ZX7 J2 Rebuild

[sixstring]

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.

[sixstring]

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:










Peace

[matthew]

Great write up so far. I'm looking forward to the progression of your project.

[arekzjawin]

Peace

Kawis bleed green..

[Freestyle72]

Nice build man. Love the level of detail and the pictures. Keep it up.

[ROOKIE]

good stuff bro.
I'd like to hear how this build goes.

[TheDirty]

Great write up so far. I'm looking forward to the progression of your project.

+1...

[Rotten_Ronnie]

I've subscribed.

Thanks for sharing!

[omnivore]

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.

[sixstring]

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):

http://zixiaozx7.blogspot.com/

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

@Omnivore
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

[omnivore]

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

[sixstring]

Updates! Lots of pictures! Engine finally out!

http://zixiaozx7.blogspot.com/

[sixstring]

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:
http://zixiaozx7.blogspot.com/

[Brian P]

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:
http://zixiaozx7.blogspot.com/

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.

[sixstring]

Bumping for a few more updates on the rebuild since my Pine Sol fiasco
http://zixiaozx7.blogspot.com/

[frekeyguy]

are you just sending parts out to get machined? but doing the assembly yourself?

[sixstring]

Yup - save what you can right?

[Shaman]

You could have bought my nearly pristine ZX7 and had a working bike right off. But I tip my hat to you anyways!

[omnivore]

Someday I wanna build a ZX7 into a kickass racebike!
Hat's off to you.

[inreb]

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.