jayel
#9 Guru 74 TX650A
find some rebar, water pipe, or electricial conduit whatever you got laying around and hard tail it!
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Any ideas what swing arm will work here?
gordonscott
XS650exhaust.com
Nice frame by the way 
Couldn't I just bolt a couple of adjustable wrenches in as struts?
jayel
#9 Guru 74 TX650A
you would need double box ends
MrBillohnooo
XS650 Addict
No need to half-a$$ it....go for the gusto...hardtail it...after all the original "real" flat trackers were hardtails....lol
An alloy one from a GSXR would be good. A few mods to fit.
special-k
XS650 Member
Knight is custom dirt track frame maker that glass usually came on their frames. That frame was probably sized for a dirt track swing arm out of a knight or champion. Find another old dirt tracker with a good memory and he could probably point you in the right direction.
gentlemanjim
More Wrenchin than Ridin
Monoshock it. Early Yamaha Virago's to 1983 or there are a couple on EBay from a XS400R/k for 79.95. Very stout items.
I have a 98 yz125 swing arm coming. It is a monoshock arm but I plan to use it for a two shock set up by welding on shock mounts. Not sure if that will be the final answer but it was reasonable, light and the dimensions closely fit the frame. so it will serve for the first mock up at least. This frame seems to have rather steep steering head angle so I really need to get the suspensions on it and an engine in it to see how it will work/look set up. Thanks for all the replies so far!
Some great XS650 flat track/ street tracker builds here (and others). Lots of pictures!
http://vft.org/StreetTrackers/StreetTrackers.html
http://vft.org/StreetTrackers/StreetTrackers.html
gentlemanjim
More Wrenchin than Ridin
Does that YZ125 swing arm fit the frame spacing? WIll it fit a stock XS650 frame too?
gentlemanjim
More Wrenchin than Ridin
Thanks for the VFT link lots of great pics and information.
MrBillohnooo
XS650 Addict
The mid eighties YZ swingarms can be made to work in a stock xs frame. Longer, heavier, and a lot of fab work to make em work.
The later ones are waaay lighter.
I think ya are on the right track Gary! The way the gap in the middle is, it shouldn't take too much to make it work
The later ones are waaay lighter.
I think ya are on the right track Gary! The way the gap in the middle is, it shouldn't take too much to make it work
Good choice on the swingarm. Some light weight coils in the back would top it off. You'll have to start a whole build thread cause I want to see how this turns out! And chromoly has been used for yeeeeears on racing frames. It may be thin (.070" walled) but it is RIGID. Welds do look good though. If I where you, I would look real close at the welds and check for under cutting and any imperfections. Might save you in the long run
I'm on that,I would look real close at the welds and check for under cutting and any imperfections. Might save you in the long run
thanks! Buddy of mine who welds aircraft frames mentioned the exact same thing about undercutting, a lot of those guys still prefer gas welding. Doing some comparisons on a stock arm, TX750 arm and the YZ125 arm now, there are a few surprises on swing arm weights!
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Swing arm comparisons.
With axles, adjusters, and pivot bolts.
XS650 12.5 lbs
TX750 13.8 lbs.
YZ125 11.8 lbs.
A fair amount of the weight savings come from hollow axle and pivot bolt on the YZ set up about .7 lbs. The YZ pivot bolt and axle are shorter and would not work on a stock frame or swing arm.
The XS and TX750 arm are near identical dimension wise, the TX750 is about 1/2" longer axle to pivot, the shock mount outer flange is a bit wider than the XS650s maybe an 1/8" but the inner mount and all other dimensions are the same.
The YZ arm is about 1/16" wider at the pivot. and the pivot to axle length is 4 1/4" longer. The YZ pivot has beautiful dual needle bearings (4 bearings), needle thrust pivot bearings, and full dirt seals.
The pivot bolt and axles are the same diameter on the 650 and 750 arms. The YZ125 is a little narrower at the axle but there is plenty of room for the brake, sprocket, and tire.
The axle on THIS YZ arm is 20mm the same as the XS. The pivot shaft is shorter and a bigger diameter than the XS shaft so that would mean work to use it on an XS650 frame.
With axles, adjusters, and pivot bolts.
XS650 12.5 lbs
TX750 13.8 lbs.
YZ125 11.8 lbs.
A fair amount of the weight savings come from hollow axle and pivot bolt on the YZ set up about .7 lbs. The YZ pivot bolt and axle are shorter and would not work on a stock frame or swing arm.
The XS and TX750 arm are near identical dimension wise, the TX750 is about 1/2" longer axle to pivot, the shock mount outer flange is a bit wider than the XS650s maybe an 1/8" but the inner mount and all other dimensions are the same.
The YZ arm is about 1/16" wider at the pivot. and the pivot to axle length is 4 1/4" longer. The YZ pivot has beautiful dual needle bearings (4 bearings), needle thrust pivot bearings, and full dirt seals.
The pivot bolt and axles are the same diameter on the 650 and 750 arms. The YZ125 is a little narrower at the axle but there is plenty of room for the brake, sprocket, and tire.
The axle on THIS YZ arm is 20mm the same as the XS. The pivot shaft is shorter and a bigger diameter than the XS shaft so that would mean work to use it on an XS650 frame.
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Patches
XS650 Junkie
Ok, I know this is an old thread but I just wanted to hopefully save somebody time and money and they can learn off of my experience.
After reading this thread I became very excited to do a mono shock rear swing arm build. I found a 98 YZ 125 swing arm on eBay and started ordering parts. Well it turns out despite the previously given information, the dimension for the swing arm pivots bolts ARE NOT the same. Unfortunately the YZ bolt is slightly larger in diameter. I was hoping to use the factory XS pivot bolt with the YZ swing arm but when I installed the YZ swing arm there was some play between the bolt and the bushings. I removed the arm and pivot bolt and compared the diameter against the factory YZ pivot bolt. It turns out the YZ pivot bolt is a bigger diameter and this build is going to get a lot more difficult.
Maybe gggGary can chime in since he posted the original information that I was going off of.
I hope this info helps somebody that was thinking about doing a YZ swing arm swap like myself.......
After reading this thread I became very excited to do a mono shock rear swing arm build. I found a 98 YZ 125 swing arm on eBay and started ordering parts. Well it turns out despite the previously given information, the dimension for the swing arm pivots bolts ARE NOT the same. Unfortunately the YZ bolt is slightly larger in diameter. I was hoping to use the factory XS pivot bolt with the YZ swing arm but when I installed the YZ swing arm there was some play between the bolt and the bushings. I removed the arm and pivot bolt and compared the diameter against the factory YZ pivot bolt. It turns out the YZ pivot bolt is a bigger diameter and this build is going to get a lot more difficult.
Maybe gggGary can chime in since he posted the original information that I was going off of.
I hope this info helps somebody that was thinking about doing a YZ swing arm swap like myself.......
This frame is actually moving towards being my next project. I am currently tig-ing small pieces of scrap into larger pieces of scrap. I will review pivot bolt sizes. I am fairly sure I will not be using the YZ swing arm in any case since I do not like the thick arm section appearance on a "flat tracker" themed bike
Sorry that my custom project idea thread misled someone who was looking to bolt a swing arm on a stock frame. Yes the YZ125 arm has a 17mm pivot bolt the XS650 is a 16mm more or less. As mentioned the YZ bolt is too short for an XS650 frame also so just drilling the frame bosses to 17mm won't get you there either. I guess you would have to look into different bushings or bearings to match the swing arm to an XS pivot bolt if they can be found.
Patches
XS650 Junkie
This is correct. I am currently looking at two different routes. The first is to find a reducer bushing. The second is getting another YZ pivot bolt, and cutting then welding two together to make one the appropriate length, and drilling out the pivot bolt holes to 17mm. I'm going to make it happen one way or another.
Gary, maybe sometime we can exchange notes.
BTW I did find some bronze bushings that are the proper dimensions, but Im afraid that the needle bearings will chew up the material. If anybody has any input that would be great. I'm thinking that I'm going to have to stick with a steel bushing however.
