One problem, many possible causes

[[mXm] andy19]

Last year, around August/September I took my bike out for one last ride on a nice day. While out cruising the country back roads, a couple bikers came up from behind me, taunting me. They were just a couple kids, maybe 12-14, on 125 dirt bikes. Smaller tires, smaller drive sprockets, quick acceleration. I made the decision to show up these kids on my Kawasaki 440cc bike. They took off ahead of me and it took me a bit to catch up, but I flew past them once I got up to speed. After doing this a couple times, my bike started slowing down, not responding to the throttle. I had to pull full throttle just to keep it going, and even then it was gradually dying. Took about 5 minutes for me to get back to my house, and once I hit the driveway it died. After a couple attempts, immediate and again in the spring, I couldn't start the bike.
After talks with my dad who is a mechanic, and posts on old Kawasaki message boards, it seemed to be a combination of burnt valves, worn rings, or bad head gasket.
I finally got the time recently to tear the engine apart, and after inspecting each of the possible at-fault components, they all look decent. Not bad enough to cause the engine to break down like that. Even a (cold) compression test showed pressures that are in working range.
The main symptoms were loss of power, bad leaking oil from the heads, and a distinct metal rattling/knocking sound when it happened.
After a bit more research and replies from message boards, the suggestion came up that it could be main bearings.
So it looks like more of a rebuild is in order. It would be nice to get all the seals/gaskets replaced, valves reseated, and rings replaced anyways, just because I don't think it has as much power as a 440 should have. I'm losing it somewhere, plus I'm not sure how long it's been, if ever, since the last rebuild/valve job.
This will be my first engine rebuild on an engine that goes back into a vehicle of my own, so it's exciting and a little nerve wracking at the same time. I don't want to mess anything up, but bike engines are simple which is awesome - the main reason I love working on them.

Here are some pictures of the rebuild so far. I think I've run into a few extra problems since I started looking into it - the pistons and cylinders look a bit scored/worn. There's a distinct ring around the cylinders, possibly from the bike sitting for a long time and the rings seizing there before I bought it.

Should be fun, but more expensive than I originally thought, and more involved. I kind of wanted the bike to be back on the road this summer, but I doubt that will happen.
I'll keep posting updates in here if anyone's interested.

[[mXm] BalzOnYer4Head]

I do not know alot about motor cycles, but a motor is a motor. Metal clanking is bad. I am thinking cylinder arm, broken valve(s), valve springs? I would like to see pics of it with the head off and and the tops of the cylinders.

I bet if ya do some askin around, you may find some breaker yards where you can just snag another motor or in your case maybe even another donor bike.

[[mXm] andy19]

The suggestion about main bearings sounds about right. If the bearings came out, that could have been what was rattling around.

I haven't found many bike scrap yards. There are a few in Ontario, but none seem to have the same bike. Maybe I'll try to upgrade to a 550 or 650. I think the frames are the same. Gotta double check that.

[[mXm] BalzOnYer4Head]

[quote name='andy19' timestamp='1311082529' post='1418']
The suggestion about main bearings sounds about right. If the bearings came out, that could have been what was rattling around.

I haven't found many bike scrap yards. There are a few in Ontario, but none seem to have the same bike. Maybe I'll try to upgrade to a 550 or 650. I think the frames are the same. Gotta double check that.


LOL I forgot that youre way up in an area not conducive to motorcycles eighty percent of the year, so the pickins might be slim. Ill take a peak around the local market here and see what I can find. We'll figure out shipping if I find something.

[[mXm] andy19]

[quote name='BalzOnYer4Head' timestamp='1311123495' post='1419']
LOL I forgot that youre way up in an area not conducive to motorcycles eighty percent of the year, so the pickins might be slim. Ill take a peak around the local market here and see what I can find. We'll figure out shipping if I find something.

That would be fantastic. I know there are a hell of a lot more, and I'd suspect quite numerous in southern states.

[[mXm] BalzOnYer4Head]

[quote name='andy19' timestamp='1311165007' post='1422']
That would be fantastic. I know there are a hell of a lot more, and I'd suspect quite numerous in southern states.


Would a KZ1000 motor mount to that frame?

http://tampa.craigslist.org/hil/mcy/2486795307.html

And that's just a quick search here in Tampa, I'm sure if I do some sniffin around Ill find a breaker yard for em.

[[mXm] andy19]

[quote name='BalzOnYer4Head' timestamp='1311199254' post='1428']
Would a KZ1000 motor mount to that frame?

http://tampa.craigslist.org/hil/mcy/2486795307.html

And that's just a quick search here in Tampa, I'm sure if I do some sniffin around Ill find a breaker yard for em.

From what I'm reading, the 440's are basically the only engine I can put in my particular frame. Anything above have bigger frames.

[[mXm] BalzOnYer4Head]

[quote name='andy19' timestamp='1311254352' post='1429']
From what I'm reading, the 440's are basically the only engine I can put in my particular frame. Anything above have bigger frames.


Found something to get you started, call him up and see if hes got whatya need, and if he doesnt, can he refer you to someone who might. Arrange to purchase it, and ill pick it up. ITs a bit of a haul sanford, but Id do it for my fav Canadian.

http://jackscyclessalvage.com/hondasalvage.html