What could have caused this engine problem?

[400exBro]

This past weekend I decided to rip into my 04 Honda's engine to replace the rings because I felt it was lacking a lot of power. When we pulled the top end off I noticed that the piston was severely discolored which I can relate the discoloration to the time I boiled it over during a moto. We then pulled the wrist pin out and noticed that the wrist pin was also scored, but only on one side of the engine, this caused wear onto the connecting rod. As well on the same side, the crankshaft was discolored to a blackish color. The cylinder walls are still fine, can see all the OEM cross hatching, has a few scuffs from when I cracked my connecting rod.

So I was wondering what could have caused this to happen? Why did my wrist pin score and cause abnormal wear on to the connecting rod? And why did it only happen on one side of the engine and not the other? (it occured opposite to the oil jet)

I will attach some pictures to help you guys get a better idea.

[400exBro]

crank

[400exBro]

piston

[400exBro]

wrist pin and piston

[400exBro]

Looks like implosion? maybe water in the fuel causing these indents in the piston and head?

Are you sure the right side crank gearing isn't going bad. If I were you would split the cases and check to see if the crank hasn't started to dig into the right side case. It slowly shaves down the side of the case putting metal throughout the engine.

[400exBro]

Bump

We did not find any traces of metal through out the oil, We will pull the clutch cover and everything off and see if we can find anything wrong on that side as well...

Any other suggestions ?

[chad502ex]

I'd say that all your problems are due to that piston! :devil:

Good luck.;)

Originally posted by chad502ex
I'd say all your problems are due to that piston!:devil:

Originally posted by chad502ex
I'd say all your problems are due to that piston!:devil:

Originally posted by chad502ex
I'd say all your problems are due to that piston!:devil:

Originally posted by chad502ex
I'd say all your problems are due to that piston!:devil:

Originally posted by chad502ex
I'd say all your problems are due to that piston!:devil:

So are you trying to say it was the piston? LOL!!

[chad502ex]

Originally posted by TRX450R_Racer
So are you trying to say it was the piston? LOL!!

LOL!!! That was funny...

something wrong with the posting huh? LOL!!!

hehe...

[Jersey450R]

maybe the piston?

[tchonda426ex]

I had this happen to me but my crank wasnt colored that bad. My mechanic told me that it was from over heating the bike.

[chad502ex]

ok, here's my thoughts.....

actually, I was blaming the piston believe it or not,.... too bad for venom... hehe

:devil:

looking at all the oil deposits on top of the piston dome its no wonder that you felt a power lost.... oil on top of the piston dome is real bad.... I can see it all over, even in the squish areas of the piston... the squish areas is crutial for cooling the piston.... unburned oil deposits is all over...

It seems to me that the problem originated from the lateral gas porting pulling oil up around the back side of the compression ring onto the top of the piston. Usually when the compression ring lifts off the ring landing, oil is pulled from vaccuum underneath the compression ring up thru the lateral gas ports, up and over the anti-detonation grooves, into the valve pocket reliefs and all over the dome as evident in the picture.... Look at the oil burn marks how it trails upward from the pistons lateral gas port...

BINGO!

Once the compression ring is no longer seated into the ring landings caused from burned oil deposits, power loss falls off substantially..

[quadgod440ex]

Originally posted by chad502ex
ok, here's my thoughts.....

actually, I was blaming the piston believe it or not,.... too bad for venom... hehe

:devil:

looking at all the oil deposits on top of the piston dome its no wonder that you felt a power lost.... oil on top of the piston dome is real bad.... I can see it all over, even in the squish areas of the piston... the squish areas is crutial for cooling the piston.... unburned oil deposits is all over...

It seems to me that the problem originated from the lateral gas porting pulling oil up around the back side of the compression ring onto the top of the piston. Usually when the compression ring lifts off the ring landing, oil is pulled from vaccuum underneath the compression ring up thru the lateral gas ports, up and over the anti-detonation grooves, into the valve pocket reliefs and all over the dome as evident in the picture.... Look at the oil burn marks how it trails upward from the pistons lateral gas port...

BINGO!

Once the compression ring is no longer seated into the ring landings caused from burned oil deposits, power loss falls off substantially..

Yea what chad said!

[400exBro]

SOB :mad:

well i guess you live and you learn... last time i will deal with them.

Going to go back with the JE 12.1:1 piston because this engine is going to by my practice machine now.

Do you think the crank is still fine? or would I be better off buying a brand new crank assembly with bearings? I just put that crank and bearings in this Summer...

crap

[pro-rider46]

Originally posted by 400exBro
SOB :mad:

well i guess you live and you learn... last time i will deal with them.

Going to go back with the JE 12.1:1 piston because this engine is going to by my practice machine now.

Do you think the crank is still fine? or would I be better off buying a brand new crank assembly with bearings? I just put that crank and bearings in this Summer...

crap

idk about the crank, but chad502ex has some of his own pistons that really are awesome. ask him about it, hes got what ever you need.