Long Intake, bigger than normal jet?

[Echotraveler]

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.

 

[Echotraveler]

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?

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.

 

[Echotraveler]

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

 

[Ilikeabikea]

It's all about having the correct air/fuel mixure. To much of either one = less power. It is better to have a little to much fuel than a little to much air, but the correct amount is best.

Do you not have a fuel filter on it now? If you don't get one and put it on before you do anything else..............

 

[Echotraveler]

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

 

[Echotraveler]

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

 

[drhofferber]

iy looks that if you purchased a straight intake from jim at manic mechanics and ground it at a angle it would work...or even created a wedge for the intake...what size engine...if its a 50 or below, you can buy this system for thirty dollars, it put 5 mph on my top end...thats with shipping....ebay...type in mini pocket bike exhaust...i'm experimenting with the dual exhaust now...here is a pic...

 

[Echotraveler]

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.

 

[drhofferber]

well the one you were looking at is a 80cc...35 mph...now my freind says put a big one on the 80cc and take the small one on the slant 50cc...pic included...i've built 3 bikes, my first a cruiser...steel frame but poor suspension...went to the mountain bikes one triple butted cromoly and one triple butted aluminum...i prefer these...now i,m in the process mentally to build everything from scratch and use alot of manic mechanic parts...but its time and money...and i'm in know hurry...i've got alot of parts...ha...thats something that happens....here is a few pics...keep everything tight and check everything after every ride...Dennis...the gary fisher cruises about 27...32 top end...lots of tork...the one above cruises at 30...36 top, but i believe it will go close to 40...their is no vibration in these two...i also use amisol sabre...80 to 1 which i bought from Pablo...that in itself will add about 3 mph...now in the one above i just added a pulse plug...30 bucks...low end tork...fast...i dont reccamend any of these things, i just like pushing the limit without to muc effort...ha...63 yrs old and going on 20...ha...if i can help let me know...

 

[Echotraveler]

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

 

[oldcliff]

dr, where did you buy the intake runner and the exhaust chamber from? The carb on my mountain bike has a big interference problem with the frame. I think an intake like you have will work for me. Thanks in advance,
Oldcliff

 

[oldcliff]

Dr, I forgot to mention that I don't do ebay any more. got ripped off real bad on an Apple Computer. I only deal direct now. BTY I am 71 and still biking. Just took a 200 mile trip yesterday on my Harley.

 

[drhofferber]

yea i've had the same problem...OK...first i made the intake because that is a slate50cc and the hole pattern is the same as the exhaust...but you can purchase a straight intake frame manic mechanic here on the forum and alter the angle by grinding it and it will work...you dont need much or you can make a wedge with a angle...short doesnt hurt when it com to a intake...just try to get as straight as possible...mine isnt perfect but it works...i'll go on ebay and see if i can get the site address or phone...check for another reply...Dennis

 

[jtgolden]

iy looks that if you purchased a straight intake from jim at manic mechanics and ground it at a angle it would work...or even created a wedge for the intake...what size engine...if its a 50 or below, you can buy this system for thirty dollars, it put 5 mph on my top end...thats with shipping....ebay...type in mini pocket bike exhaust...i'm experimenting with the dual exhaust now...here is a pic...

Did that exhuast bolt straight one? That looks awesome and did increase the performance on acceleration and hills?

 

[drhofferber]

yes they bolt on...but depending on your bike you might have to cut and tweek and wield, to set it right...my other bike....i used the single muffler with small expansion chamber...it fit perfect...that is a old gt...good luck with everything...Dennis...oh the performance in the low end...i have went to a 41 sprocket...it helps the top end a little, but gives me more chain clearance...