Swing-arm, Shock, Dogbone & Link - Questions

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ricar
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#16 Post by ricar » Thu Jan 28, 2010 11:29 pm

Thats what I did as well.
84 RZ. Half naked, SpecIIs, GSXR front end, FZ swingarm, SV rear wheel, trail tech speedo/tach

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Off Road
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#17 Post by Off Road » Fri Feb 05, 2010 1:30 am

Thanks for everyone’s input.
I think it’s only fair that I wrap this up and let you know which way I’m going.

Riicar & nikfubar, nice work on your bikes & thanks for the ideas. However….
Off Road wrote: Disclaimer: - I am not an engineer, a designer, a machinist, and I’m certainly not an artist.
.
I am also not a welder.
I will be paying someone with your skills to do the machining/welding for me.

So, here’s what I decided

RZ350 - Link
FZ600 – Dog-bones (to start, I will look into getting the RZ dog-bones shortened later)
FZR400 – Swing-arm (with the dog-bone pivot relocated to match the FZ600 swing-arm)

WTF???

I do have reason’s, it’s not just the voices I hear.

I’ll post the details in the Low Budget thread.

Again, thanks for all the help.

savethe2strokes
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Re: Swing-arm, Shock, Dogbone & Link - Questions

#18 Post by savethe2strokes » Fri Feb 02, 2018 10:56 am

Can anyone get the pictures for this thread?
85 RZ350-Messed up wiring

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Evans Ward
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Re: Swing-arm, Shock, Dogbone & Link - Questions

#19 Post by Evans Ward » Fri Feb 02, 2018 11:02 am

savethe2strokes wrote:Can anyone get the pictures for this thread?
Not here either. Photos are the victim of Photobucket holding them as well as everyone's hostage due to greed.
84 RZ350-Toomeys,SCR milled head, stk 26 carbs,300 M, 35 P, stock regrooved needles AS 2.5 turns out,stk air box,Banshee reeds Zeel non-progr CDI,TSRL Program YPVS,alum rad,R6 shock,GV emulators w/RT springs,fork brace,Shindy steering damper.

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Smoker
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Re:

#20 Post by Smoker » Fri Feb 02, 2018 3:58 pm

Off Road wrote:
alexandros wrote: No rush here as I know you too are building at a leisurely pace too. Let's see what the engineer students compile.
Calling it a leisurely pace is being too kind. I haven’t picked up a wrench in forever. :smt009

It’s Friday night. Engineering Students are on a pub crawl.
alexandros wrote: ...Dean stated that we need a longer shock.
smurph wrote:Another way is to shorten the dog-bones and use the RZ relay link. This retains the original RZ rise rate on the linkage.
Steve

Both a longer shock and/or shorter dog-bones will raise the ride height with the FZ 600 swing-arm.
Dog-bones will be harder for me to do.

The stock shock is 290mm,
the R6 shock is 305mm
& my Works Perf. Shock is 295.mm

Like Smuph said, use the RZ350 Link as it will retain the original rise rate.
It’s 5mm shorter than the FZ and this will also help retain ride height.

Image

With the bikes on the center-stand I took ride height measurements and got the following numbers

The measurements were taken from center of the axle, straight up to the top of the frame rail.

Image

Stock 83RZ - Ride Height = 445mm (17.5�)

With FZ600 Swing-arm, FZ dog-bones & RZ Link – Ride Height = 425mm (16.75�)

With FZR400 Swing-arm & RZ Link (when swing-arm hits shock) – Ride Height = 405mm (16�)

Bear in mind, these dimensions were taken late at night, in the dark, using a very precise Tape measure.

The numbers should be close, but you might want to get a second opinion, Alexandros. :smt003

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Smoker
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Re:

#21 Post by Smoker » Fri Feb 02, 2018 4:01 pm

Off Road wrote:
ax-racing wrote:can you make housing for spring grinding material on swingarm ?
I don’t think I can.
If I grind 10mm of material from the swing-arm,
I will be into the dog-bone pivot

Image
slinger wrote:How about if the dog legs where made with a bend in them so they fit both ends and fit a spacer where they bolt to the swinging arm.
Straight dog-legs will clear the shock and line up with pivot on the swing-arm.
(if I understand you correctly, on which way the bend goes)

Image

I found the following write-up in my Manual.
Pretty good explanation on how the rear suspension works.
Yamaha refers to the Link as a Relay Arm & the Dog-bone as Arm 1.

Image

I find this part interesting
“The relay arm amplifies the movement of arm 1, as the wheel strokes more.

So what happens when you lengthen Arm 1. (as you do when you install an FZ600 swing-arm)
I can’t visualize this in my mind. Will have to see it on paper.

Hopefully, I can get the 4 CAD drawing done by the weekend.
(Stock suspension, FZ600 suspension and Mod 1& Mod 2 of the FZR400 Suspension.

I will set L=10mm and then calculate l1, l2, l3…..l10.
I should be able to graph the results and see how the modified set-ups compare to stock.

I’m trying to keep my suspension rates as close to Stock as I can.
After all, Yamaha had a team of really smart engineers design this suspension.

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Smoker
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Re: Swing-arm, Shock, Dogbone & Link - Questions

#22 Post by Smoker » Fri Feb 02, 2018 4:04 pm

Off Road wrote:The Task: - Install an FZR400 swing-arm on an RZ350 & still have the bike handle well.

The Problem: - The pivot for the dog-bones, on the FZR400 swing-arm, hits the shock.

Image

If I lengthen the dog-bones so that the pivot clears the shock, then the ride height is 40mm (about 1.75") too low.

Image

Possible Solution #1: - Shorten the Link, from shock to frame, by 10mm and use 90mm long dog-bones

Then the swing-arm can drop down further and I can get the OEM ride height.

Pro- I can keep the center-stand
Con – The Link will cost about $500 + dog-bones

Image

Possible Solution #2: - Lower the Top Shock mount by 35mm and use 115mm dog-bones.

The bottom of the shock pivots down & forward about 10mm.
Once again, the swing-arm can drop down further and I can get the OEM ride height.

Pro – Cost will be about $20 + dog-bones
Con – will have to lose the center-stand & I don’t like the angle that the link is on (pointing down).

Image

Assumptions: - Changing the Link length, Dog-bone length, or dog-bone pivot location on the swing-arm,
will affect the rate at which the Shock compresses when compared to Rear axle travel.
This will affect the handling of the bike.


Drawings: - I measured the OEM rear suspension setup and made sketches of what I thought was relevant.

I then measured & made sketches of the 2 proposed solutions.

Image

The Next Step: - Transfer the dimensions on the 3 sketches into CAD drawings.

Then move the rear axle through its 100mm of travel and determine the rate at which the shock compresses.
From this I should see how each of the proposed solutions compares to the OEM suspension.

I could then use the modification that more closely resembles the stock set-up.


The Questions: -

Does any of this make sense?
Am I on the right track?
Will one idea work better than the other?
Does anybody see problems with either idea?
Does anybody have a different solution?
If anyone has done either of these mods, how well did it work?


Disclaimer: - I am not an engineer, a designer, a machinist, and I’m certainly not an artist.


I’m just looking for advice, so that this bike doesn't end up handling like a 25 year old 4 stroke. :smt003

Any information would be appreciated.

Thanks.

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kpke
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Re: Swing-arm, Shock, Dogbone & Link - Questions

#23 Post by kpke » Wed Feb 07, 2018 11:40 am

Smoker, do you have easy instructions on how you made those photos appear?

That's cool. :smt023

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Smoker
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Re: Swing-arm, Shock, Dogbone & Link - Questions

#24 Post by Smoker » Wed Feb 07, 2018 1:37 pm

I know a little about computer hacking, but not enough.

Sometimes it works, sometimes, it doesn't.

Not sure about posting hacking techniques.

PM sent.

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