My shocks turned up today, I have some clevis fittings to suit the GS swingarm, will test fit tomorrow.
These shocks are Chinese, They are an Ohlins copy and are very well made, We have already pulled one set of these apart to see what they were like, My friend has a set on his Honda CB 750, They have threaded preload , 16 position compression and and 24 position rebound damping. The damping all works as it should and these are relatively easy to set up.    They should look good on the bike...  Also the shims for the front wheel bearings arrived, I can get pics of those later if anyone is interested.



 

And this is where mine sits at the moment with the front end fitted and the GS swingarm and my wheels and brakes....

 

I probably should have spread these posts out over a few days/weeks as I have to travel about 80 mile {120 Kilometers} round trip just to work on it ....

I've been a member of this forum for over a decade, and I don't think I've posted a single picture of my bikes. So here is my first project thread.  I'll give it a shot.  We'll see what happens.

This is my first Z1R (from 2009).


 


My dad had a ‘78 Z1R, which he let me borrow for my motorcycle license test around 1995. At the time I was between my first and second Kz650. Once I rode that Z1R I really wanted one. Such an unusual looking bike, and it rode really great. But at that time there really was no easy way to find one. To this day I’ve never seen another one in person (one that I don’t own).

It wasn’t until Ebay became popular that I started to see them for sale. I bought this bike on Ebay in 2001. I drove a box truck from Boston to NJ to pick it up. In person it wasn't as nice as I had hoped (digital pictures were low-res in 2001), but it was good enough. I rode it as-is for a couple months. In that time it stranded me twice with electrical gremlins, so I put it away for the winter. I had a Kz650 with the engine out at the time, and I decided I should probably put that back together before I ended up with two basket cases. Then 7 years passed. I did get the Kz650 back together, and gave it to my best friend (who I had bought it from 10+ years earlier).

So in 2008 I rolled the Z1R from my garage to my basement and did a bunch of work. I had the battery box and swingarm and other bits power coated. I replace the swing and steering bearings. I went through the entire brake system. I sorted out the electrical gremlins, which involved completely reworking the self-canceling turn signal system. I replaced a bunch of missing bits, swapped some aging chrome with better parts from ebay, and many other small things.

I bought it in 2001 with 41482 miles. When it rolled out of the basement in 2009, it had 41950. That right there is how you keep a vintage bike in top condition. Forget about it for 8 years.

I don’t ride the Z1R a lot. I’ve add about 4000 miles since I got it. I took it on a nice trip around the coast of Maine in 2010. In 2011 I got a mint 2006 ZR750S, which was cool except it had the worst seat ever put on a bike. Sold that, and found a 1995 GPz1100 mid-project with the head pulled off. Put that back together, rode it for a few years, and sold it in 2019. I also picked up a 2000 ZRX1100 but let that sit for 4 years without touching it. Oh, and along the way I picked up a basket case Z1R, and then my dad gave me his as well. But those are projects for some other thread.

At this point it’s been about 7 years since I last started the Z1R.

Now it’s time dust if off and get it back into good running condition. Of course I’ll need to redo a lot of what I did the first time. And get around to those things I forgot. For example, I’m embarrassed to say that somehow I never did a valve adjustment. I have no idea why not. Seems obvious. But I guess better late than never? I also never replaced the front tire, which based on the date code I think is from 1985!  

SF:   to tell ya the truth, I don't know what's been done to the motor but it was changed A LOT before I picked it up and USED to be one of the featured bikes on website exileturbo.com.
The website appears to be gone now but I've done a lot of "UN-Modifications" to make it a little more street friendly as it was a lot different that it looks now - but I didn't change the motor
at all. When I got the bike, there was little or no suspension (great for drag racing but no too street friendly).  There was a long extended 4 point swing arm and nicely done wide rear
wheel, an extra 15 degree rake  (which still exists) and a few electrical "mods".  According to the website (if I recall correctly) max boost was 30psi and 1/4 miles were mid 9s. I've removed the boost adjusting  handle  and passenger foot pegs to try and counter any possible temptations I might have on a nice day.
    For street use it should probably have an oil cooler. 

Hope the weekend is good!

wrote:

The early GSXRs used a tube profile like that. I don't know if it would be cheaper to cut up a frame to get the tube but its an option. sub-frame tubes are 20 x 25, main down tubes are 27 x 30. this is a proprietary alloy similar to 7005.

 

Funny you should say that, I actually have a 1988 GSXR1100J  Frame {last of the slabby's}, I won't be cutting it up though, they are starting to fetch good money....

The early GSXRs used a tube profile like that. I don't know if it would be cheaper to cut up a frame to get the tube but its an option. sub-frame tubes are 20 x 25, main down tubes are 27 x 30. this is a proprietary alloy similar to 7005.

 

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wrote:

Thanks zed, I'll come back to this when the forks are apart but that means I can go to 20-25mm and have some room to move on the rake. I assume you haven't noticed any extra flex in the forks? I'll probably be putting a brace on so it shouldn't be an issue anyway.

EDIT: Removed brain fart

No extra flex or any other issues.
Have done this to both RWU and USD forks into Z frames.
I have used GSXR, RF600, ZXR ,ZX7R, 9R, ZX10R, FJR1300 forks to name a few with their matching yokes and all handle very well.
Despite the differing offsets etc the main factor is keeping the frame stance and consequently the rake close to stock.
Having the back end jacked too high or the front to short results in shopping trolley handling that will tank slap to death and try to kill you once you are approaching 100mph.


 

Not trying to be argumentative but its a balance, The rakes used in the 70's and early 80's were all over the place, Kawasaki went from relatively normal, with poor offsets on their clamps, early 900's and especially the first Z1R's, to majorly conservative with the early GPZ's, 1000R's, 1000J's  and the like, they were much more stable,  but pigs in stock form to get around corners quickly, that's why most people who raced those bikes altered the frame rake. I helped a racer here recently take 4 degrees out of his GPZ1100B race bike by cutting the frame and repositioning the headstock, this was a common mod. His stock rake was 29 degrees. As long as the bike is set up properly there will be no "shopping trolley" effect, that happens when trail becomes dangerously small, raising the rear, or lowering the front is usually done to get the weight balance right, or more weight on the front wheel, you can reduce rake marginally and improve swingarm angle at the same time, again, you have to know what you are doing and stick between the accepted parameters... .....

Your numbers are looking ok, I think the swingarm is a bit long but it should work, we are only talking about 10 to 15 mm, this shouldn't make too much difference on a road bike, Your rake trail and offset are very similar to mine. I'm using Yoshimura's angle for the rear shocks at 54.5 degrees or 35.5, depending which way you look at it, apparently that was the ideal measurement Yoshi came up with on his late 70's, early 80's superbikes, I got that from a PDF file about his GS1000 superbike raced bike raced by Wes Cooley, Moriwaki used similar angles.  Just note that when you lay a shock down, you'll need heavier springs. The spring has less resistance the more angle is used.    What brand of shocks are you using, they look like Ohlins, or are they the Chinese replica's , If they are the multi adjustable Chinese shocks they are insane value for money, My friend pulled a set apart and they are very well made ?  I still haven't bought my shocks yet because I haven't set the swingarm angle , I want to be able to utilise the extra height adjustment on the shocks I'm buying, so i want my shocks to mount in their shortest position so I can raise the back a little when I eventually switch to 17 inch wheels, just to bring the rake back a bit.

@kzstreetfighter71: you don't use the quote too much, your posts are just wrapped up in the quote which makes them hard to find (I have enough problems with reading as it is!). The sticky is a really good idea. If I'd known what I know now (or rather, known what I didn't know) I would have been a lot more specific when ordering parts. As it was I went with the recommendations of the people I was getting the parts from (who really do have enough experience, but maybe haven't really spent the time getting these things to their full potential). One of the places definitely goes for form over function, the other place left me with the impression I wasn't really being taken seriously. Without you guys I'd be screwed!

@750R1: I'd really appreciate it if you could give me one last opinion on the current state of things. If I extend the forks and move the shocks as stated I'll end up with the following (with the rear axle at the front of its adjustment range):

• Rake: 24.5°
• Trail: 100mm
• Offset: 40mm
• Wheelbase: 149.5cm
• Swingarm angle: 11°
• Swingarm length: 520mm
• Shock angle: 62°

I figure this is an OK starting point- I can always lengthen the shocks or the forks depending on which way it needs to go and could even deal with swapping out the triples for a set with a drop if I needed to (though extending the forks may be cheaper). Changing the wheel base/swapping out the swingarm is something I'd like to avoid. The longer swingarm will give me more clearance - but probably more than I need.
Bear in mind this is for a street bike with the occasional track day and I'm not really one to push the limits. I like the corners but don't often get right up on the edge (although I haven't really spent any time at the track). I also don't really do high speed straights - comes from learning on the roads back home, much prefer the corners

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wrote:

The wheelbase is at 151cm so may offset the steep front end 

Unfortunately it doesn't work like that, its all about balance between the two, lengthening the swingarm a little can be beneficial to handling, but too long and the rear is wanting to react slower to turn in while the steeper front wants to turn faster. these older Kawasaki's have been developed for racing for well over 40 years, there's plenty of info online and I've posted some here, don't guess, do some research, you'll find the information you're looking for...

So not to come across a cheeky asking the question and only asking it for the hundreds of wanna be bike builders and myself.. that will want to do a front and rear end change for a variety of reasons.. what is the model or models swap to a modern running gear system that would best suit the big four?  Taking away rear shocks from the equation, this is something I have been pondering on since I have in my possession 2 frames, engine and bodywork sets that I will be building at a later date to a resto mod finish. I have 2 maybe 3 bikes in mind but what are your thoughts on it?

The biggest problem with a lot of these type of builds is people just bolt on what looks good, as you can see, there's far more too it than that. first you need to know what the stock rake of your frame is, for the Z900's, it was common practice here in Australia to use the Z650 triple clamps on these bikes, it made a noted improvement in handling, I think the 650's had a 45mm offset, I  do have a set of 650 clamps but they aren't here at the moment. They liked a slightly longer swingarm as well, Yoshimura and Moriwaki worked this out quite early on.
As I've said above, it also matters what size wheels are being used, and of course what your expectations are, do you want a lazy high speed bike, or do you want a race orientated suspension, or one that does both relatively well?   A lot of development of these bikes was done in the late 70's, early 80's, I've read that much stuff my head spins at times, luckily I have a couple of well know vintage racers to work off, these guys really know their stuff, my friend, where I work on my bikes, is a multiple Australian champion and a genius with engines and suspension, You guys would love the triple plug head he designed and built for a FJR1200 engine running on methanol, it runs 2 ignition systems to fire the plugs slightly at different intervals to burn fuel that's pushed to the outside of the piston crown, even with 2 plugs there was still unburnt fuel in the combustion chamber , so the 3 plug head has 1 central plug that fires first, spreading the flame front out from the centre where the second two plugs burn off the rest either side, its ingenious and worked brilliantly, it also gave a substantial HP boost. 
Maybe I just get caught up in the challenge, I'm a classic over thinker...!!!