phil240
XS650 Addict
What do you guys think is the ideal swing arm length is for these bikes?
The main theme I've heard is about 2" over.
The main theme I've heard is about 2" over.
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IDEAL SWING ARM LENGTH
- Thread starter phil240
- Start date
Why? Stock works great. What are you trying to accomplish?
phil240
XS650 Addict
Starting a conversation, trying to get a discussion going. As you know some of us do perform modifications to these bikes. And different length swingarms do alter handling. So I'm just trying to pick some people's brains to find out the ideal length.
Some people say to just swap it out for an earlier year one, which is about 1.5in longer, others do the 2in swing arm extension and others do complete swing arm swaps for the length difference.
Earlier one is shorter.
Ask someone who has a Radian swingarm. I think it adds over an inch.
Ask someone who has a Radian swingarm. I think it adds over an inch.
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It does Taffy has a Radian arm which works great for me. To be honest the new longer custom shocks had a bigger effect on handling as it made the head angle steeper and quickened the steering.
phil240
XS650 Addict
https://www.xs650.com/threads/stock-swing-arm-length.54012/post-579410
older post shows them 1.5 longer.
States that the 74 on swingarm is longer than earlier.Here's a pic of my swingarm, for reference.
From the pivot center to axle center (axle full forward).
'71 XS1B swingarm length = 16.5"
That should be the same for all 70-73, XS1, XS2, TX650 models.
74-on swingarms should be 1.5" longer, at 18".
phil240
XS650 Addict
You're right, sorry i read that wrong. happens sometimes, overworked.
phil240
XS650 Addict
But still, aiming for what people think is an ideal length. So when most people lean towards 2in extended, is it from the earlier shorter swing arms or the later ones.
Since Yamaha extended it and then left it alone for the rest of the production run, they felt they had arrived at the best length.
What is it you want the bike to do, or not do?
Indeed. Good enough to satisfy Percy Tait etc......
I think your question is too vague to prompt a useful answer. Ideal length for what? Just speculating but Id be surprised if anyone is extending an early swingarm that is a direct swap for a later year longer one…
I’d say leave it alone and if you’re a tinkerer move on to higher yield areas. There are a few.
OR extend your swingarm x amount see if it feels good to you and report back the details.
I’d say leave it alone and if you’re a tinkerer move on to higher yield areas. There are a few.
OR extend your swingarm x amount see if it feels good to you and report back the details.
jaybar6
XS650 Addict
i always thought the swingarm was too long. as there is big gap where an 19 inch wheel would fit in there. sure yamaha was copying norton. they even sloped the engine to look like it.
shortening the swingarm , maybe one could pull wheelies on the throttle, that would be fun.
shortening the swingarm , maybe one could pull wheelies on the throttle, that would be fun.
A longer swing arm would improve weight distribution somewhat. All stock, any XS is really tail-heavy. With a rider, I suspect even more so, especially with a high handlebar.
Then give us your use case?
Prolly most going to a longer arm are looking at lower seat height? Moving the tire back allows room in front of the tire for a lowered seat position.
Use of radian arm is usually attributed to stiffer, longer is just along for the ride. Fairly constant rate is about as good as can be achieved with dual shock geometry.
If on a stock frame, the specials already have a lower more forward top shock mount than the standard frames, a longer arm will lay the shock down even further, that changes spring action to lower rate as the the spring compresses. Isn't rising rate considered to be desirable?
Ridden the shorter arm early bikes a fair amount, 5K miles? as well as a lot of miles on later bikes. Some of both at "sporting" street pace.
Later bikes (70-73 vs 74 and later) went to reduced triple offset between stem and fork tubes as well as stiffer reinforced (and heavier) frames.
My
If you are looking for street handling a wider 18" front rim/tire and slightly longer rear shocks will give a more modern feel. I'm no track meister but the stock set up tends to "fall in" on corners, the changes result in a more linear planted cornering action/feel without resisting direction changes.
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jaybar6
XS650 Addict
Because of that weight distribution, I keep thinking about mounting the battery at the front of the engine along with all the electronics with it. that would shift the center of gravity forward.
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phil240
XS650 Addict
There is no case. I'm going to be making extended swing arms in the very near future for these bikes. And I'm setting up my jig so it can extend, shorten, narrow or widen based on what someone would want.Then give us your use case?
Prolly most going to a longer arm are looking at lower seat height? Moving the tire back allows room in front of the tire for a lowered seat position.
Use of radian arm is usually attributed to stiffer, longer is just along for the ride. Fairly constant rate is about as good as can be achieved with dual shock geometry.
If on a stock frame, the specials already have a lower more forward top shock mount than the standard frames, a longer arm will lay the shock down even further, that changes spring action to lower rate as the the spring compresses. Isn't rising rate considered to be desirable?
Ridden the shorter arm early bikes a fair amount, 5K miles? as well as a lot of miles on later bikes. Some of both at "sporting" street pace.
Later bikes (70-73 vs 74 and later) went to reduced triple offset between stem and fork tubes as well as stiffer reinforced (and heavier) frames.
View attachment 334498
My
And yes, I know depending on riding style different lengths come into factor. I know if you are drag racing the longer the better.
I know most people say the stock one needs about 2 more inches to be ideal.
So I was just trying to generate some conversation and see if there was a general consensus. The first one I make and try out I was aiming to go with a 2in stretch. But if say there was a general consensus that 4in is more ideal then I would of tried that.
jaybar6
XS650 Addict
I think people would like including me a standard swingingarm which was larger in diameter that one could just bolt in/on, Knowing that it is stronger than original without losing its classic looks.a bit like a ducati bevel 900ss arm.
measured pivot to axle all with fairly new chain.
73 17"
81 special 18"
madness special with a custom arm. 19"
Joe Wiseguy on the West Coast used to do a fair business selling a swing arm brace. both kit and welded on your arm he also did extensions.
yes something onlookers will notice helps custom parts to be successful.
73 17"
81 special 18"
madness special with a custom arm. 19"
Joe Wiseguy on the West Coast used to do a fair business selling a swing arm brace. both kit and welded on your arm he also did extensions.
yes something onlookers will notice helps custom parts to be successful.
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I believe a TX750 swingarm does that, they can sometimes be found used online.
