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Post by veg on Mar 6, 2017 17:44:20 GMT 1
So I have stripped and rebuilt my 31k forks got new bushes top and bottom new seals, circlips, springs etc etc put them into the yokes and the right hand side leg (as you sit on the bike) is approx 12mm shorter, consequently the lowers don't match up with the spindle. The forks were used and bought 2nd hand,I have stripped and rebuilt them completely, fork lowers are the same type and length the stanchions are the waisted 31k type, before I re-strip them any ideas? I can only think that maybe 1of the stanchions has been previously cut down however although I didn't measure them I didn't notice anything untoward.
Not a happy bunny.
Thanks in advance
Also when compressed they compress to the same length when no oil and springs fitted
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Post by bare on Mar 6, 2017 19:06:33 GMT 1
Reads like an assembly error.. It happens.
Small choice but to open 'em up and look.
Any length issues will be instantly apparent when stanchions are side by side.
Possibly a Damper rod is not in there/seated adequately ?
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Post by wallcraft on Mar 6, 2017 20:26:26 GMT 1
Yep get them apart , will probably be something silly left out like the bottoming spring or the spacer type sleeve that goes on the end of the damper rod ?
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Post by veg on Mar 6, 2017 20:29:51 GMT 1
Thanks chaps, I know that all the springs and top hat spacers are in place I know they are torqued up it is baffling and bloody annoying.
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Post by LC_BOTT on Mar 6, 2017 21:37:47 GMT 1
At a guess, I'd be looking at the 'longer' one as the problem, maybe something not quite done up properly? as mentioned, the bottom alloy spacer?
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Post by Shytalk on Mar 6, 2017 21:43:40 GMT 1
I don't know whether these are going to be of any use but here's some pictures of mine that I took when I did mine, maybe a problem with the damper rod? :-
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Post by midlifecrisisrd on Mar 6, 2017 22:04:44 GMT 1
I'd be measuring the small spring on the damper rod
If they are different lengths it will let one leg extend more than the other
Steve
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Post by 4l04ever on Mar 6, 2017 23:09:08 GMT 1
You may need to take them apart and measure the length of the two stanchions, plus any other bits and bobs. Post some pics.
You could measure from the top of the stanchions to the waisted section on both to see if one appears to be cut down or not.
Maybe a difference in the length of the damper rods?
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Post by veg on Mar 6, 2017 23:43:59 GMT 1
Will do that probably in next couple of days could do with knowing what the overall length incl stanchions they are supposed to be. Anyone know the measurement?
TIA
Probably need to re order another set of bloody new seals
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Post by Tobyjugs on Mar 6, 2017 23:51:57 GMT 1
I think if you knock them out using the forks you will be ok.
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Post by veg on Mar 8, 2017 14:07:39 GMT 1
Ok so I have re stripped the forks and found the following stanchions same length, damper rods same length however internally there are differences on the stanchions as can be seen by how far the damper rods protrude also the stanchion ends are ever so slightly different maybe one aftermarket one original? Now I am not sure whether I can remove the internal bushes? Any one or if indeed some else has previously hence the 12 mm difference
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Post by veg on Mar 8, 2017 14:09:48 GMT 1
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Post by veg on Mar 8, 2017 14:19:43 GMT 1
So rather than feck about it may be a case of contacting norbo for a new set of stanchions, at least that way I am dealing with a known quantity
More feckin expense the never ending money pit that is my Lc project
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Post by Shytalk on Mar 8, 2017 15:19:01 GMT 1
So rather than feck about it may be a case of contacting norbo for a new set of stanchions, at least that way I am dealing with a known quantity More feckin expense the never ending money pit that is my Lc project That's going to be the way forwards, at least everything else will be able to be re-used. |
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Post by Tone on Mar 8, 2017 15:48:55 GMT 1
As you say it looks like you have two different stanchions looking at the different size holes just above the bush and also the machined part just above the oil seals. The parts list shows them as the same part number so as you say maybe one is aftermarket.
Tone
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Post by 4l04ever on Mar 8, 2017 18:46:24 GMT 1
I have lots of 31k fork legs, so will have a look see if I have one that will match either of the ones you have.
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Post by veg on Mar 8, 2017 19:52:39 GMT 1
Thanks guys, had a thought, these are the 2 forks I bought non matching , now by my reckoning if 1 is 12 mm shorter is that because someone has put a spacer in one of the stanchions? they weren't matching ones, and I cannot imagine that aftermarket would be that much out. I will have a proper look tomorrow.
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Post by Tobyjugs on Jul 24, 2023 11:10:15 GMT 1
Thanks guys, had a thought, these are the 2 forks I bought non matching , now by my reckoning if 1 is 12 mm shorter is that because someone has put a spacer in one of the stanchions? they weren't matching ones, and I cannot imagine that aftermarket would be that much out. I will have a proper look tomorrow. Hi Tim I'm really interested in how this saga ended? I've got a set of forks apart due to a leaking seal and don't have any of Bare's favourite fork fluid so trying to get an idea of which weight fork oil to use from previous threads. |
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Post by midlifecrisisrd on Jul 24, 2023 11:39:38 GMT 1
Thanks guys, had a thought, these are the 2 forks I bought non matching , now by my reckoning if 1 is 12 mm shorter is that because someone has put a spacer in one of the stanchions? they weren't matching ones, and I cannot imagine that aftermarket would be that much out. I will have a proper look tomorrow. Hi Tim I'm really interested in how this saga ended? I've got a set of forks apart due to a leaking seal and don't have any of Bare's favourite fork fluid so trying to get an idea of which weight fork oil to use from previous threads. 31k forks are 10w oil Manual says use 10w30 engine oil 🤣 As an aside I have had lc2 pattern stanchions and the were a good 10mm shorter than OE Steve |
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Post by Tobyjugs on Jul 24, 2023 12:59:35 GMT 1
The forks worked quite well with a 12 stone rider on the bike. This year fat boy has been riding it and the forks look like they have been bottoming out plus an seal has gone. The Mobil 1 ATF is 36 cSt at 40c which is what Bare reccomended. After looking at fork oil viscosity charts and lots of old threads on this forum i've gone for 15w oil from Belray. It's heavier so hopefully it will combat my weight a little better.
Some members are happily riding around with 20w but all the makers of fork oils have different viscosities for the same numbers.
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Post by stirling11 on Jul 29, 2023 14:23:56 GMT 1
I bought a new set of stanchions via Yahoo Auctions for an F1 out of Japan
The washer at the bottom of the forks would not allow the damper rod to go through it, comparing the old stanchions, they were bent and pitted, the hole in that locating or slide washer was too small
I presume they were a 250 ypvs or a different part completely, so I’m presuming the damper rods to suit these forks were narrower in diameter too
I couldn’t drill out the washer as they spin as they are held in place with a spring type washer that is pushed down the insides of the stanchion after the lower washer is installed, a groove is machined into the bottom of the stanchion to hold the spring washer
Said spring was not removable as the bottoms of stanchions are pressed together then the ends rolled over
I ended up ordering a set off Norbo that were perfect, I didn’t win the argument with Yahoo even though photos showed the difference
It could have been you had mismatched stanchions too
All my others had the inner diameter of the guide washer the same as were the dimensions of the damper rod
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Post by veg on Jul 31, 2023 13:06:58 GMT 1
Hi Tony
Sorry I’m just back from my travels. I ended up buying a matching new set up. Never did get a conclusion as to why they were different. My advice is always to buy new from a reputable seller (the seller wasn’t dishonest in this by the way and was as much a surprise to them and they were brilliant in helping me out). These were a used set of forks and I wouldn’t have been aware had I not stripped them for a complete rebuild and the seller would also would not have been aware.
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