Sticking it

spincycle

Member
While under yellow the other night, motor abruptly died and subsequently would not refire, first year with 2 cycles, i assume if i "stuck it" the motor would not turn over? egt was showing normal temps, spark plug looked a touch wet but not black, "wet line" on exhaust looked a little wetter than what ive experienced so far....would it be safe to pull the plug out and spin the motor to check fir spark (dont want a bunch of raw fuel to come out spark plug hole and catch the sparking plug)....thanks for any help, suggestions....🙂
 
If you stuck it there usually won't be any compression. I bet it is something else. It's really hard to stick it at low throttle or blipping the gas. Feel how it spins over by hand. If it feels OK spin it with the starter. My bet is no gas or no spark or something broke.
 

bpr

Member
More than likely you just fouled the plug. Yamaha's ignition isn't the most powerful and a lot of times the plug will foul under those conditions. Just install a new plug and try it.
 

spincycle

Member
More than likely you just fouled the plug. Yamaha's ignition isn't the most powerful and a lot of times the plug will foul under those conditions. Just install a new plug and try it.
its a dual carb open sudam 131 on alcohol...its got a selectra (sp?) ignition coil on it...will have time on Wednesday this week to look at things much closer....THX!
 
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sundog

Member
Check your wires and the ground connection if a new plug don't work. Also maybe check if the crank seals are still in.
 

flattop1

Dawg 89
everything I ever stuck was either full song to dead stop or immediate loss of power .
Hilton may have the good reeds.
 
If Under caution, I'd bet it fouled a plug. They foul and die very fast. If you stuck it you would know it! They "sing" real well right before!
 

rainman

Premium User
I would 1st check if you have spark. If you do change plug or check reeds, and go through carb and check for dirt on screen and check diaphragm and replace it if it feels to stiff and not flexible as it should be.
 
I was breaking in a new engine at the track one day, just putting around, and it stuck. Strange. Clean the piston up, clean the rings up, went out and tried it again. Same thing. Very very strange. Back in the pits, as I was again doing the same thing, it came to me what the problem was, I forgot to put oil in the fuel. Dumb dumb dumb. I can't think of any other reason, (assuming the engine was assembled correctly and there are no air leaks, no carburetor problems and no reed problems) an engine would stick while just putting around. The engine did not lock up. It was a very light stick. I have had plugs foul during lineups. Sometimes those plugs looked no different at all. There have been occasions when, after having run a heat, when we tried to start the engine for the next heat, it would not fire. As we always came to the starting grid with a new plug and a plug ranch, change the plug, off we go.
 

x3m

Member
quickest easiest is to pull the pipe off and look at the back of the piston, you'll know if it stuck. if the piston looks good, put pipe back on, check spark with a new plug, if you have spark try to start, if it don't run pull the carb and look for broken reeds, only take about 15mins to narrow it down.
 
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Don K

Member
If you can't pull the head and look to see if it has crap on the cylinder, like Pete said, just pull the motor and send it to him to look for you. Screw all the other baloney on this thread.

DK
 

spincycle

Member
I went ahead and pulled the carb tonight, reeds look fine, pulled the head and cylinder off, there is some scoring on the cylinder wall at the point where the hole in the piston is for the wrist pin, piston itself looks fine, except for some "dings" across the top that faces the combustion chamber. one thing that stood out, the head bolts didn't seem like they had much "torque tightness" on them when I loosened them, and there was a little of dirty oil/fuel all around where the head and cylinder come together, like maybe the head bolts were loose? What would be the proper torque on the head bolts when I put it back together? I don't have a spare coil and any spark plugs to check those things next, where can I find a coil and a few plugs? Thanks for all your help, ive learned a lot! :)
 

spincycle

Member
if piston rings were wore down to the point it wouldn't allow enough compression for the motor to start, how could that be checked?
 
I went ahead and pulled the carb tonight, reeds look fine, pulled the head and cylinder off, there is some scoring on the cylinder wall at the point where the hole in the piston is for the wrist pin, piston itself looks fine, except for some "dings" across the top that faces the combustion chamber. one thing that stood out, the head bolts didn't seem like they had much "torque tightness" on them when I loosened them, and there was a little of dirty oil/fuel all around where the head and cylinder come together, like maybe the head bolts were loose? What would be the proper torque on the head bolts when I put it back together? I don't have a spare coil and any spark plugs to check those things next, where can I find a coil and a few plugs? Thanks for all your help, ive learned a lot! :)
Pictures are very helpful.

Brian #89
 
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