Changing carburetor jets on your Motorized bicycle engine

Changing the jets of any 2 stroke engine is considered a fundamental aspect of tuning. The jet on your motorized bicycle engine determines whether your engine will last 5 minutes or 5 years (if that much). It will also determine the speed of your engine, if your running too rich (too much fuel to air) good luck squeezing out your max rpms. Likewise, if your running too lean (to much air to fuel) make sure to wear a helmet!In this JuiceMotoParts tutorial we will show you guys how to access and replace the jets of your motorized bicycle engine. Feel free to comment or shoot us a message if you have any questions or need any trouble-shooting advice. Check us out at Juicemotoparts.com for more information on how to tune your motorized bicycle engine as well as our line of line of high performance products. Thanks for watching and as always, GET JUICED!

[@TheChensoccer]

Could you make a video of how to adjust the needle on a high performance carb. Please. Thank You

[@arefalkouatli3750]

Yeah that would be great!

[@leedunlap92]

hay i live in Florida whats the size of the jets do u use and what size would u recommend to plz help

[@zragevii4705]

Where would you suggest getting jets for a chinese bicycle engine kit?

[@Pipe_Piper]

What's a good resource for the jets? Are there kits you can pick up?

[@motorizedbicyclenation53cu90]

Anywhere Amazon worx. 5mm jets for Delorto sha #50-80 65 go to for 66/80 70/75 for 100 depending on wich 100 it is

[@jeremylmassey]

where is a good place to get jets ? I can't seem to find any

[@davidbean5621]

I have the hp carb and I am at 876ft above sea level what jet would you use for my carb

[@chavvis447]

I ordered the jets from 70 115 but they are a little big. They're not the same size as the stock jet. How can I order the same size?

[@paulgoodman7716]

wrong way to get the main jet out. the tube that came out with the main jet, has 2 small flats on it. use a small adjustable spanner. on this and screw out the jet. the vice is the last straw

[@HobieKatt]

im a 255 lb guy , i bought one of the racing carbs , yet its sloooooooow , which jet would you suggest for more speed?

[@jett-rampartflyer2852]

moofasa1211 I think he's trying to say the carburetor is the cause behind the bike running so slow.

[@anonymousanonymous471]

A racing carb that sells for a motorized bicycle is a general carb for many bikes most requiring more fuel than are motorized bicylce's.. you probably need a much smaller jet... but my opinion.. If your 255 lb your looking for more torque.. forget the carb upgrades there mostly useless 1st cheapest easiest upgrade you will notice a difference NGK BPR6HIX Iridium IX Spark Plug 6.99 to 9.99 2nd not to expensive ,not to difficult to install fairly large torque upgrade... depends on your motor.. if you have 49cc get RSE Reed Valve Air Intake Kit gasbike.net has them for 34.99 if you have a 66cc or 80cc get CDH-G2 Racing Reed Valve Kit -Suitable for 40mm and 32mm Intake amazon has them 39.99 3rd and and very big upgrade very much added torque, very costly and can be headache to install and keep the exhaust gasket sealed.. and you will most likely need to rejet whatever carb your using if you get one.. Specifically from sickbikeparts.com Expansion Chamber - Exhaust Pipe 75.00...Any other pipe is going to be harder to install and or to loud.. If your not even hitting 30mph.. Just take the end piece off the stock muffler.. Take the bolt off then end and it should come right off.. And bam huge Instant torque increase.. but wont rev high enough to go over 30mph The absolute last thing you wanna do is get rear sprocket with less teeth, especially if you hard time climbing hills/gaining speed unless you have many other upgrades already and are reaching so high rpms that you let off the gas in fear of excessive motor wear.. Then its time to drop down to a smaller rear sprocket... im running a 36t and hit 38mph today and my motor was really winding... gonna drop down to a 30 Tooth CNC Sprocket & Adapter but im only 180lbs with all the above mention upgrades and a racing head plus a ported cylinder

[@man_ofthe_year6568]

Do not buy any reed valve unless you have a windowed piston and port your motor with a boost port. I am a 300lb guy with a 49cc and can reach 34mph. Go to bicycle-engine.com buy the “power jug” its ported and had a rounded exhaust port and a 40mm intake inlet (you will need a 40mm intake) skirt your piston but only take off 1/8 -2/8. (On the inside of your piston there is a little line the runs around the bottom of it shave off about half way to that line) do that to the intake side of the piston. And of course get a good spark plug and youll be flying.

[@renochuy74]

cool vid. my carb seams to leak a lot and i set the needle all the way down as to stop the fuel from leaking throw the jet. I'm in Reno about 5000 feet above sea level. do i need a smaller jet? i don't know whats going on. any help would be nice thanks.

[@MileytheJeepV2]

Yeah it fucking broke so thats cool guess I need a new carb... idk how im getting to work till I do

[@jimjohnston5009]

What’s a good jets size for Cleveland Ohio

[@asphaltcowboy7868]

I was told stock npt jet is a 70..if that helps anyone..

[@asphaltcowboy7868]

I have done a reverse jug and placed my intake in the front and my exhaust exiting from the rear..now more air is being drawn into the carb..which has caused my engine to run too lean, so I'm wanting to rejet the carb. to get more fuel in..to compensate for the extra air..I'm currently running 50+ mph but I know that I could get even power out of my engine if my air/fuel ratio was better..my engine will cut out at full throttle and my spark stays white to slightly gray..so I need to richen up the carb..

[@tamerfahmy435]

I am having a hard time finding the correct replacement jets for the same carb..,what are the dimensions please ? Thanks

[@motorizedbicyclenation53cu90]

My bt80 used a 75 jet!

[@cfmechanic]

Very nice straight forward video. I am gonna swap my jet bike seems to 4 stroke at wot after I reach 25 ish mph. So best I can tell from everything I read is in am too rich at wot causing power loss and 4 stroking. Do I siund like I'm on right track

[@Andrew-my1cp]

Hey my bike is doing the same thing. I first discovered it after taking off the muffler cap making it possible to hear. Did re-jetting to a smaller jet work for you? Thanks!

[@Andrew-my1cp]

Hey I am having the same problem with mine. I have many signs telling me I'm running rich. Did re-jetting fix your 4 stroking? My jets are on the way and I can't wait for them to arrive.

[@Andrew-my1cp]

@Trevor charger Downjetting helped and when the engine was hot it stopped 4 stroking. It took 2 pulls to get it hot though.

[@Andrew-my1cp]

@Trevor charger It's not overheating if it burns you. It could be but only a thermometer could tell.

[@memoherrera2607]

yo quiero qué las charlas sean en español plis

[@buzzardsbass1137]

It defeats the purpose of your vise if it is NOT ATTACHED to your bench.

[@integrationofmanandmachine4714]

My bike is running rich what to do

[@kinggggg08]

hp carb needle adjustment? is it possible

[@gmoneyga84]

its not-- The nt carb is so much easier to tune/adjust

[@kylekampourakis3889]

Your float is stuck you need to take the bowl off an reset it or you could gently tap it with the handle of a screwdriver or something similar which will usually break it free an float properly

[@jgbelmont]

I moved up to an .80 larger and still no top end. I guess i will keep going. Plug says its lean still. What do they typically use in this carb if you performance tune the bike a medium amount? No reeds or anything crazy.

[@flyingsky1559]

it could need a pretty high jet, they make them up to like 130s

[@bigdevil1310]

I live in sf cali shoud i make it bigger

[@sanesaint8725]

How many millimeters is it for a new filter

[@dennisleger9229]

Not a main jet its an emulsion tube...

[@KipIddy]

What type of air filter is that and whered ya get it?

[@ronathey5287]

howe do you adjust the fork at the right adjustment every time i hit a bump it fluds out the filter, then i have 2 adjust it all over.

[@DudeWithALude97]

Did you Ever figure this out?

[@brandonkellogg9590]

Where'd you get that air filter?

[@moddedcars8942]

what jet should i use with a straight piped 80 cc Chinese engine took off all the mufflers with a saw

[@moddedcars8942]

right now the spark plug looks lean

[@DonovanNorthup]

What size do you run

[@gbonfil]

Hi should I replace the jets on 4-stroke 49cc engine as well?

[@donrodriguez8615]

If needed yes , tuning takes time

[@ravencruz7576]

thank you you rule

[@JuiceMotoParts]

usually if you are at a higher altitude. it means that you have less oxygen to you. That in turns translates to lower/smaller jet sizes so that you can correct the fuel/air ratio of your engine. I'm not sure what Carb you have but try getting a jet size like 62/64 if you have a 66/80cc engine! Thanks and let me know if this helps!

[@Michal_S0L]

JuiceMotoParts so i live in canada and my engine runs but it has very low power so will changing the jet fix my problem? And how does the "automatic" choke shit work??

[@Michal_S0L]

JuiceMotoParts oh and by the way i have the delorto ebay nick off hp carb

[@bobbywagner9803]

I live on mt everist and mine has lots of power

[@Bubbascoot1999]

What is better smaller jets or bigger

[@zragevii4705]

Depends on situation... you would have to look at your engine to figure it out.