06 cracked head WTF!!

[KrazyKeith]

My intake valves kept needing adjustment like every 2-3 weeks so I just did it and didnt really think anything of it. Well after the last time I realized the one valve was really shot cuz I had to use the smallest shim and It was still a little tight. I figured 1 more ride and I'll pull the head off and put in some ss valves. Well I rode all day and it worked fine, even started good. A couple days later I tried starting it and it didnt wanna go. I finally got her to fire. It was smokin pretty good and some water came out the exhaust. I shut it off and then it wouldnt start again. I noticed the oil was milky and we took the head off and pulled valves out. The ti valves are wasted the one is really bad! A freind took the head and called me a little while ago said he bead blasted it and found a big crack between the intake seats. I had no clue that could happen from bad valves. This really sucks!

[czrider263]

Yeah that sucks! was it a ported head or stock?

[AtvMxRider]

A crack between the valves is cause by heat. Was it running lean?

[lumi]

i have seen this before i will get a picture of it if i can find it..... but if u can post a pic.... might be from heat for sure....

if the valves werent adjsuted and too tight might have caused the transfer of heat from the valve to the seat to be too great and overload the seat with heat and transfer threw the head causing serious problems..


but damn, u must have beat it to death or something..... i kno guys on nos not doing that... but u must have had alot of dirt causing bad transfer of heat to the seats and the cupping... bad air filter?



-lumi

[Rich250RRacer]

Originally posted by AtvMxRider
A crack between the valves is cause by heat. Was it running lean?

Could be from heat, but I'll bet he let the original valves beat themselves into the seats for so long, causing the crack.

[lumi]

well photobucket isnt working so, gonna have to wait for the pic from me... the pic i have is from the seat to the sprak plug threads.....

once the head gets a crack or slit crack the coolant passes threw there and u begin to loose collant which makes more heat and at the same time the crack becomes even bigger, but the main culprit is heat.....

how is the head gasket? any coolant loss?

if u think about it if the valve were too tight cuasing so much heat the ti valve seat will expand and react differently comapred to the surrounding material of the head which of caused the crack... just a theory of course....

good luck man

200bucks for a new head not too bad i guess...


btw was the engine ever taken apart before?


-lumi

[KrazyKeith]

no coolant loss
head gasket looked good
engine has never been apart before
got a new head in box for $150
yes I beat the spit of it and will continue to do so

I dont think it was running lean 4th clip on needle w/ a 172 main
Uni filter in good shape