Sudden and repeated loss of cash.. aka restoring GPz900R engineering help needed Auck

[Mal]

Hi - long time lurker but this is my first post, nice to meet you folks!

I've decided to throw caution to the winds.. and probably my marriage with it and have a go at getting the old Geeper running and back on the road this winter. I really don't want to be outside anyway....

First order will be sorting the fuel tank out - at long last Ive sourced a reasonable tank from a legend called Stephen.. thanks buddy! Now I need to get her acid dipped and then rust removal / braze up any small holes. Has anyone Auckland based done this before? Lots of places to get wheels acid dipped etc but looking for some recommendations please. Also any suggestions on rust removal and someone to braze up a couple of pin holes? I'll line the tank after with POR15 or similar.

Next task - wheels swap out to 17 inch. I've got the front end from an A8 GPz which features the elusive 17 inch wheel and I'm going to change the 18 inch rear to 17 inch also, either ZZR600 4.5 wide or ZZR1100 5.5 wide. I'm pretty handy with the spanners but need an engineering place preferably close to me in Waterview that can help with machining up some spacers and milling down the sprocket carrier if I go the ZZR1100 route. Any suggestions would be gratefully received !

Also does anyone have a ZZR1100C model rolling chassis? I could use the entire front end and swing arm/wheel/caliper/sprocket carrier etc.

I'll start posting some pics of the progress to keep me motivated, I'll get her running again first which means the sodding carbs are going to have to come off again.. putting them back on is an absolute nightmare.

On that note did you know that if you soak the old hard carb rubbers in wintergreen oil it makes them soft and flexible again.. and as an added bonus makes the old girl smell kinda sporty...

Thanks for your help folks!

[husaberg]

Good stuff i understand the wintergreen oil only works if they are not cracked.
Years ago there was tire dope for tires that a Kiwi guy used to make that's main ingredient was clearly wintergreen oil'.
we used to use rubber grease wd40 brakeklean to help, plus multiple people.
Funny enough i was just reading up about the GPZ750 today.

[F5 Dave]

Every man needs a resto project at least once.

Fan heater aimed at rubbers before you try esp in winter. I've never tried but some use ratchet tiedowns around block at pull carbs in. Bit of grease of course, I have used a block of wood on the flats and mild persuasion with rubber mallet.

Wheel swaps are always fun because there are so many moving parts. Research what tyres you intend to use after the swap, (unless you ended up with ubiquitous 120/180 but that isn't the plan), may be BT46s are available for old wheels or new just slightly wider is only benefit.

[pete376403]

https://www.wemoto.com/parts/picture/pw-706-109 - not worth the hassle if new ones are available, carbs should go on easily

[Mal]

Thanks Dave, yes agree & the main thing is its such a waste having what was once a great bike waste away in my garage.. she deserves better, much better.!

The carb rubbers to the airbox are the nightmare... they need to be rolled back on themselves before the carbs can slide into place.. not easy when they are completely solid! But everything is possible and I've done this same job many, many times.
The carb to engine rubbers are best warmed up by soaking them in hot water with 10% wintergreen oil then assemble while still warm.. works a treat!

Do you have any leads on engineering places that may be able to help with the new rear wheel? I could just ring around but would prefer a place others have used and recommend!

cheers Mal

Every man needs a resto project at least once.

Fan heater aimed at rubbers before you try esp in winter. I've never tried but some use ratchet tiedowns around block at pull carbs in. Bit of grease of course, I have used a block of wood on the flats and mild persuasion with rubber mallet.

Wheel swaps are always fun because there are so many moving parts. Research what tyres you intend to use after the swap, (unless you ended up with ubiquitous 120/180 but that isn't the plan), may be BT46s are available for old wheels or new just slightly wider is only benefit.

[F5 Dave]

Yes, but at wrong end of the country for you. You need to find a gnarled old toolmaker still with manual machinery and a few motorbikes tucked into the recesses of the bombsite of a workshop.

If you have to cut the wheel back, say to inboard the disc a little that requires quite a big lathe.

Kawi onto Kawi should maybe be easier if not generations apart. I've done it maybe a dozen times both ends.
The most important starting point is axle diameter and then if you can line up discs and drive clearing frame and bigger rear tyre while staying in centre and inline with other wheel.

Alternative bearings can sometimes help with axle issues but need to consider bearing rating and complete left to right interface with other parts. Internal hub and cushdrive spacers need to still be there to take the load or bad things will happen fast.

Consider calipers. I made a stunning improvement using CBR calipers on my old GS11. But about when I was selling it they started bringing in LVV certification so the poor guy who bought it may have failed a wof the time after next inspection I guess. Sorry dude not my fault. So if you change any brake parts from std you may need to get an inspection certificate from an engineer.
Or if keeping it in the family GPZ era you might expect they will not notice and this model just happened to have that. I'm applying that approach to a bike I got LVV certification but later updated calipers but looks stock.

It used to be you could change wheels and shocks without certification, as people do that all the time on cars.

But rock on up with GSXR wheels and upside down forks and expect to get serious push back from wof guy.

[F5 Dave]

Hmm, A8 appears to have 120 so that will be 3.5" rim, looks like a good idea if my 1min google is right. If you can get a 150 on the rear that could be ok. Would be worthwhile checking the rolling diameter of existing wheels and proposed new wheels. You don't want to chopper the attitude.

Single opposed calipers perhaps? Or those twin sliding? Can work OK but full rebuild to get best. Various places do rebuild kits. If you put braided lines on that may make it feel like wood. If on the other had you can find a smaller master cylinder that looks like stock one that will improve matters considerably. I'd expect standard will be 5/8", written on bottom of casting. 14mm would be next size down. Probably.

[pete376403]

Yes, but at wrong end of the country for you. You need to find a gnarled old toolmaker still with manual machinery and a few motorbikes tucked into the recesses of the bombsite of a workshop.

If you have to cut the wheel back, say to inboard the disc a little that requires quite a big lathe.

Kawi onto Kawi should maybe be easier if not generations apart. I've done it maybe a dozen times both ends.
The most important starting point is axle diameter and then if you can line up discs and drive clearing frame and bigger rear tyre while staying in centre and inline with other wheel.

Alternative bearings can sometimes help with axle issues but need to consider bearing rating and complete left to right interface with other parts. Internal hub and cushdrive spacers need to still be there to take the load or bad things will happen fast.

Consider calipers. I made a stunning improvement using CBR calipers on my old GS11. But about when I was selling it they started bringing in LVV certification so the poor guy who bought it may have failed a wof the time after next inspection I guess. Sorry dude not my fault. So if you change any brake parts from std you may need to get an inspection certificate from an engineer.
Or if keeping it in the family GPZ era you might expect they will not notice and this model just happened to have that. I'm applying that approach to a bike I got LVV certification but later updated calipers but looks stock.

It used to be you could change wheels and shocks without certification, as people do that all the time on cars.

But rock on up with GSXR wheels and upside down forks and expect to get serious push back from wof guy.

Don't ask, don't tell. USD forks on the KLR (but with KLR disk and caliper) and Concours calipers and CBR disks on the GS1100GK have passed warrants. Won't say where.

[BMWST?]

gpz 900 .I remember looking at one when they first came out and wondered which bimota someoe had stolen for some of the parts. So tidy and sexy compard to most jap bike s then

[F5 Dave]

Appears KZ200, 400, 550 etc have large old style master cylinder with 14mm bore. Might be worth a try. Not saying for certain and would be hard to find. Could try with more common master like ZXR250 or R1 just to try it.
Often 80s bikes had bulging rubber lines. Yamaha in particular you put braided on and they were hard lever. Smaller master cylinder and you got feel back with the added mechanical advantage.

[SaferRides]

Often 80s bikes had bulging rubber lines. Yamaha in particular you put braided on and they were hard lever. Smaller master cylinder and you got feel back with the added mechanical advantage.

Or fit better pads. The R1 has a very solid lever with braided lines, all it needed was a set of decent, sintered pads.



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[F5 Dave]

The R1 was launched with Sumimoto (sp) blue dpots that were a sea change. Owners of older Yamahas started fitting them to FZRs etc. But the all had 5/8" masters, so you needed to use the R1 mc to get some lever travel and corresponding power. But yeah, ctrap pads are crap pads.

That said, pistons seize up and lever feels stiff. Forcing pistons back to fit new pads will unseize them.

[Grumph]

Cheapest and most readily available 14mm master is GN250.....

There's a guy down here in CAMS who's running exactly what you're building in pre 89. Has RS36 carbs and warm cams in addition to the forks/wheel swap.
Goes very well indeed.

[SaferRides]

The R1 was launched with Sumimoto (sp) blue dpots that were a sea change. Owners of older Yamahas started fitting them to FZRs etc. But the all had 5/8" masters, so you needed to use the R1 mc to get some lever travel and corresponding power. But yeah, ctrap pads are crap pads.

That said, pistons seize up and lever feels stiff. Forcing pistons back to fit new pads will unseize them.

I found a video sometime ago on how to clean pistons the Japanese way. I'll see if I can find it again.

The R1 now has gold spots from the 2002-03 model. Identical, except they have ceramic coated pistons which don't corrode. They came with the OE Sumitomo pads, which were replaced after one ride!

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[Mal]

Lol, you could have been looking at my bike currently, sporting USD front end from ZXR400 and gsxr rear wheel. Yes I've had a few looks at the wof station but always got away with it so far!
However will go back to a more 80s look, and hopefully not lose any of the improvements in handling and brakes that I've already gained.
I'm planning to use 4 pot Nissins on the front, off VTR1000 replacing the 4 pot Tokicos currently fitted.

Yes if I go the Zzr1100 wheel route the sprocket carrier needs milling down a few mm to centre the wheel and sprocket correctly

Yes, but at wrong end of the country for you. You need to find a gnarled old toolmaker still with manual machinery and a few motorbikes tucked into the recesses of the bombsite of a workshop.

If you have to cut the wheel back, say to inboard the disc a little that requires quite a big lathe.

Kawi onto Kawi should maybe be easier if not generations apart. I've done it maybe a dozen times both ends.
The most important starting point is axle diameter and then if you can line up discs and drive clearing frame and bigger rear tyre while staying in centre and inline with other wheel.

Alternative bearings can sometimes help with axle issues but need to consider bearing rating and complete left to right interface with other parts. Internal hub and cushdrive spacers need to still be there to take the load or bad things will happen fast.

Consider calipers. I made a stunning improvement using CBR calipers on my old GS11. But about when I was selling it they started bringing in LVV certification so the poor guy who bought it may have failed a wof the time after next inspection I guess. Sorry dude not my fault. So if you change any brake parts from std you may need to get an inspection certificate from an engineer.
Or if keeping it in the family GPZ era you might expect they will not notice and this model just happened to have that. I'm applying that approach to a bike I got LVV certification but later updated calipers but looks stock.

It used to be you could change wheels and shocks without certification, as people do that all the time on cars.

But rock on up with GSXR wheels and upside down forks and expect to get serious push back from wof guy.