’79 KZ Top ends?

Hey folks, I’m looking at replacing the gaskets for the whole top end of my ’79 KZ650 and am while I’m at it I thought I’d replace the top end of the head due to some questionable leakage. My question though is; which models and years of 650 KZ’s will be compatible with mine. I’m thinking that any KZ 650 from ’77-’79 will fit. Is that correct?

Also, the bike is new to me and I don't know much of it's history... I'm relatively sure that I have a '79 650C but it could also be a "B" model based upon some of the information I've read recently.

Post edited by: nebx, at: 2008/01/17 14:36

Welcome to the site, the two choices are e bay, or z1, wich has a link,
there are a few experts hereon the site, with the vin number that can tell you if the guy who built it was right or left handed,

First of all welcome to KZR nebx.

First let's try to figure out which 650 you have. In 79 Kaw made 3 models of the 650, the B model came with wire spoke wheels, had a single disc brake in the front and a drum brake in the rear. The C model had mag wheels with triple disc brakes. Kaw also made the D model which like the C model had mag wheels and triple discs but used a 16" rear wheel, lacked a rear tail fin, had painted fenders instead of chrome and had a criss-crossed exhaust. From this description you should be able to nail down which bike you have.

The next thing we have to do is figure out exactly where it is leaking. Common to this bike is a leak from the area of the tachometer drive which is at the front of the head inbetween cylinders 2 and 3 (not a major deal). You also could be getting leakage from the camcover gasket and or cam end plugs (also not a huge deal). I guess we need to get a better description of exactly where you have a leak before any good advice can be given. All the members here are photo junkies so maybe you can shoot some pics of both your bike as well as the problem areas and we can give you some good advice.

nebx wrote:

Hey folks, I’m looking at replacing the gaskets for the whole top end of my ’79 KZ650 and am while I’m at it I thought I’d replace the top end of the head due to some questionable leakage. My question though is; which models and years of 650 KZ’s will be compatible with mine. I’m thinking that any KZ 650 from ’77-’79 will fit. Is that correct?

Also, the bike is new to me and I don't know much of it's history... I'm relatively sure that I have a '79 650C but it could also be a "B" model based upon some of the information I've read recently.<br><br>Post edited by: nebx, at: 2008/01/17 14:36

Bike bandit has the OEM part breakdowns for the whole engine with part numbers. Look up the Kawi part number on the head and see if it tracks to other years.

77-80 will interchange, the 650 motor went through some changes in 81.

The only thing you have to watch out for when swapping parts is the charging system.

Thanks for the replies, based upon the descriptions of the different models I've got a "C" model. And I recently stop the leak from the tach drive. The leak is definitely coming out of the front end of the head behind the pipes. But, it's also leaking from down low, possibly the base gasket? This weekend, if the weather is tolerable I'm going to pull the engine, I'll post more info and pics shortly after that.

Thanks for the replies, based upon the descriptions of the different models I've got a "C" model. And I recently stop the leak from the tach drive. The leak is definitely coming out of the front end of the head behind the pipes. But, it's also leaking from down low, possibly the base gasket? This weekend, if the weather is tolerable I'm going to pull the engine, I'll post more info and pics shortly after that.

The ’77 & ’78 share the same cylinder head, but it changed in ’79. The cylinder head cover changed then also when the reed valves were added. You can check the part numbers on buykawasaki.com for compatible parts.

650ed, don't know what changes were made in '81 but other than timing chain arn't all 77-80 heads the same? (other than emissions) Even if chain changed, can't you swap idlers over to "new" head?

Post edited by: Bluemeanie, at: 2008/01/22 14:37

Bluemeanie, I can't speak to this one from personal experience. I got my info from buykawasaki.com parts diagrams that show the part numbers for the head and the head cover changing beginning with the '79. I don't know what changed between the '78 and '79 other than the reed valve being added to the head cover. Maybe someone on this site has torn down both models and can identify the differences? Ed

The difference is the 79 has holes cast in the head that extend from the exhaust ports to the bottom of the valve cover, and then through passages to the reed valves mounted under those square covers you see on top. That allows fresh air into the exhaust to reduce emissions.

Other than the cast in holes the heads are identical, you can plug the holes with JB Weld and use the head on a 77 with the 77 cam/valve cover. The 77-80 head won't work on an 81 though, it uses a HyVo cam chain.

Kawasaki.com tells you what parts are identical (and it's not always right), not what parts will interchange. That's where experience steps in

You can use a 1980 KZ750E/H head on a 77 KZ650, but it will lower the compression ratio a smidgen. Reborn650 is using a KZ650 cylinder head on a KZ750 cylinder block bored for a 810 kit mounted on a KZ650 bottom end. I guarantee that Kawasaki.com will not tell you that is possible

As far as swapping the 77-80 cam chain idler sprocket onto the 81 head, I can't say for sure, but it wouldn't surprise me any since Kawasaki left those mounting bosses on the 750 heads all the way up through the 85 GPz750, and the 750 fours never used a roller cam chain. The bosses are not drilled though, you'd have to drill and tap them. Reborn650 had planned on doing so but I don't know if he has.

Post edited by: steell, at: 2008/01/22 23:27