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Post by Burns on Dec 29, 2011 18:50:44 GMT -5
WARNING: KINDA LONG
My re-assembly starts at zero (everything off) since I'm putting things back together after their trip to the powder-coater.
Like everything else related to my perpetual but less-than-professional tinkering with this motorcycle, this task has been educational. What figured to be a straight bolt-it-back-together operation sent me on yet another information gathering quest.
As always, all XS650 roads lead to this Garage.
This particular search started when I bolted every thing back-up and noticed that the swing arm would bind as the pivot shaft nut was torqued down; something that is not noticable with the shocks mounted.
I had Mikes brass bushings in that swing arm. Inspection revealed that the flanges of those bushings were flush with the center-tube (a.k.a. "bush center", item 2, Fig 4.5, pg. 98 Haynes 1993 manual).
Since the flanges of the bushings stuck out further than anything else in the swingarm assemble they bottomed against the inner grease caps and frame members when the pivot bolt pulled those frame members in.
The bushings are a press-fit, so functionally they are the ends of the swing arm itself and when they bottom against the frame they bind the entire assembly and the grease caps become de facto bushings
As Hank Hill would say, "that's just not right."
There is a fair amount of confusion in posts regarding swingarm mounting generally. Not everyone who has posted on the topic understands that the center tube is designed as the "pinch point" (with the grease caps acting as washers abutting the frame itself). The tube is held static when the frame members are pulled together by the pivot bolt.
Also, many do not understand that the factory shims (if you had any in your stock grease caps in the first place) are not intended/designed to take up any of that "pinch" space. They do not affect the distance from the frame to the outside of the grease cap (i.e. the end of the swing arm assembly). They effect only the distance from the flange of the bushing to the inside of the grease cap. What function they serve is beyond my comprehension.
Well, bottom line is the tube has to protrude above the bushing surface and this one doesn't.
Ok, located the bind. But what was the problem?
I suspect that a batch of mikes bushings are too long. Generally speaking, tolerances are not his historical strong suit as anyone with one of his two-lobe points cams will attest.
My word of warning to anybody putting brass bushings in (other than don't) is to be sure that the center tube protrudes from the bushing flange surfaces enough to give you something to pinch between the grease caps in the frame.
I've read some other posts that suggest that powder-coating can be a culprit sometimes, but in my case there was no powder-coating on the surfaces of the swing arm fork that touch the bushings. There was just too much brass.
BTW that tube was frozen to the brass bushings and had to be driven out.
I knocked out the bushings, ordered the needle-bearing kit/new pivot bolt/zerks, and started looking for assembly instructions.
Which stalled here at: two on each side " install them in the right position."
Any clarification on 'right position" would be most appreciated.
p.s. If the kit comes and its center bearing is shorter than the swing arm is wide, I may have to eat all these words and my understanding of how this stuff all fits together will have to enter its next phase. I'll be back.
Please correct anything that I have wrong. I live by the motto: It ain't what you don't know that gets you in trouble, it is what you do know that just ain't so.
Happy New Year
burns
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Post by Burns on Dec 30, 2011 21:00:27 GMT -5
I be swingin'.
I located the innermost 2 bearings flush to the ends of the wide spots in the tunnel meant to house the bushings (i.e. I stopped twisting the nuts on the threadsall "press" when the resistence spiked). The outmost two are a couple washers' widths deep from the ends of the tunnel. I don't think there really is a wrong place to put them though.
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Post by preston on Dec 30, 2011 21:38:41 GMT -5
Thanks for the updates,
are you saying, your swing-arm, is now in place ? and all is good.
( I just replaced my nylon bushings, , with the Brass, and i am fine with that, as my bike handles great, but that may due some also, to the new Avon tire..... but this needle bearing topic, has me wondering....)
Preston
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Post by Burns on Dec 31, 2011 3:39:09 GMT -5
Yep, it's all cool and groovey. Very easy to do. I put allen head bolts in the zerk holes (had to grind the ones I had down to get them short enough); they look pretty cool.
Finding the right washers for the "press" was the toughest part of the job (10 minutes at Home Depot matching washers to the bearing)
It so easy a cave-person could do it.
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Post by tomterrific on Jan 3, 2012 9:29:28 GMT -5
Preston,
The bronze bushings should work well as long as they are greased every 1000 miles or more. It is better to use 1/2 the grease every 500 miles than over grease at 1000. Lack of lubricant is one area I have found to be the culprit in over 40 years of dealing with worn mechanical parts. As soon as the lubricant is done, the part is done for shortly thereafter.
Tom, with the oily, greasy motorcycles that last. If it moves, I lube it.
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Post by preston on Jan 3, 2012 17:23:13 GMT -5
TomT
thanks I will do that...
I read about placing a grease fitting in the center of the swing-arm "after the power coat was done ",,, but i still may drill that hole in the center of swing arm , for a 3rd grease fitting, as it seems to make sense also.
Preston
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Post by Burns on Jan 4, 2012 22:07:35 GMT -5
how does puttng a grease fitting in the middle of the swing arm do any good? the bearing survaces (either bushings or needles) are at the ends.
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Post by xsleo on Jan 15, 2012 14:09:26 GMT -5
In the stock grease fittings, I take one side out. The grease will flow from one grease fitting in between the bushing and pivot tube, inside the swing arm. From there in between the other bushing and tube and out the hiole for the other grease fitting.
I then do it from the other side the next time.
With a grease fitting in the center of the swing arm pumping in grease, the grease flows both ways along the pivot tube, flowing between the tube and both bushings and out aroung the seal.
I think adding the swing Arm zerk is a waste of time.
Leo
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Post by preston on Jan 15, 2012 16:28:19 GMT -5
Tom, Burns and XS,
thanks for the advice. I will head what you say.
On my pivot bolt (shaft) while it was out and bike apart... i drilled a small hole in the center.
( one small hole from each side of shaft,outside in to the center )
My tube, by design is hollow in center,, however, not all the way through.
No amount of air and or grease from the ends, would flow out the center 1/ 16" hole that I had just drilled.
I had to assume on mine, this shaft is not hollow all the way from left to right...
i took out the end zerks, and used a stiff wire to push through the hole, I recall it went about 3" in, and stopped.
Bike went together fine, and with new Brass bushings, and Avon rear tire, all is good.
I will take your advice, and i will not add a zerk in the swing-arm, but do think i read about that, here on the forum.
Preston
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Post by tomterrific on Jan 16, 2012 10:12:36 GMT -5
The center grease fitting would be needed if the swingarm bolt were changed to a solid undrilled bolt. Although I don't have a needle bearing kit, I think you'll also find no grease can get through the large cross spacer tube the needle bearings ride on. This means the drilled SA bolt is usless for greasing the needles so a center fitting must be installed to get grease moving along the outside of the center spacer tube and out through the needle bearings. Please correct if this is wrong.
Tom Graham
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Post by dfphoto on Oct 19, 2015 3:27:47 GMT -5
Thanks to the previous posters, I know this thread is very old... I added this to my 73 RD250 the other day took 2 hours but I had to clean out the swing arm and i only had a 1/4-20" long bolt and I bent it and broke it because I inserted the sleeve to make sure the 2nd bearings went in straight and forgot the sleeve is longer than the arm (duh) anyway the roller bearings are pretty smooth and I figure it should last a long time.
Once I learned you need to press in or maybe pound with a rubber mallet it made perfect sense.
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Post by grizld1 on Oct 22, 2015 8:00:02 GMT -5
I don't know how I managed to miss this thread when it was fresh, but to get any positive results from a needle bearing kit, you need to brace the frame across the swingarm pivot. Reason: the kits use needle thrust bearings in place of the OE thrust covers (grease seals), and those thrust bearings will be damaged if the swingarm bolt is tightened to much more than 25 ftlbs. That's nowhere near spec, and will result in excessive flex; the swingarm bolt acts as a pinch bolt to draw the open part of the frame together. You won't notice anything wrong if you're just cruising around, but if you do anything that challenges the suspension at all you'll feel it, and eventually the swingarm bolt will shear at the small end.
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