Yamaha TRX850 Enthusiasts Forum

Ok ,thats the bike with the garage for a new cam chain and getting the MOT done.Now im told the bike has a water leak ,something about corroded pipe,aluminium corroded and a washer.I assume this is on the cylinder head area.What couod he be on about? Cam chain fitted and he says it sounds sweet by the way so no more tickety tick .But this water leak is worrying me.He says he has tried this an that but its stubborn.I can only assume its because of his removal of the radiator hoses etc to do the cam chain and something is so badly corroded its buggered up.

Ther's a cast metal connecter to one of the radiator hoes that bolts to the cam cover with two small bolts. If I remember correcly this has an o ring or copper washer, could be this.

hmm, he seems to be pissin around trying to fix this leak unsuccessfully.Surely this would be easy to remedy

Can't rememember how easy it is to access, radiator off etc, but I seem to remember, when I had mine in bits, that the design didn't impress me much and was a good place for water to collect. Sorry if i'm a bit vague but i'm not at the bike to check and it was a while ago.

It`s likely the coolant inlet stub on the cylinder head, near the right hand plug (if sitting on the bike).
Barstard things corrode like mad, just mild steel, Yamaha have got some greenish coating on them (some kind of chemical blacking, manganese phosphating or similar) that`s meant to resist corrosion but it`s pretty shite really.
I had a huge problem getting mine out of the head after I discovered how pickled it was.The steel and aluminium create that nightmare situation often found with dissimilar metals, the electrolytic corrosion that occurs is a MF to shift.
I ended up snapping it off completely then utilised a 1/2" drive extension pushed into the broken portion still in the head, lots of easing it backwards and forwards, lots of diesel to help free it,(great for freeing corroded and seized things) then lastly an old pair of Mole grips were used to grip it and they were tapped with a hammer to persuade it out!
Took the best part of an hour or more to shift it though.
It`s secured by a 6mm cap screw (allen headed) also steel, so that tends to seize as well, (I replaced the steel cap screw with a stainless one).
Under the inlet stubs oval securing face is an o ring to provide the watertight/coolant seal.
About 20 mm or so of it actually fits into a recess in the cylinder head and it is this portion that corrodes itself into the aluminium.
My guess is that the technician knows this, so is hoping to patch the pipe up, it`s not likely to be very successful over the long term. If that stub is corroded and holed it`s by far best to replace it or it`ll only be a matter of time before it leaks again.
I was lucky, managed to get one from a broken bike in VERY good condition, covered it in black Smoothrite, baked the paint hard in my oven at 100 degrees overnight (interesting smell) and now hope never to be troubled by it corroding again.
As for getting one from Yamaha, from memory it was around 26 quid, which is extortionate for three inches of mild steel, 14 mm or so bore pipe with a flange on one end.
My advice, get that mechanic/technician to replace it, you`ll just have problems in the future if you don`t.

Pics of the pipe can be found in this thread.

Yes that`s the rotter, cheers JL.

for the record, thats a problem area on yamaha's in general. Its a common leak point on rebuilds. Bitch of a place to get too to boot.. Basically have to drop the radiator and a few other things..