New piston small end bearings and rings!

Rcannon

~SPONSOR~
Nov 17, 2001
1,886
0
Ok, I get the top end problems. That crank looks very discolored as well. Lack of oil???
 

96717

Member
Sep 23, 2002
41
0
to find out if u have been useing enough oil is to let the motor rest. then spin the crank useing the rod, and see if there is oil on there. if there isnt oil then make sure u change your gas mixture leaner. (more oil less gas) sorry if it doesnt make sence, let me know if u dont understand.
 

Rcannon

~SPONSOR~
Nov 17, 2001
1,886
0
96717, is this what a crank would look like if a person tried to run 100:1 or something like that? Would it look different if it were just lean jetting???
 

langston7

Member
Jul 27, 2002
66
0
we found out we running like 25:1 the performance of this bike was always crap so we leaned it out to 50:1 then after a year..this is what we ended up with


but it hasnt ever had a piston changed ...weve used it for about 70 hours on that piston and i dunno how many hours the last person used it on..
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
The piston has alot of blowby-not surprising really-the big end looks like its about to seize-that blue on the crank is scary-i would get a new rod kit/main bearings/seals/top end and have the cylinder checked to see if the plating is ok.
 

Glitch

~SPONSOR~
Dec 3, 2001
630
0
limitless, not when you are comparing gas to air ratio, like what I think 96717 was comparing.
 

Luft

Member
Dec 24, 2002
105
0
What brand oil have you been mixing at 50:1? I'm not selling anyones oil, it's good to know what happens in the real world with different brands. 32:1 is actually leaner than 40:1 because more oil is used in 32:1 and the oil does not burn. It lubricates and is blown out the exhaust. If the sparkplug and combustion chamber temp are not hot enough the oil is not vaporized and stays liquid through the exhaust and out the back of the pipe.
 

A-RustyDemon

~SPONSOR~
Dec 9, 2002
152
0
Leaner.. On oil yes 50:1 has less oil then 32:1. But on the other hand it's making your fuel-air mixture richer. Give that the volume of a cylinder is constant at BDC (Bottom Dead Center) .. with the same jetting the air density being equal.. The cylinder with the 50:1 ratio will have more fuel to air (richer) then the same cylinder exact cylinder with the 32:1 ratio pumped in to it(leaner). The amount of oil that is needed to lubricate the bearings is effected by the load excreted on the motor. Some one that is slow trail riding will not need as much oil as the same guy that rails the local track. Then you get into the whole natural Vs. synthetic thing but that a entirely new/old thread.... Hope that helps some. It's a widely misunderstood concept in the whole lean/rich jargon on 2-strokes. ;)
 

MikeyG

Mod Ban
Nov 28, 2002
100
0
Mix at AT LEAST 32:1. 50:1 will kill your motor. I'd run 25:1 on that bike, and richen up the jetting.
 
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