thundercat rider Posted January 28, 2009 Report Share Posted January 28, 2009 Currently I own a yamaha thundercat. I have modded it with a yzf 750 usd fork and a fzr 1000 swingarm (will post pictures and how to very soon). For quite some time i've been looking for a nice FZR 400 rr frame for my next project. I have some questions though. Is the fzr 400rr frame really any good? How does is it compare to a more modern frame, say a r6 frame from the first generation? Link to comment Share on other sites More sharing options...
Liamo Posted January 28, 2009 Report Share Posted January 28, 2009 Have a read of this. Link to comment Share on other sites More sharing options...
fran9r Posted January 28, 2009 Report Share Posted January 28, 2009 Yep pics of the cat please...sounds good. Link to comment Share on other sites More sharing options...
thundercat rider Posted January 28, 2009 Author Report Share Posted January 28, 2009 Yeah I really like that yamonda hybrid. I'll ask the owner if he can make any comparrisons to more modern hardware. My bike is currently in the shop waiting for new inner tubes for my forks. no pics right now. FZR 1000 swingarm swap is quite straight forward. Swingarms are nearly identical in appearance; the swap doesn't change geometry of the bike at all. The swingarm and some other bits are exactly 2kg lighter than stock (would be even lighter if the custom swinarm bush was lighter). -get a fzr 1000 deltabox swingarm, wheel spindle, chain adjusters, torque arm, chainguard and hugger (quite rare) -you can re-use your thundercat wheel, brake arm, rear brake, complete shock linkage and shock. -the fzr 1000 swingarm is a bit wider than the yzf600r swingarm between the frame mounting (1cm if i'm correct). remove yzf 600 swingarm. take both the fzr 1000 swingarm and the yzf 600r to a skilled machinist. First, remove the bearings. Next, have him machine off EXACTLY the same amount of material from BOTH sides of the FZR 1000 tube of the swinger (where you're bearings are pressed in; something like 0,5cm per side I think). You should be able to use original FZR 1000 bearings. -The hardend steel FZR swingarm bush has a larger diameter than the yzf600r bush. My machinist advised me against using spacers because the spacers would be too thin. He machined a new bush using the outside diameter of the FZR 1000 bush, and the OUTSIDE DIAMETER OF YOUR SWINGARM SPINDLE; this will remove any unwanted slop (like a blueprinted frame). Spindle should still slide in smoothly though. Next have the machinist harden your custom bush. NICE!! -You also have to machine new spacers. Use the outside diameter of the FZR 1000 spacers, inside diameter of your yzf600r swingarm spindle. They should be as thick as the orignal yzf600r ones (which are also as thick as the fzr 1000 ones) if you didn't powdercoat anything. -I reused the swingarm covers. Next: install the swingarm. Now comes the tricky part. I had my swingarm and frame poadercoated, 3 layers. each layer should be about 0,4mm. When I installed the rear wheel, the chain lined out flawlessly while using the orginal wheel spacers. The wheel only fits with some aggro though. If the chain doesn't line out, you probably have to make a spacer to move the wheel 1-2 mm to the left. This also means the torque arm won't fit any more. Maybe it can be heated and bent a bit? Have a happy ride: you just junked 2kg of useless unsprung weight and lost a rusty swingarm! Link to comment Share on other sites More sharing options...
Evilchicken0 Posted January 29, 2009 Report Share Posted January 29, 2009 The FZR400RR frame is pretty strong, it's alloy whereas the ThunderCat is steel making it much lighter. The TJ's swingarm would have probably bolted up to your T'Cat too. I think the frame / swingarm saves about 20kg but don't quote me. The T'cat engine's crankcases are common to the 400's too so the front and rear sproket line up. The top mounts ar about 20mm further up the barrels so you need a pair of plates to do the conversion .... this makes the airbox sit higher and it's this that's the only real sticking point. The TY'cat has a charged airbox and the TJ hasn't ... most of the people doing the conversions are trying to find out how to make a satifactory airbox ... after that it will be all systems go go go. The YZF750 has a bit of a heavy front end for the 400 (or 600 conversion) it uses 320mm disks with 6 pot calipers. I've got 400RR SP forks which use 300mm and the standard calipers with a radial master cylinder it still stops better than it needs to. The RGV250 front end drops in as well. Link to comment Share on other sites More sharing options...
thundercat rider Posted January 29, 2009 Author Report Share Posted January 29, 2009 I got a yzf 750 front end at home. It's in fact lighter than a thundercat front . To be exact, it's 1kg lighter. The bottom yoke from the thundercat is cheapo cast iron, yzf 750 bottom yoke is cast aluminium. I used gold spots in stead of thundercat blue spots. 750 clipons are also a wee bit lighter. Wheels and disks weigh about the same. The 750 wheel is lighter than the 600 wheel, 750 disks are heavier. I think that's no coincedence. Airbox should be no problem, I got that figured out. This guy (http://bikepics.com/members/canflyboy/90fzr400/) gave me the idea to fab my own airbox. I'll cut some holes in the dummy tank for ram air tubes. Next I'll use the thundercat fairings cuz I need the surge tanks. I got the idea from the cbr600f4 ram air system. Airbox problem solved. Link to comment Share on other sites More sharing options...
Evilchicken0 Posted January 29, 2009 Report Share Posted January 29, 2009 Airbox should be no problem, I got that figured out. This guy (http://bikepics.com/members/canflyboy/90fzr400/) gave me the idea to fab my own airbox. I'll cut some holes in the dummy tank for ram air tubes. Next I'll use the thundercat fairings cuz I need the surge tanks. I got the idea from the cbr600f4 ram air system. Airbox problem solved. The 3TJ doesn't have a dummy tank, that's the earlier 1WG model, although I can't remember if the tank is 2 plys thick over the airbox Link to comment Share on other sites More sharing options...
thundercat rider Posted January 29, 2009 Author Report Share Posted January 29, 2009 3tj does really have a dummy tank. You can check bikepics.... Link to comment Share on other sites More sharing options...
Evilchicken0 Posted January 30, 2009 Report Share Posted January 30, 2009 3tj does really have a dummy tank. You can check bikepics.... I own a 3TJ and a 1WG ... maybe you could post a link Link to comment Share on other sites More sharing options...
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