're dealing with a 30 year old e50, your're probably going to want new seals and even bearings at least, so why not spring for a new crank while you're at it?

http://www.mopedarmy.com/wiki/Rebuild_a_Puch_E50_Engine

Re: another "first kit" thread: 50cc k-star?

do you mean the spi seals? that could be done easy with some bolts nuts and washers

Re: another "first kit" thread: 50cc k-star?

If your stock piston and cylinder are in good shape, I really don't see the point in buying a 50cc kit (french race bikes aside, of course).

Just port your stock cylinder... it won't cost you anything but your time and research. and you will get comparable results. Not to mention when you do decide to kit, you'll be ready to port/casematch that.

This is a great port map for a stock E50 jug I recently tried out...took it from a post from Graham Motzing:

"a killer port map for a hi-torq is up 1.5-2 mm on the exhaust port, 1.5mm wider on each side, 2-2.5mm wider on the intake port and 1-2 mm cut off the bottom of the piston."

If porting sounds daunting... just go with the 70cc and a bottom end rebuild.

Re: another "first kit" thread: 50cc k-star?

-Brian- The Ruffians STL /

The 50cc kstar is pretty boring. I went with it as my first kit and should have just jumped all the way in and went with the 70 instead. With the 50 and a boss pipe/14mm bing I was hitting upper 30s but it took so long to get there and forget about starting out uphill. The 70cc kstar is pretty bulletproof and you don't need to change your crank out unless it has some other issues. I had a stock crank with around 7k miles on it when I first kitted it up and ran it several thousand miles more before I changed it out and had no issues. Just gear up and keep your rpms reasonable(this isn't hard on a stock kstar, they don't rev out like crazy) and you don't need to worry about it immediately.

Re: another "first kit" thread: 50cc k-star?

getting high 30's is pretty darn easy with a stock puch

ditch the head gasket

get the 14mm intake and bing carb

put a proma gp on it

jet 64 in the stock bing.

if that doesn't get you there a tiny bit of porting will really wake that setup up.

those 50cc cylinders are kinda bitchy to tune, i've ridden some really fast ones but if you only want to go 35-ish and you want reliability start with something to get your feet wet with tuning and such. going right for a kit can be tricky because it drastically changes your tuning.

Re: another "first kit" thread: 50cc k-star?

fuck all that. you can slap that shit on there and be fine. true story.

people run the treats party setups all the time on stock shit and it works fine.

but it's so fucking lunatic crazy easy to rebuild an e50 it would be pretty foolish not to.

Re: another "first kit" thread: 50cc k-star?

Mike Lyions /

I put the 50cc K star on my wifes maxi with the techno circuit and 15mm bing, 3 shoe clutch with paz springs. My god this thing rips clear to 40. You just need to tune the clutch right for take off. Now I am going to have to put some kind of resistor in the wiring for the head light and tail light because the new rpms are blowing them up.

Re: another "first kit" thread: 50cc k-star?

-Brian- The Ruffians STL /

Run 12v bulbs if you aren't already. It takes much more to blow them up. If you are using a 6v stock coil you can through a 12v coil in pretty easily and have brighter lights at idle if you want to.

Re: another "first kit" thread: 50cc k-star?

You can also run the tailight and the headlight off the same coil to bring the peak voltages down

Re: another "first kit" thread: 50cc k-star?

Wiring shit... a whole 'nother alien world to me. Are the 12v lighting coil and bulbs just simple swaps, or do I have to change other stuff in the electrical system to make them work?

For now, gonna wait for the 15 SHA and intake to come in and see what kind of boost I can get out of that plus a pipe. And can't forget getting that rust outta the tank...

Re: another "first kit" thread: 50cc k-star?

take your e50 apart, get a rito crank or some cool shit like that in there. shit will be bomb proof. get allen key hardware and torque wrench back together.

then get a nice dmp 70cc and go all out.

wiring is pretty easy once you do it.

e50s are super easy motors.

Re: another "first kit" thread: 50cc k-star?

-Brian- The Ruffians STL /

The bulbs are an easy swap (you have hands that rotate, right?). The coil is pretty easy too. You just pull the flywheel off and take two screws out of the stator that hold the 6v coil on, swap out the coils, screw in two screws and connect the new wire to the old headlight wire, put the flywheel back on and you are done,

Re: another "first kit" thread: 50cc k-star?

the 50cc kit sucks, i'm sorry to say. you have to gear incredibly short to get any low end power out of it (13 or 14x45) and then at that point you are spinning such high rpms you will be lucky to break 40mph.

go with a 70cc kit.

Re: another "first kit" thread: 50cc k-star?

Cool, thanks Brian, just wasn't sure if other stuff in the electrical system needed replacing for the higher voltage coil and lights to work properly.

What I really need is a sacrificial 'ped that I can tear apart and learn on without fear of ruining, so I don't have to learn the hard/expensive way on my runners.

Re: another "first kit" thread: 50cc k-star?

Overpriced Parts /

The kstar 50cc is ok

I got over 40 mph with mine 14mm bing, techno circuit pipe, 18x45 gears

Re: another "first kit" thread: 50cc k-star?

Rob @t ATTN! Burrito /

agreed with ken except i had a proma on it with the 50 kstar. ended up running it for a year, no problems and kept up with traffic so long as it wasn't uphill. the low end is horrible on them, takeoff is slow but otherwise ran great. it would take most hills if i stayed in the powerband. if you're running mostly flats you'll be fine.

Re: another "first kit" thread: 50cc k-star?

Ignacio Hennessy /

I got low 40's with the 50cc Kstar + Proma circuit +15mm Bing + Blue clutch springs and 0-20W oil. They can go pretty fast, they just take forever to get there.

Re: another "first kit" thread: 50cc k-star?

When my ZA50 stock piston skirt broke off and ruined the cylinder, i put a treats 50cc k star on as replacement. Just after bolting it on and breaking it in i get like 35ish on flats with a jammy pipe and a 15 SHA. I though this was still pretty slow, but I had never really gotten into tuning. Left the timing stock and it did pretty well, probably couldve used a good adjusting though. After 100 miles or so of this, i did some investigating and found that the squish with the stock head is way too big, like 2.0mm+. So now that i'm upgrading to CDI, I'm getting a higher comp head, probably ditching the gasket, and trying to really tune this thing in. It seems solid though for a first time tuner's kit like myself. I know my next build will be a 70cc K Star. Do a lot of research.

Re: another "first kit" thread: 50cc k-star?

I'm running:

50cc kstar decked a bit (no casematch, yes intake match)

minarelli 14mm intake

12.12 SHA

hi comp o-ring head

tenco bullet

45mph no problemo on a stock crank and 15-45 gearing. stock 2 shoe blows with this setup, but i can peddle off the line until i get a 3 shoe. moves just fine from 10-45 mph

Re: another "first kit" thread: 50cc k-star?

Overpriced Parts /

Just tune your 2 shoe with thick springs . ^^

Max you better start saving your money for a needle crank upgrade because your way over 9,000 rpm stock crank limit . 15x45 @ 45 mph is about 10,250 rpm

Re: another "first kit" thread: 50cc k-star?

Nice! My guess by sound was 10k. I have a stuffed crank to drop in - just been lazy..

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