crf250 r 2005 blowing out the side of headgasket??

[merky369]

hi all . im new to the forum and thanks for having me..

ive rebuld my crf 250 r from the ground up as it dropped the big end bearing out on me. anyway i went to start it today and started fine. sounded fine. but when i went to rev the bike putting it under load. i could hear a loud cracking as though there was a blow direct from the exhaust manifold so i looked down the side of the engine to confirm but it was not coming from the exhaust it was spitting out the side of the bore where the headgasket is.... baring in mind a brand new headgasket kit was fitted..

has anyyone seen anything like this before?
do the heads have to be skimmed prior to a new gasket fitted? both surfaces were thouroughly cleaned.....

theres no oil or water leaks ....
no mixing of fluids...

any help would be greatly appreciated

thankyou for reading
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hear the ping? see the smoke? youve been passed, by a two stroke!

[pepperami]

[merky369]

i did get some oil on the coating of the facing of gasket but i wiped all clean before bolting up. i was extremely careful not to nip or crease the gasket.....


hmmmmm???
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hear the ping? see the smoke? youve been passed, by a two stroke!

[jaffa90]

All mating surfaces should be flat, the head warps more, on low revved engines i have used a tile or a glass panel with a sheet of fine ????
(age thing) and rotated the head surface upon it.

[bikenut]

What torque did you torque the cylinder head hold down nuts to ??

A picture of the area of the blowing would also help
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nuts about bikes

[doggone]

Torquing the bolts evenly from each side is important, it shouldn't need skimming unless perhaps it somehow got very hot beforehand.
I can't see that happening on a bike though, more likely on cars, trucks, tractors with drivers good at ignoring developing issues.

[merky369]

39nm on each head nut. in criss cross formation taking 3 or 4 steps to reach desired setting.

heres a pic of where blow is . im pointing to it with my feelers. litereally if im on the rev fire is coming out lol.
____________________
hear the ping? see the smoke? youve been passed, by a two stroke!

[bikenut]

Nice green oe gaskets, you see flame coming from there??

cmsnl not toooo clear but is there a dowel on the rear head stud area on that side??

If flame coming out then either head and gasket not nipped enough or gasket damaged, may be warpage but did bike overheat in the past??

https://images.cmsnl.com/img/products/gasketcylinder-h_big12251KRN731-01_1b1f.jpg

This one yours form cmsnl list ?

When cold re torque and run again, else its head off and examine more closely.

If there is a dowel on that side, is it sitting in the holes deep enough or is it "bottoming" and or "topping" before enough nip between head and barrel for some reason?

Gasket looks as if it may be a laminated steel or metal type ? It would be very very difficult to fit upsidedown or the wrong way round.
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nuts about bikes

[merky369]

flame is coming from head gasket. directly where i am pointing the feeler gauge..

ill take your advice and double check tourque.

if same ill rip head off and get more pics see what you guys think?

thanks for input so far much appreciated
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hear the ping? see the smoke? youve been passed, by a two stroke!

[Robby]

Well something is wrong. You're only going to diagnose it from taking it apart and looking.

It could be an easy problem - head gasket was bent or broken, mating surfaces weren't clean enough (I really, really hate cleaning mating surfaces). It could be a bigger problem, like a warped head. Easy to check - put it on a sheet of glass and measure with feeler gauges.

Of course, to split flames out the side, it needs to be quite a big hole. Not something as simple as using the wrong torque settings.

[merky369]

seems head werent touqued down enough. destoryed head gasket in process. what using a crap torque wrench gets ya !

anyway sorted that issue and fell into another. thanks for the input guys
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hear the ping? see the smoke? youve been passed, by a two stroke!

[bikenut]

Good tools always helps as does the correct torque values. Always a good idea to check torque after an engine run and allowed to cool right down, except for the modern dam stretch bolts.
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nuts about bikes