Just bought 3 KZ 650 1977-78

Hi everybody! I been looking for a clean bike from the 70's since this winter but couldn't find a good deal. I finally got one last week for 3 KZ 650 (one 77 and two 78) so I jumped on it.















The black one (78) has compression but the carbs are removed and some parts are missing. Could get it running with some work I guest. This one has cast wheel and dual disc brakes.

There's another 78 that will make a good parts bike (I already removed the fork and other things so I can load all those motorcycles in a 4'x8' trailer.

The cleanest functionnal bike is the red 1977 B1. It hasn't started since 3 years but I've been able to get it running before I bought it (just enough to know the bike will hit the road without to much work or $$ because my car broke down and I can't use my wife car for too long. So buying a motorcycle was a good option that leaves me time to fix my car). The exhaust on it look like brand new, good tires and wheels, nice seat and paint. Only thing I have to do for the look is the engine that has some white stain on it (the guy told me the previous owner cleaned it with acid before storing. Do you know a good product or something I can do to clean all this?

The mechanical stuff now. Let me say first that I'm a 34 years old heavy duty mechanic so my experience on motorcycle is limited (here's what I owned: 2 yamaha moped (when I was 12) scooters, 2 Kawa KE100, YZ80, Suzuki GT500 1977 (at 20) a XL250R 1985 and a Honda CB750SC since 2007 (really fun bike but the chain for the starter broke last year and I don't have time to fix it (doing a complete rebuild is about the same amount of work!)

OK. About my KZ now. I cleaned the carbs but I will have to go deeper. The bike is hard to start and after a 10 minutes test drive, the exhaust temp is at 300F for #4 and #2 but only 230F for #3 and a very low 150F for #1. I have the Kawasaki manual so I will take my time and do a more intensive cleaning.

The points gap is OK, I put new spark plugs and the voltage at the coils is 12.8 volts but sparks are kinda weak. Should it jump from a good gap when I check it with a spark gap tester or those things are mainly for cars? (it barely jump 1/8 and miss lots of time too).

Please let me know if you have good tips or links in this forum. I'm not wanting you guys to do my homeworks and brings me all the infos but I will really appreciated your help as there is really lots of threads on kzrider when you search for these keywords. I don't have much spare time with my family (2 and 4 years old sons), my job and all the work I have to do on our house so I'm really glad there is ressource like this forum to help passionates riders!!

Thank you!

Welcome aboard; the bikes look good! You're gonna love the KZ650! Take a look at the link below as it contain some info that you may find handy - especially the discussion under Tools regarding JIS screwdrivers (Phillips screwdrivers are a BIG no no.).

Keep in mind that there are some important differences between the '77 and '78 models including the charging systems. If you're going to use the '77 make sure your manual covers it specifically. One other tip, the '77 must have a healthy battery to run right because it uses a 3-phase excited field generator. Also, do not jump start any of the KZ's from a vehicle that is running as it will wreck the bike's electrical system.

Good luck with them. Ed

kzrider.com/forum/10-new-members/580406-...biker-from-mn#580410

Way to go , your set for life

JD

Thanks for the infos! I got lots of spare phillips bits so I'll grind some to fit those JIS screw. I can tell previous owners didn't know about that tough! :dry:

About the charging system. Does the 78 is somehow better than the 77? If so, would it be a good thing to replace everything on my 77 with the 78 parts?

The battery is surprisingly good for it age but it ain't like new. Maybe a sign that the bike need a better battery is when it got warmed up, starter turn ok but it doesn't start very well (or not at all even with the headlight off). I use the kick starter and it only take 1 or 2 kick to get it running. Does it tell something to you?

I sure like the look of those old Kawasaki! And for the 8 miles I did just test driving, I really like the feel of it too. My CB750SC has 91hp and I was wondering about the KZ 64hp but I'm surprised by its acceleration. And the bike isn't really top shape as you can read in my post above. Don't know if it'll get really better than that once tuned fine but I'm not asking for more (I don't have much self control and the CBR900 and other sport bikes I tried are definatly not for me :whistle: )

Just a few more questions now. The clutch is slipping and it might be because of the oil the PO put in it. Do you think the clucht can get better after a while if I do a oil change with the recommanded oil or I should just replace it right away?

I would like to know something about cam chain too. How much noise should it makes? Barely hear it or it's normal to hear the chain rolling on the sprockets (it's hard to describe how loud it is)? What happen if it breaks? Is it a interference engine that will have the pistons hitting the valve?

What about the points? Lots of guys replace them by electronic ignition. Is it a good move?

I wanted to replace the airbox by 4 K&N pods but I read here that the carbs are a pain to adjust after. Is it worth it? I see lots of KZ with this modification, is it mainly for look or what?

If you have good links for carbs, ignition and other useful stuff let me know. Reading the manual is a bit boring and technical when you're just looking for the essential.

Thanks for your help!

Actually, the ’77 charging system is better than the later systems, so keep it as is.

Sounds like you may want to invest in a new battery, but using the kicker when the engine is cold is what I do 99.9% of the time. I have done this since the bike was new.

Change the oil using JASO-MA approved oil and adjust the clutch using the instructions in the Kawasaki Service Manual. You may get lucky and the clutch may stop slipping – it’s worth a try.

The cam chain isn’t going to break. However, use the instructions in the Kawasaki Service Manual to adjust it; this must be done correctly. The cam chain will never be dead silent, but it should not be noisy.

I’ve been running points for 36+ years in my KZ650. I replace them every 10,000 miles or so. Some folks love the aftermarket electronic ignition system, but it draws more power than the points and isn’t cheap by the time you buy the proper coils to go with it. Electronic ignition is nice – set once and forget it, but if it fails it leaves you on foot; points gradually degrade but don’t leave you stranded.

Switch to pods only if you like the looks better and want to spend hours and $$$ becoming a carb expert. They provide zero performance improvement on a stock street bike and you will most likely lose the linear power curve that the bike has with the airbox. Personally, I would only install pods after removing all my teeth with a hammer. See the following link for a professional test and opinion:

kzrider.com/forum/3-carburetor/585949-po...-a-free-lunch#585949

Ed

Perfect then! Only thing I have to do now is make sure all the carbs work good (using the manual), adjust the timing chain and test my coils. I can't wait to take it for a long ride!

I almost order pods this week so good thing I came here first!

Thank you very much! I guess my next posts will be in the technical forums.

Be careful of those tires

Thanks for the advice. Why should I care so much? Because they're old and dry (but no cracks in it) or just because of the thread design?

I wanted to use those from my CB750SC but they're 5 years old (but the bike is on my garage cement floor in the shade since then). Do you think I'll have to be careful with those too?

Anyway, I won't really be taking sharp curves at 100 Mph. I might drive in the rain tough so I guess this where good tires make a difference.

Let me know if you got brand/model you recommand (or I'll search this forum later).

Thank you!

I've been using Pirelli Sport Demon tires and I like them a LOT! 100/90-V19 front 120/90-V18 rear with Metzeler tubes. Ed

Those look like good tires for sure!!

I think I'll try the dryed up tire carefully for a while tough and then put those from my Nighthawk later. I don't have much money to spend on my KZ right now and I wouldn't like to waste tires that still have a good thread depht. I'll take it easy until I get used to the bike and buy good rubbers!

For my cam chain everything is fine now. Some adjustement fixed almost all the noise. Thank you!

bluej58 wrote: Be careful of those tires

If you aren't going to replace those tires at least don't even think too much of riding in traffic or cornering or going fast.
My experience with new tires that were ages old was that twice I almost bought the farm on emergency braking. Both tires broke traction at 80MPH! A semi didn't signal and came in to my lane as I was about half way through. I had to panic brake and just barely missed the business end of the trailer. As he came further in to my lane he saw me. That was the last time I kept the tires on a bike without wearing them out after a season. The first time was when some idiot slammed on his brakes in front of me and I skidded toward him. No, broke or not I will not ride a bike with hard old rubber.

650ed wrote: I've been using Pirelli Sport Demon tires and I like them a LOT! 100/90-V19 front 120/90-V18 rear with Metzeler tubes. Ed

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Those look nice too.