Brand new engine wont stay running

[Indy420]

The thread below will help set up the carb.
http://motorbicycling.com/showthread.php?t=195

Thanks, I already have that part down. My only question about the carb, (which I didn't see addressed in that thread) is can the float be adjusted? Do I have to bend the fork to adjust it? Should I not touch it?

BTW... I've worked in a transmission shop for 20 + years. I am mechanically inclined, I just don't know jack about these small engines and carbs. lol

 

[crassius]

yes, just bend each of the brass prongs the same amount gently until the level is where you want it - ideally the float should sit level on the prongs

 

[2door]

Your problem isn't the stock carburetor and replacing it with a "racing carburetor" isn't going to fix your issue. And 'Racing' doesn't mean it is better, or faster than what you have. It's marketing hype only. Stick with the kit carb. You'll be better off.

My guess is a clogged fuel passage because you didn't clean the tank before installing it. Every kit tank I've seen has come from the factory with rust, scale and dirt in it. The engine is probably flooded due to excess fuel and a stuck float valve or it s starving for fuel because of restricted flow.

Remove the fuel line from the carburetor, open the petcock and see if you get a steady flow of fuel from the tank. By steady I mean a steady stream. Not dripping, and it doesn't need to be like a fire hose. Just a steady stream.

If you have a good flow then start looking at the float valve to make sure it isn't blocked open by trash. This might explain why after you have cleaned the carb the engine will run for a few seconds. It will until it floods again if the float can't close off the flow due to the float needle valve and it remaining open.

Ignition isn't your problem. If the engine starts and runs as you describe the only ignition issue could possibly be the kit supplied spark plug boot which is notorious for bad electrical connections. You're wasting your money by replacing the magneto or CDI.

Tom

 

[Indy420]

Just checked my head bolts. They were awfully loose. Turned all 4 about a full turn. Would that cause the carb to not suck fuel? I had good compression, I checked it the other day. It's hard to believe I had any compression as loose as the bolts were.

 

[Indy420]

Your problem isn't the stock carburetor and replacing it with a "racing carburetor" isn't going to fix your issue. And 'Racing' doesn't mean it is better, or faster than what you have. It's marketing hype only. Stick with the kit carb. You'll be better off.

My guess is a clogged fuel passage because you didn't clean the tank before installing it. Every kit tank I've seen has come from the factory with rust, scale and dirt in it. The engine is probably flooded due to excess fuel and a stuck float valve or it s starving for fuel because of restricted flow.

Remove the fuel line from the carburetor, open the petcock and see if you get a steady flow of fuel from the tank. By steady I mean a steady stream. Not dripping, and it doesn't need to be like a fire hose. Just a steady stream.

If you have a good flow then start looking at the float valve to make sure it isn't blocked open by trash. This might explain why after you have cleaned the carb the engine will run for a few seconds. It will until it floods again if the float can't close off the flow due to the float needle valve remaining open.

Ignition isn't your problem. If the engine starts and runs as you describe the only ignition issue could possibly be the kit supplied spark plug boot which is notorious for bad electrical connections. You're wasting your money by replacing the magneto or CDI.

Tom

I used the petcock to drain all the fuel from my tank earlier today. It had a steady stream the whole time as it drained into my gas can. Right now my tank is empty. I'll try to flush it out.

The only reason I got the "racing carb" is because of the red air filter.... lol
(It matches my bike)

Like I just posted above, my head bolts were loose. I had good compression but maybe not good enough. Would that cause the fuel to not suck into the carb?

 

[2door]

Loose head fasteners can cause you a lot of problems. Whatever you do, don't over tighten them. If you don't own a torque wrench, beg borrow or steal one (no, don't steal it) but make sure the nuts are torqued to 120 to 140 inch pounds. If you worked on automatic transmissions then you know how easy it is to over tighten bolts into aluminum castings and damage threads. Same for your engine.
After the engine has reached operating temperature a couple of times re-check the torque but don't exceed that 140 inch pound setting.

Good luck.

Tom

 

[Indy420]

UPDATE:

Head bolts were slightly loose. I don't have a torque wrench anymore so I just used a 3/8 ratchet and snugged them up. (I didn't go crazy)

I drained my fuel tank, took out the petcock (it was flowing fine) I rinsed out the tank with gas and dumped it out. Reinstalled it.

I took my carb apart again and this time I adjusted the float. I bent the prongs down towards the float just slightly. Reinstalled it.

I checked the plug, it looked fine.

I took it out and just like before, it was hard to get going. It seemed like it wasn't firing at all until I pedaled it for 100ft. It started up, like it did the first few times, wanted to die, kept feathering the throttle, then it started to go.
This time I was able to ride it around the block 3 times and it never died on me. I was able to let it sit and idle and adjust the idle screw. It never seemed to be running correctly this whole time. The engine felt hot. I put my finger over the exhaust hole and it died instantly. I went to start it again and like always, I had to peddle it forever before it acted like it wanted to fire. Choking it did not help. Priming the carb did not help. It finally started again and I rode it for another 3 blocks and it died again. I was unable to restart it and I ended up pushing it home.

So, wtf? lol

I think I need a carb. But I don't understand why it feels like it isn't firing when I'm trying to start it at first, unless of course there just isn't any fuel at all in the piston.

Someone please confirm I have a bad carb.

 

[Greg58]

Thanks, I already have that part down. My only question about the carb, (which I didn't see addressed in that thread) is can the float be adjusted? Do I have to bend the fork to adjust it? Should I not touch it?

BTW... I've worked in a transmission shop for 20 + years. I am mechanically inclined, I just don't know jack about these small engines and carbs. lol

You need to go back and read through that thread, its all about the carburetor.

 

[Indy420]

You need to go back and read through that thread, its all about the carburetor.

lol, I did. I thought he was finished when he stopped on the first page. It seems he picks back up all throughout the thread. I found the float adjustment and I got a 3 block distance instead of a 1 block distance this time.

I'm going to work on getting it 4 blocks tonight.

 

[skitchfish]

Hey Indy, You simply stated " premium gas with correct mix". What exactly are you calling correct mixture?

The reason I ask is that a lot of first timers use 16 to 1. I've read back through the post and no members have mentioned this. It is generally accepted that attempting to use a 16:1 will certainly make your bike run very poorly or not at all. Hope that's the problem.

Good luck and have fun

 

[Indy420]

Hey Indy, You simply stated " premium gas with correct mix". What exactly are you calling correct mixture?

The reason I ask is that a lot of first timers use 16 to 1. I've read back through the post and no members have mentioned this. It is generally accepted that attempting to use a 16:1 will certainly make your bike run very poorly or not at all. Hope that's the problem.

Good luck and have fun

16:1 is what I used for my last bike. It is 8 ounces per 1 gallon.

On my first bike I used 8 ounces per 1 gallon of gas. It ran perfect, but smoked a lot and dripped oil everywhere. (Which is normal)

Right now I am using 6 ounces per gallon of gas.

After the break-in period I switch to 4 ounces per gallon of gas.

I'm pretty sure this isn't the problem. My last build fired right up using more oil. I am having a fuel shortage problem, a vacuum leak problem, or a spark problem.
Being off a little on my oil mixture won't make my bike backfire and run the way it is.

Thanks for the advise tho. I will dump the gas and start over. I am going to keep it around 20:1

I have 2 new carbs and a new CDI/Magneto on the way. If replacing these doesn't get it going I'll be shipping the engine kit back and requesting a new one, because it is under warranty.

 

[skitchfish]

Indy, I think changing your gas out is a excellent idea. Get that ratio up there and i think you will have a lot more fun. 20:1 is still really thick even for breaking in but that's just my thought.

One more question, Where do you have your clip set on your needle at carb end of throttle cable?

OH, and what kind of oil are you using?

It would be really cool if it is something simple and you don't need all that stuff. Good luck

 

[Indy420]

Indy, I think changing your gas out is a excellent idea. Get that ratio up there and i think you will have a lot more fun. 20:1 is still really thick even for breaking in but that's just my thought.

One more question, Where do you have your clip set on your needle at carb end of throttle cable?

OH, and what kind of oil are you using?

It would be really cool if it is something simple and you don't need all that stuff. Good luck

----------------------------------------------------------
"Where do you have your clip set on your needle at carb end of throttle cable?"

I thought it could only go on one way. I really do not know. I always fight that thing trying to get it installed.
I think it is at the end of the spring, where it goes.

 

[Indy420]

UPDATE:

I took my carb apart again and bent the float tabs towards the float even farther this time.
I also put an old plug I bought for my last motorized bicycle in it. It isn't the right plug, it made my last bike run like crap, but it's all I have right now so I used it.
The bike started up a lot easier this time and I rode it for about a mile. It got up to around 30mph. I shut it off a few times and it started right up again. It still seemed to be running rough.
I put the brand new plug that came with the kit back in it to see if it ran, and it wouldn't even start.
I put the junk plug back in it, and it started hard again, but it did start back up.
I think I have a combination of problems here.
#1. The new plug is crap.
#2. The new carb is crap.
I am going to go get a NGK B6HS spark plug tomorrow.
I am also still going to replace the carb when it gets here, either this weekend or Monday.
I think it's going to be fine after I replace those 2 items, because it wasn't running too bad tonight.
I'm sure my spark is fine, my CDI is fine, my plug wire is fine, my magneto is fine, and my fuel is fine. Otherwise it wouldn't have ran like it did tonight. It was still not 100%, but like I said, I am using the wrong plug (NGK B-4L) right now and my floats are still off.

 

[Indy420]

This bike is bad luck... lol

 

[Indy420]

Indy, I think changing your gas out is a excellent idea. Get that ratio up there and i think you will have a lot more fun. 20:1 is still really thick even for breaking in but that's just my thought.

One more question, Where do you have your clip set on your needle at carb end of throttle cable?

OH, and what kind of oil are you using?

It would be really cool if it is something simple and you don't need all that stuff. Good luck

BTW... I have no clue what oil I'm using. Just some junk my buddy gave me that he had lying in his garage.
I am buying new gas and oil tomorrow and I'll get the best oil Walmart has to offer.

 

[Indy420]

Indy, I think changing your gas out is a excellent idea. Get that ratio up there and i think you will have a lot more fun. 20:1 is still really thick even for breaking in but that's just my thought.

One more question, Where do you have your clip set on your needle at carb end of throttle cable?

OH, and what kind of oil are you using?

It would be really cool if it is something simple and you don't need all that stuff. Good luck

I just watched a video about this from BikeBerry.com. I had no idea you could move that clip....lol
I don't know where it's at. It's wherever the factory set it.

 

[Chaz]

I have to agree with Skitchfish here. The mix you have is pretty thick. I've been reading these threads heavily for a few years now and the guys who I'd consider to be experts agree that 32:1 is fine for break in. It's more how you break it in. Lots of threads to read on breaking in. If you used a heavy mix in the past and it worked fine that is not a surprise as these engines are not all created equally. Maybe your previous engine had a bit more spark.

Good you found the needle clip adjustment. Second slot from the top is considered a good starting point.

And, yes, it's a good idea to use some fresh oil and gas. You can also close the gap down a bit on the spark plug. That could help with starting and running as well.

 

[Indy420]

UPDATE:

This engine is junk!
I installed a brand new carb today.
I installed brand new fuel line.
I installed a brand new NGK B6HS spark plug today.
I drained out my tank AGAIN, cleaned it, made sure petcock was flowing good, and I put in brand new premium gas with the best 2 stroke oil Walmart had and mixed it at 24:1
I took it out for a spin and it started right up. I rode it around for about 3 miles.
Shut it off and it never started back up again.
I loosened up exhaust bolts to make sure my exhaust wasn't restricting my air flow, it changed NOTHING.
I walked a mile home with it and stopped at a local garage that works on motorcycles and cars and the guys there loved the thing and started helping me right away.
They checked everything they could and they couldn't even tell me what was wrong with it. I didn't have the diagrams with me for them to check the magneto or the CDI so they didn't know what it was suppose to be set at. They played with the floats, the adjusted the clip in the throttle spring, they checked for vacuum leaks, they tightened down the head bolts and a few other case bolts, they checked the magneto to see if it was wet, and they couldn't figure it out either. I gave the man $10 for 2 hours of work and I pushed the bike home.
The only thing left to replace or check is the magneto, the CDI, and the spark plug wire.
I should be receiving all those in the mail tomorrow.
If those parts do not fix it, I'm done. I'm sending the engine back before my warranty is up and having a whole new kit sent to me. This is total BS!
I'll never buy from this clown again. A brand new engine shouldn't be a nightmare.

 

[Indy420]

Oh,,, and it's "4 stroking" too.
What a joke!