50cc kstar low end


50cc kstar

high comp head

15 bing, 82 jet. needle at richest setting.

dmp reverse unmodified

case matched

stock 2 shoe, screws turned 720 out


when i first start the bike it pulls off the line decent, but after running a minute it pulls really slowly til 10mph almost completely bogging out.

it always rips once its on the pipe(about 10-15 mph), the midrange is great, and the top end is pretty good.

any ideas on helping out the off the line pull?

Re: 50cc kstar low end

I have a similar setup with a 50 TCCD (similar kit) and had what sounds like the exact same problem. Clutch tuning is definitely the secret to fixing the problem. I had a two shoe with Paz springs tightened as far as they could go and it still would not engage high enough once the motor got warm. I was able to fix the problem by taking a bit of weight off the shoes. Now I have great power all around (and that is with 16x45 gears).

Re: 50cc kstar low end

id say tighten your clutch screws but the fact that it runs fine sounds carb tuning to me.

whats your plug chops saying?

Have ya tried just running around with the thing at 3/4 throttle then checking the plug? Maybe the needle is too high?

OR maybe the kits just not even close to broken in yet, and the compression ratio is all over the place and your trying to tune to a moving target? Thats what i always find when i try tuning too much right off that bat. Run it rich and put 100 miles on it?

Re: 50cc kstar low end

The Human Beans /

what type of tranny fluid are you using.

i was having problems with cheap atf. making not slipping as well when it was up to operating temp. i over filled it just a tad and it worked otu better

Re: 50cc kstar low end

i'm glad i'm not the only one.

how's the compression? looking at the cylinder with the head off there looks to be quite a bit of room before the piston would hit the head. you could probably take a full millimeter off the head and the piston still wouldn't hit.

i sanded the hi comp head and cylinder ultra flat and got rid of the head gasket. runs a bit better now on the low end, but like i said, there looks to be a lot of room for improvement.

Re: 50cc kstar low end


50 cc Kstar, 14 Bing 72 jet, lowest clip/needle setting, Proma pipe...


Mid Rips!

Im gonna start looking at the clutch as well an maybe case match eventually... im getting lazy :)

Re: 50cc kstar low end

50 kstar

hi-comp head

16 dellorto

boss pipe

case matched

2 shoe tightened

15/45 gearing

low end kinda junky

mid rips

tops out at 44mph

im gonna try 14 or 13/45 and see how it changes things, ill let ya know

Re: 50cc kstar low end

Shitty low end is in the port map of that kit. It's a top end ripper, and unless you do some serious, serious work, it's never going to have good low end.

Re: 50cc kstar low end

^thats what i was thinking too. i ported a stock open port and the low end sucks. but it is a ripper for sure on the top end. but im at 18x40 and that could be an issue too.

Re: 50cc kstar low end

I've kind of gotten used to it my set-up is just like crazyjay and sometimes I'll throw in a couple of courtesy pedals to get it off the line but other than that I just kind of eat it

Re: 50cc kstar low end

Just gotta do all the obvious stuff you've heard before:

drop to 14 tooth front, mill the head, better clutch springs/lighten shoes, 16 tooth freewheel

Re: 50cc kstar low end

or maybe just deal with it being a top end ripper. a little specialized kit like that is kinda a cool one trick pony. Id put blue or paz springs in it and crank em in and have fun

Re: 50cc kstar low end

turned my springs in another 360. its better but still adog on low end. gonna turn them all the way in today.

Re: 50cc kstar low end

Put a electric hub motor on the front wheel

Re: 50cc kstar low end

you are a lil too rich. Downjet. plugchop. Also, try and get your compression around 180 to 210.

Re: 50cc kstar low end


del clone 16.5

Uni filter

tecno boss

need at one down from top

66 main

idk low speed

three shoe springs turned out 900

now 14/45 gearing

my low end so so mid and top great

45 gps confirmed

id say its the carb or gearing idk i suck at this stuff still pat sorry:(

i miss richmond

Re: 50cc kstar low end

I guess I'm part of the kstar no low end club. It's better when cold but when it warms up I too lose some low end until around 20mph. Then it rips.

Here's my setup

Puch Korado e50

Kstar 50 w/ high comp. head (not port matched)

Dellorto 15.15 with a 70 jet

Currently has biturbo pipe, but had tecno boss pipe. both pipes had bad low end.

Plug chop shows a light to med brown

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