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Discussion Starter #1 (Edited)
DUB's ZXR750 J1 rebuild.

Hi all from Perth, Western Australia. I've been having a look around at dedicated Kawasaki forums and yours looks pretty cool.

I've been mocking up parts I've accumulated over the years to build a custom ZXR750, or as you guys call them a ZX7R. Going to do things like lower the front suspension drag-bike style, slightly lengthen and widen the rear end to something like a 240-300 rear tyre. Maybe put a later model rear subframe on it.

I'm missing a top triple clamp and motor/box and this is where I was thinking maybe a ZX9 motor might go well in this frame. I haven't seen anyone do it but was wondering if anyone knows of a similar conversion, or if they even fit? There's been a couple of times I've seen a loose reference to using the 900 motor but I haven't seen any threads specifically for this yet. The frame is a ZX7RR K1. I was going to use this frame on my old J1 (after I polished it) but as it was never registered (race frame, never even had sidestand bolt holes) the rego authorities here wouldn't let me register it. Something stupid about it not having enough VIN numbers! Might as well make a mind blowing custom/show bike then!

A few pics>>




I've dropped the forks through the bottom clamp to get it sitting where I want it, but was just going to reset the springs to suit once it was loaded with motor etc.


Any advice would be very much appreciated. Cheers!
 

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Kind of liking that blue. Might be an option for the J I'm building. That or some shade of grey. Triple trees are are over e-bay for cheap as well.
 

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Discussion Starter #5
Kind of liking that blue. Might be an option for the J I'm building. That or some shade of grey. Triple trees are are over e-bay for cheap as well.
Yeah it's the stock colour the J1 came with. Liked it from the moment I first saw one when I pulled in the driveway of the guy selling the first bike I ever bought :)

The frame was the OEM gloss black but thinking an anodized silver or brushed black might be the way to go this time.

Was thinking of upgrading the forks to a much later model so I can fit radial Brembo brakes. These forks have a little rust and pitting in the hard chrome and the front ends now-a-days just make the older fronts feel ancient.

Really like the 96 ZX7R front fender too, it suits the bike so much better than the original.
 

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Discussion Starter #8
Hey, another West Aussie. :)
Be good to see how this turns out :)
Haha, feel like a new kid in the class standing up the front telling everyone my name and what I've been up to :rolleyes

Some stripped down beginning shots of the K1>>







 

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Discussion Starter #9
Well it's all happening now!

Got a lead on a '92 ZXR750 that had been sitting for at least 4 years in a blokes shed collecting dust. Got in touch and came up with a complete bike he had intended to make into a track bike but just never got around to it. Laid down the cash then and there and had it home in an hour, and stripped in another 2. Carbs look clean, a little sediment in the bowls. Should be only needing a carby clean spray and a balance.

Battery is stuffed as you'd expect, so new one tomorrow.

Will degrease, wash, scrub, detail the chassis/motor in the morning, and get new coolant, oil, filter, brake fluids, spark plugs, fork seals/oil too.

Pull all the little brackets off and send them off to the powdercoater to be sandblasted and refreshed.

Hopefully have it running and heading towards rego by the arvo, then let all the fun stuff begin :D

Should have taken a 'before' stripping shot but it just looks like another stock ZXR with a custom paint job on it.







 

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Discussion Starter #11 (Edited)
She runs :)

Gave it a good degrease this morning and had a better look at what was in need of attention. Left a nice oil slick heading out the driveway, especially after nearly 9 cans of degreaser.



Found one very heavily welded piston block. Never seen anything like this before. Looked like it had been cracked, welded, machined and re-installed so continued on.



Continued on and changed the oil, filter, new battery, replaced fuel lines and filter, re-installed carbs and tank. Started it up :) In need of a good tune, revs ok but short on fuel. Might replace the fuel pump tomorrow with a spare and see what happens. Getting a fast clicking sound from this pump every now and then. Symptom of a failing pump?

Electric fan works, stays under 1/3 temp, but carbs are all over the place.

Found an oil leak coming out the clutch slave area. Looks like there should be some kind of seal where the clutch rod passes through the motor and over to the clutch itself. Anyone confirm this?



Lowered the front about 1 3/4" and put a ZX7R front fender on it. Just mocking it all up at the moment. Then once it's all running complete I'll tear it back down and paint/polish/powdercoat/detail :)



 

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She runs :)



Found an oil leak coming out the clutch slave area. Looks like there should be some kind of seal where the clutch rod passes through the motor and over to the clutch itself. Anyone confirm this?

Yes, you are missing the clutch rod oil seal... its about $10
 

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Looks like who ever fixed that cracked block knew what they were doing... thats some nice tig work and not for the faint of heart to repair that
 

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Discussion Starter #14
Looks like who ever fixed that cracked block knew what they were doing... thats some nice tig work and not for the faint of heart to repair that
Yeah you got that right. My guess is the cam chain might have cracked the outer casing and hence the welds. The cam chain is still pretty noisy so might be doing some maintenance on that shortly. That should be fun.
 

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Discussion Starter #16
As I've mentioned before I would like to widen up the rear end of this ZXR for a fatter look. Ultimately a stupid wide rear like a 300 for shows would be great, but that's a long term engineering project. In the mean time I'm going to see what I can achieve with later model Kawasaki stuff.

Took an original 5 1/2" rim off to the wreckers to see what a late model 6" ZX7R rim looked like next to it, and came away with a stella deal on a whole swingarm/wheel assembly! Ultimately this is a far better set-up as it has the wider rim, wider swingarm to suit, and the rear caliper mounting is a lot cleaner too as it does away with the caliper torque arm. Something I really wanted to do as I want to put in a shorter exhaust muffler in the forward area the arm mounts to. The big question being does the swingarm fit in the frame?






Short answer, YES!!!:D (apologies in advance if this is a well known mod. It's all new to me!) I trial fitted it all up to my spare K1 frame with no issues at all.







I had to use the older swingarm main bolt, but the internal sleeve on the new swingarm is the same diametre, and the outer spacers are the exact same width as the old swingarm too. Looking at the shock it looks the same, but will have to mount it up to confirm this. I might try a later ZX7R shock to suit, but I'll have to move the battery to allow clearance for the gas cylinder.

Next is polishing and painting :D:D:D

Also found some Harris Engineering billet 6 pot calipers. Should add just the right amount of bling to the front end I reckon :)



 

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That swingarm looks great on there. Very nice factory mod. Is it the same length? How about the pickup point for the rear shock? My only concern would be throwing the rake and trail too far off, but it might be dead nuts.
 

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Discussion Starter #19
That swingarm looks great on there. Very nice factory mod. Is it the same length? How about the pickup point for the rear shock? My only concern would be throwing the rake and trail too far off, but it might be dead nuts.
Cheers, I was pretty stoked to see it all fitting in there too.

I'll be disassembling it to send off to the polishers shortly, but before I do I'll put the two swingarms together and see how they compare and report it back here.

The rear shock pickup looks dead-on. Don't think there'll be any issues there either.
 

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Discussion Starter #20
That 300zx is pure sex, i envy you to have both of my loves.
Cheers mate. That's a pretty old photo. I decided to rebuild it again but before I tore it all apart it looked like this>>









It's a juggling game between which one out of the Z and the ZXR gets the attention atm :)
 
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