srxman06
New member
Lost my center cylinder when i was riding on sunday. took off the head and found damage to the top of the piston,pulled the jug off and found that the ring broke and ruined the piston and jug. Any ideas what caused this? Carbs were cleaned at the begining of the season and put about 200 miles on with no problems. Did notice that the oil injection cable was pulled apart and stuck extended and i went through about a qt of oil in 40miles 
motorhead327
VIP Member
Thats probably what caused it. Too much oil means less fuel and leaned it out.
midwestoffroad
New member
yep to much oil would be my guess as well, shooting you a pm
YAMMIEGOD3:16
Active member
NEVER EVER SEEN A RING BREAK BECAUSE OF TOO MUCH OIL ? HOW CAN THE MOTOR GO LEAN THAN. RING WAS CAUGHT ON SOMETHING AND SNAPED. PROBLEY INSTALLED WRONG. I HAVE SEEN THAT HAPPEN. 3:16 (yammie tony)
ring failed went the top of the piston burn down to it then it seize and broke and ................................... nice cylinder job it does lolll
X2.... the amount of oil shouldn't affect the fuel charge.
snopax said:
yes it does effect .........oil doesnt cool down the piston
Fuel doesn't technically cool a cylinder... A richer fuel mixture burns cooler, but that is about it. Oil is about as effective as fuel at cooling a piston / cylinder walls. Additional oil in the A/F mixture is not going to cause you to run lean, unless the additional oil is replacing fuel in the mix and driving the ratio of O2 to fuel up.
fuel does cool down the piston crown ,,,thats why if it run leaner it will melt ...oil lubrifcate the crank and piston but doesnt do nothing about cooling the piston..... .
It melts when lean because the charge burns hotter.
http://en.wikipedia.org/wiki/Air-fuel_ratio
Fuel cooling a piston is a layman's term and is a way of achieving the same result, although the understanding of the "cooling" method is extremely skewed. The additional fuel in the charge is a cooler burn. The fuel itself, as posted above, has no more of a cooling capacity then the atomized oil in the charge.
http://en.wikipedia.org/wiki/Air-fuel_ratio
Fuel cooling a piston is a layman's term and is a way of achieving the same result, although the understanding of the "cooling" method is extremely skewed. The additional fuel in the charge is a cooler burn. The fuel itself, as posted above, has no more of a cooling capacity then the atomized oil in the charge.
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cause the gaz cool down i know its because of air fuel ratio but the oil can do what gaz do .................................. try to add oil and remove gaz u will not decrease the exhaust temp ........
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Like i said "Unless the oil displaces fuel" in the mixture.
Like i said "Unless the oil displaces fuel" in the mixture.
so verdict is ..he probably run lean for some reason burn top piston till it burn to ring and then seize ring and ...........
Pull carbs and check,, could have picked up some crap from tank... Check carb boots,(air leak) as they are now 10 years old,,, reeds also..... find potential cause so that it doesn't happen again once rebuild is complete..... Let us know what if anything you find.......
motor tech
New member
you are right sno pax glad you posted that to clear up the misconception that most have. modsrx a ring breaking DOES NOT ALWAYS COME FROM A LEAN BURN, MOST OF THE TIME IF THE PISTON IS MELTING AWAY, AS THIS IS HAPPENING THE RING IS BEING HEATED TOO, WHICH IS MAKING IT FLEXABLE, MOST MELTDOWNS IVE SEEN THE RINGS ARE THERE BUT THE PISTON IS MELTED AWAY! srxman 06 it could be a flawed ring, you could break or lose the locating pin, you could have detinated at one time, the ring is hard and brittle in a way, if you dont use the right tool (IT EQUALIZES THE PREASURE AS YOU EXPAND THEM, NOT ONE POINT LIKE BY HAND) to put them on you (could) fracture them. is the piston melted smoothly flowing away from top of the ring? if not then the ring broke first.
srxman06
New member
That would do it...
no1chevyboy
New member
looks like intake right side? are all locating pins there? not a lean problem, ring failure or ring pin failure, looks like bottom ring may have gone first.
srxman06
New member
only a small chunk of ring was gone from the top ring. The rest of the rings were still on the piston. Do you think that loose boot from the back side of the carb had anything to do with it?
no1chevyboy
New member
me personally no, the top ring had a piece missing? how did you get the second ring off with the score filling the ring groove without removing it? i have never seen the diaganol gouges on the side either, sorry cant help ya as to why.
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