Long Intake, bigger than normal jet?

Hello Norman,

I have a Worksman LGB and mounted a Chinagurl motor. To do so i had to custom mount the motor and make a new intake, because the carby dosn't have space inside the frame triangle. My tool & dimmer friend wants to look at it further to see if we can make a shorter intake today.

BUT, i keep spending money!

and was wondering if opening up the carb jet a bit more would counter the lag my intake may create.
I had to buy a speedometer, and discovered i was going 19 at WOT, i think this is too slow. i dont really want to go much faster...but 25 or 30 would be a very big improvement...yesterday the motor did 24 mph for like 30 seconds then came back to 19, im doing my hills at steady 14mph

On a phone call i expressed to him how im not finding any of the spark plugs i need, and he responded we could start tuning the one i got, so thats good.

Hes also very into getting an expansion muffler...i told him about sbp's and he acted esceptical, becuae its 64.00 bucks..lol i guess hes too used to 150+ expansions.


heres a photo of your back light .... it working great now, tweaked the iddle and after the engine is hot i can iddle with light on.

Bikeguy Joe said:

A two stroke tuner should weigh in here, but I think your longer intake will make more power at a lower RPM, if that's the case, then your best bet for higher speed would be to use a smaller (like 36-40T) sprocket.

Opening up the jet may cause it to run worse.

What color is the plug?

Click to expand...

right now the porecelaine is black, not cruddy, but yea its black.....the needl is on the 3rd slot from the fat end down.

2-stroke tuner?


NOTE: also the intake is 5.5" long and 3/4" thick


dax mentioned that if anything i should thin out the main jet, cause the long tube is creating a bigger vacum. what do you think Norman?

he also mentione dthat my 130+ miles im still breking in...another thing is that if i wer to change the jet had to be sure the carb had a good fuel filter.

i dont want to rejet. im confused here....

could it be my muffler is holding me down? i remember that with my old muffler a motorcycle driving along told me i was 21mph WOT max and some police radar told me 23mph...

thats why i think maybe the muffler is still the culprit here. a friend just told me that police radars need to be calibrated every time they shoot, so maybe i was going 19 and the 21mph from the motorcyclist could be off too since 19 is almost there.

my tool & dimmer want to make a shorter intake, but im not sure how we can make it work sicne the space is very restricted.

rejeting is the last resort, but ill measure it to see if its .026"...how can rejecting smaller make more mph???? im not understanding this

yes it does have a fuel filter actually its on backwards since day 1, so i guess its better to replace soon, when i see one on sale, cuase sears has one for 12.00 thats simply ridiculous!

im on a psycho quest for more speed!

when i lean it out the iddle gos wild

Hey Norman i just came from tool and dimmer, and tried many spark plug combos...the fastest was 22mph with a .032 gap......the light didnt work at all
at .020 they work.. but my max speed is 15 to 16....

he was like 'i dont care about a light, i want this motor to feel good.

right now im gonna save money to buy a new sproket and change the intake to a shorter one, were thinking of putting the carb directly to the wind so it gets more air.

hope you guys are not tired of my posts

thanx for the reply Dr. that looks sick! great MB you got there friend! my motor is 67cc (80cc advertised) it runs with tons of torque so i just bought a nice clam adapter and 40t sprocket...yesterday on a 10 mile ride my chain went inside, not alligned perfectly.....after that i get an expansion, right now im considering pablos and this sounds interesting, maybe too small for my motor. Is your motor the 80cc, whats your mph rating, and experience adapting the expansion.

sound like your litterally having mad fun...lol
so you hooked up a 50cc exhaust on a 80cc motor? i guess theres not a big difference afterall... and that your other bike is 50cc and has an 80cc exhaust?


hey Norman lets suppose my jet is .026" im going smaller but were to begin? can you recomend were to start?...im thinking of buying an expansion new plug and air filter, and the 40t sprocket...the thing is leaning it out as much as i can without messing with the carb. i cant run my lights having a .32 gap on the plug