TOPIC:

Hey everyone,
Im new as a member to the site, however I have spent what seems like months on here doing research and cruising forums while building my kz this last winter.
My question is regarding weather or not its worth it to fix what I suspect is a major issue with the bike. I have a knocking noise coming from the lower to mid range of the engine, which I suspect to be a bad rod bearing or something to that degree. I finally and reluctantly brought the bike to a mechanic to have him diagnose and quote. Right off the bat, when I mentioned possibly the rod bearing, he said between parts and labor costs to pull the engine and split the case would be close to or upward of $1000. Here's where the dilemma lies. I bought the bike cheap for only $350 as a good motor and rolling frame and now have roughly $1000 into bringing it back to life. Now if I put another $900-$1300 into the bike, am I pushing my way to putting in much more money than its worth? I have great personal attachment to this bike after I put all this work into it, but I really don't want to have $2500 into a bike if its never going to be worth more than $1200. Just looking for input from other kz lovers to help me decide if I can justify to myself putting in around another $1000 or if I need to just sell the bike and start over with a new project. Not to mention if I just throw in the towel now, how much can I realistically get for a beautiful looking bike with a bad engine? I'd probably loose money after what I have into it already. BTW check out the pics i attached and let me know what you think! Thanks Guys!

As far as I know most kz's have needle bearings on the bottom end, Have you synced the carbs, that can cause a knocking sound if not done, Im sure someone with more brain power than me will chime in shortly. BTW the bike looks nice.
Good Luck

Seems to me you owe it to yourself to check out the obvious stuff like the clutch hub, starter clutch, and rotor. The repair might not be as bad as you think. Worst case you can figure out what to do with it at a later date, after you have all the proper information. Performing engine work really isn't overly difficult either, as long as you have a proper place to work.

I never considered any of those in diagnosis. Hopefully it is something easier than I expected. I had just checked for any air leaks, and replaced the carb boots. Replaced the exhaust header gaskets. Had the valves shimmed and figured It was something to do with that. But the ticking turned into a louder knock over time and I found that it was lower in the case. It's a constant knock in neutral or in gear and under load. Consistant perfectly with rpm increase until the engine noise overpowers it. Sound firmiliuar to anyone?

cafebrat wrote: Hey everyone,
Im new as a member to the site, however I have spent what seems like months on here doing research and cruising forums while building my kz this last winter.
My question is regarding weather or not its worth it to fix what I suspect is a major issue with the bike. I have a knocking noise coming from the lower to mid range of the engine, which I suspect to be a bad rod bearing or something to that degree. I finally and reluctantly brought the bike to a mechanic to have him diagnose and quote. Right off the bat, when I mentioned possibly the rod bearing, he said between parts and labor costs to pull the engine and split the case would be close to or upward of $1000. Here's where the dilemma lies. I bought the bike cheap for only $350 as a good motor and rolling frame and now have roughly $1000 into bringing it back to life. Now if I put another $900-$1300 into the bike, am I pushing my way to putting in much more money than its worth? I have great personal attachment to this bike after I put all this work into it, but I really don't want to have $2500 into a bike if its never going to be worth more than $1200.!

Question is: what's it worth to you. You are not building it up to sell, you're building it up to ride. A few years back I spent about $1000 and a bunch of my time rebuilding the engine on a '79 750 that I had since new..... while some might think that's crazy (my wife for example) because it's not "worth" it, I like riding it.

cafebrat wrote: I never considered any of those in diagnosis. Hopefully it is something easier than I expected. I had just checked for any air leaks, and replaced the carb boots. Replaced the exhaust header gaskets. Had the valves shimmed and figured It was something to do with that. But the ticking turned into a louder knock over time and I found that it was lower in the case. It's a constant knock in neutral or in gear and under load. Consistant perfectly with rpm increase until the engine noise overpowers it. Sound firmiliuar to anyone?

Another thing that can "knock" is an exhaust leak, but the mechanic is right that most knocking from the bottom end is a rod bearing.

moneypit wrote: As far as I know most kz's have needle bearings on the bottom end, Have you synced the carbs, that can cause a knocking sound if not done, Im sure someone with more brain power than me will chime in shortly. BTW the bike looks nice.
Good Luck

That's because you are only familiar with the 900/1000/1100 motors, all the rest have plain bearings.
So, most KZ's have plain bearings

cafebrat wrote: But the ticking turned into a louder knock over time and I found that it was lower in the case. It's a constant knock in neutral or in gear and under load. Consistant perfectly with rpm increase until the engine noise overpowers it. Sound firmiliuar to anyone?

I just looked at your pics and saw you have a 900/1000, and those do have roller bearing bottom ends. And I don't believe it's possible to have either a rod or a main bearing knock on a roller bearing bottom end, so it's something else.
Use a short piece of heater hose, garden hose, or similar, to track the location of the noise by putting one end against your ear and moving the other end around the motor till you find a point where the noise is loudest.
Then tell us what you found.

Lots of things can cause a knocking noise, but it's just so damn hard to hear them over all the noise on the net.

Worn clutch dampers in a 650 sound just like a lower end knock not sure if the same is true for the bigger 4's. If it is a rod or main bearing, finding another engine is cheaper than a rebuild.

I agree with Tyler, worse case scenario is you have to replace the engine. I don't even want to how much money I have invested in my bike so far. It is more than you I can promise you that and I would never get my money out of it but it doesn't matter because its the bike that I want.
Nice bike by the way, I wish I could offer help on the diagnosis but I think everyone else has handled that already. Have you drained the oil? Was there excessive metal in it? If there is it would lead me to believe there is internal damage. If there is internal damage and a lot of metal particulates in the oil what is stopping you from cracking the cases? If its already broke what do you have to loose. Start with some on the suggestions of the other guys. Take the things you can handle apart and inspect them for excessive wear and tear. Just my .02

kaw-a-holic wrote: I don't even want to how much money I have invested in my bike so far. It is more than you I can promise you that and I would never get my money out of it but it doesn't matter because its the bike that I want.

I'm pretty sure that's some kind of pledge you have to make before buying a thirty year old UJM.

Says the guy who has well over $3000 in a 79 KZ750 twin

The bike is an 82 kz1100 LTD shaft. according to my clymers manual it has roller bearings. As guys mentioned, I had already used a metal rod to listen and pinpoint where the noise was coming from. I noticed it most on the left side right where the the crankshaft is. I've also checked the oil every time I've done a change and there's no sign of any metallic flakes. I'm really leaning towards it being a worn crankshaft bearing. Between checking for and replacing any intake/exhaust leaks, valves shimmed and carb tuning and listening to the engine I have done all I can without some professional help. The mechanic I brought the bike to is very knowledgable about kz's and hopefully he'll get back to me next week with what he thinks is going on. I'll make sure to update as soon as I know and ask you gurus as well about the best way to tackle whatever it is. I've definatly decided that whatever it is, I'm keeping this bike. Being that it's my first bike ive ever built/fixed up, I'm too proud of it and absolutely in love with everything about it to just sell it away.