2stroke head problem???

[gray84]

Hey everyone need a bit of help please..
My step dad has bought a 2001 cr125 to come out with me and we bought it knowing the head was on its way out..
When we got it and ran it it all runs fine but on the ns head gasket it had 1 specific area where a droplet of coolant would trickle out of very slowly.
We took the head and cylinder off and had it skimmed also had new piston ect while it was off.
Anyway we put it all back together using a non genuine Honda gasket and it's the same still a tiny trickle in the same place.
Went and got new studs/nuts and genuine Honda gasket and just put it back together and it's the fucking same lol..
Now it seems to seep from the top part of the gasket as you can see in the pic and video so I'm thinking a pores/cracked head? You can't see any mark AT ALL.
What do you think?

https://i61.photobucket.com/albums/h62/graygti/e62fd5ba.jpg

https://i61.photobucket.com/albums/h62/graygti/th_ee892e65.jpg
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Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[gray84]

Oh and yeh the water does seem to trickle upwards I'm not working hanging upside down.
The vid was taken just as we turned the bike off it doesn't get any worse than that really.
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Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[orac]

is the top of the barrel flat???

i freind of mine works in a shop, they found that some bike like to have the barrel lapped along with the head before putting it all together
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[Mikey CB500]

Possibly needs a smidgen shaving off the barrel maybe thats got some indents in?

The mtx we had in leaked coolant and that was the barrel slightly dented/pored not the head

[gray84]

The cyclinder/barrel was re sleeved then skimmed at the same time as the head?
All smooth and no marks at all. Checked everything is clean so it all mates together nice.
____________________
Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[Teflon-Mike]

[gray84]

It's the same now as it was before the rebuild and skim its been stripped down twice now and both times new gaskets and torqued right. The head and barrel were skimmed. It can't be anything to do with the new sleeve as again it's the same as before that was fitted. It's always seeping out the 1 spot.
Is it possible that there is a hairline crack we can't see?
Is it worth a new head?
The bike has been run correctly since rebuild with no hard riding but it was leaking from the word go.

I don't know what to do apart from a new head.

Can you view the video I've put up?
____________________
Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[jimmyRS]

[gray84]

The 1st time we fitted it yes we used a good gasket sealant but this time no.
____________________
Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[jimmyRS]

not saying that'll fix it but as a temporary solution until you get round to buying a new head it might be worth another try.

[gray84]

Nope all checked again and used gasket seal too. Still the same.
New head I'm thinking.
____________________
Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[Ichy]

They way the bead is forming suggests that there is some porosity in the head. It looks like the water is moving upwards because you are assuming that it's coming from the gasket area. To test it you can just try a small amount of exopy resin, or even tape, on the head just above the joint. If there is still water pooling then it's the gasket area if not then its the head.
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[gray84]

[Teflon-Mike]

I'm with Marki; gravity defying droplets do suggests pourocity.

'the Black Magic'.... if all else is definitely eliminated.

Was the head vapour-blasted or chemically cleaned when it was skimmed by any chance?

If the metal is pourus, it tends not to just 'happen', its a casting flaw and will have been there since it was made, thouigh a fizure may have opened up through cyclic thermal fatigue.... expanding & contracting getting hot & cooling.

If you clean area with solvent and dry thoroughly and give it a wipe of epoxy of chemical metal, it might seal.

If it does though, it will be a semi-temperary fix. Better brazed, possibly with lumiweld or similar.
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[gray84]

I'm not sure how it was cleaned after but I know I had to spend ages cleaning it out after too.
So if it is pourus it is fixable? Or is it again best to buy a new head? They seem to be £90 for a new head
____________________
Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[gray84]

I imagine it would be hard to braze something if you can't see whe its coming from. Honest even with the head off there isn't a mark anywhere to be seen. Can't see any marks where it's creeping though the gasket or join and it has all be tightened down correctly ect.

So do you agree it seems to be the head at fault?
____________________
Road bike - 2002 YAMAHA R6(SOLD) 2008 YAMAHA R1(SOLD) 2007 APRILIA SXV 550(SOLD) 2007 SUZUKI GSXR 600
Dirt bike - 1989 HONDA CR80sw(SOLD) 1996 YAMAHA YZ125(SOLD) 2006 yamaha yz250(SOLD)

[kestrel]

A dye penetrant check will find cracks and porosity on components such as heads, including those invisible to the naked eye. The kit consists of three aerosols, penetrant, cleaner and developer. The component is cleaned then sprayed with dye which penetrates into any flaws. The excess dye is removed after about ten minutes using the cleaner then developer is sprayed on. Any flaws will immediately be highlighted in red.
You can buy the kit yourself for about £20 from somewhere like Weldspares, alternatively any decent welding shop that does pipework/tanks etc will use it. I have a set here but the Isle of Man is probably a bit far away!
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Isle of Man.........Road Racing Capital Of The World

[Ichy]

Just noticed you've listed your location as Staffordshire. If you fancy a trip to Crewe or Biddulph I have dye penetration that we can test your head with. I might even have a can of dye you can have.

A less accurate, and certainly not 100% reliable, homebrew detection is to spray the head with wd40 in the area you think it might be cracked. leave it for a few minutes and then give it a quick wipe with some solvent. when that's dry puff some talc onto the head. The wd40 that has got throught the leak should discolour the talc.
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[jjdugen]

Stick a bit of Bar-seal in the rad, that stuff would fix Niagra Falls.
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[gray84]

[st3v3]

Small thing but the actual gasket is ok, isn't it?
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[jimspeed]

K seal would prob seal this up.worth a try and it doesnt clog rads like other stuff
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[gray84]

[st3v3]

[Ichy]