2 stroke won't start/stay running

[MitchP]

I have a Grubee GT5. Using 87 octane fuel w/ 10% ethanol (I live in Cali) and redline 2 stroke oil. NT carb. 20:1/exact measurement

The problem I am having is that the bike has been starting less and less. At first it wouldn't then I got the tip to remove the cap on the exhaust. And it worked, and that's how she's been running since I got it. I put a 2-quarter inch holes in the cap to relieve the back pressure. These are just the things I have done.

A week ago it started OK. Then after a bit it would sputter while running. Like the motor would lurch and then try to quit. It's gotten worse to the point that the bike will just not start. It may make the crackle/pop of the exhaust igniting and might even start but it dies immediately. Won't idle either.

I've been good about shutting off the fuel when she's parked.

Some notes-

-Taking the cap off today I noticed oil in the exhaust tube. Like it's oil, not burnt
but I can rub it between my fingers.

-There is burnt oil/gas coming from the spark plug. It's running down the head. I'm sure because I looked in that space between the head and the (piston wall?)
And it was clean. I tightened it a little.

-I torqued down the head also to about 8lbs pressure with wrench doo-higgy.

-I undid the carb to clean up the cables. Is there something I botched? I will check anyways.

It's cold. Usually 40-50 degrees if it's not raining. Today I was off to Ace to make a cool adjustable flow exhaust cap.

I have an NGK B6 and new plug coming. My general feeling has been a deep sigh.

 

[fatdaddy]

Could be a few things Mitch. (Just looked at yer link,) I would say see what a new spark plug does. But while yer waiting, pull the bowl off, unscrew the jet tube, take the jet off off that, and make real sure there's nothing clogging it. I say this because you didn't say anything about checking any of this. A clogged jet is the first thing to check. If the bowl is filling with fuel, then I would check the jet and tube. If thats all clear get back here and we'll go down on the check list.
fatdaddy.
You make that old saying of mine look good.
IT'S YOUR BIKE, BUILD IT YOUR WAY.

 

[JonnyR]

will it run without the endcap? the muffler might be clogged

 

[fatdaddy]

will it run without the endcap? the muffler might be clogged

The endcap/baffle is not usually where it clogs up. If you've ever taken a PooPoo pipe apart, you know that there's a honeycomb baffle way up inside connected to the inlet tube of the pipe. If it's clogged, It's probably clogged there, and I personally don't know how to clear that. (solvent maybe?)
But yeah, yanking the end baffle unrestricts the pipe some. In fact, I take old PooPoo pipes and cut them down, leaving the honycomb for some back pressure, and run my bikes on them. I use old ones because the honycomb DOES clog some, and that gives me enough back pressure. See post#4559 for a pic of it.
http://motorbicycling.com/showthread.php?t=24753&page=456
fatdaddy.

 

[JonnyR]

sloshing gas around in it works or carb cleaner anything tthat breaks the oil down and flushes it out some people stick the black one in a fire to burn it out but yea a solvent works on them i just wanted to see if it was to much back pressure first not having the end reduces it alot and some of the oil might just blow out when you start it like a giant snot

 

[fatdaddy]

sloshing gas around in it works or carb cleaner anything tthat breaks the oil down and flushes it out some people stick the black one in a fire to burn it out but yea a solvent works on them i just wanted to see if it was to much back pressure first not having the end reduces it alot and some of the oil might just blow out when you start it like a giant snot

If it was like snot, ( I like the analogy,) It would prolly blow out, end cap or not. If it's burned hard in it, then I guess you could soak it in whatever.
But before we get too deep into pipes and crap, let Mitch try just cleaning his jet and tube. I'm guessing it clogged little by little and thats why it would only kinda run and went downhill from there. If it's getting fuel, air and spark it WILL run. Lose even one of those and she quits.
fatdaddy.

 

[MitchP]

So the plug and boot came today. I meant to replace the plug and then try. But I stupidly ripped the boot out by the end on the CDI and screwed the new one on. Did not follow norm's guide so idk if it's sparking. Fuhhhhh. There is crap/fouling on the old plug.

To compliment this I had to ride my bike just under 20 miles today where a week ago I was hoping I could go everywhere on this MB. No dice so far.

 

[fatdaddy]

So the plug and boot came today. I meant to replace the plug and then try. But I stupidly ripped the boot out by the end on the CDI and screwed the new one on. Did not follow norm's guide so idk if it's sparking. Fuhhhhh. There is crap/fouling on the old plug.

To compliment this I had to ride my bike just under 20 miles today where a week ago I was hoping I could go everywhere on this MB. No dice so far.

Hold the plug against the motor and give it a kick. use an insulator to hold it or you'll get a shock. You might need to get a neighbor kid to help hold up the back of the bike. I can do it myself but it ain't easy. Look for a good bright spark.
If the plug is fouled that bad you might be running too heavy on the oil, or you might have a coil or CDI getting weak and not producing a hot enough spark.
Replace the plug and wire, yank out that restrictive end cap/baffle, run it and see what happens.
fatdaddy

 

[MitchP]

I installed like this one here, the pooch may not have been screwed. I think there may be too much oil? there is black fouling on the piston head and plug. I think the failure to start is because the crap was insulating the spark.

http://www.motoredbikes.com/showthread.php?4940-Spark-Plug-Wire-Replacement-pic

So I'll have a picture later,

Is it too much air from the choke or too much oil?

 

[MitchP]

There is a (weak?) spark between the head bolts and the plug. Definitely is not a compression issue. How strong should the spark look?

All it does it make a putting sound when I go to pedal it.

 

[fatdaddy]

I installed like this one here, the pooch may not have been screwed. I think there may be too much oil? there is black fouling on the piston head and plug. I think the failure to start is because the crap was insulating the spark.

http://www.motoredbikes.com/showthread.php?4940-Spark-Plug-Wire-Replacement-pic

So I'll have a picture later,

Is it too much air from the choke or too much oil?

Thanks for the link Mitch, but most of us got that covered.
If your plug was fouled then your not burning the fuel in the cylinder properly. If changing the plug and wire didn't fix the problem then obviously that wasn't the problem. And, You can use A LOT of oil and it will still run. On break in on the real, real cheap engines I've gone as high as 8oz per gallon. It smokes some but the plug still comes out tan. I'm starting to think you have a coil gone bad. If you're using the white wire for the kill switch then it's even more likely. You said you were getting spark between the plug and the head bolt? If you hold the outside metal part of the plug against a head bolt, you should see the spark at the electrode of the plug, not between the plug and engine.
I'm betting it's a weak spark, Bad coil. That has fooled me a couple of times. You can get a spark at the plug and think everything is fine, but try to start it and it KINDA wants to start, but wont. I'm betting COIL.
http://www.ebay.com/itm/Magneto-Coi...Parts_Accessories&hash=item4d021f2602&vxp=mtr
fatdaddy.

 

[MitchP]

The kill switch is not plugged in. It's wrapped around the handlebars for now.
The white wire is just hanging, not capped but not installed anywhere.

Is there a way to test the coil?

PS, there was no plug activity unless it was near metal, and in that case I don't think it was arcing to the motor. I will be tearing apart the carb at sunrise tomorrow. Then check fuel line.

 

[fatdaddy]

Yeah, check all that stuff while you wait for your new coil to arrive.
The plug will not spark AT ALL unless grounded to something. It wont spark by simply putting it in the plug wire boot and holding it in the air. The metal side of the spark plug has to be against the engine or the likes. THEN you can see if the electrode is firing. BUT, the way you described everything, I'm betting on a bad coil.
fatdaddy.

 

[MitchP]

So my dad is now involved and he is convinced it is the carb. Even if the carb was tuned like **** by a monkey, wouldn't the bike at least start?

 

[fatdaddy]

So my dad is now involved and he is convinced it is the carb. Even if the carb was tuned like **** by a monkey, wouldn't the bike at least start?

Yeah, It would at least POP. UNLESS the jet was TOTALLY plugged or your float needle was TOTALLY stuck shut or plugged. Before you let yer dad tear the carb apart, try just dumping a little fuel down the throat of the carb. If it is the carb AT ALL, this will bypass any problems and you should get it to POP a little. If it don't POP a little, then it's not the carb.
You don't have to tear the carb APART to check either of these things, just the float bowl. If yer good you don't even have to take the carb off the bike. Remove the float bowl, usually only two screws. The float will drop out with it. Then, VERY GENTLY, put a wrench on the jet at the bottom of the jet tube, (I think it's an 8mm, but may be smaller.) Unscrew the jet and hold it to the light. If it's plugged you will probably see it. Hold it TIGHT, (don't wanna lose it,) and blow it out anyway. NEXT, blow out the jet tube. Take off the top carb slide and needle (throttle,) assembly to do this. This will take care of any plug's or problems there. (Screw the jet back on.)
NEXT, See where your fuel line hooks to the carb? Remove the fuel line and unscrew the fitting. When you get it off you will see the float needle in the hole. The other end of this fitting is the needle seat. This is your gas shut off for the float bowl. If this fitting is plugged you will get NO GAS to the bowl. Check it in the light, blow it out anyway.
----BE VERY CAREFULL PUTTING IT BACK ON.----
Make VERY sure the needle is centered back into the fitting before screwing it back in.
This is the easy way. You don't have to tear apart the float, float pin and float needle and take a chance of dropping very small parts under the bench. The only small part yer dealing with is the jet.
These carbs are pretty simple and very little can go wrong with them. Clean the jet and float needle as I described, adjust the float and yer DONE. If it don't POP now, it wasn't the carb.
Did you order the coil yet?
Let me ask you this. If you peddal the HE!! out of it, get it going as fast as you possibly can before letting out the clutch, Does it ACT like it wants to start? Just BARELY a little ALMOST POP, but not quite? IF SO, IT'S THE COIL. But try the carb cleaning first, That won't cost you $12 with FREE shipping.
fatdaddy.
Propably not, but could also be a bad CDI. They don't go bad as often as the COIL.
If it's NOT the COIL, I will say sorry for all the.

 

[MitchP]

IT WAS OUT OF GAS

 

[DIANY]

thats the 1st thing you check!!!!! lol i was gonna say too much oil... figured it to be a fuel problem..20:1 is a bit rich (unless your still breaking it in).. try 32:1... still plenty of oil....AND OIL IS MORE EXPENSIVE THAN THE GAS IF YOUR RUNNING IT THAT RICH...

 

[maniac57]

I always carry a spare plug. Sounds to me like a partially fouled plug. If new plug does not fix it, I'd look at the mag coil.

 

[BikeBerryJen]

IT WAS OUT OF GAS

I read this WHOLE post and was about to respond when I came across this. This made me laugh out loud and caused my coworkers to look at my strangely. Well played MitchP!

 

[fatdaddy]

OK, It wasn't the COIL. SORRY, SORRY, SORRY about all the . But C'mon dude, Thats the FIRST thing to check. So I'm gonna do it to you again. just for another reason this time. .
Good one bro, ya got me .
fatdaddy.