Thundercat fork swap question?

[joebloggs]

I know many have done the swap using the 87/88 FZR1000 yokes, but whats to stop someone using the whole front end inc yokes?

[Millietant]

I don't understand what you're asking here - why would people swap the yokes for FZR 88/89 but keep the rest of the FJ front end ? Am I missing something, or have you made a typing error?

I swapped a whole 1992 FZR1000 USD front end into my FJ (but with early R1 blue dot calipers and a FZ1 brake master cylinder).

It was quick, easy and I love it.

[joebloggs]

I don't understand what you're asking here - why would people swap the yokes for FZR 88/89 but keep the rest of the FJ front end ? Am I missing something, or have you made a typing error?

I swapped a whole 1992 FZR1000 USD front end into my FJ (but with early R1 blue dot calipers and a FZ1 brake master cylinder).

It was quick, easy and I love it.

Ah, I meant swapping the front end using YZF600 Thundercat forks and yokes from the cat rather than the forks with FZR1000 Genesis yokes

[Millietant]

Jon Cain did a full write up on the YZF 600 R Thundercat front end swap - I think it's somewhere in the files on here.

[joebloggs]

Jon Cain did a full write up on the YZF 600 R Thundercat front end swap - I think it's somewhere in the files on here.

I think I've just about read every post on the subject, someone fitted the forks in the FJ yokes, one using the YZF, but all others suggest using the FZR1000 yokes.

I'm not trying to reinvent the wheel, just wouldn't mind knowing if I can swap the whole front end, as its complete.

I also don't want to strip it down to find out it doesn't fit and then have to start ordering parts.

O course I could just leave it alone but wheres the fun in that

[Millietant]

Then Jon Cain's write up on the Thundercat front end swap is exactly what you need.

My FZR USD complete front end swap was a piece of cake, could be done with a hand file, a hacksaw and a drill - no special parts (easy to source handlebars and risers - 2001-2005 FZ1), no special engineering, basically just "plug and play".

[joebloggs]

Thanks for the heads up, will have a look for it, I imagine quite a lot of info got lost on FJmods as the link doesn't seem to go anywhere

Nice job on the front end, seen plenty for sale but many needing a full rebuild inc fork legs or re-chrome.

Not planning on spending much on the FJ. Already have a money pit of an GPZ1000RX project on the go, Brembo everything has already cost me a kidney lol

[joebloggs]

Jon Cain did a full write up on the YZF 600 R Thundercat front end swap - I think it's somewhere in the files on here.

Think I've just found his post re why he doesn't recommend the Thundercat yoke, less offset = slower steering, so if thats the only issue I'll use it, lots of countersteer and grab it by the horns.

Time to order some steering head bearings.

[JCainFJ]

I recommend using the 87-88 fzr1000 triple clamps because it has the same offset as a stock FJ and it has the same width as the YZF600r. The FZR1000 triple keeps the stearing geometry the same as a stock FJ while allowing all of the YZF600r parts (wheel, axle, spacers, rotors, fender...) to bolt right up. You are welcome to try using a YZF triple, they are cheep and kind of ugly. I have not checked to see if the stem details are compatible, and I don't know how the change in offset will effect the handling, so you are on your own if you try it.
Let this forum know how it works (or doesn't work) if you try it.

[fj1289]

Jon Cain did a full write up on the YZF 600 R Thundercat front end swap - I think it's somewhere in the files on here.

Think I've just found his post re why he doesn't recommend the Thundercat yoke, less offset = slower steering, so if thats the only issue I'll use it, lots of countersteer and grab it by the horns.

Time to order some steering head bearings.

The decreased offset/increased trail might work ok in conjunction with raising the rear ride height.  Then again, the back of my street bike is raised higher than most and the stock 35mm offset is stable and handles well. 
My race bike (drag and land speed - NOT road course!) uses triple clamps with just 25mm offset (FJ is 35mm) and is lowered and long swing arm - it does NOT like turns and does NOT feel right when you force it through a turn - but it IS stable as a freight train at speed!!! (Even in a nasty cross wind)

[joebloggs]

I recommend using the 87-88 fzr1000 triple clamps because it has the same offset as a stock FJ and it has the same width as the YZF600r. The FZR1000 triple keeps the stearing geometry the same as a stock FJ while allowing all of the YZF600r parts (wheel, axle, spacers, rotors, fender...) to bolt right up. You are welcome to try using a YZF triple, they are cheep and kind of ugly. I have not checked to see if the stem details are compatible, and I don't know how the change in offset will effect the handling, so you are on your own if you try it.
Let this forum know how it works (or doesn't work) if you try it.

I'm not trying to reinvent  the wheel or go against the grain for the hell of it but with the forks being shorter and the jacked up rear the rake angle will be reduced so that may help me turn the thing. And already having the complete front end means I'm not going out buying the yokes as in which case I'd go with your suggestion.

One positive of the conversion, if the bitch wont turn it'll be nice and stable as I ride off the road lol

[JCainFJ]

Joebloggs,

Did you keep going with this project? If you did, how did it turn out?
 One thing I recommend for every motorcycle and especially every FJ, make sure you set up the static sag. My 89 is set to 25mm sag in the forks and 30mm sag at the rear wheel.
 FJs are good handling bikes (even totally stock) if the static sag is correct!

[fj1289]

John Cain and Marc Ritter posting in the same week ... are back on yahoo groups again! 

[joebloggs]

Joebloggs,

Did you keep going with this project? If you did, how did it turn out?
 One thing I recommend for every motorcycle and especially every FJ, make sure you set up the static sag. My 89 is set to 25mm sag in the forks and 30mm sag at the rear wheel.
 FJs are good handling bikes (even totally stock) if the static sag is correct!

I ended up using the FZR1000 Genesis lower yoke with an LSL top yoke for handle bar conversion.

There was an option for a bar conversion for the Thundercat top yoke, but it wasn't as neat.   

[jannickz]

You're right, while many opt for the 87/88 FZR1000 yokes for a front end swap on the FJ1100, there's no inherent reason why you couldn't use the entire front end, including the forks, yokes, wheel, axle, and brakes. The FZR1000 might have a more aggressive riding position due to lower clip-on handlebars. You might need to change handlebars or add risers to achieve a comfortable riding posture for the FJ1100.