Putting a YZF600 front end on a RZ500

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Ken Smith · #16 Post by **Ken Smith** » Sat Sep 27, 2008 10:24 pm

Steve; Have a YZF600 ft end on one of my bikes and YZF750 on 2 others. Can still raise the tank at the ft on all of them. It's real tight though. Need to have the ft wheel centered then pull back and then up will just so clear, the bracket will almost rub. But it will clear.

Mike Cichetti · #17 Post by **Mike Cichetti** » Sun Sep 28, 2008 10:16 am

Very nice job! You can still raise the tank up at the front if you pull the rear pivot, slide the tank and lift it. I slide a skinny screw driver back in the rear to keep it stable.

rd84 · #18 Post by **rd84** » Mon Sep 29, 2008 8:53 am

Hi Smurph,

Thanks for the pics - Those forks look the same as the FZR600R forks that had been fitted on a RD500 that I bought - except the FZR600R forks stuck thru' the top of the Yokes quite a long way. The previous owner said the steering was very heavy with the YZF600 yokes so bored out the RD500 yoke to accept the larger diameter forks.
Is the ride angle the same on your bike as the standard RD500 ?? - The gap between the wheel and the fairing looks greater than the original - just wondering ?

Did you consider the late model YZF600 Thundercat forks ?? - they look like early R6 forks but have a speedo drive ??.

Anyway the above mentioned bike now has as a set of 2003 R1 forks and a 1991 YZR500 fairing so is now looking quite a bit different !!

Cheers
Paul

#19 Post by **smurph** » Mon Sep 29, 2008 12:41 pm

Paul,

The ride height/angle is the same. I measured this before I took the RZ forks off (with me sitting on the bike). However, with the increased spring rate of the YZF600 forks and the bike is on the stand, the front lifts a little more. I set the sag to drop the front exactly where it was with the original forks.

Originally, I wanted the later model YZF forks. 97-05, I believe. I just got tired of bidding on them because they were going for ridiculous prices. Every time would end up losing the auction by a new person on eBay with a feedback rating of like 1 or 2. You know the type. They are the ones that make 25 bids on one auction. But I guess they were just willing to pay more than me.

There is no doubt that they would make a better conversion. Mainly because the front wheel they carry is very similar to the RZ wheel, rotor spacing wise.

I had thought about boring the original clamps, but the bore would have had to have been offset and there wouldn't be enough material left for me to feel comfortable. My sole use for boring the RZ clamps would be to eliminate the tanks molding that I had to do. Other than that, the YZF clamps have the same stem to fork offset, So I don't know why the steering was heavy. I'll measure the offset again to be sure, but I can say that there was no detriment to my bike's handling.

Steve

rd84 · #20 Post by **rd84** » Mon Sep 29, 2008 9:01 pm

Hi Smurph,

Thanks for the extra info. - you obviously put a lot of effort into the research. Your forks certainly look much nicer on the RD500 than the FZR600R forks.

The bike I mentioned in the last thread also had a FZR600R swingarm which fitted nicely - the sprocket offset was perfect for the RD500. It would take either a 160 or 180 tyre. Altho' the previous owner said the 160 worked better. Perhaps the 5" wheel didn't suit the 160 tyre profile - or perhaps a 180 is too much anyway ?? - unlike the front end the FZR rear end looked like it belonged in the RD500 - anyway its also in storage now since I replaced it with one of Wolfgang's excellent RS250 swingarms and a R6 5.5" rear wheel.

BTW the FZR600R swingarm is made of steel - which would make shock link mods easier but is also VERY heavy.

Cheers
Paul

snimmisnai · #21 Post by **snimmisnai** » Mon Oct 13, 2008 6:32 am

smurph wrote:This weekend is rear wheel/tire time. I hope to get the majority of the machining and wheel fitment in the swingarm done. But I have rear sprocket issues that I have to work out that may delay the final outcome a week. I have an aluminum RZ sprocket that I may bore to fit the YZF carrier. It's solid (no lightening holes), so I can drill a new bolt pattern in it. But it may take longer than I have to work on it.

Hey Smurph, any news on the back end?

#22 Post by **smurph** » Mon Oct 13, 2008 12:26 pm

Well, I have not had a chance to finish up the rear wheel conversion. I've been working on other people's parts.

I thought I would get a chance this weekend, but I forgot about family birthdays. If I had worked on motorcycle projects instead, I wouldn't be here typing this up.

It turns out that RGVSteve has done a similar swap. We were talking about it and were comparing notes. But we are not sure exactly what wheel he had. Or exactly what wheel I have for that matter.

Steve

RGVSTEVE · #23 Post by **RGVSTEVE** » Mon Oct 13, 2008 6:17 pm

Steve,

Found out the 600 wheel I had to work with is the 1999 YZF600. From
looking on MotoGrid like we talked the drawing of the '94 cush drive
appears to be different in design then the other years shown. It's
done, meassure's out good, chain alingment required removing 2mm
from the cush drive sprocket face, I used the Vortex front sprocket
for the CBR900RR ( same spline as the RZ motor ).Front sprocket
alingment will differ with different brands. I took some pictures just
for my own record. Your welcome to them, if nothing else to compare
what you come up with as opposed to what I came up with.