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Just bought a Suzuki JR50 - need to know some stuff

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I just bought my son a Suzuki JR50, I think its a 2003.

It doesn't run and needs some work. The oil tank is missing, no kick starter, been sitting for ages so the carbs need a cleaning.

It doesn't have the owners manual, so I'm wondering if you guys could let me know some of the stuff I should know about the bike.

What fuel to run?

What oil to use?

What spark plug (I want to replace it but I'm not sure if it needs it or not.)

What are the stock carburetor settings (I'm not sure if they have been tinkered with or not.)

I assume since it has a centrifugal clutch that I can't push start it, hopefully I'm right otherwise something is messed up since when I put it in gear I can push the bike without spinning the engine.

Any general tips or tricks you have about the bike would be greatly appreciated!

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I just bought my son a Suzuki JR50, I think its a 2003.

It doesn't run and needs some work. The oil tank is missing, no kick starter, been sitting for ages so the carbs need a cleaning.

It doesn't have the owners manual, so I'm wondering if you guys could let me know some of the stuff I should know about the bike.

What fuel to run?

What oil to use?

What spark plug (I want to replace it but I'm not sure if it needs it or not.)

What are the stock carburetor settings (I'm not sure if they have been tinkered with or not.)

I assume since it has a centrifugal clutch that I can't push start it, hopefully I'm right otherwise something is messed up since when I put it in gear I can push the bike without spinning the engine.

Any general tips or tricks you have about the bike would be greatly appreciated!

1st run 91 oct unless its old gas then i would rather have fresh 85 they will run fine on 85 very low compression.

br4 plug is what you want to run

stock carb settings god i cant remember stock main or pilot i have changed them around so much i dont remember OEM.

but fyi they have 2 pilot jets stacked ontop of eachother take the first one out and leave it out. if you tell me the main or pilot im sure it will jog my memory and i can tell you if its oem,

this bike has a 2 speed tranny BUT only 2nd gear is activated in the USA you can activate 1st gear if you mod it.

you should be turning the motor when pushing it in gear if your not check compression you probably are but dont feel it compression should be over 100.

i wrote a entire how to make a jr50 or how to get more power out of a jr50 trick and mod threads in here.

i have owned a 01 03 and 05 jr50 and have modded the heck out of them any questions just ask. im sure i can help you et it running:thumbsup:

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You mentioned in a previous post that the 1st gear in this bike is really low. If you go to a 14 tooth front sprocket would it be a little better? Have you seen less tooth rear sprockets? IYO, how fast do you think the JR would go on a flat surface with the engine modified and a high gear ratio? Just curious....

I did order a new head gasket set this weekend and plan on doing the head job when it comes in. I also had a funny experience this weekend while looking for parts. I went into a bicycle shop looking for shocks that might be a close fit with more travel (the thing lands like a brick!). I thought I read on here somewhere that someone used mountain bike shocks as an upgrade. Anyway, you'd have thought I called the shop owner's momma a bad name when he found out what I was trying to do. He suddenly didn't know anything and went off to find a "real" customer. I thought sellin' parts was sellin' parts.... who knew? :thumbsup:

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I can spin the rear tire and move the piston, it just has such light compression (and a tiny little piston) that while pushing the bike in gear I couldn't even tell it was spinning.

I assume that means that I can jump start the bike? I would prefer to get it running before I spend the $50 on a kick starter.

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I can spin the rear tire and move the piston, it just has such light compression (and a tiny little piston) that while pushing the bike in gear I couldn't even tell it was spinning.

I assume that means that I can jump start the bike? I would prefer to get it running before I spend the $50 on a kick starter.

i have never been able to push start a jr50 yet but i only tried once for about 20 min before i got tired and gave up :thumbsup: i dont think it is possible to jump start one.

pull off the plug wire and take out the plug then check for spark first thats were to start, then check to make sure it is getting gas and air, thats all it really needs to run if it is wore out i doubt it will start so you might need a new top end put your finger over the spark plug hole and have someone kick it, does it blow your finger off the hole?

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You mentioned in a previous post that the 1st gear in this bike is really low. If you go to a 14 tooth front sprocket would it be a little better? Have you seen less tooth rear sprockets? IYO, how fast do you think the JR would go on a flat surface with the engine modified and a high gear ratio? Just curious....

I did order a new head gasket set this weekend and plan on doing the head job when it comes in. I also had a funny experience this weekend while looking for parts. I went into a bicycle shop looking for shocks that might be a close fit with more travel (the thing lands like a brick!). I thought I read on here somewhere that someone used mountain bike shocks as an upgrade. Anyway, you'd have thought I called the shop owner's momma a bad name when he found out what I was trying to do. He suddenly didn't know anything and went off to find a "real" customer. I thought sellin' parts was sellin' parts.... who knew? :thumbsup:

if you do the 1st gear mod then yes a 14tooth would work nice or even the stock 13 works well, im guessin top speed with the 28 rear and 14 front is about 35 depends on what other mods you havedone im guessin my sons jr50 might hit 40 to 45. i have seen 26 rear made for street scooter but i have never put a smaller rear on a jr50, you can by a light weight aluminum moose rear sprock that will help turn that rear tire the OEM sprock is a very heavy steel sprock. every ounce you take off these bikes helps a ton in power and speed.

yep im the one that mentioned mtn bike shocks i went to wally mart and they had a kids mtn bike i measured the eye to eye length on several found on that would work then i bought 2 of them from a bike store they ordered them for me, i had to use a sleeve washer but thats it and they work nicely, you can also just have heavier rear springs made for the jr50 i believe it will cost 90 dollars for the rear springs and 90 for the front./

someone mention using valve springs in the front forks and they said that worked well.

im sorry to here the bike guy was a jerk, wow some people huh to me a sell is just a sell no matter what it is or for. im sure he not only lost you asa customer but anyone you would have recommended to him

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