Katana Owners Club U.K.

Ok I’ve been de-greasing and scraping all the old gasket bits off the head and barrel today. I’ve measured the bores up and they are all within the specs given in the manual. However as the very observant Mr Blix spotted there is a problem with no2 cylinder? Sometime in the past the engine has been subject to a fairly big blow up and no2 combustion chamber has had a real pasting. I’m fairly sure the damage is confined to the sealed area of the combustion chamber and placing the new gasket over the head would seem to bear this out but I would like some advice from someone more familiar with these motors than I am before I carry on. Other butchery shown is an exhaust stud that has ripped the metal out of the head and what appears to be a repair to an over long rocker mounting bolt that’s punched it’s way through the other side!

I can repair the exhaust thread myself Mick and as the repair/bodge to the over long bolt is oiltight I will ignore that but the combustion chamber damage is beyond what I can do. Putting a straight edge across the damage shows a dip of around half a millimetre but as it all seems to be contained inside the gasket would it matter a great deal?
I’m thinking it’s a ruddy great 1100cc lump with power to spare and not exactly going to ride it like Jamie Witham

Thanks Mick, I could skim the head but I reckon it would need more than half a millimetre to clean it up which might raise the compression ratio a bit much
I’ll put a wanted ad on the forum to see if I can find a decent replacement before I go any further.

if you skim the head you can add an extra base gasket to lower the compression a bit to counter the skim.

Mmm now there’s an idea, thanks John. I’ve been talking to a mate of mine who raced all kinds of four stroke dinosaurs back in the mists of time and he seems to think that as long as the damage is contained inside the combustion chamber it will make very little difference in normal road riding? The only fly in the ointment is he’s never raced a TSCC Suzuki so is unsure on that side of things as the blow up has damaged the chamber profile.
I’m going to pop over to his place and let him cast an experienced eye over it. I’m confident I can repair the exhaust thread damage but I don’t want /can’t afford to strip it down again in the future so I’ll await the verdict. I’ve been scouring tinternet for a good used head but they seem to start around £350 and go up to £500 which means I will miss the summer season as I can’t afford to buy one just now.

If you skim too much don't you run risk of valve touching the piston?

Seen similar damage to an old Hon** when the head of the valve snapped.

katmarch wrote:If you skim too much don't you run risk of valve touching the piston?

Seen similar damage to an old Hon** when the head of the valve snapped.

I’m thinking the same tbh, it looks very much like it’s dropped a valve as there isn’t any cylinder damage.

I'd ignore what's in the combustion chamber. Just make sure the gasket surface is mint.
In case anything fails I got a head here BUT it is off a tuned race engine obviously. Intakes are opened to the maximum. I got it from Johnr for nowt, so you can have it for the same. Cannot tell by heart if it is GSX or EF but could have a look.

Thanks Pedda, I’ll have a go at repairing the exhaust stubb and if that turns out ok I’ll just screw it all together. The gasket surface is good and I’ve got a genuine Suzuki head gasket to go on so it should be good to go. Does your tuned head have standard size valves? If it does and I can’t repair the exhaust thread it may be my only option. I will of course cover postage costs.
Thanks, Paul

Just had a quick look at it. It is a black 24 bolt camcover GSX head, can't tell of which model. Valves are standard size. There have been made a few minor repairs to it in the past, appearantly. Still a few stud threads looking a bit tatty. But everything's there short of the cam cover.