Katana Owners Club U.K.

Is there a special knack?

This one is putting up one hell of a fight!

Most of the nuts around the spark plugs I've had to chisel off due to them being corroded to oblivion.

I've removed the 3 bolts (outboard of 1 & 4 plugs) and the upside down one on the cam chain tunnel at the front, the 4 chrome dome nuts on at the ends, and chiselled off the 8 in the middle (went out and bought a 14mm deep socket - that was only useful for 1 nut!).

Something is stopping it from coming off!

Looking at the studs, all but one have "wiggle room" in the holes. The one with the particularly corroded nut (front, no.3 plug) has none. It would appear that there is corrosion between the stud and the head. I've tried double nutting it and trying to unscrew the stud from the bottom end, no good. I've flooded it with Plus Gas on numerous occasions (but looking at it, it's been dumbed down like most good stuff has been), I've scraped the corrosion away as best I can with a pick, but it goes pretty deep.

What's next? Heat??

I also managed to extract a bit of gasket at the front - it looks like it's been covered in red Hermetite.

Double bumgrapes!

Any suggestions appreciated!

J

you've got the washers off too have you?.... i've found in the past that if the odd one is left on it can wedge itself in and make it feel like something else if still bolted down?... head isn't usually the issue. barrels on the other hand will be more fun than you can shake a stick at!.. l o l

Steve,

I think 2 of the studs have corrosion welded themselves to the head (the ones either side of the timing chain tunnel, at the front).......

All the washers are off!

The barrels actually are moving with the head - If I push the whole lot toward the back or the front, I can see a miniscule gap open up, I don't think they are going to be the problem!

I'm not prepared to hit it any harder than I already am (hammer and 2x4), I've applied heat and virtually a whole can of Plus Gas (that just isn't penetrating). The only other option is to put some Jenolite on (which literally makes corrosion fizz), which I haven't got.

I've had this before with an old series 1 Jag 2.8. Took the head nuts off, and the engine hoist had the front wheels off the deck, and still it wouldn't budge!

I've got a stud extractor, which is like a big drill chuck with a 1/2" drive hole in the end. That sorted the Jag, but it won't do the Kat.

To me, the 650 head nuts are a bit of a design flaw.... I cannot think why a Japanese designer would engineer it so that the head nuts are right in front of an opening that is going to allow water to be forced through the cooling channel right onto them. At the very least they should have used dome nuts & copper washers like the ones on the outside of the head to try and keep corrosion to a minimum!

Another Japanese 650 (I won't mention the name) has all but 4 of the head bolts inside the cam casings, so they are nice and easy to get out!

Beginning to wonder why I didn't just take Fossies advice now.......

J