'81 KZ750 - Project for an Aspiring Greasemonkey

It started about a year ago when I found myself admiring the old "standard" style bikes I would occassionally see being hacked into choppers on Craigslist. I thought they looked like they would be fun to have as daily commuters or weekend riders. However, I consider myself an extreme novice when it comes to auto/motorcycle repair. Don't get me wrong; I change my own oil and do basic maintenance, but I know what my limitations are.

Fast forward to a few weeks ago when I get the bright idea to sell my trusty '01 Shadow and buy a "vintage" bike. The extra cash would go to savings for a newer bike next summer. A couple strikeouts on Craigslist, and the wife and I made a drive about an hour away to check out this damsel in distress.




After a test ride and a thorough run down of the problems, I rode her home. The first casualty of my purchase was my right boot which was splattered with oil during the ride. I'm assuming this was from the leaky cam end plug.




No problem. After some research here, I think I'll take those out and apply some Yamabond (or similar) sealant in order to keep the seeping to a minimum. I plan on using this to ride to work, so I can't have oil on my pants and shoes every morning.

Now the fun part. When looking for bikes, I needed something that was running and shifting. I do not have the knowledge, patience, or resources needed to do a major overhaul. I was looking for a bike that just needed some love. Here's a quick rundown of the issues I've found other than the leaky cam end plugs (so far).




New ignition switch (uses a flat head screwdriver to start)
Broken Speedometer/Odometer (I'm hoping this just needs a new cable. Suggestions???)




Electrical tape seat (Actually very comfortable, but I plan on ordering a new one)




New grips and levers (on order from bikebandit.com)
Front brake needs bled and filled with new oil (current oil looks like peanut butter)




PO duct taped the headlight b/c he was too lazy to buy screws

I've found several other locations where screws and bolts are missing. I plan on going over the bike thoroughly the next couple of days and making a list of new bolts and screws to buy.

I also plan to change the oil and filter as well as getting a new air filter. First thing I did was buy a new battery.

Now for the issues that I'm less confident about. I'm hoping some of you may be able to offer some advice.

Idle issue: The bike starts up fine with the choke 'on', however it will rev up to about 4,000 rpm after a few seconds. When I back off the choke, it goes down to 500 rpm and I have to gas it to keep it alive. Am I not waiting long enough for it warm up? The PO had the carbs cleaned and synced by a pro (gave me name and showed receipts) recently, so I don't think it's carbs.

Gas drip: There's a small gas leak that seems to be coming from the oil pan. I see no leaks above the engine on any of the fuel lines. Can gas leak out of the oil pan? Maybe the drain plug is leaking?

Oil drip: There's also oil drip under the bike, but I think this could be from the cam end plugs. The PO just said to fill it with oil each week and it will be fine, but I'd rather remedy the problem.

So, as you can see, I have my work cut out for me, but I'm looking forward to every minute of it.

Looks like we are headed down similar paths. I just brought my '81 750 home last night....except mine was on a trailer because I don't think its seen the road for many many years. Look forward to following your progress on getting yours squared away. Not sure if you have already found one but I got a pdf shop manual from kz.bike-night.com/manual which was great. Pics were a bit dark but overall very useful to get started with.

J

Thanks. I tried looking at the downloaded manuals, but the pictures were too dark so I went ahead and ordered a hard copy through bikebandit. I'm waiting anxiously for it to get here since I'm not wanting to start tearing things apart without a proper diagram.

Looks like it'll be a great project for you.

I hope you bought the Kawasaki Factory Service manual, the Haynes is just so-so.

Anyway, check the hoses that run off the bottom of the carburetors. They should run to around the rear swingarm and if you're leaking gas out of those, you should check out the drain screws near the base of the hose and make sure it's torqued down correctly. (Not REALLY tight, but tight enough; it's only brass.)

If the seat is comfortable, you should just buy a new cover. Much cheaper that way.

And you should definitely find a new ignition switch :laugh:

Cheap way to test the tachometer is to pull the cable off the back of the tachometer and start the bike. If the square plug in the cable is spinning, then the cable is okayish. You should still replace it if you can. If it checks out up until that, you can make sure the tachometer is working with an electric drill if you're careful not to damage the tachometer. Put the cable back on the tachometer, then remove it from the engine and tighten the drill chuck on the square peg carefully, so you don't damage it. Spin the drill up slowly and the tach should eventually start to move. If that works, the pinion in the engine might not be connecting with the exhaust camshaft. I guess you could do a similar thing for the speedometer. I did this because I couldn't think of a better way to do it, I imagine there's a better way somewhere.

As for the carbs, if they're freshly rebuilt then just turn the big screw in the middle of the carbs under the throttle assembly. It controls the throttle. I'm not 100% sure, but I think it should idle around 1000 - 1200 RPMS. Ensure that the valves and breathers on top of the engine are sealed up and not leaky. The breather box on these bikes can be tricky.

Good luck!

-E

The manual, grips and levers came in today. I got the Clymers manual since I heard good things about how easy it is to understand. I took the throttle assembly apart and the removed the left hand grip. Just need to get the throttle grip off of the assembly (may need a box cutter for that) and then the grips will go on. The new ignition switch is scheduled for delivery tomorrow!

Going out of town for the weekend, so I won't be able to get much done for the next couple of days. Now that I have the manual to guide me, I'm going to start disassembling next week. I won't be going too deep, just removing the tank, headlight, seat and meters (so I can put in the new ignition). I'll try and get some more pictures up once I get moving.

Thanks for the tips. I'll check that out before I tear it down too far.

Well, I got the new grips and front brake lever replaced Friday night before leaving town for the weekend. I was ready to start disassembling tonight, but I realized that I have almost a full tank of gas and no container big enough to hold 4 gallons. Rather than go buy a bigger container, the wife and I decide to take advantage of the mild weather and go for a quick 50 mile jaunt to burn some fuel. After riding the bike home 50 miles when I bought it, I figured it was plenty worthy for a ride tonight.

Of course, we were just blocks from home when the damn thing died and wouldn't start. My first thought was a dead battery, but since the battery is new, I suspected a blown fuse. The wife rode her bike home and brought back the car and some tools. Sure enough, pop open the fuse box and there's a burnt fuse. A quick replacement had the bike back home on its centerstand in the garage, truly ready to start tearing it down tomorrow.

Here's my plan of attack. Please feel free to offer any suggestions:
1. Take off tank and use rust removal on inside (not too rusty, but just making sure)
2. Take off headlight/gauge cluster in order to install new ignition switch. May replace the headlight as well.
3. Remove front wheel to check bearings and remove fender for painting. I will undoubtedly have to get a new front tire as this one just doesn't feel or look right. It has "waves" if you run your hand over the strip that contacts the pavement.
4. Remove exhaust and replace exhaust gaskets.
5. Remove the oil filter and the pan. I think I've located the source of the oil leak to a bad crush washer in the drain plug.
6. Remove back cowling for paint.
7. I want to replace the fuse box with bladed fuses, but I am hesitant to perform anything too complicated with the electrical system. But, if I have a faulty wire somewhere, I know it will need replaced. Just going to give everything a good look-see.
8. I don't think the seat is stock. So, I plan on just seeing what type of seat is on here and just find a replacement cover.
9. Check carbs to ensure everything is in working order. I am assuming my over-revving is due to a bad air-fuel mixture. If everything looks good with the carbs, I'll bet it's an air leak somewhere around the boots.
10. Paint and re-assemble.
11. Once mostly re-assembled, I plan on completely diagnosing the issue with the carbs/air mixture. I think this may be the main culprit of my idle/high rpms when warm. I will probably end up replacing the air filter just to be safe as well.

Once I start to disassemble, I'll be sure to post some pics for reference and ridicule. :lol:

If the carb holders are original I would replace them while the carbs are off the bike. They tend to develop very fine cracks on the mating surface that cannot be seen while they are mounted on the engine. Use Kroil or another high quality penetrant (NOT WD40) for a couple days to soak the screws that attach the holders to the cylinder head. Otherwise you may find them difficult to remove without stripping. Be sure to use JIS screwdriver bits or Phillips that have been modified to JIS standard or the screwheads will strip (see link below). Also, if you decide not to replace the fuse holder go ahead and replace the other fuses with new ones. When the fuses get very old the little metal caps on the ends can loosen up a little from age & vibration (I believe the glue that holds the caps on dries out too much). As a result, the caps can move around a little and break their connection with the filiments so the fuse "blows" even though the electrical system is fine. I found this to be true of mine when they were about 25 years old. Ed

kzrider.com/forum/2-engine/452802-loud-c...hile-cranking#452872

Finally started stripping the bike down tonight. First came the (Yamaha) headlight.



I noticed an extra headlight plug. I'm guessing that was for the stock headlight. Not sure if I'm going to replace the headlight or not. I'll have to see how my budget stands once the other essentials are on. There's nothing wrong with the headlight, other than needing a brighter bulb.

Question: Should I be worried about all the wires back there? They have insulation on them, but since my previous experience is on newer V-twins (that have plastic covers near the triple tree) I want to make sure these aren't posing a threat.

Once the headlight was off, I removed the speedo and tach cables. I think the speedo malfunction is in the cable. It was pretty gummed up, so I'll probably just replace it.

Finally, I unscrewed the damaged ignition switch and replaced with the new one. Installation was pretty easy, although I think I may need to secure the ground wire a little more before I get set to ride.

It will be nice to start the beast without a screwdriver. :lol:


Oh, almost forgot to throw up a picture of the new grips and levers.



Hopefully I will have the tank off tomorrow night.
Thanks to those of you offering advice so far! I'll definitely be going back to it once I get to those points in the process.

It's been a busy few days (had a plumbing problem that needed fixed asap since we are trying to sell our house) so I haven't been able to work much on the bike. I was able to get the valve cover removed this past weekend, and was discovered the gasket was in pieces. I also took out the cam end plugs, which subsequently broke into pieces. So, I have gaskets, cam end plugs, and other odds and ends on order from Z1. Once those are in I will be able to get everything pieced back together and focus on paint.

However, I have a small - albeit very important - issue. The screws holding the lid for the front brake fluid reservoir are pretty much frozen in place. I soaked them in Liquid Wrench over night and then hit them again a few minutes before trying to remove them. But, they wouldn't budge and I ended up stripping them pretty bad. I'm going to swing by Home Depot and get a screw extractor tomorrow, but does anybody have any other suggestions???

Left-hand drill bit.

Good Fortune!

That trapezoid brake reservoir is some piece of junk! Do what Patton said though. And get some new screws, put some lube on them before installing them next time.

Patton wrote: Left-hand drill bit.

Good Fortune!

Hmmm...never heard/thought of that. Sounds like that will be the ticket. Thanks for the advice, guys!