Thanks Pierre. No, I took the simple option. The 4.5 rim fits well in the original swingarm, and I can run a 160 or maybe even a 170 section tyre with the available clearance. However a 5.5 or 6.0 from a ZZR1100 would look pretty good in a GPz900r. And you would need to change the swingarm. If you did, you would only have to make the rear fit to the frame/engine bolt. And check the movement, and clearances, when installed. There would be no mucking around with the wheel and brake, as it would all be from the replacement rear you are grafting in. So maybe actually less work to take this option. You would still need to get the centreline correct, but you would do that from the centreing of the swingarm itself. You would need to measure the shock mounts and length of shock. The original shock may no longer fit. I am sure many people have done it, just not sure on any available info. See the GPz's from Japan in AC Sanctuary for example. They all have FAT rear ends, and look great. Cheers.
Blogspot ate my long comment, so here is short version:
I have a 1986 A3 model GPZ900R which has a 1997-1998 (I forget which) ZX-9R rear wheel of 5.5" in stock swing arm with no modification to swing arm except for chain guard mount. The work was quite involved, e.g. machining of sprocket carrier, changing studs to bolts (for clearance), custom brake mount modification, 25mm axle, special bearing for sprocket carrier, etc... The wheel is within 1mm of centerline and chain run also within 1mm (I used ZX1000B front sprocket which has offset, be sure to replace lock plate from said model too, ask how I know).
I included a ZX1000B complete front end conversion and ZZR1100D rear shock with upside down eccentric adjusters in rear, and the ride is now good. Some of the changes were evolutionary, and with stock shock the bike had heavy understeer when two up riding.
I did consider a complete swing arm swap but this was deemed too much work as the original swinger had the clearance to cope (barely) and the ZX-9R swing arm I had was junk. I know there is a blog which features an entire ZX-9R swing arm swap for the GPz... I think it was for GPz750R. Chalelenges abound due to shock hole not being in the middle, etc.
Thank you for the site. It would have been very useful when I was doing my mod in winter 2012/2013. And greetings from Finland!
Thanks for reading, and yes, greetings from Sydney AU as well.
It seems you have done some excellent work to graft a 5.5" rim into the original GPz900r swing-arm - Is that correct ? I assume a nice tight fit. And I bet it looks good with the fat rubber. It sounds like the offset is fine, and chain as well.
If you wish to send a link to a blog you have, or if you wish to send me a few pics, I would love to add them as part of this blog. People can have a look at your work, and even contact you for advice if you wish to leave a contact.
I appreciate anyone who wishes to contribute their conversion process for the sake of information on this blog, and other GPz900r owners. I suppose any GPz range of the era. The process is what matters.
I laugh in anticipation... what happened to the front sprocket ? Hope you didn't come off in the process.
The ZX9 front end conversion also seems a popular and good choice. But I think yours is from the 1988 ZX10B1 model is that correct ?
Also... I see you put some effort into sorting the rear suspension so it rides correctly. This is important and I would regard this as a complete effort. No use making modifications if it doesn't work.
Also, if you do happen to find a link to the full swing-arm conversion for a GPz then please pass it along and I will make sure I add a link here.
Hi! Nice work on the write up!
ReplyDeleteI was wondering, did you check in on the option to switch out the swingarm itself to fit a wider rim and tire? (5-5.5")
// Pierre Broberg
broberg@pierrejavel.com
Thanks Pierre.
ReplyDeleteNo, I took the simple option.
The 4.5 rim fits well in the original swingarm, and I can run a 160 or maybe even a 170 section tyre with the available clearance.
However a 5.5 or 6.0 from a ZZR1100 would look pretty good in a GPz900r.
And you would need to change the swingarm.
If you did, you would only have to make the rear fit to the frame/engine bolt.
And check the movement, and clearances, when installed.
There would be no mucking around with the wheel and brake, as it would all be from the replacement rear you are grafting in.
So maybe actually less work to take this option.
You would still need to get the centreline correct, but you would do that from the centreing of the swingarm itself.
You would need to measure the shock mounts and length of shock.
The original shock may no longer fit.
I am sure many people have done it, just not sure on any available info.
See the GPz's from Japan in AC Sanctuary for example.
They all have FAT rear ends, and look great.
Cheers.
Blogspot ate my long comment, so here is short version:
ReplyDeleteI have a 1986 A3 model GPZ900R which has a 1997-1998 (I forget which) ZX-9R rear wheel of 5.5" in stock swing arm with no modification to swing arm except for chain guard mount. The work was quite involved, e.g. machining of sprocket carrier, changing studs to bolts (for clearance), custom brake mount modification, 25mm axle, special bearing for sprocket carrier, etc... The wheel is within 1mm of centerline and chain run also within 1mm (I used ZX1000B front sprocket which has offset, be sure to replace lock plate from said model too, ask how I know).
I included a ZX1000B complete front end conversion and ZZR1100D rear shock with upside down eccentric adjusters in rear, and the ride is now good. Some of the changes were evolutionary, and with stock shock the bike had heavy understeer when two up riding.
I did consider a complete swing arm swap but this was deemed too much work as the original swinger had the clearance to cope (barely) and the ZX-9R swing arm I had was junk. I know there is a blog which features an entire ZX-9R swing arm swap for the GPz... I think it was for GPz750R. Chalelenges abound due to shock hole not being in the middle, etc.
Thank you for the site. It would have been very useful when I was doing my mod in winter 2012/2013. And greetings from Finland!
Eros,
DeleteThanks for reading, and yes, greetings from Sydney AU as well.
It seems you have done some excellent work to graft a 5.5" rim into the original GPz900r swing-arm - Is that correct ?
I assume a nice tight fit.
And I bet it looks good with the fat rubber.
It sounds like the offset is fine, and chain as well.
If you wish to send a link to a blog you have, or if you wish to send me a few pics, I would love to add them as part of this blog.
People can have a look at your work, and even contact you for advice if you wish to leave a contact.
I appreciate anyone who wishes to contribute their conversion process for the sake of information on this blog, and other GPz900r owners. I suppose any GPz range of the era.
The process is what matters.
I laugh in anticipation... what happened to the front sprocket ?
Hope you didn't come off in the process.
The ZX9 front end conversion also seems a popular and good choice.
But I think yours is from the 1988 ZX10B1 model is that correct ?
Cheers Mate,
And thanks again.
Muz.
( Muzwaa@gmail.com )
Also...
DeleteI see you put some effort into sorting the rear suspension so it rides correctly.
This is important and I would regard this as a complete effort.
No use making modifications if it doesn't work.
Also, if you do happen to find a link to the full swing-arm conversion for a GPz then please pass it along and I will make sure I add a link here.
This comment has been removed by a blog administrator.
ReplyDeleteAll comments and contributions welcome, but I was not sure how your product services related to this blog.
ReplyDelete