Suspended versus Cradled RZ500 engine hybrid builds

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RC45
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Suspended versus Cradled RZ500 engine hybrid builds

#1 Post by RC45 » Tue Apr 26, 2016 2:25 pm

OK folks.

Lets hear it for long term serviceability of under-slung/suspended RZ500 hybrids versus the cradled builds.

The RZ/RD500 (and even RG500) cases where designed for and built as cradled engines - how are the hybrids with suspended RD/RZ500 and RG500 engines "hanging" after extended use? The frames are not my concern, the cases are.

I see some builds with threaded received welded/machined into the cases and others where the barrels/cylinders do the heavy lift (suspension) work.

Thoughts and comments about the different build styles/methods.

Eliminating the cradles really opens up fairing options, but how well do the suspended motors age structure wise?

(the fact that most hybrids never get ridden may skew the longevity data though :))
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Re: Suspended versus Cradled RZ500 engine hybrid builds

#2 Post by Ax-Racing » Wed Apr 27, 2016 11:26 am

I can not tell you a definitive answer

i used to supend engine by head in a couple of project with RZ350 engine, since 1990
honestly bikes doesent run a lot, but they worked fine in several track day and other small run.
As I told not high mileage but seems to be all perfect without any stress simptom on engines.

of course there is less space to operate on engine and often you need to take off entire unit
for some manteniance operation. (moslty due to frame configuration)

in my 500 project also choice to suspend engine with a mounting bracked bolted on cranckcase
(better than bolt on head).

in conclusion I support suspended mount, if you build a solid brackets
and i'm quite sure that this configuration doesen't stress cases in a wrong way.
Alex

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#3 Post by RC45 » Wed Apr 27, 2016 1:21 pm

Alex, thanks for the response.

Do you have a preferred area of the case you like to hang it from?
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Re: Suspended versus Cradled RZ500 engine hybrid builds

#4 Post by Ax-Racing » Wed Apr 27, 2016 2:34 pm

Image

Image

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#5 Post by frame maker » Thu Jun 09, 2016 9:39 pm

Interesting question. My solution is to use the original mounting locations. Now if I could just find time to finish it :???:

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#6 Post by two-stroke-brit » Sun Jun 19, 2016 6:05 pm

thats impresive
She might not be pretty but always a fun ride !!

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#7 Post by giron » Sat Sep 17, 2016 12:14 am

lets continue with the cradle idea. We need to ask why the Yamaha and Suzuki engineers design the RZ500 and RG500 to be fitted into a cradle style frame for the Yamaha and the Suzuki enclosed frame. Can it be they know something we don't. Maybe is because they have degrees in engineering. I'm sure they measure stress point in the engine cylinders cases. Do you think that maybe just maybe they have a lab where they did the testing. Do you think?
1991 3MATZR250SP
!993 3XVTZR250SP
1996 RGV250(Lucky Strike)
1994 MC28SP
1995 MC28SP
1996 MC28SP
1985 RG500(Walter Wolfe)
1984 IT490
1985 RZV500R
1985 NS400R
1985 NS400R
1997 VFR750
1992 FZR1000
RGV400
TZR500
TZR350
1990 RZ350
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Re: Suspended versus Cradled RZ500 engine hybrid builds

#8 Post by Questo vecchio rz » Sat Sep 17, 2016 3:17 am

giron wrote:lets continue with the cradle idea. We need to ask why the Yamaha and Suzuki engineers design the RZ500 and RG500 to be fitted into a cradle style frame for the Yamaha and the Suzuki enclosed frame. Can it be they know something we don't. Maybe is because they have degrees in engineering. I'm sure they measure stress point in the engine cylinders cases. Do you think that maybe just maybe they have a lab where they did the testing. Do you think?
I understand your viewpoint, but I'd say, its original cradled frame is primarily due to the simple fact there based on 40-45 year old ideas...lol
No one needs reminding that these bikes are F-ing old school as far as design. Originally delivered w steel frames, bicycle sized bias tires, spindly anti dive forks, engine issue re-designs/fixes etc... Clearly outdated by their 2nd year of production as far as being cutting edge.

If they were designed today, a good bet they would all be stressed membered.

I also think, the engineer's developed these bikes as best they could at the time, While a nice built bike, and impressive at the time even with all its faults, Its not the same level of engineering as lets say the team of the same era that developed the stealth bomber.
If the RZ was engineered to that level, they wouldnt have been faced w so many lil issues & people wouldnt be modifying them every which way.

So that being said, I certainly beleive they can be "modified" for use in almost any capacity without worry, by a "competent indavidual". And yes it would have to be thought out carefully and (done right), or just plain good ol fashioned over engineered by whatever various methods.
One doesnt have to hold a degree in mechanical engineering or hold every aerospace welding certificate to be able to fabricate/create or modify something to become something truly awesome. History is full of "average Joes" with alot of creative ambition.

I'm primarilly referring to indaviduals ( many are members here) whom modify original components or machines such as our beloved bikes.
It's quite obvious that a mass produced machine for profit/research etc.. requires said degreed engineers and only a fool would think otherwise.

Remember though..The ESA JPL & NASA crashed the Mars lander straight into the surface of Mars because the so called "brilliant engineers" forgot to transfer metric #s into American data...lol :smt021. :mrgreen:
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Re: Suspended versus Cradled RZ500 engine hybrid builds

#9 Post by giron » Sat Sep 17, 2016 12:34 pm

Do not get me wrong. I'm the first one to change the swingarm and front end on my bikes. By the way RZV frame is aluminum not steel. As long as the geometry bike is the same, but I have better wider wheels with softer compound. A good example was my Kawasaki 750 Turbo. Talk about old technology, but I had RGVSteve set the swingarm and the front end from a ZZr1200. What a difference with better tires and wider wheels.
Now you mention old technology. That should also include the engines RZ500 and RG500. The metal on these engines were set up to go into a cradle frame. The only way to alter will be to fabricate the external engine components with newer metals.

Listen to what you are implying that people on this board are more knowledgeable than Suzuki and Yamaha engineers from forty years ago
1991 3MATZR250SP
!993 3XVTZR250SP
1996 RGV250(Lucky Strike)
1994 MC28SP
1995 MC28SP
1996 MC28SP
1985 RG500(Walter Wolfe)
1984 IT490
1985 RZV500R
1985 NS400R
1985 NS400R
1997 VFR750
1992 FZR1000
RGV400
TZR500
TZR350
1990 RZ350
1971 Porsche911S

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#10 Post by Speed Freak » Sat Sep 17, 2016 2:25 pm

Today they still use the same cheap material for the engine cases as 1980.
There isn`t so much to improve.

Problem is, that the RD engine cases are not made for this loads - doesn`t mean that they are not stiff enough.
It can work, but they also can get cracks or the bending behavior of the frame is bad.

What has changed?
CAD/CAE...
You can make a design, check the loads inside the material, change it again, add some ribbs here and there, check the loads again...
In the end you have a design which basically works from the first prototype.
1980 they didn`t have all this possibilities and i think the idea of using the engine as a stressed part was a too high risk for a mass production bike at this time.

This is a good example for such a development:

Take the same engine case which are made for a cradle type frame (XTZ750), add some material at the right places and you can use it as stressed part of the frame (TRX850, TDM850/900).

A friend is converting XTZ750`s to 850 or 900 engines.
If you look at this engine cases you can clearly see that they have the same base (you can exchange a lot of internal parts between this engines) but they were improved over time.
And they have added a lot of stiffness to the engine cases to use it in the TDM frame.


Look at new Ducati bikes... They do not have this old fashioned "frame" design. The engine itself is the frame.
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Re: Suspended versus Cradled RZ500 engine hybrid builds

#11 Post by giron » Sat Sep 17, 2016 4:57 pm

I'm sure the metal in a ducati is a lot better than a Japanese bike. I remember in the 60's a CL305 (scrambler) was a cradle frame but a CB305 (dream) the engine was part of the frame. I heard that engine cases and I saw it myself. The cases were different on the mounting points between a CL and CB
Maybe an engineering degree does make a difference
1991 3MATZR250SP
!993 3XVTZR250SP
1996 RGV250(Lucky Strike)
1994 MC28SP
1995 MC28SP
1996 MC28SP
1985 RG500(Walter Wolfe)
1984 IT490
1985 RZV500R
1985 NS400R
1985 NS400R
1997 VFR750
1992 FZR1000
RGV400
TZR500
TZR350
1990 RZ350
1971 Porsche911S

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#12 Post by RC45 » Sat Sep 17, 2016 10:12 pm

The absence of a lower cradle does not mean the engine is a stressed load bearing component. In many of the large twin spar frame setups the engine is still not a stressed load bearing component.

I think there may be some confusion between what constitutes a stressed load bearing component versus simply hanging a component from a frame using the same mount point previous used to cradle it.

Take holding a car battery out in front of you by the handle versus placing it on your forearms - in either case your back and arms take the stress not the battery. If you replace your own forearm with the battery it is a different story, but this is not what is being discussed with cradled vs under-slung in the context of the RZ engine.
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Re: Suspended versus Cradled RZ500 engine hybrid builds

#13 Post by silverstrom » Sat Sep 17, 2016 10:47 pm

Thank you for that. There is indeed a big difference being a stressed member and simply being supported by the frame. The discussion about the TZR frame supporting the engine in a way some feel is inadequate is a good example of what you have mentioned. Being supported by the frame does not mean the engine itself is acting as part of the frame. In that TZR instance the rear mount takes the brunt of the load and force. Engine rotation is on the longitudinal axis and the forward mounts simply support the engine without bearing significant stress at the mounting points.

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#14 Post by giron » Sat Sep 17, 2016 11:52 pm

John lets get back to the RZ500 and RG500 hanging from the cylinders. Why are they breaking? A shop in the UK had to fix several RG500 in a VJ22 frame. Now If the cylinders came with a boss like om the YZR500 and Brian I believe pointed out. This board keeps going around fabricating home made hot rods some good and some total &^%%$. Again how many people in this board have been to Japan and sat with the Yamaha Moto GP team to my knowledge only one. Give credit whee is due and not local shop
1991 3MATZR250SP
!993 3XVTZR250SP
1996 RGV250(Lucky Strike)
1994 MC28SP
1995 MC28SP
1996 MC28SP
1985 RG500(Walter Wolfe)
1984 IT490
1985 RZV500R
1985 NS400R
1985 NS400R
1997 VFR750
1992 FZR1000
RGV400
TZR500
TZR350
1990 RZ350
1971 Porsche911S

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Re: Suspended versus Cradled RZ500 engine hybrid builds

#15 Post by RuZty » Sun Sep 18, 2016 12:04 am

Giron, I don't know what your background is but you talk about the engineers at the Japanese factories with god-like reverence as if they are the only people in the world who understand how things work. If you appreciate technology but don't work with it and understand what is behind it I can understand that, but not everyone is in the same boat.
You say "you are implying that people on this board are more knowledgeable than Suzuki and Yamaha engineers from forty years ago"
Why can't this be so? I would be disappointed if it wasn't. It was mentioned that times have changed and so has technology and our understanding of materials and our ability to simulate the loads and forces in a design. I have been working in technology for 30 years, including international motorsports. I am not suggesting I am smarter than anyone else, quite the contrary, the more I learn the less I realize I know, but I've worked with Japanese engineers and they have good and bad just like any other group, and any design is a compromise of budget, schedule and original design goals. They are making a bike to appeal to the target market specified by the sales department and a budget set by finance, and have boundaries to work within. When I modify something I do it to suit me alone and I am free of the constraints that tied them down. Sure many people get in over their head when 'improving' things, we've all seen examples of it, but not everyone is like that. You obviously are smart enough to know your limitations and also to realize what is quality work when you choose to hire someone, but that doesn't mean we all need to do that.
Half the fun of motorcycles for me is working on them. I would honestly design and build my own pipes, just to learn how, I can weld so why not? They might not be as good on the first (or 50th) try as what I could buy from Brian or other tuners on this board, but they would be better than stock and mean more to me. They all had a first too, how do you improve without doing? The day I stop learning and improving is the day I stop living.
You also say "I'm sure the metal in a ducati is a lot better than a Japanese bike." WTF? how can you think they are the smartest people on the planet and suggest they have a poor grasp of metallurgy? Sure you can have a lousy casting process and get porosity and misflows, but that is what a good quality system is for, and that is what they are very good at. I'm pretty sure they know how to alloy aluminum as well as Ducati, both then and now. I can appreciate being in awe of incredible workmanship and creations when you don't know what went into them, I feel the same way about things I see, but I do not consider myself inferior because I cannot do that, I consider that I have not had the time, desire, opportunity or finances to explore it and become good at it. I think many others on this board are the same, and many have demonstrated that with the fantastic projects they have shared with us. I don't come on here to read about RZ500s and much as to be exposed to these types of creative individuals. Go ahead and sell yourself short, but leave the rest of us out of it.

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