Winter project questions.

[1993Kat600]

Okay. Start from the beginning. A couple of summers back, we purchased a 1993 600 Kat from a friend. A project, to say the least. I was riding a 1987 Hurricane 600 at the time and my wife wanted her a sporty bike. An almost complete bike with a clean title. PO said it had cams swapped but didn't get any other info on specifics. Bad was the transmission was stuck in 2nd gear. Not sure of which gear myself, but definately stuck. Had another friend who had a 750 Kat engine in a parts bike he wasn't using. Didn't know any history, believe it was a '90 or '91. Swapped out engines. Used the 600 carbs (I know, before anyone says, it was just to get it running) because the 750 had no carbs on it.

.....Now for the problem. Engine cranks. Check. New spark plugs spark. Check. Carbs cleaned. Check. Fuel flowing through carbs into engine. Check. No bang. No check. Tried starting fluid. Put old plugs back in. Choke, no choke. No throttle, WOT. Combination of all or some. No bang. Checked timing marks on camshaft and crank. Always lined up perfectly.

Had fire. Had fuel. Hmmmmmm. Oh yeah, compression. Need to check that. For some reason, project is put on hold. Old Kat is left in the back corner of the garage. Wife found her a lowered pink EX500 Ninja she fell in love with. I found myself a new love in a pristine 2000 Honda RC51.

Fast forward to present day. Looking for a winter project. Time to dust off the old Kat. Hooked her up to a good hot battery. Still turns over good and has good fire. Still won't start. Picked up a compression gauge and checked her out. Now I know I couldn't do a proper test due to the engine not being able to run to warm it up. But, results were.

Cyl 1 - 25 psi
Cyl 2 - 30 psi
Cyl 3 - 60 psi
Cyl 4 - 20 psi

Think I may have found my problem. Poured a little oil into cyl 2 and tried again. Jumped to 65 psi. Then steadily started to drop back to original reading after checking a few more times. Could feel the pulse in the compression gauge every time the piston came up on #3. And on #2 the first couple of checks with oil. After that and on the other 2 cylinders, nothing. Which points me to ring/cylinder issues. The engine had sat outside in the frame for awhile before I got it with no exhaust or carbs.

Now for the reason of the post. I am going to check the compression on the 600. Hopefully it has good even numbers. If so.....
Is it possible to put the 600 pistons, cylinders and head on the 750 crankcase? I am not wanting to sink a ton of money into this. Just looking for a winter project. Possibly a streetfighter type build. Something to commute and have a little fun on. The 600 would be more than sufficient. I get my power fix on the big V-Twin. And I hate to see it just sit there.

Re ringing (if the cylinders are okay) is an option. Do they make a kit?

Or, will the transmissions interchange? (swap the 750s into the 600)

Open to suggestions. Sorry for the "article". I ramble sometimes.

Thanks

[1993Kat600]

Update. Did a little online research today at work on the transmission issue with the 600. More than likely, a shift fork/drum issue, but maybe an off chance it is a problem with the shift shaft and the part on the end of the drum it engages. Saw it as a problem with later model gixxers. But they have a star wheel that gets bound up in the shift shaft when the retaining bolt loosens itself. That check is for another day.

Put 600 engine on the bench. Set up a battery to use to turn over the engine. Checked compression. Engine has no carbs or exhaust.

Cyl #1 - 95 psi
Cyl #2 - 55 psi
Cyl #3 - 10 psi
Cyl #4 - 60 psi

Getting worried that this engine is a paperweight. Crappy compression and a stuck trans. Checked #3 a couple of more times and not much change. Grabbed a can of WD40 and shot some into the #3 cylinder. Jumped to 30 psi and started getting slightly less. Kept soaking each cylinder and turning over the engine. Wish I had some Marvel Mystery Oil handy, but WD is the best I could manage. Checking compression on random cylinders as I went along. Final readings. Consistent measurements.

Cyl #1 - 95 psi
Cyl #2 - 90 psi
Cyl #3 - 90 psi
Cyl #4 - 95 psi

This engine has been sitting in the corner of the garage since 2009. Just pulled it when we first got it and installed the 750. And apparently the rings must have been stuck from sitting. Will pick up a bottle of Marvel tommorrow and give the cylinders a good soak before further diagnosing the trans issue. But the 750 engine also sat for an unknown time, outside in the elements. So....I am gonna give those cylinders a good soak and recheck. Fingers crossed.

I am actually kind of looking forward to splitting the cases and digging in the transmission. But if the 750 cylinders clear up, that would be fine with me. Will still dig into the 600 and fix it for, #1- the experience, #2- the fun, and #3- to have a spare engine for future replacement or maybe a cart.....

[ep87]

Sounds like your the engine is "a paper weight". I had the same problem with my 600 project, and found it was a lot cheaper to find a good motor then fix the old 89 600. I bought a 2001 Bandit 600 motor with about 7500 miles and think I paid about $300+ shipping.

Richard

[jetta90]

You may be better off looking for a used engine. It will be cheaper in the long run.
That aside, did you ever check your valve clearances before doing a compression check? I would make sure your valves are properly adjusted first.

[1993Kat600]

While a used engine is not completely out of the question, it is definately a last resort. Getting this bike running is not a have to, just a want to. It just got pushed off to the side for one reason or another (cannot remember exactly) and it seemed time to go at it again. I just get in the mood to tinker. Something to do while the snow is falling as well as the temps. I enjoy exploring new territory. With a manual and the net as my resources, I look forward to tackling the trans. If there is no hope for either engine, the search for a replacement will begin. I have a 2000 RC51, 1987 CBR600 and a 1985 Kawasaki 700 LTD. So this will be another toy in the toybox. And some experience under my belt. I am an ASE qualified auto technician but a motorcycle tech not so much.

To answer the question, valve clearances are all within spec.

[1993Kat600]

Started to pull apart the 600 to see about the transmission. Got the clutch out and look what I found.




Loose screw keeping the shift mechanism from moving. Causing it to be stuck in gear. Loose screw this whole time. From the looks of all the screws I could see, they have been removed at some point. Heads all slightly stripped. Obviously not tight enough. Plus the clutch hub nut seemed awful easy to loosen. No need for a tool to hold the drum. So I am going to pick up some loc-tite tommorrow and thread lock them all. After snugging it down, the shifter cycled through all gears.

Time to pull the 750 out of the frame and slide the 600 back in. Cross fingers and try again.

[Wild-Bill]

Loose screws cause all sorts of trouble...

[1993Kat600]

I bet the PO would crap his pants if he knew it was only a loose screw and not a jacked up shift fork, drum or transmission. He was sure it was a major issue and according to online research, it pointed to one. We didn't pay much for the thing. And a supposedly good 750 engine for very little. But I tend to overanalyze things and look at the worst case first. So I just swapped engines first thing. Hey, bigger is always better, right. Then sooner or later I come to my senses and look for the simpler problems that could be causing the issue. Like the time I overhauled my jeep engine because of oil blowby in the breather, when I discovered it still did it afterwards. Only to figure out the orifice for the crankcase vent port in the valve cover was just stopped up. At least it got fresh rings, bearings and gaskets.

[Jman2343]

Reminds me of my sisters Buell Blast... Long story short, bike wouldn't shift into second gear, counter shaft bolt fell out behind the clutch basket.

[scottynoface]

Had that same issue with my RM after the last rebuild, got stuck in first and wouldnt shift. D'oh.

[1993Kat600]

Swapped out the engines this weekend. Fired up fairly easily. Now to clean the carbs, replace the tires, new chain/sprockets......I guess it is time to start a build thread.