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Custom Pivot Bolt
- Voodoosoup
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I've been trying to source someone to make me a new pivot bolt for my zephyr swingarm swap on my 650. I need to go fro m a 16mm to a 17mm bolt. I haven't found anyone local that has a die larger than 10mm to turn the threads.
I've received a couple of online quotes for around $180usd.
Does that sound right on the price or should I be able to find someone cheaper?
I've also tried to source some metric tube to make a sleeve, but I haven't been able to find the right size.
Any suggestions?
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- hwms
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- steell
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(Ignore the 1/2x20, the link takes you to a M17x1.5)
From MSC www1.mscdirect.com/CGI/NNSRIT?PMPXNO=12344053&PMT4NO=43009867
But you'll probably need a handle also for $6.16 plus shipping.
Also from MSC
www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1721812&PMT4NO=43010378
Or just take it to a machine shop, but that will probably cost more ($50 hour, 1 hour minimum).
And instead of a sleeve, you could just drill out the pivot bolt holes in the frame.
KD9JUR
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- Voodoosoup
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I think I'll go that route.
I think I found a place to buy the metric stainless bar, as long as they don't have a minimum order!
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- PLUMMEN
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Still recovering,some days are better than others.
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- steell
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if you have a zephr swingarm bolt how about just boring it out on a lathe and ushing it as a bushing?
Easier said than done
17mm - 16 mm = 1mm
1mm = approx .040"
That's a wall thickness of .020"
ID is 16mm, that means the largest boring bar that's going to work is 1/2" (12.7mm), bolt is approximately 12" long, that means the boring bar is going to be hanging out of the holder by at least 12.5". That means that the boring bar is going to flexible as heck, no rigidity as all, chatter and squeal (think ear plugs) and very unlikely to make a round hole.
Beyond my capabilities, can Solmrus do it?
Now, why stainless? Less tensile strength than some of the other alloys, and a total bear to thread. Stock pivot bolts aren't stainless (on the KZ's anyway), 1018, 1045, or 4140 (overkill) would be better, in my opinion anyway. Stay away from 12L14 or drill rod, 12L14 rusts easy and drill rod lacks the tensile strength needed.
Whatever you use, buy some cutting fluid (like Tap Magic) to use when cutting the threads.
That's why we just enlarge the pivot bolt holes in the frame to 17mm
KD9JUR
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- Voodoosoup
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I was going to use stainless based on someone else's zephyr swap.
That was the only basis for my decision. I'm now trying to find someone to sell me some 1018 or 1045.
Steell, thanks again for all the info, it is much appreciated!
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- StreetfighterKz
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Later, Doug
1978 z1000 Streetfighter
1976 z900 Stripfighter (work in progress)
1983 Gpz750 Resto-Mod
1989 Vmax
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- steell
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The bearings are needle bearings, roughly an inch or so long, and the actual bearings fit inside a race with a lip on each end to keep the bearings from sliding out. The race is hardened and ground to final tolerance with an ID grinder, and not something your average machine shop is going to be able to make.
This does give me another idea that I hadn't thought of though. How about removing the needle bearings and replacing with sleeve bearings? There are places that specialize in doing this for racers because at least some racers consider the sleeve bearings to have less flex than the needle bearings. And some (at least) of the earlier KZ's used sleeves bearings (bushings) instead of needle bearings (76-77 KZ750 twin for example).
The sleeve bearings (bushings) would be a whole lot easier to make than a full length sleeve, a new pivot bolt, or a bearing race.
I'm going to give that some more thought and take some measurements, have to do something about seals also.
KD9JUR
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- OnkelB
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With the end spacers installed the Zephyr arm is exactly the same width as the stock 650 arm with the caps installed - if you add any width to the Zephyr arm whatsoever it won´t fit between the pivot studs on the inside of the 650 frame.
By far the easiest solution is to have a 17mm pivot bolt made (or find one that fits) and drill the frame - the way mine is made is simply a length of round bar threaded at each end with a dome nut on both sides.
Btw Phil, sorry if I gave you the impression that you needed stainless, that´s just what I chose for no other reason than that I´m passionate about rust - I hate it with a vengeance. I realize it has less tensile strength than other alloys but so far I have been running it for a couple of years with no problems.
I posted a write-up about the swap over at KZ650.info, here´s a link - you might need to be registered/logged in to see the pics.
77 KZ 650 B1, 82 GPz 1100 B2.
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- steell
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In my case (83-85 GPz750 swingarm, KZ750E frame) it's either two new sleeves (long one and short one) or drill the frame to 17mm and cut down the inside of the pivot bolt hole bosses on the inside.
The 83-85 GPz swingarm uses the needle bearings, but it also uses a roller bearing on one side, so that limits me to the above two options, unless I want to re-engineer the swingarm pivot anyway, and that would make things entirely to complicated for me.
KD9JUR
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- OnkelB
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77 KZ 650 B1, 82 GPz 1100 B2.
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