Engine trying to start and after that it stops on first run

orcun

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Apr 13, 2024
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Türkiye
My engine has hp carb and when i tried to start it 2 times. it tried to start in first, it runs like 1 sec and second time it runs like 5 sec. So, i need help, i need to fix this bike in 10 hours <----- it's running video, to see the second run look at the 1:00. Have a good day.
 
If it wants to run i can guess it has the correct timing, good spark and gets some fuel.
Dumb question but are you using the choke? On my engines i have to play with the choke for about 15 seconds before they even think of running... I start my bike with the choke in the fully closed position, after it starts and dies i put it to half open. Start it again and if it keeps running play with it until it doesnt bog while giving it throttle. After that i let it warm up before riding off.
 
Do you have another carb? Once you let out the clutch, keep pedaling, pedal hard. It will fire and run. I hope you have fresh fuel.
 
THe fueling is still likely either a touch rich or lean. Those HP Carbs are also notorious for being difficult to run right, either being easy to start and idle, but struggle with going beyond half throttle, or impossible to start and get to idle, but run great past half throttle. Personally, I would toss the original carb back on, or get a JRL Bofeng carb if you can.

In the meantime, since you only have 10 hours, follow the above suggestions. New engines are usually much more difficult to get started, so following Chainlube's suggestion to keep pedaling is spot on. Keep that engine turning so it can build some compression and heat and it will eventually kick off.
 
If it wants to run i can guess it has the correct timing, good spark and gets some fuel.
Dumb question but are you using the choke? On my engines i have to play with the choke for about 15 seconds before they even think of running... I start my bike with the choke in the fully closed position, after it starts and dies i put it to half open. Start it again and if it keeps running play with it until it doesnt bog while giving it throttle. After that i let it warm up before riding off.
i think i've found my problem, my fuel line is so long and it goes up and down. Could this be the reason why it's not working? (my carb doesn't have choke thing :) )
 
i think i've found my problem, my fuel line is so long and it goes up and down. Could this be the reason why it's not working? (my carb doesn't have choke thing :) )
The most direct path you can manage without kinking the line is ideal.

Not having a choke is why that thing is going to be very hard to start. Cold engines require a richer air/fuel ratio in order to start and run until they warm up. It is possible to start without a choke, but it will require a lot of cranking (aka you pedal a lot) to get it to fire and stay running, and it will be very prone to stalling out for a couple of minutes until it gets hot. If the fueling is already lean for the idle, it may never start at all, or never stay running whilst cold.
 
The most direct path you can manage without kinking the line is ideal.

Not having a choke is why that thing is going to be very hard to start. Cold engines require a richer air/fuel ratio in order to start and run until they warm up. It is possible to start without a choke, but it will require a lot of cranking (aka you pedal a lot) to get it to fire and stay running, and it will be very prone to stalling out for a couple of minutes until it gets hot. If the fueling is already lean for the idle, it may never start at all, or never stay running whilst cold.
i don't think so. because i bought this engine from a guy and it was running well on his bicycle. so i bought it and he doesn't have choke too and it was started on 2nd attempt when i was testing the engine.
 
Do you have another carb? Once you let out the clutch, keep pedaling, pedal hard. It will fire and run. I hope you have fresh fuel.
i have old fuel and it's very oily, but i'll use to go to gas station. Because in my country they don't give fuel in to the bottle. It's illegal
 
i think i've found my problem, my fuel line is so long and it goes up and down. Could this be the reason why it's not working? (my carb doesn't have choke thing :) )
Get rid of the HP carburetor and use a JRL BoFeng carburetor instead, it also has a working choke which you DO need to have.
HP carburetors are the worst pieces of junk I have seen for carburetors for these 2 stroke motors.

You want to get your bike to start easily and run smoothly???...You want to solve your problems???...Then start listening to the advice given you already by guys who have been answering you that have been doing this for many years now.

And stop saying "well it ran for the other owner on his bike", it is not on his bike anymore and neither are you.
 
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