85 GPz750 Refresh Project

Petcock blown apart and finished cleaning and removing the ethanol deposits/oxidation, then buffed and polished the plunger seat inside of the petcock main body, reassembled after lubing with WD-40 and shows the plunger spring that I stretched to double its original length from ~26mm to ~52mm.

Carb bank installed after setting float bowl fuel service level height which for the 83-85 GPz750 is 3mm+/- 1mm so ranging from 2-4mm. Note the soft pliable airbag boots and the new carb holder boots via Z1E. Also note the new vacuum lines from the t-junction below the frame tube to the carburetors, everything cleaned and looking very nice.

Finally changed the oil with Rotella 15w-40 and STP Oil Additive to up the ZDDP content, life is good and by the end of the night got to fire her up and listen to her purr Can confirm there is NOT a problem with the starter, maybe something in the electrical circuit will have to wait and see but the starter worked perfectly every single time and the bike lit on the very first crank after putting the carbs back on and hooking everything up again.

I have a short 40 second video of firing her up for the first time, will have to find a way to upload and post it since I have never done that before, but should be able to have it up sometime today.

Still need to flush the front and rear brake system and replace with new DOT 3 fluid and then bleed the brakes. Based on the supplemental information section in the FSM it seems the proper way to bleed these is in separate stages for the front. I read somewhere that taking the calipers off the bike but still connected to the lines helps and gets a better bleed and therefor less squishy brake feel, can anyone chime in on that? Will do whatever way is best, but if I can properly bleed with the calipers on then would prefer that as it is less time and effort to take them off and then reinstall. Lastly, need to do a running dynamic sync on the carbs, properly adjust and set the idle, and adjust and set the pilot circuit (I think thats the right way to say that?) and then she will be fully ready for the road. Over the follow 4-8 weeks will pull off the front forks and rebuild them with progressive springs, 15W fork oil and new bushings and seals, and then clean and de-scale the inside of the donor gas tank and install the Murphs petcock conversion kit and swap tanks. That should be all of the major "rebuild" or "modification" steps for this riding season though I am sure I will be cleaning, or refurbishing or adding small things here and there. Next fall/winter will be taking all of the plastics and fairings off and stripping them and repainting to factory new with new decals as well, hope to also get a replacement smoked windscreen on it at the same time too since mine is cracked in a number of places near the mounting holes.


- Brett

Irish-Kawi wrote: hope to also get a replacement smoked windscreen

I'd be interested to hear which route you go with this, since I'll be doing the same soon. Near as I can tell we've got four options:

1. There are several suppliers in the UK, but shipping puts the cost above $120.
2. There are the Maier (sp?) aftermarket ones available here in the US, but those are close to $90 with shipping.
3. There's Bikescreen.com (aka Gustafsson), which I suspect are probably the best quality but also above $120. They also need to be hand-drilled.
4. There's an OEM one floating around on eBay, but the cost is over $400.

ayeckley wrote:

Irish-Kawi wrote: hope to also get a replacement smoked windscreen

I'd be interested to hear which route you go with this, since I'll be doing the same soon. Near as I can tell we've got four options:

1. There are several suppliers in the UK, but shipping puts the cost above $120.
2. There are the Maier (sp?) aftermarket ones available here in the US, but those are close to $90 with shipping.
3. There's Bikescreen.com (aka Gustafsson), which I suspect are probably the best quality but also above $120. They also need to be hand-drilled.
4. There's an OEM one floating around on eBay, but the cost is over $400.

Great info and thanks, I'm planning on getting one of the Maier pre-drilled smoked screen because I have no desire to drill the mounting holes myself and risk cracking it. I have found a number of windscreens in Japan.webike.net too fyi, just not overly excited about waiting for shipping time from Japan and to possible shipping costs.

- Brett

Been sick the past few days so not much progress. However on the road to recovery so have an evening lined out tomorrow night to flush and change the brake fluid (including properly bleeding as per th FSM and the supplemental information for the ZX750-A3) as well as change the spark plugs and put a few more pieces back on. Then Thursday will spend the day in the garage doing a running sync/tune in the carbs and get the idle and choke dialed in then fully button her back up. If all goes well (knock on wood) I should be riding her back from Pops' to my place where she will live anytime I'm not working or modifying her this season

- Brett

Irish-Kawi wrote: I'm planning on getting one of the Maier pre-drilled smoked screen

I wound up grabbing a clear one on eBay this morning, clouded but with no cracks. I'm hoping I can polish it to the point that it's acceptable. I also wound up getting several other small items that I haven't been able to source. Mine is very close to being road-ready.

ayeckley wrote:

Irish-Kawi wrote: I'm planning on getting one of the Maier pre-drilled smoked screen

I wound up grabbing a clear one on eBay this morning, clouded but with no cracks. I'm hoping I can polish it to the point that it's acceptable. I also wound up getting several other small items that I haven't been able to source. Mine is very close to being road-ready.

Congrats and very kewl, best of luck on shining it up and getting her running!

I just got back from picking up brake fluid and plugs for mine (proper B9ES NGK's for the USA model GPz, the EU and other KZ's used different ones) and those go in tomorrow night. The list to get her riding is getting small...

1. New plugs
2. Flush brakes and replaced and bleed
3. Tune/sync carbs running and idle/choke
4. Check tire pressure and chain deflection
5. Ride the dirty girl!!!!!

Brett

Well got to put in a good 3.5hrs tonight work in the bike after wrapping up at my day job lol. Got all but two things left in my "list to riding" done! Got the collar spacer sanded and polished down a bit more, spent a few hours sanding and shaping down a PVC flange plug into a custom made PVC washer to ride between the grip and the brass collar, throttle responds flawlessly now

Flushed the front and rear brake system and bleed all the fittings and components. The front MC under the cap and the rubber seal was horrid, filled with crystalized salt looking deposits that looked like a corroded battery deposits actually. Cleaned those pieces up and removed all of it and clean with wire brush.

Replaced the spark plugs and gapped at .75mm right in spec and saved the old plugs to examine closer tomorrow. Checked the chain deflection and set it to within spec, looked at the eccentrics to see about flipping them but when I looked at the identical swing arm three feet away on the other 85' donor/project bike those eccentrics were 180 out from mine. So one of them has already been flipped by a PO but I have no idea which one is stock and which one has already been flipped???

heres a pic of each swinger...

Donor/Project 85'

Mine:

Set the tire pressure, tried to adjust the antidive units to find out that yes the dials do turn but unless it is set on setting 1 the dials spins like it's not even connected, so no mechanical click or detent or anything like when the dial is on 1, so thinking the units are likely shot but don't know. Set the air pressure and dampening up in the rear shock too and checked the end okay if the clutch lever and within spec. A lot of very small little things but thanks to all of that there are only two items left until I can't start riding her whenever I want and have her live here, and that's to bolt in the reworked to manual petcock, and do a running/dynamic tune in the carbs and setup idle. Then it's slap back on the tank, put the body pieces back on and head off into the sunset calling phase 1 of the resto-mod complete!!!

Speaking of riding off into the sunset, since she is going to be parked and living on the back patio under the 10' X 10' awning, I got a few goodies in the mail today and built the little ramp I need to bridge the 6" step up from the parking lot to the patio. Picked up a disc lock and came with a long helmet lock and disc log reminder cable. Scored a super heavy duty steel cable that used to be used in construction sites from Pops and will be able to fully lock and secure behind the fence and gate out of view and covered by the awning to keep most of the elements off her.

Will post up the last chapter in phase one tomorrow when I get it tuned and fully back to beautiful and riding, and will try to get a video as well!

Brett

Few more pics of the lock stuff...

Very nice.
Steve

Well she is 100% done with Phase One and is now home with me and locked up in the back porch! Licensed, registered and insured woohoo! Got the carbs synced up and tuned and everything back in it together and I gotta say she just purrrrrrrrrrrs idling flat and solid perfectly at 1050rpms, very quiet mechanical ticking from the valve train and carbs if you listen closely and it's just like music so so nice! Got geared up and took her for a short 35 min ride home and so pleased I did all the work I did. The throttle is extremely responsive nearly twitchy (in a pleasant way) and the brakes are three times as good as they used to be and haul it down fast. As soon as you twist the throttle back it just wakes up and howls like a banshee and pulls hard all the way to 10.5K!!! Look I know it's nothing like the power of most y'alls bike but holy cats was this a gas and made me grin and hold on every time I rolled her back

Was pressed for time so didn't get a video, but her she is at home safe behind the fence locked up with multiple locks and a perm any awning over her. Turn 28 Sunday and doing a good multi hour ride with Pops, going to clean her up and make her shine and get some good pics and a good video then and post. Thanks for listening to my meandering ramblings and hope it was at least interesting to read.

Stayed tuned for Phase Two coming up!!!! :evil:

Keep the rubber side down y'all,
Brett

looking good and keep the rubber side down you stole my saying lol thats what i tell all of my biker friends .looks like my a3

Honda was still holding out with their CB 750. I think it was the Super Sport. Yeah they came out with the DOHC but by then they were reading plates. That machine is no slouch. I'd ride it. :woohoo:
Steve