Feeling like a Newbie

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2door

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Staff member
Sep 15, 2008
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Littleton, Colorado
How many times have you and I read this? "My engine won't start"?
Look at my post count and join date. In other words, This ain't my first rodeo. I've seen that message countless times. So many times in fact that my eyes sort of glaze over when I see it because I know it is something obvious and all it takes is to analyze the situation and find out if the engine has the three critical components, air fuel and ignition, to run. I don't usually even reply anymore because the answers will be provided by the members to get the newbie on the road. They're so obvious.

Nevertheless, late this afternoon I was going to go for a short ride while dinner was cooking and jumped on my newest bike, it has about 100 miles on it, and took off. This is a Chinese 2 stroke that has some mods but nothing exotic. The engine started before I reached the end of the driveway, as usual, and ran great for about a half mile from home, naturally, all downhill. I came to an intersection, slowed and as I pulled in the clutch, the engine died. Never did that before. It was as if I'd punched the kill switch. It never ran again. Not even a pop. I had to pedal and finally get off and walk that sucker uphill for a half mile to home.

I was pooped and disgusted but came out after dinner and started troubleshooting to find out what the problem is.

Fuel? Yes. Disconnected the fuel line from the carburetor and had good flow from the tank. This is not a new batch of fuel. I've been burning it for over a week. Pulled the float bowl off and the carburetor is getting fuel. The bowl was full.

Ignition? Pulled the plug and laid it against the head and spun the engine. Great spark! Even so I disconnected the kill switch, just to be sure I wasn't seeing an intermittent problem.

Air? Yes, the choke is wide open and nothing blocking the carb throat. Air filter is clean.

Compression? This puppy has a lot. I'm running a new experimental slant plug head from one of our sponsors and it will easily lock up the rear wheel if my speed isn't up before popping the clutch.

It just won't run!

Frustrated I replaced the CDI with a known good one and the magneto coil with a new one. The plug wire and boot are copper core wire with an automotive boot that I know is not the problem. I even put a new NGK plug in just to assure myself that I wasn't seeing a defective plug. I still get good spark, same as before the parts change.

Still, nothing. It will not run!
It is violating all the laws of physics and natural progression.
It has fuel, air, ignition and compression but this little SOB will not start.

I'm tired and don't want to screw with it anymore tonight but tomorrow I WILL find out what's happening, or not happening, and let you know.

This gives me a whole new perspective on the poor guy with little to no mechaincal experience and trying to get his engine to run. I'll be much more tolerant of them in the future; I can assure you.

Tom
 

Desert Rat

New Member
Jul 30, 2012
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Apache Junctoin Az
I had that happen to me when my bike was new.
the clutch cable was not tight enough or to tight, I don't remember now
that was several years ago. maybe the cable slipped a little in the collar.
only thing I can think of, that or it's haunted:) if it is sell it on ebay for a mint!
HAUNTED BICYCLE hahaha
 

2door

Moderator
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Sep 15, 2008
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Littleton, Colorado
And, like a newbie I forgot to mention, the carb is an NT with the main jet soldered and redrilled to .0225 which is almost perfect for my altitude, about 6000 msl.

Tomorrow I'll pull the carburetor apart and see what's what. The plug is a dry grey color which looks normal because I run Opti-2 @ 100:1.

Keep in mind this engine has been running strong and good since day one. Starts almost immediately and has performed well even at the low milage.

Tom
 

Greg58

Well-Known Member
May 1, 2011
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Tom working on one of these things is kinda like bull riding, everything is going well then the dang thing throws you for a loop and sometimes comes back to haunt you.
 

2door

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Sep 15, 2008
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Littleton, Colorado
This is a weird one, Greg. I have a theory but I'm not going out and get gasoline smelly again tonight. I'll check it tomorrow.

As I said, a plug reading isn't accurate because of the odd grey color I typically see with the Opti-2. It's hard to tell if it's wet or dry. I have to think maybe the main jet is plugged with something even though I use an in-line fuel filter. If so, the thing isn't getting fuel to the combustion chamber even though the bowl is full.

I'll let you know what I find.

Tom
 
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maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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Clogged jet is the only thing it could be. Does it spray wet when the plug is out?
Fuel to the carb does not mean fuel to the engine.
 

2door

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Sep 15, 2008
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Littleton, Colorado
One in a million!!!!
I've been around here for a while, read almost every post and thought I'd seen about everything but this I've never seen.

The 'C' clip on the needle broke. That allowed the needle to drop into and block off the main jet. I've seen spring steel snap rings break before in other applications but I've never heard of one of our carb clips breaking. I've installed and moved quite a few over the years and never had one break and certainly not after it was installed and the engine has run for as long as this one has.

My main jets are small because I have to run lean here at this altitude. The needle is bigger after the taper than the orifice in the jet so when the needle dropped it completely plugged the jet. In fact it was stuck in the jet and I had to use a pair of small hemostats to pull it out.

This makes me wonder how many times it might have happened to guys who didn't quite understand how things in the carb work and just replaced the carburetor and went on their way. So I'm asking if anyone has ever seen a 'C' clip (some call them 'E' clips) break? I know they're easy to loose and I had one needle with the grooves not cut deep enough for a good fit, but just breaking in half is new to me.

Tom
 

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CTripps

Active Member
Aug 22, 2011
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Wow, that is.... unique.. Never seen that before, but I'll keep it on my list of things to check when having problems. Glad you got it figured out, and thanks for sharing that. I would never have thought about that clip breaking.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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living the dream in southern california
that's kinda funny. after my post at 2:17am, i was thinking about your problem, going through everything in my mind that i was sure you checked, and i thought, "what would happen if the e clip popped off and the needle dropped into the jet opening?"

that came to me about 4am right before i went to sleep so i didn't post it. (my sleep schedule is ruined because of my shoulder pain...)

i never had that problem before, either, but i've had ruined needles from changing the clip setting so much the brass won't hold it anymore.

this is a good lesson in the process of elimination... :)
 

Greg58

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May 1, 2011
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Newnan,Georgia
Tom I had one nt that would not idle with clip in the top groove, I had to keep the throttle cracked slightly or turn the idle screw all the way in so it ran at around 2k. I never measured the length of the needle, I do still have that carb so I may take a look.
 

2door

Moderator
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Sep 15, 2008
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Littleton, Colorado
Well it was a good learning experience. That's for sure. The bike is running great again and no problems.
But, the question remains: How many times has it happened to a newbie who just replaced the carburetor and never found the real problem?

Maybe not that many when you think about it. I mean, what are the chances that a clip that is essentially under little to no stress snap in half? Darn small, I'd bet.
But then I live under Murphy's Law. It dictates my life. "If something can go wrong, eventually it will". I flew airplanes for Uncle Sam and for a living for a long time. I saw some strange failures during that time too but they were just a little more serious than a motorbike.

Leave it to me to possibly be the first that has experienced this weird-o problem. I'll chalk it up to fate, bad Karma, or just dumb luck. Whatever, it did give me and you guys something to ponder for the last 24 hours.
Baird, I hope you didn't loose any sleep over it. :)

Tom