i recently tore apart the ride and noticed that there was tranny oil in the bottom of the crank, anybody know what seal could be bad and causing this, also does anyone know what happens when u use too little octane with a head milled down?
OIL IN THE CRANK
- Thread starter blasterfreek30
- Start date
hey i have a piston that i will take a picture of and u can see what happened when it was ran on too low octane
ohh but what will happen is ur piston won't be getting lubricated right because low octane gas detonates easier, the higher octane dectonates slower
B
blasterpro
Guest
kablooey thats what happens with premature detonation, or more commonly known as pre-ignition, if you could retard/advance your timing you could affectively reverse this problem but then you kinda lose the benefit of higher compression from the head mill ( what would be the point, huh? ) anyways just run the higher octane ( i know gas prices are getting steep 
) and as far as the tranny oil in the crank, correct me if im wrong but isn't that how it gets lubricated? piston is by gas/oil mix but the in the cases is by clutch fluid ( i think 
)
) and as far as the tranny oil in the crank, correct me if im wrong but isn't that how it gets lubricated? piston is by gas/oil mix but the in the cases is by clutch fluid ( i think )
i have tranny fliud in the crank area which is sealed off from the tranny, and yes it does get lubricated through the gas/ oil mix
well i pretty sure someone else can chime in hear and help out but i could've sworn the crank was lubed by the tranny oil maybe not tho...
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tranny oil is only in the tranny. The oil from your pre mix or injection is what lubricates the crank. If you take the cylinder off you will see the piston and piston rod. The rod is connected to the crank. If you look down in the cases you will see the crank. There should be no way tranny oil can get into the crank. They are two completly different sealed compartments, with no connections between them. Maybe the yamabond (gasket sealer) has a small void between where the cases seals and it in forcing tranny oil into the crank case
OK lets get this sh*t straight!
"DETONATION" and "PREIGNITION" are not!, never have been!, and never will be the same thing!!!
A fuels "octain" rating is it's RESISTANCE to burning, the higher the octain the harder it is to ignite and the slower it burns, higher compression engines need higher octain fuel because of the compression pressure, the higher the pressure the HOTTER the air fuel mixture gets, if it's hotter it'll burn faster, you want "PEAK" burn to occur at a few degrees before TDC (top dead center) and fallow threw a few degrees after TDC, this is where ignition timing comes in, it set to make this event occur at the optimal time.
So basically detonation is fuel that reaches peak burn BEFORE the piston reaches TDC, so the piston, crank and rod have to fight the force rather than use it!, it usually breaks ring lands and piston crowns!
Preignition is when the air/fuel mixture gets ignited by a source other than the spark plug, usually a sharp edge or a carbon deposit that's glowing enough to touch off the mixture.
Both are BAD!
As for the oil in the crank case, FastLANE got it close, the seal on the crank could also be worn out, the vacuum from the crank case could be pulling tranny oil into the case thrue the worn seal!?, make sure the vent hose is not pinched or plugged?
"DETONATION" and "PREIGNITION" are not!, never have been!, and never will be the same thing!!!
A fuels "octain" rating is it's RESISTANCE to burning, the higher the octain the harder it is to ignite and the slower it burns, higher compression engines need higher octain fuel because of the compression pressure, the higher the pressure the HOTTER the air fuel mixture gets, if it's hotter it'll burn faster, you want "PEAK" burn to occur at a few degrees before TDC (top dead center) and fallow threw a few degrees after TDC, this is where ignition timing comes in, it set to make this event occur at the optimal time.
So basically detonation is fuel that reaches peak burn BEFORE the piston reaches TDC, so the piston, crank and rod have to fight the force rather than use it!, it usually breaks ring lands and piston crowns!
Preignition is when the air/fuel mixture gets ignited by a source other than the spark plug, usually a sharp edge or a carbon deposit that's glowing enough to touch off the mixture.
Both are BAD!
As for the oil in the crank case, FastLANE got it close, the seal on the crank could also be worn out, the vacuum from the crank case could be pulling tranny oil into the case thrue the worn seal!?, make sure the vent hose is not pinched or plugged?
yeah i understand that preignition and detonation are not the same but the term "premature detonation" had me cornfused...my bad if i mislead anyone...as far as the crank being lubed by the oil/gas mix, not the tranny fluid i do stand corrected, thanks i mustve been having a blond moment
lol, regal is right with the kablooey, but retarding ignition timing will not always fix the problem. premature detonation is cuased by the gas/air being too compressed and it spontaneously combusts. although if this happens it's kinda to late to try to retard the ignition to fix it (which it won't b/c the spark plug is not what is igniting it.)
retarding timing only fixes it if too advanced timing was the problem in the first place. when its ignited a little prematurely the pressure wave begins to hit the piston while it is still traveling up. retard it a little, so the wave hits the piston going down or when it is at the top.
with too low octane and spontaneous combustion, the combustion is pretty much done before the piston even gets to the top. so if the piston being pushed up really hard by the crank but being pushed down really hard by the gasses, somethings gonna break. usually either piston or rod.
retarding timing only fixes it if too advanced timing was the problem in the first place. when its ignited a little prematurely the pressure wave begins to hit the piston while it is still traveling up. retard it a little, so the wave hits the piston going down or when it is at the top.
with too low octane and spontaneous combustion, the combustion is pretty much done before the piston even gets to the top. so if the piston being pushed up really hard by the crank but being pushed down really hard by the gasses, somethings gonna break. usually either piston or rod.
well i found what seal was the problem, a leaking right side crankcase seal will allow oil to be drawn into the crankcase, so the case does not have to be split in order to change this seal, just the primary drive gear,and thanx to battbike for bringing over the clymers manual,( it probably just saved me aton of money and headaches) also thanx for everyones help
