The GPz1100 Collection

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I have managed to accumulate a couple of Kawasaki GPz1100’s over the last couple of years. All are in running order and all will get a “make over” in due course.  The collection consists of (in date order), a 1981 GPz1100B1,  1982 GPz1100B2 and a 1983 GPz1100A1 (also known as a ZX1100A1). To help others I wrote an article on the GPz1100 series on Wikipedia as a reference between the different models.

1981 GPz1100B1

In July 2008 I purchased a complete and running GPz1100B1 for $2000. it had been sprayed black with gold pin stripping, it rode OK but could be substantially better and it needed some suspension work done, the rest of the history is unknown. its been sitting now for 9 years in the garage and plans are afoot to build it as an ELR replica to match the B2 currently being completed.

At this stage I will keep the DFI system as its still (mostly) fitted and working OK but I will try to convert it to a Megasquirt and tweaked to suit the 1100 engine characteristics. Recently I caught a glimpse of one fitted with a GP exhaust and that’s given me ideas to fit one.

1982 GPz1100B2

I purchase my GPz1100B2 in February 2008 for $2000. It was up for auction on eBay but I missed getting to a computer in time and the auction ended! lucky for me there were no bids as the model was not popular despite it being in my opinion the most reliable Zed ever build prior to the GPz900R. I contacted the seller and he agreed to let me have it, subject to inspection, for the offer price. The owner had it for 16 years but had only ridden it a few times in the last couple of years and due to a lack of maintenance the brakes were seized and the clutch often locked up when the lever was pulled in. The disks were worn but the motor starts first go and purrs as it had just been rebuilt with a 1175 kit and a bit of extra work. I have not confirmed the large pistons but in the future when the engine needs a strip I will be able to measure everything and see if this is the case.

Other points to note are that the calipers were full of crap and needed a good clean up to remove the build up of grime that often occurs around the seal.


4 thoughts on “The GPz1100 Collection”

  1. very interested if you managed to fit new calipers to the b1?
    l have a b1 and now the old calipers are fairly worn out.Do you know if the late 900r A twin pot tokico calipers will fit?
    many thanks

    • Sorry for the delay Peter, If the centres of the mounting bolts are the same then the should fit but you then need to see if they align evenly over the disks. I suspect the disk on your source bike will sit tighter to the forks so you may need to include spacers between the caliper mount and the fork leg. Either way its going to take some experimentation.

      The A1 calipers fit the GPz1100B2 but need spacers and sit slightly up off the disk by a few mm and work brilliantly. As the B1 has slightly smaller disks I suspect they also work but juts sit off the disk a bit more. You could always make a new caliper mounting bracket or try to re-drill the original one. Maybe a GPz750 caliper bracket is a better fit?

  2. vince baker said:

    Have you found a replacement for the throttle valve switch (throttle position sensor)
    on the B1.
    This part is no longer available. Is there a megasquirt system to replace the B1 system

    • Hi,

      I doubt highly there is a direct plugin compatible TPS, however there are numerous TPS modules that could be adapted to fit. If you visit the various megasquirt pages and have a look I am pretty sure many will list TPS’s available that could be made to fit.

      As for a direct replacement, no, you will need to do a fair bit of work to fit it and get the tuning right. The B1 and B2 have different injection systems and will require some work to convert over.

      It will make a great project so let me know how you go.

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