View Full Version : ZX7 J2 Rebuild

11-08-2010, 02:09 AM
Visit my rebuild blog here: http://zixiaozx7.blogspot.com/

I got ahold of this rough J2 about a week ago. The plastics were in good shape but just about everything else needed some attention. The main problem being some serious engine knocking and shot suspension.

So after a few hours of work, here's what the bike looks like:

Battery box and undertail - gross

Cockpit fixtures look good

Getting the subframe off

Gas tank is in decent shape

Body plastics arn't bad either

Oooooo... color matched seats

The rear hugger came with this little guy attached to it. Apparently one of the previous owners is an anime fan

D&D end can sounds nice... Would still rather have a muzzys

The headers and midpipe are a different story. Yikes! Apparently all ZX7s suffer this ****** header problem. Even the late P models are plagued by rusty pipes. Anyone notice the exhaust is WELDED onto the mid pipe? Odd no?

Airbox to be tossed and replaced with pod filters

Carbs are in surprisingly good shape

Closeup :)

Manifolds in good shape

An indication of the neglect this bike has gone through

Engine cover looks surprisingly clean

I'm currently cleaning the subframe and the rust/calcium cacked bolts. Next I'll be removing the radiator, headers, and ultimately the engine. I'm also trying to decide if I want to redo the coating onthe subframe/frame or just clean it up a bit and call it a day. Decisions decisions.

11-13-2010, 03:04 AM
Stopped working on the bike for a few days to make plans for the garage. Did some more tearing into tonight. Tonight, I managed to take off the radiator, headers, headlights and instruments, wiring harness and rear wheel.

Taking off the radiator was a huge mess. I wasn't sure exactly what the correct procedure was so I just started unplugging hoses. I managed to catch most of the coolant that came out but things still got pretty messy. Ended up through half a roll of shop towels.

Look at all those pipes! I wonder which one to remove first...

With the radiator removed, the headers came next. The pipe was basically welded into a one piece unit. Because it was so big and I was alone, it was a bit of a pain taking it off... and I'm rewarded with the filth thats built up on the engine cover. Gross

Headlights came off pretty easily.

The wiring harness was by far the most time consuming thing to remove because I had to take pictures of the wire routing, where wires were hooked onto the frame and of course label each wire on the harness to it's corresponding component. I hope all this work makes putting the bike easier to put together.

This picture makes note of the main wiring harness' routing but you can see all the lables I put on the cables

And after a long and grueling battle, the beast lays defeated on my floor

The rear wheel also came off without much incident.

Good god the swingarm is FILTHY. This pictures does NOT do justice at all to how down right raunchy this piece is.

The area behind the front sprocket cover also deserves mention for being especially nasty.

So thats where my bike sits now. It's basically ready to drop its engine so I can crack it open and have a look at whats causing it to knock. Some more pics:






11-14-2010, 12:36 PM
Great write up so far. I'm looking forward to the progression of your project.

11-14-2010, 01:57 PM


Kawis bleed green..

11-14-2010, 03:43 PM
Nice build man. Love the level of detail and the pictures. Keep it up.

11-15-2010, 04:53 AM
good stuff bro.
I'd like to hear how this build goes.

11-15-2010, 09:25 AM
Great write up so far. I'm looking forward to the progression of your project.


11-16-2010, 06:53 AM
I've subscribed. :)

Thanks for sharing!

11-16-2010, 09:23 AM
Way cool. I love old ZX7's.
I'd pass on the pod filters though. Unless you are building a highly tunes racebike, it may just cause carbeuration glitches on humid days, cold days, rainy days etc etc.

Airboxes don't hurt performance anymore like they did 30 yrs ago. Besides, the pods will only have access to hot air under the tank being blown outta the rad. The airbox gets a dose of cool air thru the hoover tubes from the nose of th ebike.

11-16-2010, 10:20 AM
Thanks for the responses everyone. In addition to posting here, I've also started a much much (in my opinion) better written and laid out blog here (I've also updated the first post with this link):


I'll continue to duplicate major posts on this forum.

The ZX7 J's don't have any ram air! Those massive hoover tubes do nothing but waft cool air onto the gas tank... and look awesome. The system is rumored to cool the top of the engine which does what....? Anyways, the angle and material of the tube makes it such a useless air conduit that whatever its intention may be, it's effects are negligible.

I see your point about drawing in warm air however... Maybe I'll do some experimenting when the time comes.

Thanks again everyone

11-18-2010, 11:55 PM
Iknow it's not true ram air. But cooler air, even wafted in is much better. Every 10 degrees you can cool the intake charger equates to roughly a 10% increase in power....this obviously will be an increase of diminishing returns of course. Youc an't continute to increase power indefinitely just by lower intake temps, but the oxygen density is greatly increased with cooler temps.
As an example, early R6's with the plastic shroud between the rad and airbox have been tested to dyno as much as 10 hp lower than equally prepped ones with the shroud left intact.

This is why I always try to use a large an intercooler as possible on my turbocars. Same level of boost, run thru larger intercooler = lower intake temps = torque steer and wheelspin at 125 kmh in 3rd! LOl

11-24-2010, 08:40 PM
Updates! Lots of pictures! Engine finally out!


12-05-2010, 11:49 PM
Some more updates and a question:
This is the second time I've tried to clean some parts using a soaking solution. First I used CLR, and now Pine Sol.
Each time I the results are stripped finishes on the parts and this white crap that ends up caking on the parts and on the containers.

Refer to this picture:

Or my blog:

Brian P
12-12-2010, 05:18 PM
Some more updates and a question:
This is the second time I've tried to clean some parts using a soaking solution. First I used CLR, and now Pine Sol.
Each time I the results are stripped finishes on the parts and this white crap that ends up caking on the parts and on the containers.

Refer to this picture:

Or my blog:

The household cleaners that you are trying to use are not meant for degreasing engines, they could cause corrosion, and could damage seals. Don't try to do that again!

WD-40 and kerosene both work decently for breaking down grease. Spray it on, leave it for 15 minutes. For really heavy grease, use a grunge brush or an old plastic-bristles brush. Old toothbrush works for small parts, old dishwashing brush for bigger parts. Then spray a proper de-greaser at it. You can get several kinds of engine de-greasers at Canadian Tire. The "Gunk" engine degreaser is a very strong de-greaser. Simple Green is a very mild de-greaser. I've done this by first kerosene then Gunk, then spray it with a strong stream of water, then Simple Green, then another spray with water.

DON'T, and I repeat again, *DON'T* use this approach on assembled carburetors! You have to be gentle with carbs and you have to NOT get water or solvents or foreign substances of any sort into critical areas. Usually carburetors are best dealt with by taking them apart and dealing with individual parts but BE CAREFUL and don't get foreign liquids into places that it shouldn't get to!

I have heard good things about ultrasonic cleaning, but I've not tried it myself.

Also, anything that you clean using water or water-based solvents should be thoroughly dried afterwards - a jet of compressed air works well - and any steel/iron parts should be immediately sprayed with a light coat of oil to protect them from rusting.

12-29-2010, 03:03 AM
Bumping for a few more updates on the rebuild since my Pine Sol fiasco

12-29-2010, 07:33 PM
are you just sending parts out to get machined? but doing the assembly yourself?

01-01-2011, 04:57 AM
Yup - save what you can right?

01-01-2011, 12:01 PM
You could have bought my nearly pristine ZX7 and had a working bike right off. But I tip my hat to you anyways!

01-01-2011, 02:46 PM
Someday I wanna build a ZX7 into a kickass racebike!
Hat's off to you.

01-02-2011, 10:13 AM
Use the airbox. To many downsides to pod filters.

I use a big plastic tote box, water and dish soap to remove 95% grunge then lay the parts on old towels and work them over with liberal amounts of kerosene. Then spray with wd40 to remove all traces of water.

Good write up, btw.

03-27-2011, 04:07 AM
Been a while since my last update. Here's a copy-and-paste from my blog:

Well I've been wrestling t-rexes, drop kicking space aliens, and most definitely NOT cowering from the bitter cold of my garage. However, between head-locking thunder lizards and double-legging Xenu, I have managed to order a bunch of parts and prep my crank cases for bottom-end assembly.

So far the most tedious part of this entire rebuild is prepping the mating surfaces of the two crank cases. This basically involves removing the silicon-based gasket material from the upper and lower crank case halves.

You can see the black gasket material in the holes. The funny texture is due to some liquid gasket remover I tried which was a waste of $15.00

My impression is that most people use a die grinder with some abrasive pads. Now, I have very little confidence in my ability to use power tools so I figured the next best thing is a razor to shave off the excess gasket material. This resulted in a decent scar on the mating surface... nothing serious but its definitely there. Lucky for me having (apparently) twitchy hands is well suited for scrubbing away with scotch brite pads and occasionally steel wool so thats exactly what I did... Except theres so many silicon filed holes that the pads can't easily get into which were a HUGE pain to clean out but in the end I think I did a pretty good job.

BAM! Cleaner than eating utensils

Cleaner than surgical instruments

The first thing I was about to do was to reinstall the alternator shaft bearing. However its a REAL tight fit and needs to go directly into the upper crank case. I decided to put the bearing in the freezer can do a little shop cleaning and the end result is:

Tada! Now I'm more organized

Crisp new pistons

Clean enough to eat off of

Tub o tranny parts (mostly)

and I cleaned up my bench too! New additions to the bench include the 4 inch vise and parts cleaner courtesy of Princess Auto :-)

OEM goodness! Notice the Tsubaki timing chain. I've got a APE manual tensioner too (not in pic)

For more pics from this post, go to my photobucket page here (http://s1232.photobucket.com/albums/ff372/zixiaoliang/ZX7%20Rebuild%202011_03_27/).

04-05-2011, 12:23 AM
An update from my blog (http://zixiaozx7.blogspot.com/)

So like I mentioned in my last post the first order of business was to install the alternator shaft which required an interference bearing to be pressed into the clutch side of the upper crank case. This turned out to be a huge pain. Heating the case and cooling the bearing didn't work. I even tried to make a half-assed bearing press which not only failed to press the bearing into place but did more harm than good.

This reeks of fail

Pictured above is a simple bearing press like any other home made device. You have a threaded rod, the bearing is fitted against a socket as shown and on the other side we have a washer to serve as a solid surface.

Oh damn, the stench of fail is overwhelming the senses

But what could go wrong with such a simple contraption? Well when the designer is a ****ing moron (yours truly) apparently a lot can go wrong. Long story short, I torque the end with the socket, the bearing starts to slide in a bit and the next minute I realize the washer pictured above had got bent and pulled through the hole it was sitting in. FUUUUUUUUUuuuuuuukkkk!!!!! At least that was my initial reaction. Upon closer inspection about half a mm of aluminum got taken out of the lip and no substantial damage was done.

See? No harm done here, moving along then....

How did the bearing finally get put in place? Well I brought it to a local shop and by gently tapping the bearing with a socket, the dude got the bearing to slide right in.... I was overcome with shame, awe and relief. I imagine this is what people feel when the suffer from premature ejaculation; something real men like me don't have to worry about har har har

This bearing is responsible for ruining my life

Yayy!!! All put together now :)

I turn my attention to the crank and bearings while the transmission is still out; makes mating the case halves much easier.

So much wasted plastic

Alright, LETS DO THIS!!!

Crankshaft, check...

Knockoff plastigauge, check ...

Engine bolts, check

Why, hello there Mr. Plastigauge ...


~0.040mm ... well, a tad on the loose side but well below the maximum

Anyways I move on to the transmission starting with *drum roll*

...the shift drum...

...and shift forks

Next I take a look at the main shaft and ...

... WTF HAPPENED HERE!??! Lucky for me I bought half a spare motor

Thats me peeing on the main shaft...

All the main shaft components in their glory

... continue ...

04-05-2011, 12:23 AM
... continued ...

Now that I have a (small) parts washer and air compressor, I don't know how I ever lived without them

Cleaner than a shaved beaver. Note the ball bearings, I nearly lost them TWICE! Yes I'm that retarded.

The gears look to be in good shape...

...and the fork cavities look to be within spec

Now all we need to do is add some engine oil ...

... and we're off. Note the heavy(ier) duty snap ring pliers; the transmission shafts are a massive pain


Into the engine we go now.

Now for the output shaft

Doesn't that just look magical? New bearings, fresh bearings, and clean aluminum... oops I just messed up my pants

Here's some more tranny porn for your fapping pleasure

Next I do a test fitting of the crank shaft, crank case, and transmission starting with some molly grease

With the crank shaft in and gears in neutral, I mate the two halves together


Everything looks (and feels) about right

So my next step is to find a high quality and calibrated torque wrench to torque up the rod bolts as well as the case bolts. The ****** Canadian tire and Harbor Freight stuff just isn't giving me all the confidence in the world right now. Plus I'm curious as to how a better torque wrench will effect my oil clearance readings....

04-05-2011, 01:16 AM
This thread and blog is all kinds of awesome. Subscribed.

Brian P
04-14-2011, 10:41 PM
First time doing an engine? Every time I do this job, I'm so focused on getting it done that I never take pictures.

It looks like your next step will be mating the cases together. Use a good quality RTV and use very little of it! Don't miss any spots, but a fine line of it around the perimeter is all that's needed. I like to put that line of RTV on one of the mating surfaces but towards the outside of the engine, so that when it squeezes out, more of it squeezes towards the outside than towards the inside. Loose bits of excess RTV sealant can cause trouble later, thats why you should use as little of it as you can get away with.

I know some mechanics who swear by the Suzuki crankcase sealant. It is expensive but it is good stuff. But, I've been using Permatex black and I've never had an issue with it - and it's cheap and you can get that at Canadian Tire.

06-17-2011, 12:56 PM
More updates from my blog (http://zixiaozx7.blogspot.com/):

With riding season in full swing I've found it increasingly difficult to find time to work on the J2. Between rides to cottage country and doing crap around the house, the J2 has a hard time getting on my calendar.

http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0276.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0276.jpg)

Fast bikes ...

http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0274.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0274.jpg)

... sweeping hills ...

http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0285.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0285.jpg)

... peaceful lake towns ...

http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0291.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/Port Sydney/IMAG0291.jpg)

... and ducklings! Its a good summer :)

On top of all that I bagged myself a ZX7 N1!

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 N1 2011_06_17/IMAG0047.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 N1 2011_06_17/IMAG0047.jpg)

The first and last generations of the ZX7 P/N

Anyways, about a month back, I had my cylinder head and valves machined. The cylinder head had its mating surface leveled and ports ground down a bit to help with flow into and out of the engine combustion chamber. The valves got a two angle cut. All the work came out to roughly $200.

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0300.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0300.jpg)

Clean! Hard to see, but those ports have been rounded out

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0302.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0302.jpg)

Looks cozy in there

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0313.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0313.jpg)

Can you see the two angles? ... well its there!

Other goodies include fancy new BLUE valve seals and valve seats, caps, and springs off of a ZX7 K1.

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0320.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0320.jpg)

Dear lord they're SO BLUE!! Nothing says 'aftermarket' like fluorescent, flamboyant colors.

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0315.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0315.jpg)

ZX7 K bits! Neat!

So now I get to put all this stuff together which was a massive pain. Lots of small pieces to get lost and plenty of nooks and crannies within the head itself for things to hide. The fact that there are 16 valves just multiplies the grief.

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0340.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0340.jpg)

Nothing like some good 'ol fashioned valve lapping to bore to you sleep at night

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0337.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0337.jpg)

ZZZZZ... zzzzzzz...

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0356.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0356.jpg)

All that *** pain gets you a hazy ring around your valve seats as demonstrated by the valve on the left

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0360.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0360.jpg)

The same effect can be seen on the valve port (left is lapped)

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0363.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0363.jpg)

Just repeat that 16 times and your done!

Next, it was time to get the springs back in the head. Installing the valve locks was the BIGGEST pain in the *** EVER. They're so bloody tiny and you've gotta manipulate them with tweezers in this confined space within the valve spring compressor. I've lost count of the number of times I had them squirting out form between the tweezers and shooting across the room. This is usually followed by a flurry of curses followed by 10-20 mins of crawling around my garage looking for a piece of metal approximately 5x5mm. Grrrr

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0372.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0372.jpg)

Half way there

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0375.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0375.jpg)


http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0381.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7 Rebuild 2011_06_17/IMAG0381.jpg)

Sexy blooming effect :)

06-17-2011, 12:57 PM
Installing the rocker arms afterwards was simple in comparison.

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7%20Rebuild%202011_06_17/IMAG0382.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7%20Rebuild%202011_06_17/IMAG0382.jpg)

Rock out with your block out!

http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7%20Rebuild%202011_06_17/IMAG0384.jpg (http://i1232.photobucket.com/albums/ff372/zixiaoliang/ZX7%20Rebuild%202011_06_17/IMAG0384.jpg)

More blooming sexiness

You probably haven't noticed but the resolution of all these pics are different from ones in my previous post. That's because I got a new HTC Incredible S which has a 8 megapixel camera! That's right all these AWESOME pics were taken with a freaking PHONE!!!! Win.

11-21-2015, 04:37 PM
I hope you finish your project by now !;)