Engine Build

Hey guys, I have a 79' and a 78' 650 engine. I want to strip the 79' completely and rebuild it to include blasting and paint. I am a little nervous since these Jap bikes don't just break down into nice little pieces, but come apart like a jig saw puzzle. Does anyone have any suggestions for a successful build? Also, anyone have pictures from an actual professional mechanics shop manual of the correct gear setup, not just the Clymer or Haynes pictures? I feel ok doing everything up to the tranny so any help will be appreciated.

Taking pictures, labeling and placing related small parts in plastic bags as you're tearing it down (which I neglected to do on my recent carb rebuild on my ZN :S) goes a long way in getting everything to go back together properly.

The diagrams listed on the Kawasaki.com website can give you a rough idea on parts break-downs.
I have the FSM for the 650, so if you want directions and actual pics of the disassembly process just shoot me a PM with your email addy and exactely what pics/disassembly procedures you need and I can scan and email them to you.
Also let me know if you want them in PDF (Adobe acrobat) or JPEG (.jpg)/TEXT (txt) form.

Sorry I can't help you But I LOVE your quotes!!! I have used both for years!!
There are many 650 and 750 guys on here who can and will help you;)
Pat

Hey Kellen -

The bottom end on these bikes are pretty much bullet-proof, so unless there is a problem upon inspection I wouldn't touch anything from the connecting rods downward.

Pull the cam cover and check the cam chain (single roller-type on your bike if I am not mistaken) for stretch. The service limit is measured on 20 links. Pull the cams and pull the cam chain tight. If it is between 160 cm and 162.5 this is the serviceable limit from the Kawasaki factory service manual for mechanics. If the measurement is beyond half way, I would put in a new chain while the motor is apart. Jeff at Z1 Enterprises can help you out with the rebuild parts you need.

Take off the head and once you have the motor out of the frame remove the cylinders. Split the top and bottom cases and take a look inside at the bottom end. This visual will give you an idea of how the bike was treated. I would get a set of stainless steel allen head bolts to replace the old factory fasteners.

You haven't said if you are going for a big-bore kit but I will assume that you are going for a complete rebuild including more displacement.

Replace all gaskets, oil seals and O-rings. If you are going with a big-bore kit, get the machining done by a shop that specialises in motorcycle engines. Make sure that they put a nice chamfer on the bottom of the cylinders to make re-assembly easier. It wouldn't be a bad idea to get the cylinder's mating surface and the cylinder head mating surface checked by a machine shop for trueness.

I had my cylinders bead blasted for a nice clean casting look. I prefer this to paint. The head was also also bead blasted and the rough aluminum finish is pretty trick.

Lastly, grab a cup of coffee and spend some time checking out the old archives of Kzrider.com I believe there is a link to a step-by-step rebuild of the Kz650 engine by a member from several years ago.

As R4 said, take lots of pictures and make sure that you bag and tag all of the itty-bitty parts so you won't have to kick yourself later on for losing key engine ingredients.

Cheers-Colin Firth-Ontario Canada

Colin? Don't touch anything below the con rods? How do you change out the cam chain? Do 650 owners normally change out the primary chain when they rebuild? Are replacements available? If I were to rebuild an engine, I would probably want to swap out cam chains at a minimum...

Kellen, I´m in the process of putting a 79 650 D (SR) engine back together after doing just what you are planning (bead blasting/paint etc.) - I did just like the guys suggest, so I´ve got heaps of pics of the disassembly and various bits and pieces, anything you want to see just ask.

Here´s an older pic of how it turned out, just the empty shell stuck together for a photo shoot - should have been finished long ago, but moving house and getting a GPz 1100 kinda got in the way:









Edit: As for the primary chain, I have heard lots of people complain about primary chain noise/clatter at low rpms, but I have never ever seen a primary chain break, nor have I ever heard about one breaking so I would just leave well enough alone (they do cost a pretty penny).

Post edited by: OnkelB, at: 2007/08/28 15:11

Guys, thanks for all the great advice. I have a better idea of where to start. Found the rebuild thread in the archives and think that will really be helpful.


Colin, I will most definetly take your advice and try to leave to bottom end alone. Where do you recomend getting a big bore kit from?

OnkelB, thanks for the offer of pics. I'm sure you will be hearing from me. Still have a ton fab work to do on the frame and tins along with the rest of my laundry list for this build but hopefully with all the help on this site it will be ready for next summers season.

wiredgeorge wrote:

Colin? Don't touch anything below the con rods? How do you change out the cam chain? Do 650 owners normally change out the primary chain when they rebuild? Are replacements available? If I were to rebuild an engine, I would probably want to swap out cam chains at a minimum...

George - As I said.....The bottom end on these bikes are pretty much bullet-proof, so unless there is a problem upon inspection I wouldn't touch anything from the connecting rods downward.

From my (admittedly limited) perspective having focussed only on this engine for the past few years, there are not a lot of examples of members having problems with the bottom ends of the 650 platform.

It has been said here before that the 650 crank, primary chain, transmission and connecting rods are pretty durable items. I would like to use the term over-engineered, but this is a term relative to how much effort you want to put in to break a part.

Perhaps this is because 650/750 guys don't build them to the maximum limit like they do for the 900/1000/1100 platforms which are often used for drag bike applications where welded cranks, backcut gears and high strength clutch parts, wild cams and heavy duty engine studs are mandatory to keep the engines together. In short, the big motors are stretched far beyond the levels that are asked for with traditional 650/750 upgrades in my opinion.

As I mentioned, an inspection will likely point out any potential weak spots, but there is no sense on tearing everything apart if it isn't warranted from a good, thorough inspection.

As far as the primary chain replacements, I haven't touched mine and so far it has held up to my regular hard abuse. I cannot supply any information on whether the primary chain is available from Kawasaki but I suspect one would have to mortgage their house to buy one from Kawasaki:(

As far as the cam chain, obviously the absolute best way to do a new chain swap is to pull the bottom end guts out and slip and new endless chain in. But as you know George, the old roller chains may simply be split and the new one looped through and peened to connect the two ends thus eliminating having to pull the crank and pay for new seals.

My comment regarding from the connecting rods down would exclude the wrist pins which will have to be changed if you are putting in an aftermarket big-bore kit.

Just my 2.5 cents worth of experience on this type of rebuild which I have done twice in the past few years with the Wiseco 700 and 810 kits.

Cheers-Colin Firth-Ontario Canada

Kellen79_650 wrote:

Guys, thanks for all the great advice. I have a better idea of where to start. Found the rebuild thread in the archives and think that will really be helpful.


Colin, I will most definetly take your advice and try to leave to bottom end alone. Where do you recomend getting a big bore kit from?

Kellen - Just to clarify something here, the stock 650 cylinders can only go to 700 with the Wiseco kit. To go all of the way to the 810 you will need to get your hands on 750/4 cylinders and have them bored to handle the 810 pistons.

You will have to split the bottom end engine cases and slightly enlarge opening in the top cases to handle the larger 750 cylinders.

I ended up getting my Wiseco 810 kit from a local bike shop customer of mine whom I do a lot of business with. I try to spend my cash with customers who support my newspaper business.

I would suggest getting in touch with Jeff @ Z1 Enterprises. Even though he doesn't list them on his website, I am fairly confident that Jeff can source the 810 kit for you at a very competitive price. He is a member on Kzrider, is very knowledgeable and truly understands exemplary customer service.

If you are looking at some other upgrades check into a set of Kz or Gpz750 cams and bigger valves. Perhaps you can even locate a complete 1980 Kz750/4 cylinder head that will be a direct bolt in for your cam chain set up. The Gpz cams are more potent than the Kz cams and they really come on strong in the upper rpm's but you will have to run without a tach (like me) or wire up an electronic one as the Gpz exhaust cam doesn't have a tach drive machined into it like the Kz650/750 cams do.

A bit of time spent on porting the head will garner you some better breathing and extra power. This is not too difficult of a job to handle for anyone with a little time and mechanical ability. If you do decide to go with the porting route, you might want to check out www.oldkawman.com where he has a little step-by-step display on how to do porting (just try not to linger too long on his daughter's bikini/bike collection pics.)

There is a ton of information here on Kzrider that will help you head down the correct path on your chosen rebuild, and if you have any questions, there are many members that are always willing to lend some advice as the 810 is a fairly popular option given the high number of 650's that are being brought back to life.

Keep us posted on your progress.

Cheers-Colin Firth-Ontario Canada

Gee, THANKS, Colin. And then of course had to click on "oldmankaw" and scroll down the left side and click on "more pics of melissa". Was there a bike in there somewhere?


Edit --Oops, it's oldkawman instead of oldmankaw. Well to heck with him, I got the melissa part right.

Post edited by: Patton, at: 2007/08/28 19:25

Patton wrote:

Gee, THANKS, Colin. And then of course had to click on "oldmankaw" and scroll down the left side and click on "more pics of melissa". Was there a bike in there somewhere?


Edit --Oops, it's oldkawman instead of oldmankaw. Well to heck with him, I got the melissa part right. <br><br>Post edited by: Patton, at: 2007/08/28 19:25

Uhhhh...sorry there Patton. I hadn't been to the site for a few years and my memory has been known to waiver when the barometric pressure is on the rise:)

Anyhow, his info is a good place to start as far as the basic information on the porting project. There is a reasonable explaination with pictures of the porting - before and after.

www.oldkawman.com/

Oldkawman has a link set up from APE's page under used Kz parts but I don't think that the parts pics are updated very frequently judging from the 650/750 parts I first saw a few years back.

Any more details one wants to delve from his site is up to the individual user. I was kinda puzzled to see the pics of his daughter modelling beside the old K bikes the first time I went to look at the site. To each his own I guess



Cheers-Colin Firth -Ontario Canada

I was kinda puzzled to see the pics of his daughter modelling beside the old K bikes the first time I went to look at the site. To each his own I guess



Cheers-Colin Firth -Ontario Canada[/quote]

I'm with ya man! Don't really look old enough to me, but...

Still, the info is pretty good, especially the big bore stuff was pretty interesting.