my bike will die randomly

[simonbauman]

I will be riding my bike and sometimes it will just die randomly. also sometimes when im idling and i give it a bit of gas it will rev up very high for a few seconds. i wont have any control over the throttle. any idea what could be the problem. the carb it brand new. i also have a homemade pipe that has a blown gasket so it leaks. it was also working fine for 5-6 tanks of gas

 

[Greg58]

It sounds like you have a air leak somewhere on the intake or a leaking crankshaft seal. This will cause the engine to rev up.

 

[simonbauman]

It sounds like you have a air leak somewhere on the intake or a leaking crankshaft seal. This will cause the engine to rev up.

how could i fix this

 

[Greg58]

Check the carb to intake, make sure the carb is seated all the way on the intake and is tight. If that doesn't help remove the magneto cover and clutch cover and look for fuel leaking from the seals on either end of the crankshaft. The problems I have had was with the seal behind the magnet, that seal is thinner than the one behind the small gear and sometimes will come out of the case when the engine back fires.

 

[simonbauman]

Check the carb to intake, make sure the carb is seated all the way on the intake and is tight. If that doesn't help remove the magneto cover and clutch cover and look for fuel leaking from the seals on either end of the crankshaft. The problems I have had was with the seal behind the magnet, that seal is thinner than the one behind the small gear and sometimes will come out of the case when the engine back fires.

i checked this and it dosint seem like there is any gas leaking out also the carb is all the way on . any Other ideas?

 

[allen standley]

Be sure your tank cap is venting properly. Test by loosening the cap then go for a ride. If that's the prob- drill a tiny hole in the top of cap.

 

[simonbauman]

Be sure your tank cap is venting properly. Test by loosening the cap then go for a ride. If that's the prob- drill a tiny hole in the top of cap.

ok i will try this but i think it is venting fine

 

[javy mcdees]

when bike randomely dies you just reach down and jerk off the fuel line and see if you have fuel delivery at carb inlet. if no fuel, there is your sign.

 

[simonbauman]

when bike randomely dies you just reach down and jerk off the fuel line and see if you have fuel delivery at carb inlet. if no fuel, there is your sign. View attachment 100443

ok thanks. Any idea why it will rev up?

 

[allen standley]

If the engine is starving for fuel it will rev then shut down.
Also Do NOT "reach down and jerk off the fuel line" if the fuel inlet tube is pressed in and not threaded and turned in, chances are you will pull the inlet tube out of the carb.
You could also check by closing fuel valve then carefully unhooking the fuel line at the carb and placing it over a gas can. With cap tight on tank open fuel valve to see if you have a good constant flow of fuel.
A dribble or small trickle will tell you if you have poor flow. Pop tank cap off to see if flow increases. If it does--- drill a 3/16 hole in top center of tank cap.

 

[simonbauman]

If the engine is starving for fuel it will rev then shut down.
Also Do NOT "reach down and jerk off the fuel line" if the fuel inlet tube is pressed in and not threaded and turned in, chances are you will pull the inlet tube out of the carb.
You could also check by closing fuel valve then carefully unhooking the fuel line at the carb and placing it over a gas can. With cap tight on tank open fuel valve to see if you have a good constant flow of fuel.
A dribble or small trickle will tell you if you have poor flow. Pop tank cap off to see if flow increases. If it does--- drill a 3/16 hole in top center of tank cap.

thank you also which way should the fuel valve be?

 

[allen standley]

When valve is open, lever and fuel line will be in a line with each other. When closed lever will be "T" in relation to line.

 

[simonbauman]

When valve is open, lever and fuel line will be in a line with each other. When closed lever will be "T" in relation to line.

oh ok thanks
i did this and the fuel is only driping out of the line. i put the valve in various positions

 

[javy mcdees]

I lose engine power while in motion i just pull the fuel line right away before I stop to see if that is the reason my engine is not running. the fuel lines and fittings are so small and the volume tough to keep flowing, that is how I test my system for a clogged fuel filter. usually the tank strainer gets clogged and kills my flow. just rode 80 mile round trip today 40 miles on 1.8 quarts to work 1.8 qts to get home. runs amazing! But could run better! cruises good at 30to 40 mph

 

[allen standley]

Hey Javey,
Save yourself from the problem. Throw the "Tank Strainer" away. You don't need it. Use the transparent external inline fuel filter.
To Simon. Possible you may have a defective fuel valve. Go here
http://thatsdax.com/ENGINE_KIT_PARTS_PAGE_1.html
---scroll down about 10 items on left of screen. $3.98. As advised above -- don't use the strainer.

 

[Greg58]

I have had gas tanks with rust inside in kits, a old trick I've used several times to clean them is simple, I add a couple hands full of marble size gravel with diesel or kerosene add shake the tank vigorously till the inside looks good. I did this to the tank on my 50 years ago.

 

[Greg58]

I've got a tank I'm about to use that's been in the shop for maybe 4 years, I'll clean it before I use it. The good thing is the rock will clean the areas I can't see.

 

[simonbauman]

Hey Javey,
Save yourself from the problem. Throw the "Tank Strainer" away. You don't need it. Use the transparent external inline fuel filter.
To Simon. Possible you may have a defective fuel valve. Go here
http://thatsdax.com/ENGINE_KIT_PARTS_PAGE_1.html
---scroll down about 10 items on left of screen. $3.98. As advised above -- don't use the strainer.

my fuel valve is pressed in to the gas tank

 

[allen standley]

Never heard of such a thing with a kit tank.
Good Luck to you.

 

[javy mcdees]

Hey Javey,
Save yourself from the problem. Throw the "Tank Strainer" away. You don't need it. Use the transparent external inline fuel filter.
To Simon. Possible you may have a defective fuel valve. Go here
http://thatsdax.com/ENGINE_KIT_PARTS_PAGE_1.html
---scroll down about 10 items on left of screen. $3.98. As advised above -- don't use the strainer.

the tank strainer keeps the dirt in the tank not my fuel filters I like it that way. the new tank is dirty as like india. Also the fitting in the tank is a male so need the female style valve, but all good easy to clean and get going again, the strainer is good to me. Thanks anyway!