My 84 RZ500 Suspension Upgrade

[rz500guytexas]

This has been a subject for years. I am not on here since riding the TZ more. The R6 stuff worked and was a proven aftermarket choice. The R1 components seem an overkill and I would think weigh more that the R6 parts. The swingarm on mine is 2006. None of us will never outride the stock RZ as it came from the factory. The newer stuff does give you better tire selection, brakes and suspension choices. Finding someone to fit the parts is one thing but to know it is done right will cost money. The people with the knowledge have spent years to perfect what they do and we need to expect to pay for that knowledge. The bikes are older, we are older and our pool of knowledge is becoming smaller and smaller. My RZV is as close to a race bike as one will ever become, but will never be a true race bike as the little TZ is. We need to remember that the RZ was designed as a sport touring bike, a replica race bike. I like to see people still update these wonderful bikes but sad to say I see way to many of them sit on shelves never to see the road again. Good luck with the build. I am happy to say mine will be back out after our last race at the Barber Vintage Festival. Nate Kern will have his Double R Festival on Monday after our race weekend. Will be good to get the big girl back out on the track.

[RZ 500 N]

My bike sat in storage since 1988, and the fork stanchions had rusted and pitted, the calipers were froze . So checking my options, the expense of repairing the forks, the brakes was a bit expensive, so I decided to spend the money on updated components. And that was after I had already bought a set of freshly rebuilt TZR 250 4 piston calipers for a really good price I couldn't pass on, since they bolt right on my RZ, and they in them selves make a nice caliper upgrade over the single piston RZ calipers.

But, a complete R1 front end in really good condition became available, and my offer was excepted, and I don't think it's overkill at all, actually I think the R1 front end is better suited option for my RZ than the R6 is, but that's just my opinion.

But, the money I had been saving to go thru my bike, well something came up and I had to spend it all.

[rz500guytexas]

What ever works for your budget is my same thought. Good luck getting funds back together

[RZ 500 N]

What ever works for your budget is my same thought. Good luck getting funds back together

The thing is, the money I had been saving for my RZ was used to buy another RZ. So now I have two RZ projects, the new one an 85, will be going back together stock,
my original an 84 will get updated suspension. The 85 will be completed first, but will still do things on 84.

I picked up a new rear caliper for the R6 swing arm conversion, I got the stem bearings for the R1 front suspension conversion.

After further research, I've decided to have a completely new aluminum triple tree stem made to fit the R1 suspension.

[RZ 500 N]

I had a new stem made:

Here is the old R1 Stem & Lower crown and The RZ Stem and Crown.


The new stem will be fitted with R1 bearings at the RZ length
Actually, the length increase will be in the middle inbetween
the areas where the stem is machined for the top and bottom bearings.

[RZ 500 N]

I, am setting up my R1 suspension Stem & Crown conversion exactly as the RZ was set up. The conversions I've seen, I feel have been done half assed, the conversion setups were not setup properly.

To set them up properly, the bearing seals have to be able to seal the stem bearings in the steering head, if you don't do it the way it's suppose to be done, then water is the least of the problems getting past the seal. If you get sand and road dirt past the seal, it will mix with the bearing grease and turn into a gritty grinding paste.

All you have to do is match the RZ bearing dimensions, to get the seals to seal in the steering head. The problem, the Top RZ bearing dimensions are 25 x 47 x 15, but the All Balls Racing bearing kit R1 conversion bearing dimensions are 30 x 47 x 12. Regardless how hard I searched I couldn't find a bearing to match the 15mm height, to be able to seal the top bearing in the steering head. My fix was to make 3mm shim to go under the bearing race, I took an oversized int steel valve seat and had it machined to 47 x 3mm, to get the height I need to seal the top of the steering head.

The Bottom bearing dimensions for the RZ are 30 x 55 x 17, the All Balls Racing R1 conversion kit are 31 x 55 x 18. I don't know if the 1mm taller bearing will keep the seal from sealing in the steering head or not, but didn't want to take the chance, but I was able to find the correct conversion bearing from a company in England
31 x 55 x 17, that will seal the bottom of the steering head. So, all the bearing issues resolved.

Now the Stem.

I, found a company that I thought could do a good job, I sent them the R1 lower crown & the R1 Stem that I pressed out of the crown for the dimensions I wanted the new stem cut to, I also sent the RZ lower crown with the stem still installed, for the dimensions where the bearings would need to be located on the new R1 stem.
After sending them the items, I sent an email to make sure there was no confusion about the return of my parts, which was the R1 Stem and the RZ crown & Stem, to be returned with my new stem which I paid additional to have pressed into the R1 crown.

I, tracked the package and contacted them after it arrived, looking for a time frame for the stem to be finished, they said it would be finished in 2 weeks, on site they post 6 to 10 days. 2 weeks go by and nothing, so I contact them, they inform me they will get to it. about a week later I get tracking, package shows, I open it, and guess what's missing, the R1 Stem, I call them, get the runaround and basically told they had no intention of returning my stem, that's why it wasn't shipped with the rest of my parts, and was lucky I got my RZ stem & crown back.


I finally make the time to check out the new stem, trial fit the bearings and take measurements. well of course it wasn't machined to the R1 stem dimensions I required and paid for. I call, it was a waist of time, I can fix the stem, which is what I'll end up doing. I won't mention their name, don't wan them to have any advertisement.

I'll get some pics up later

[Jeff B]

Boy that sucks! As a machinist, I can tell you that the best shops are so overworked that they wouldn't have anything to do with a small account. Because of that, there isn't one single shop in my area that I'd recommend.

[RZ 500 N]

The R1 Stem & Crown - RZ Stem & Crown



Yamaha for some reason upgraded both the R6 & R1 from 30mm to 31mm on the lower stem dia., the R6 was done in 2006 and the R1 was done in 2007, apparently the 1mm increase in the lower stem dia. was sufficient to correct the issue, what ever it was.

Now, there's an issue with my new stem, in my bearing research I purchased the correct lower bearing 31 x 55 x 17, but the company when they machined my stem, they machined the lower stem to 30mm instead of 31mm, and not only that, they made it a slip fit, so a 30mm bearing will just slide in place on the lower stem. Now, the problem is normally the the lower stem has an interference fit for the bearing, and I believe an interference fit is required due to the structural loads that are put on the lower bearing. I require things to be done correctly, that means 31mm with an interference fit. I contacted the company about their screwup, all I got from them were several excuses, and a refusal to make me another stem correctly. The bearing areas look to be in the correct place on the new stem, and I put nuts on the threaded portions of the stem, and seems to fit correctly, so all I have to do now is fix the company's screwup, I'll have the lower stem welded then machined to 31mm and for an interference fit.

The new R1 Conversion Stem & Crown - RZ Stem & Crown

[Jeff B]

If you could get a bearing with a 30mm bore, I'd locktight it on before I'd weld it up. That's assuming it's a nice slip fit. Not too sloppy.

[Luther]

What Jeff said.

6061 is too soft for a steering stem and 2024 or 7075 don't weld or you wouldn't want to if structural.

When I was racing an FZ750 in the 80's I was told by a Yamaha team mechanic to leave out 1 of the 2 ring nuts and washer between the top bearing and top triple clamp to make it more ridgid

[Luther]

This has been a subject for years. I am not on here since riding the TZ more. The R6 stuff worked and was a proven aftermarket choice. The R1 components seem an overkill and I would think weigh more that the R6 parts. The swingarm on mine is 2006. None of us will never outride the stock RZ as it came from the factory. The newer stuff does give you better tire selection, brakes and suspension choices. Finding someone to fit the parts is one thing but to know it is done right will cost money. The people with the knowledge have spent years to perfect what they do and we need to expect to pay for that knowledge. The bikes are older, we are older and our pool of knowledge is becoming smaller and smaller. My RZV is as close to a race bike as one will ever become, but will never be a true race bike as the little TZ is. We need to remember that the RZ was designed as a sport touring bike, a replica race bike. I like to see people still update these wonderful bikes but sad to say I see way to many of them sit on shelves never to see the road again. Good luck with the build. I am happy to say mine will be back out after our last race at the Barber Vintage Festival. Nate Kern will have his Double R Festival on Monday after our race weekend. Will be good to get the big girl back out on the track.

Well said Paul. I changed forks wheels and brakes a couple times over the years and i ended up with a better sport touring bike. If I had a spare motor then yes I'd be looking for an R6 chassis to make it go around a track more like a modern bike.

[RZ 500 N]

If you could get a bearing with a 30mm bore, I'd locktight it on before I'd weld it up. That's assuming it's a nice slip fit. Not too sloppy.

I would of rather got what I had paid for originally, but no such luck. Yamaha, upgraded to 31mm for a reason, and locktite is not even close to a interference fit.

[RZ 500 N]

What Jeff said.

6061 is too soft for a steering stem and 2024 or 7075 don't weld or you wouldn't want to if structural.

When I was racing an FZ750 in the 80's I was told by a Yamaha team mechanic to leave out 1 of the 2 ring nuts and washer between the top bearing and top triple clamp to make it more ridgid

The stock stems are aluminum and their not 7075 so more than likely 6061, and this one is 6061 T6 Aircraft grade, which have both weldable & machinable properties, with a 45,000 psi tensile strength, so I don't have an issue with the material, I just need it machined to the proper dimensions, it just sucks I didn't get what I payed for.

[RZ 500 N]

This has been a subject for years. I am not on here since riding the TZ more. The R6 stuff worked and was a proven aftermarket choice. The R1 components seem an overkill and I would think weigh more that the R6 parts. The swingarm on mine is 2006. None of us will never outride the stock RZ as it came from the factory. The newer stuff does give you better tire selection, brakes and suspension choices. Finding someone to fit the parts is one thing but to know it is done right will cost money. The people with the knowledge have spent years to perfect what they do and we need to expect to pay for that knowledge. The bikes are older, we are older and our pool of knowledge is becoming smaller and smaller. My RZV is as close to a race bike as one will ever become, but will never be a true race bike as the little TZ is. We need to remember that the RZ was designed as a sport touring bike, a replica race bike. I like to see people still update these wonderful bikes but sad to say I see way to many of them sit on shelves never to see the road again. Good luck with the build. I am happy to say mine will be back out after our last race at the Barber Vintage Festival. Nate Kern will have his Double R Festival on Monday after our race weekend. Will be good to get the big girl back out on the track.

Well said Paul. I changed forks wheels and brakes a couple times over the years and i ended up with a better sport touring bike. If I had a spare motor then yes I'd be looking for an R6 chassis to make it go around a track more like a modern bike.

Paul, didn't take the weight factor into consideration, the RZ is slightly heavier than the R6 by about 23 pds, the extra cost to upgrade the R6 suspension to handle the additional weight, if 23 pds would require an upgrade which would probably be new springs, and the R1 is slightly heavier than the RZ by 14 pds. The R1 is the better choice for the suspension upgrade then the R6, it will definitely handle the RZ weight without having to spend additional money to upgrade the springs to handle the additional weight. The R1 & R6 front ends are relatively about the same price in corresponding years, newer years the price goes up, best option is as new as you can afford and as complete as you can find. I got a complete 2011 R1 front end for a good price, far better choice than the R6, so no not overkill at all.

[Jeff B]

If you could get a bearing with a 30mm bore, I'd locktight it on before I'd weld it up. That's assuming it's a nice slip fit. Not too sloppy.

I would of rather got what I had paid for originally, but no such luck. Yamaha, upgraded to 31mm for a reason, and locktite is not even close to a interference fit.

The reason that I'd stay away from welding is that the weld is going to warp the part. You will probably have to weld the area that gets pressed into the triple clamp as well. Then you can machine both of those diameters true to the other end. This will not be easy. Not as easy as starting over anyway. I don't know why Yamaha upgraded to 31mm, but it seems like a rather insignificant change to me.