Topic: Monoshock, or side mount shocks, whats the handling differences?

[Soos]

I am seriously tempted to mount up a monoshock from an '85 gpz600 kawasaki on a '82 cb650 frame.

But i'm not sure whether welding shock mounts on the frame and putting on the single shock, or converting the swingarm to accept the dual shock setup stock to this cb650.


Are there stability or handling characteristics that are inherent to either shock system?
I would imagine the dual shock would be more stable in corners... but i'm not sure.



l8r

[crazypj]

If its done right the mono shock is a lot more stable than twin shock set up. you feed the loads from rear wheel directly into frame backbone, it doesn't twist rear frame/shock mounts like a twin shock will ( CB500/550/650)
 All of them rust where seat section meets front frame section ( front of seat, rear of tank)  because the frame flexes and paint falls off
PJ

[MCRider]

If its done right the mono shock is a lot more stable than twin shock set up. you feed the loads from rear wheel directly into frame backbone, it doesn't twist rear frame/shock mounts like a twin shock will ( CB500/550/650)
 All of them rust where seat section meets front frame section ( front of seat, rear of tank)  because the frame flexes and paint falls off
PJ

Those are very good points. Some others a little more esoteric: From a design standpoint, weight should be concentrated in a triangle formed by the axles and the shoulder pivot of the rider. Monoshock does this, twin shock does not. (Nor does hanging the battery in a tail section, but it does look cool) Its also a reason for flipping the forks backwards so the calipers are in the triangle and also near the pivot of the forks.

Also, unsprung weight is reduced. The bottom half of each twin shock and spring is unsprung weight. With a monoshock that is reduced to near 0 as the weight resides near the pivot.

[KB02]

From a handling stand point (and this may just be my mind making things up...) but if you have one shock go bad in a dual shock system, the handling of the bike with be very negatively effected. e.i. - twisting of the swing arm, stuff like that.

I thought about doing the monoshock routine with my 78 750 I am building. The swing arm I have would have extended the rear tire out too far for my liking.

[MCRider]

From a handling stand point (and this may just be my mind making things up...) but if you have one shock go bad in a dual shock system, the handling of the bike with be very negatively effected. e.i. - twisting of the swing arm, stuff like that.

I thought about doing the monoshock routine with my 78 750 I am building. The swing arm I have would have extended the rear tire out too far for my liking.

Not likely on a street bike, but you are correct IMO. On my racer, I had to remove both for something and realized that one was virtually seized. My numb butt was not tuned well enough to detect it, but it couldn't have been good.

[Soos]

going to have to search up if anyone has done this, if they used a jog or something to orient everything properly.

From what you all have said, and what I have read on mono shocks, it is an improvement.
Now to find out the price of a new one, or if these type are re-buildable..


I hate stiff old shocks.
When I had put new shocks on my '79 it made a world of difference.
I don't like old shocks.

And my butt couldn't tell either.
But my back could, especially on long rides.


l8r

[WFO]

Iam sure having one shock centered is alot better i remember having one shock on my old XR messing up and that made the ride all messed up so having slight differences in one shock is really hard to detect and real easy to detect in a mono shock that being said the mono is way better.

to orient everything properly

That will be the trick..

[doobiebro]

This is great info.  Just a few weeks ago I saw the ProLink monoshock and swingarm from a '81 or '82 CBX on e-Bay and I was thinking that it would be so cool to adapt my '77 750K frame to fit it.  I thought the CBX frame geometry would be close to the 750 - but perhaps too wide.  Anyways, it is good to know my thinking of better stability was correct.

[CBJoe]

Given the talk about proper orientation and such...  How does this work 

I would think that a shock mounted like this would cause twisting on bumps....

[scunny]

it's all in how stiff you make the swing arm, don't forget the single sided swing arms
CAUTION I've been thinking

[Shenanigans]

I always wondered about the side shock set up, as I have seen the Ducati sport classic which has that set up. I was surprised the shock was not so beefy but then again that bike is not exactly a super sport.

[alltherightpills]

Here is a monoshocked 350 twin from the Inspiration Gallery...





Looks cool to have it totally open like that, but unless that seat is made out of carbon fiber or some other super stiff, super light material, I don't imagine it would last very long without bracing.

[WFO]

I always wondered about the side shock set up, as I have seen the Ducati sport classic which has that set up. I was surprised the shock was not so beefy but then again that bike is not exactly a super sport.

Iam sure the frame was built to compensate for the flex.

[bigsherm]

I've been agonizing over this very decision for a couple weeks.  I was on the verge of springing big bucks for really good dual shocks and a stiffer swingarm.

Then I ran across Ducati 750/800/900/1000ss swingarms with their cantilever monoshock design.  I'm considering modifying this swingarm by cutting off the pivot tube, shortening the front of the swingarm, and welding it back on with some additional bracing.  I don't want a longer swingarm than stock because I like the responsiveness of the stock wheelbase.  This way, I'd have a strong piece that will accept modern fat rubber, and has proven geometry that you can get a shock for.

I made a geometric model to determine the difference in the forces on the shock with the shortened swingarm, and in this case they are virtually the same as with the stock length if you shorten the front instead of the rear of the swingam because you are reducing the arm length from the pivot to the wheel, and from the pivot to to the shock.

Ohlins shocks for the Ducati ss models are quite cheaper than their twin shocks, too!

One problem - where do I put the oil tank?  I think a stock oil tank would work if I don't modify the rear up tubes, but I want to keep my bike see-through, and that seat cowl will be removeable with a passenger seat underneath.

Sherm

Here's a drawing of my idea.  CLICK TO MAKE BIGGER.

[crazypj]

going to have to search up if anyone has done this, if they used a jog or something to orient everything properly.

From what you all have said, and what I have read on mono shocks, it is an improvement.

 Back around 1989 I fitted a modified Yamaha RD350LC swing arm (pre-YPVS) into a CB400f with shock pretty much parallel with frame backbone , just above carbs. Also fitted CX500 forks (for the dual disc set up) with comstar wheels from CB400T.
The difference in handling was totally awesome.
Unfortunately I don't have any pictures but there were pictures of a similar one posted a year or so ago, it looked similar to the drawing.
 That CB350 looks like it has a GSX-R shock and ride height adjuster fitted. I would think that's a bit stiff for 350?
PJ

[dusterdude]

i seem to remember someone on here either did it or was tinkering with the idea,i dont recall who it was tho

[crazypj]

Probably not me, I only do Suzuki mono shock swing arms into Yamaha XS650 nowadays 
PJ

[Industrial Cafe]

I know it's an old thread, but resurrection is fun.
look at my idea, very similar to bigsherms.
i'd use a bigger shock for sure, just trying to see what it would look like.

P.S. it's photoshop

[cafebob]

I have done this to a 750.  Riding it is much more response, I feel I can really get into corners much more than I used to.  To me it is a really nice mod.


As to doing it. Keep in mind that you really need to try and preserve the original swing arm geometry from the doner bike.  You want to make sure the shock travel and range of motion is the same, or things can bind. Also, ride height is a concern, if not done right the bike can look very cockeye.  Oh, and make sure you are using a doner bike that weights about the same or you will need to change the spring out.  Most bikes I have seen the spring/ shock usually travels somewhat up and down, on a angle like that you might have binding issues.

CB

[Industrial Cafe]

with that pic up there i'd use an '80 cb750 swingarm with the upper brace modification and try to use 2 shocks to be different. i played with the movement of the swing arm in gimp and the shock placement seems optimal with no foreseeable binding.

Then again its just an idea, I'm full of 'em... Wish my pockets were full of money

[Inferno Rider]

This bike has one from a CBR:

[Industrial Cafe]

thats a cool bike, but I never liked the "thrown together" look of the vertical shock, when it's put on the cb750. It doesn't look like something the factory would have tried.


I got the idea from a BMW in the inspiration gallery.
 It would look more factory and I could use two 12-13 inch shocks.
(I think the "mono" looks too new, and everyone does that)

[SKTP]

I saw this bike at a trade show in San Diego

[Industrial Cafe]

oh wow! Go put that in the inspiration gallery, if it's not there already!!

[tinyrobot]

I believe that and 2 others are already in the gallery.  They are different dirt bikes made to be cafes IIRC.  I think Roland Sands did one of them?