Frame Widening for R6 Swingarm Conversion

Message

RZResurection · #1 Post by **RZResurection** » Sat Jul 22, 2006 10:52 pm

First of all I want to say that this form Rocks. I wish this kind of infromation was around 19 years ago when I was working on my 87 RZ 350. Keep it going boys - this is a good thing :D

I've just completed an R1 front end USD fork conversion. Smooth and simple.

On to swing arm conversions.

It sounds like most of the guys who have done any swingarm conversions have gone with the FZ600 setup. I understand this is a good choice for ease of installation i.e. minimum cutting/modification and it accepts a wider tire upto a 160?

I'm of the "go big or go home mentality". I got myself a set of R6 rims which includes a 180 rear tire. I wanted to put the big-ass tire on the rear!!

I've also purchased 2 different swing arms. One is from an early model FJ1100/1200. I'm guessing around an '84. The nice thing about this swingarm is that it has a "similar style" (not the same) of linkage as the RZ. Instead of using 2 individual tie rods, it has a plate with 2 tabs instead of the tie rods. The overall linkage lengths are very similar. In my opinion, it is a good alternative. Plus, it will accept my 180 rear wheel :D The problem is that I would have to modify any brake hardware to work with this old swingarm.

My second swingarm is an 2001 R6. With this swingarm I could use all of the original brake hardware, wheel axle, etc. without modification, but the linkage is completely different.

I've actually cut off the original linkage mount off the R6 swinger and am thinking of attempting to fab a similar setup as the FJ. Both of the arms have about the same width of pivot tube approx. 10" wide.

I thought about milling down the pivot tube to the RZ's original width (approx 8.25") - no good, I'd be cuttining into the welds that hold the pivot tube to the swingarm.

That problem aside, here lies my true dilema. I noticed that my chain would now be running dead center into the left side of my frame. So, I now have to widen the back end of my frame to fit the R6 or FJ swinger on. I have to widen it by approx. 2"

My question (after all of that preamble) is "anyone have any feedback on frame widening?"

I'd love to hear what you guys think.

Swingarmless :(

Jeff

MBoyett220 · #2 Post by **MBoyett220** » Mon Jul 24, 2006 1:22 pm

That is one of the reasons that people don't go wider than 150 or 160. The other is, take a good look at where your chain lines up with the motors output shaft (Countershaft sprocket) you will have to tackle that as well. Michael

freddie19 · #3 Post by **freddie19** » Mon Jul 24, 2006 4:10 pm

Check out the Jamie James RZ350 Special in the Customs/Projects Restorations Forum.
They have fitted an R6 rear wheel with a 180 tyre.
The swingarm looks like a FZ6 one!
So it obviously can all be made to fit!
It says they widened the frame to make it fit but there are no details!

I have emailed them two times now for more details on the bike but they have not bothered to reply!
Not the best example of customer relations!

The bike does look awesome with the R1 front end and big 180 rear tyre!

Hope this helps.

Freddie19.

#4 Post by **smurph** » Mon Jul 24, 2006 7:38 pm

The problem with most "modern" swingarms is going to be the length. The R6 and R1 units will be 2" to 3" too long. So if you widen the frame and fit one, then you will alter the wheel base unless you shorten the swingarm up. Speaking from experience, cutting the length down is a very difficult job. (R1 swinger -> RZ500). The FZ6 swingarm may be a bit shorter or easier to shorten. But I'm here to tell you that getting a custom made swingarm is the route I'd go. This is because unless you have gobs of time, can weld aluminum, and have machine equipment at your disposal, you will be frustrated.

IMHO, the frame mods would be the easy part. And an offset sprocket could be used to correct chain alignment. I'm not a fan of the offset spockets because the further your chain gets from the output shaft's bearing, the more load you will put on the output shaft and bearing/case. But an offset sprocket is about the only choice you have. :( I may be overstating the effects that the offset sprokets have. The shaft and the bearing may be strong enough to handel it without issues. It's just something that, in my mind, might present problems. Obviously, people do use them. And either they are real silent about failures, or they work ok. Maybe I'll find out one day.

Steve

RuZty · #5 Post by **RuZty** » Mon Jul 24, 2006 8:06 pm

This might be useful with an offset sprocket; http://www.mattoonmachine.com/cgi-bin/M ... 5-120.html
They've got some really neat custom Banshee cases too.

RZResurection · #6 Post by **RZResurection** » Mon Jul 24, 2006 10:52 pm

Thanks for the input guys.

That article about the Jamie James RZ was the one that inspired me to resurrect my '87. He did a wicked job on it. I saw pictures of his bike and immediately saw what mine could become.

I know that the 180 tire can be put on with widening the frame, but like Freddie19 said, "no details" in the article.

I'm worried about cutting the frame to bits and not getting the critical parts to remain in their original locations. I figured on welding a whole bunch of tube stock to parts of the frame that I'm not widening. That way I can temporarily hold critcal locations true while I rebend the tubes.

I too took to emailing Jamie as well - also without reply. All of us probably emailed him at the same time and crashed his web site :lol: Probably pissed him off. I'm sure the guy is a wealth of information on RZ mod's, it would just be nice if he would give some of it up.

I'm prepared to go the offset sproket way. I do understand the pitfalls of shifting the load further from bearing. Anything that I've ever seen calc's done on i.e. bearings, housings, etc., usually have a good safety factor build in - anywhere from 1.5 - 2.5. = 1.5 - 2.5 x max load. I agree that I don't have much of an alternative. I'll let you know if/when the offset sproket kacks out.

How do you think the longer swingarm will alter the handling characteristics? I'm guessing that it will be more stable with the longer wheel base - which also means that it won't steer as quickly. I havent been able to look at any new rake/trail #'s (R1 front end addition) with the back end off to see if the geometry has changed dramatically. Does anyone know if adding 2-3 inches make for a comparable wheelbase to the modern bikes?

I do have access to an aluminum welder along with an experinced welder to boot as well as a machinist that loves bikes. Don't want to get into the "my swing arm fell apart at 100mph" club. I'm going to have to do some welding and machining to fab up a new linkage for the R6 swinger to work first without shortening it. I'll let you know how things go.

I still have to find a decent shock - to throw another variable into the mix.
Any ideas here?

I figure if I get all of my suspension parts figured out this year, next year will be onto engine rebuild. Got lots of questions about engines too.

Thanks for the feedback - believe me "feedback is a gift" . Please don't get pissed if I challenge some of it at one point or another. I tend to question things, so that I can understand things better.

Can any of you computer whiz's tell me how to post a few pictures? :?

[/img]

tkm433 · #7 Post by **tkm433** » Tue Jul 25, 2006 2:18 am

RZResurection wrote:Thanks for the input guys.

That article about the Jamie James RZ was the one that inspired me to resurrect my '87. He did a wicked job on it. I saw pictures of his bike and immediately saw what mine could become.

I know that the 180 tire can be put on with widening the frame, but like Freddie19 said, "no details" in the article.

I'm worried about cutting the frame to bits and not getting the critical parts to remain in their original locations. I figured on welding a whole bunch of tube stock to parts of the frame that I'm not widening. That way I can temporarily hold critcal locations true while I rebend the tubes.

I too took to emailing Jamie as well - also without reply. All of us probably emailed him at the same time and crashed his web site :lol: Probably pissed him off. I'm sure the guy is a wealth of information on RZ mod's, it would just be nice if he would give some of it up.

I'm prepared to go the offset sproket way. I do understand the pitfalls of shifting the load further from bearing. Anything that I've ever seen calc's done on i.e. bearings, housings, etc., usually have a good safety factor build in - anywhere from 1.5 - 2.5. = 1.5 - 2.5 x max load. I agree that I don't have much of an alternative. I'll let you know if/when the offset sproket kacks out.

How do you think the longer swingarm will alter the handling characteristics? I'm guessing that it will be more stable with the longer wheel base - which also means that it won't steer as quickly. I havent been able to look at any new rake/trail #'s (R1 front end addition) with the back end off to see if the geometry has changed dramatically. Does anyone know if adding 2-3 inches make for a comparable wheelbase to the modern bikes?

I do have access to an aluminum welder along with an experinced welder to boot as well as a machinist that loves bikes. Don't want to get into the "my swing arm fell apart at 100mph" club. I'm going to have to do some welding and machining to fab up a new linkage for the R6 swinger to work first without shortening it. I'll let you know how things go.

I still have to find a decent shock - to throw another variable into the mix.
Any ideas here?

I figure if I get all of my suspension parts figured out this year, next year will be onto engine rebuild. Got lots of questions about engines too.

Thanks for the feedback - believe me "feedback is a gift" . Please don't get pissed if I challenge some of it at one point or another. I tend to question things, so that I can understand things better.

Can any of you computer whiz's tell me how to post a few pictures? :?

[/img]

Now ask yourself why do you like your RZ350? Is it becasue it is a two-stroke street bike or is it becasue it is a RZ350?

If it is becasue it is a RZ350 then you should keep it an RZ350 and not Frankenbike it.

Now if you like a two-stroke street bike and you want to improve on its handling, looks, and still want to burn blue smoke and make ring a ding ding noises as you ride around town then find a current or more current frame to install the RZ350 motor into and you will have a little of both worlds.

No matter which way you decide to approach this you will still run into the offset front sprocket issue if you want to run anything wider than a 150mm tire and still have proper chain alignment.

Back to the swingarm conversion, I feel it would be best to modify a swingarm to fit the RZ frame since you can always install your stock swingarm if you need to go back to stock for any reason where as making the frame wider there is no going back.

T.RexRacing · #8 Post by **T.RexRacing** » Tue Jul 25, 2006 6:57 am

I also have a go big or go home thing.So I bought an Aprilia Tuono and left my RZ as it should be.I do not understand all you guys cutting up a classic bike so it looks like a newer bike.I bet my lap times on my RZ would be at least the same as yours with the big tires.I could bolt/weld on all I wanted and the RZ would never be as good as my Aprilia.But as they say to each his own.

S10RZ350 · #9 Post by **S10RZ350** » Tue Jul 25, 2006 3:03 pm

Looks aside the ride is a billion times more comfortable with the wider tires. Especially at freeway/highway speeds.

Using the FZ600 swingarm narrowed to fit the RZ frame and a spacer on the forks I can go back to stock anytime I want.

I dont ride my RZ like an idiot on the street anymore. If I wanted to do that I'd buy an R6 or Daytona 675.

#10 Post by **smurph** » Tue Jul 25, 2006 4:35 pm

Modding a RZ350 to the max is fun. But I do understand the classic status that the bike has as well. That's why you need more than one. One stocker and one to play with. That's how I handle it. After all, RZs are like potato chips... You can't have just one. :)

But I have to say that a nice front end and good brakes makes riding the non-stocker much more of a pleasure.

Steve

RZResurection · #11 Post by **RZResurection** » Tue Jul 25, 2006 9:59 pm

Wow a technical discussion turned philosophical. "To chop or not to chop".

I can see how it could boil down to two camps. Those who want to preserve and keep original and those who want to modify and improve.

To appreciate my need to modify my RZ, you have to understand a little bit of me and my RZ's history.

I bought my '87 in 1987 second hand. The original owner got pissed up and figured he could ride it into a tree. I guess at the last minute he bailed, the bike side swipped the tree. It ripped the left lower section of the cradle off (side stand along with the frame sectionwas not present when I bought it - and the stator/rotor was crushed). The body work was smashed to bits. I didn't even know if might run again. I took a gamble on it.

Basically I had a project bike. I liked the look of the track bikes TZ 250, RS 250, so I bought some fiberglass bodywork. I had a TZ 250 body fairing and an RS250 solo seat. I put an RG500 brake light in the tail section and cut a hole for my headlight in the body fairing. Once I completed the other mechanical repairs (and some engine mod's), I painted it blue & white (sorry I couldn't stand the red/white original scheme) I had a cool, good looking, little bike for it's day. Granted it was basterdized, but it was all RZ.

I can appreciate the challenging question "...why do you like your RZ350?Is it becasue it is a two-stroke street bike or is it becasue it is a RZ350?"

It actually made me think hard. I have mixed emotions on this, but I've concluded that my bike has never been "original/stock" from the day that I got it. I don't intend to go original now. "Stock" has never been my bike. I've always been a hybrid kind of guy. I'm the kind of guy who looks at things and says - nice bike, but I'm sure that I could make it better. It's the engineer in me. I guess that you could say that my bike has evolved to reflect my philosophy.

I think that Steve hit it on the nose for me when he said:

"Modding a RZ350 to the max is fun. But I do understand the classic status that the bike has as well. That's why you need more than one. One stocker and one to play with. That's how I handle it. After all, RZs are like potato chips... You can't have just one.

But I have to say that a nice front end and good brakes makes riding the non-stocker much more of a pleasure".

I'm not going to be riding it like I did 19 years ago - too old, too many people depend on me to stay in one piece and alive. :shock:

I'm not expecting my RZ to be a "new" bike either. I would just like "some" of the performance aspects rolled into my old RZ. I know that I can have the best of both worlds, without owning 2 bikes to do it! I don't see being able to afford 2 bikes, so I have to make this one fulfill all of my needs. I see it possible with some modifications and some fun making them happen :D

Jeff

T.RexRacing · #12 Post by **T.RexRacing** » Tue Jul 25, 2006 11:57 pm

Ah shit I still ride the wheels offa my RZ.And the Tuono.And at 47 I still race motocross on my CRF450R.A life not explored is a true shame.I guess to answer your question I'd go with the smaller swingarm and run a smaller tire.Less headache and more experience around here with that.Good luck.

freddie19 · #13 Post by **freddie19** » Thu Jul 27, 2006 2:59 am

Hi Jeff,
which R1 front end have you fitted,
the original '98 or the '02 as the Jamie James bike?
I think the gold forks would look even better than the black ones they fitted!

I'm looking to fit one to my RZ but I want to keep the original RZ clocks
so I'm wondering if a FZR1000 front wheel with std speedo drive will fit the R1 forks?

Freddie19.

RuZty · #14 Post by **RuZty** » Thu Jul 27, 2006 9:41 am

I'm wondering if a FZR1000 front wheel will fit with std speedo drive?

I know the YZF600 ('98-'03) speedo drive will work with the stock speedo, I was going to go that route and bought one some time ago.

freddie19 · #15 Post by **freddie19** » Thu Jul 27, 2006 7:18 pm

Hi RuZty,
What I want to know is will a FZR1000 front wheel and speedo drive fit in the R1 forks?
I know there may be a bit of jiggling of spacers and wheel bearings but is there any reason it cant be made to fit?
That way I can keep my std RZ clocks and not have to change to the R1 clocks!

Freddie19.