jr50 varb problem

[lov2scan]

jr50 carb problem

My son has a 1998 jr50. recently it just decided to run very poorly. It starts fine but, it stalls when you apply full throttle. I have tried adjusting the needle,cleaning the carb, and put in a new plug. nothing has helped. My son and I are very frustrated at this point. we run only premium fuel and suzuki oil. please help. :bang:

 

[Vic]

You may have dirt in the tank.

BTW, You are wasting your money putting premium fuel in a JR50.

 

[1966mustang]

Not really i have found power gains in my friends jr50 he asked me if there was anything he should do make it run better and i told him to run premium and its actually a noticable diference.

 

[Vic]

Not really i have found power gains in my friends jr50 he asked me if there was anything he should do make it run better and i told him to run premium and its actually a noticable diference.

I'd really like to know why that would be.

 

[lov2scan]

I have found the bike to run much smoother on premium.

 

[YZ165]

When you cleaned the carb, did you remove the main jet? If so, did you make sure it, and the passage it screws into were clear? Is the air filter clean? Also check the fuel filter in the tank. It's attached to the top of the petcock. After all that, check compresion. Hope that helps.

BTW-vic, a jr50 gets about 20mpg or better. So, if premium is $2.00/gal, and regular unleaded is $1.80/gal, that would work out to one penny per mile in savings. Damn, he's gonna be RICH! By the time you're advice saves him a dollar, his kid will have outgrown the bike! :moon:

 

[Vic]

By the time you're advice saves him a dollar, his kid will have outgrown the bike!

I know lots of poor people with that attitude.

A waste is a waste, no matter the size.

I didn't give any advice, I only tried to give a clue.

 

[brr]

My son's did the same thing and we found the exhaust port almost closed. Might need some cleaning.

 

[Jasle]

I second the exhaust port clogging. I've seen that several times. And you did clean the filter right?\

i think what vic was getting as was this is a bike with 5:1 compression ratio and nothing about it says premium should help unless your just getting crap quality gas to start with. But on the other hand I run premium premixed for my pw50 just cause I'm too lazy to have more than one gas can for the multiple bikes.

 

[Vic]

I run premium premixed for my pw50 just cause I'm too lazy to have more than one gas can for the multiple bikes.

I do see the value in that.


:cool:

 

[lov2scan]

hey guys, thanks for all the input. I checked the exhaust manifold and cleaned it(it wasn't very dirty),I also checked and cleaned the fuel tank and filters going to carb. Bike is still running badly. Does anyone think it could be the gaskets in or around the tranmission. I have heard if they go bad the bike will run bad. Thanks again for the input.

 

[Jasle]

when you cleaned the carb did you remove the jets and blow backwards through them with compressed air? Can you hold them up to light and see through them? It sounds like you have a plugged jet but maybe an air leak. The crank seal is what could leak the trans oil in to the motor making it run bad. You'd need to pressure test the case to check this.

 

[lov2scan]

I cleaned the carb with high quality spray carb cleaner. I did look through the holes and could see light. How do you pressure test the case?

 

[Jasle]

you have to make a plug for the exhaust port...you can use the rubber expansion freeze plugs for cars. then make a plug for the intake but you have to put a hole in it so you can put a bolt in valve stem from a car wheel.( I use a metal plate drilled to match the reed cage with some inner tube under it to seal it). You then pump the case up to about 10-15lbs. Check the case halves and crank seals with a soapy solution. If the air leaks out it will cause bubbles.
DO NOT PUMP over 15psi.In fact I'd test at around 10psi. You can blow the seals out if you overpressure.
If the case leaks you must fix it...either crack the case halves and reseal or put new seals in.

 

[Jasle]

another thing you can do is to pull the choke on then crack the throttle. If the bike picks up revs easier it will tell you your lean(air leak). if not then maybe your too rich or your timing is off. I have actually seen a bad cdi unit let a bike idle but bog badly when the throttle was opened. Pressure check the case first cause this is cheap. a new cdi is not that cheap especially when shotgunning it by just replacing it.

 

[YZ165]

I didn't give any advice, I only tried to give a clue.

You gotta have a clue before you can give one!

 

[Vic]

You gotta have a clue before you can give one!

Oh, please stop. Now you've gone and hurt my feelings.


:eek: