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Discussion Starter #1
Looking for some feedback on an extended swingarm on my 1972 z50a. I just upgraded the fronts with delrin bushings and HD springs. For the rear I have some TBparts 280mm rear shocks. I’ve been looking at the minimoto +5cm(2in) rear swingarm to try and center the rear wheel better. Has anyone run a similar combo and been happy with the stance? Worried the swingarm may be to long for 280mm shocks.


https://japan.webike.net/products/20022618.html
 

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I would be very cautious and check all dimensions as your bike is NOT a Jap Monkee or a JAP Gorilla. They would make no guarantees at all as to fit concerning my Z50R. NOR would they furnish specific dimensions or connect me to the mfgr........ But in their catalog it is a good looking piece and an unbelievable price. I personally dont feel that measly 2 inches extension is worth fooling with.
 

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The lower shock mount location varies between brand/versions/length of swingarm. I get the swingarm I want and measure for the length shock to get the stance I want.

The 2 inch extension is a good size but it has to fit what you want. If you want ride height up and you put real long shocks on it the swingarm angle will be steep and the handling will suffer.

I put +2" on both of my Zs when they were/are 50-88cc stock type heads.

My anima powered Z150r has a +16cm swingarm.

It all depends on what the application is and what you want to do with the bike.
 

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I am running a +4cm swinger on my 84 street Z. The shocks are off a vintage XR75/80 (can’t remember now) and I believe they are 305mm I believe. They are on the short list to replace actually as one is weeping...and it’s just time to upgrade.

4-5cm really does help to center the wheel within the fender. Also a must if you plan on running any tire that has a larger diameter.



Sorry, need to take a pic off the stand.


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I would first try the 280's you already have on that 2" swingarm. With the standard 3.50 tire you won't be far off.
(standard shock length is around 255-260mm?)
 

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It was from webike. I can look tomorrow but I believe it’s a minimoto. Honestly, there are so many that are just branded with different names but basically the same.

It’s of decent quality but the bushings were totally garbage. They failed shortly after install and I replaced with proper needle bearings. If you buy something similar, add that into the cost.


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It’s been awhile ago now. I measured existing bore, width, and shaft size, plugged that into the ol inter-webs and boom. It seemed to work out. They were pretty standard size.


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Looking for some feedback on an extended swingarm on my 1972 z50a. I just upgraded the fronts with delrin bushings and HD springs. For the rear I have some TBparts 280mm rear shocks. I’ve been looking at the minimoto +5cm(2in) rear swingarm to try and center the rear wheel better. Has anyone run a similar combo and been happy with the stance? Worried the swingarm may be to long for 280mm shocks.


https://japan.webike.net/products/20022618.html
 

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I recently installed the plus 20cm swingarm on my 1981 Z50A and love it. I am using the stock orig shocks as well via the use of the cheap shock extensions sold on EBAY. The bike is fully now rideable and roadable and the long wheelbase I feel makes that possible. In my opinion, a plus 5cm would be a waste of time and money and get back next to nothing in improved ride characteristics etc. I will try to post some pics of my project.
270495
270496
270497
270498
.
 

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Discussion Starter #14
I'm really leaning towards adding 1.5" into my existing stock swingarm. I've got some 7/8 -1.5" spacers made up, just going to have a local welding shop weld them in. Really just looking to re-center the wheel in the fender. It really bothers me how forward it is now.

I've got the bike apart currently for a 88cc race head kit and re-gearing w/ new chain so now is the perfect time.

Thanks 66Cooper and preventec47 for the feedback!
 

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Discussion Starter #15
Preventec47 how have those shock extensions been working out for you. Got the swingarm back, and even with 280mm shocks and 1.5” swingarm extension I think it needs more height. Thinking of getting those shock extenders!

280mm shocks w/ 1.5” swingarm extension
270512


with 1” more height on the shocks
270513
 

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Look at my photos. They show the before and after using the identical same shocks. My Swingarm is plus 20cm
and I honestly just got the shock extenders because they were so cheap and they would allow me to sort of do a mockup and make a later decision on what exact shocks I might need but they have worked so well, I just
kept them and have ridden the heck out of them on some very rough trails with frequent bottoming out of the shocks.
The problem with greater height to me is that the chain takes a sharper turn and might cause contact with your swing
arm and that cannot ever be good. People have different ideas on how bad it is and it does not bother me. I cannot personally understand why you want more height unless you are attempting to make it more like a full size motorsickle.
I am not an expert in any way re motorcycle riding but I cannot see how extra height could improve the riding
in any way since it raises the center of gravity... So are you doing it for looks ?
 

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minimoto +5 next to the stocker.
can see my full build her:
 

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The 310-315cm shocks will be the ticket to even out your ride. Always a good idea to balance out the height of any bike you are modifying, unless you are trying to get it to handle differently. The problem is the fork rake and front trail. If you lower the rear you get a slower turning, less responsive, but potentially more stable ride when at top speed. Sort of like how a chopper can do great in a straight line at speed, but barely functional at low speeds that require turning. A steeper rake (less trail) will be faster turning, more responsive, but less stable at top speed. The chopper-like rake also puts more side force on the suspension that interferes with its ability to work right. There are other considerations like where the center of gravity is and how easy it is to go over the handlebars that are controlled by the front rake as well. In short, the rake is set at a reasonable angle for safe road and off-road riding, don't go messing with it unless you want it to change.
 
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