New 'Tuna guy

[Molochnik]

Hi all,
I gave up riding around 5 years ago - even gave my primary bike to my stepson in an attempt to divest myself of at least one bike.

A few months ago I got the itch again and after considering pretty much everything from old exotics to something brand new, settled on an 03 600 Katana. I've always had some fascination with 'Tunas since I like well rounded bikes and Love the old GSXR engine.

It had suspiciously low milage (611), but for the price I figured it would be OK; nearly new, yet old fashioned enough to not require computers and software to work on.

Riding it reminded me of how much I must really like 600s and found the comfort, power and handling more than satisfactory for my purposes.

Unfortunately, I gotta open it up to replace a snapped cam chain, and also attempt to address any errant maintenance it seems to have perpetrated upon it.

Regardless, I expect to thoroughly enjoy this machine.

Ride free!

[ZukiFred]

Welcome to KatRiders.

[JIB]

Welcome

[dano68]

Welcome to KR! good luck with the rebuild

[92xjunker]

Welcome to KatRiders...

[Molochnik]

Thanks everyone!

[MNkat]

Welcome to KatRiders. Wrench on ...

[retcol]

Yes, welcome and good luck with your rebuild.

[Molochnik]

Thanks again; engine is apart and a list is begun.
I think it's going to ugly (money wise). It seems a cam sprocket bolt fell out and found its way in between the chain and crank. The crank has two broken teeth where the cam chain runs, and those are forged as part of the crank.
Gonna dig my old 750 race motor out of the shed and see if anything will be able to work.

[wired]

Welcome. Good luck.

[retcol]

OUCH! Good luck with it.

[92xjunker]

Just get a good used motor. You'll end up spending 3x+ what a used one would cost you.

[Molochnik]

It could very well...A new crank alone is $772 from Ron Ayers. That's the biggie, but I just took a look at my '90 GSXR engine and it seems to have the same primary gear, so perhaps that'll do the trick. Somebody posted a link in thread - "butt load of information" and I gotta go re-read it to make sure there aren't any gotchas.

I know you might be wondering why I simply don't bolt that one in, but it's got high compression pistons and I want to be able to use pump gas. It also never liked the tranny much, but it was a junkyard motor I bought 20 years ago so I wouldn't have to hot rod the one in my '87 when I was running in WERA vintage.

The tranny in this 600 Tuna is pretty sweet, so barring any latent issues with the cases, I'd just as soon stick with that one. I do, however, intend to use the intake cam out of my '90 which appears to be one from an '88. An extra mm of lift! Doesn't appear to have more duration, but I can only measure and compare them until I can find complete specs for Tuna cams.

[92xjunker]

That info is in the wiki or search for cam spec

[Molochnik]

I took your advice, thanks, but I was unable to find anything on the main wiki page regarding cam specs, just an article on overlap.

I did find the post addressing cams and their swappage, but the chart only lists the cam height; nothing regarding duration except some mention of the early cams having less of it.

I'm not too worried - it'll either run well or it won't. I can always go back to the stockers.

If memory serves, I originally attempted to use both the intake and exhaust cams from an '88 in my '90 motor, but found myself chasing my tail on jetting. overscavenging was suspected, so I swapped the exhaust back to stock. The engine was completely transformed and tuned up nicely. This intake cam might end up being a bit radical for a 600, but like I say, I can throw the stock one back in. The exhausts appear to be the same.