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Old 10-19-2013, 12:30 AM   #976
Prutser
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Location: The Dutch swamp
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Quote:
Originally Posted by Airhead Wrangler View Post
I'm running a 300mm EBC wave rotor and a KTM MC and caliper. Stops on a dime.

Only problem I'm having is that my steering head bearing preload keeps coming loose. I'll only ride 20 miles or so at a time and it's able to work its way REALLY loose in that time. How hard are the rest of you torquing everything?
In the first 12.000km I had 4 sets of broken headbearings and had to adjust them after almost every ride.
Than I made a new metal stem just like the 100gs system. After another 12000km the last set of bearings are still perfect without having to adjust them all the time.
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Old 10-19-2013, 10:27 AM   #977
Airhead Wrangler
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Originally Posted by hardwaregrrl View Post
I had the same problem. Had to turn the stem down as the bearing would not slide and load in the race. Dunno what torque I used, but it was excessive....akin to 40 ft/lbs to press it in.....but after I turned the stem down I used around 20 on the stem bolt. 15ftlbs on the pinch bolts at the stem. I have yet to have them loosen since turning the stem.
My upper bearing was a snug fit on the stem, but not to the point that I had to press it down into the race with the top bolt. I just knocked it down gently with a big socket and a rubber mallet. It's not that it's not getting tight enough initially, but that the adjustment is slowly backing off. I'll try torquing down the pinch bolts a little harder and see if that solves it.
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Old 10-20-2013, 12:46 PM   #978
Dmaster
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Originally Posted by e28rusty View Post
Do you have a picture of this?
I did this trick with a Kawa KX250 MC
Got no detailed pics and if i had i wouldn't show you.. lol (damn ugly but it works)
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Old 10-20-2013, 07:03 PM   #979
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Quote:
Originally Posted by Airhead Wrangler View Post
My upper bearing was a snug fit on the stem, but not to the point that I had to press it down into the race with the top bolt. I just knocked it down gently with a big socket and a rubber mallet. It's not that it's not getting tight enough initially, but that the adjustment is slowly backing off. I'll try torquing down the pinch bolts a little harder and see if that solves it.
Oh...gotcha. that's a weird one
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Old 10-21-2013, 10:32 AM   #980
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Quote:
Originally Posted by Airhead Wrangler View Post
My upper bearing was a snug fit on the stem, but not to the point that I had to press it down into the race with the top bolt. I just knocked it down gently with a big socket and a rubber mallet. It's not that it's not getting tight enough initially, but that the adjustment is slowly backing off. I'll try torquing down the pinch bolts a little harder and see if that solves it.
How about using some blue loctite or something like that?
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your bike is suitably dirty. Well done.
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Old 10-22-2013, 11:42 PM   #981
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Originally Posted by SOLO LOBO View Post
How about using some blue loctite or something like that?
I went over everything again yesterday. Preloaded the bearings, then torqued down all the pinch bolts and went for a ride. Same thing again. Within 20 miles they were knocking like crazy. ~5mm of front to back play at the front wheel by the time I got home. I pulled the whole mess apart and found a lot of grease on the top bolt and on the steering tube. I cleaned it all up again, put a BUNCH of blue loctite on the top bolt, torqued it down and torqued down all the rest. Tomorrow I'll try again. Damn it.
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Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
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Old 10-23-2013, 06:23 AM   #982
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Quote:
Originally Posted by Airhead Wrangler View Post
I went over everything again yesterday. Preloaded the bearings, then torqued down all the pinch bolts and went for a ride. Same thing again. Within 20 miles they were knocking like crazy. ~5mm of front to back play at the front wheel by the time I got home. I pulled the whole mess apart and found a lot of grease on the top bolt and on the steering tube. I cleaned it all up again, put a BUNCH of blue loctite on the top bolt, torqued it down and torqued down all the rest. Tomorrow I'll try again. Damn it.
Is any of the screws actually loosening? when you redid it did you try to torque anything to see what actually loosened???? This is freakin' weird?? where did the bearings and races come from, may the next step is replacing them. I still think you need to check that the bearings are actually seating top and bottom and measure the stem and race....this is exactly what I was experiencing but it took quite a while of riding it hard off road to loosen them.
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Old 10-23-2013, 10:35 AM   #983
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I had the clamping bolts on the triples get loose numerous times... need to check if they are tight now in fact!
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your bike is suitably dirty. Well done.
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Old 10-23-2013, 10:47 AM   #984
Airhead Wrangler
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Quote:
Originally Posted by hardwaregrrl View Post
Is any of the screws actually loosening? when you redid it did you try to torque anything to see what actually loosened????
Not that I could tell. What's weird is that I don't loosen the bottom triple in my retorquing process and each time I take up the slack with the top bolt, the fork legs stick about 1/16" over the top triple where they were previously flush. So either I didn't set the bearing races anywhere close to seated when I drove them in, or the fork legs are slowing migrating up through the bottom triple despite being clamped - 15 ft lbs on all the pinch bolts - AND the top bolt is slowing unthreading itself, AND the top triple is sliding on the stem despite being clamped. Same thing three times now, roughly a skinny 16th each time, so it's pretty much impossible that the races were still just under 1/4" from being seated. So however unlikely/unbelievable the alternative is, it has to be the case.

Quote:
Originally Posted by hardwaregrrl View Post
where did the bearings and races come from, may the next step is replacing them.
They came from BMW. This time they were a swiss brand I'd never heard of rather than the SKF or FAG bearings BMW has sold in the past. I've had good luck with the NTN bearings cycleworks sells for a fraction of the price BMW wants.
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R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.

Airhead Wrangler screwed with this post 10-23-2013 at 10:55 AM
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Old 10-29-2013, 03:43 PM   #985
redboots
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Quote:
Originally Posted by Airhead Wrangler View Post
What's weird is that I don't loosen the bottom triple in my retorquing process and each time I take up the slack with the top bolt, the fork legs stick about 1/16" over the top triple where they were previously flush.
Not pulling the stem out of the bottom triple is it?

J
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Old 11-01-2013, 01:52 PM   #986
e28rusty
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Hey guys, I finished modeling the rdubbs triple clamps in solidworks so if anybody else needs the files i can email them to you in iges or solidworks formats. I will hopefully have my bike back on the road in 2 weeks.
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Old 11-04-2013, 03:14 PM   #987
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Hey AW,
despite heavy efforts I failed to seat my lower bearing at the start... I also failed to use the stock bearing cover under the bearing. A bit of riding kept beating the lower bearing down, I kept re-torquing at the top till I rand out of adjustment (the blind nut was bottoming on the stem). Then from a bit more riding like this the upper bearing knocked bit of damage into the stem that had to get wet and dryed out in order for me to get everything back in place with the correct bearing covers on top and bottom.
Obviously these things aren't idiot proof. Also, there is very little room till 'play'.
I'd be getting a sharpie or something and marking all the fasteners and other components to see what is moving/loosening.
iPhone typing is annoying... Internet not on at our new place yet. Good luck.
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Old 11-04-2013, 04:43 PM   #988
Airhead Wrangler
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Quote:
Originally Posted by ontic View Post
Hey AW,
despite heavy efforts I failed to seat my lower bearing at the start... I also failed to use the stock bearing cover under the bearing. A bit of riding kept beating the lower bearing down, I kept re-torquing at the top till I rand out of adjustment (the blind nut was bottoming on the stem). Then from a bit more riding like this the upper bearing knocked bit of damage into the stem that had to get wet and dryed out in order for me to get everything back in place with the correct bearing covers on top and bottom.
Obviously these things aren't idiot proof. Also, there is very little room till 'play'.
I'd be getting a sharpie or something and marking all the fasteners and other components to see what is moving/loosening.
iPhone typing is annoying... Internet not on at our new place yet. Good luck.
yeah, after a few riding/tightening cycles the play seems to be gone for good. I'm guessing the stem may not have been fully seated in the bottom triple or the bottom bearing race wasn't totally seated. I still haven't been able to work the stiction out of the system and took the bike to a suspension guy. He's saying he doesn't think it's the internals and comes down to an alignment issue of some kind. Either the axle, wheel spacers, or the triples (!).
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R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
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Old 11-27-2013, 02:54 AM   #989
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Silly question.. and It may have been answered before, but how much fork oil or what level did you guys use on your shortened WP 50mms? Im rebuilding these set of these that I lowered by 10cm for my XT500 and could do with any advice on this, thanks!
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Old 11-27-2013, 05:24 AM   #990
ontic
 
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If I recall correctly I think it was common to run around 125-130mm air gap for stock forks/bikes.
With springs out and fork fully compressed the shortening of the fork with the lower spacer will only change the volume by a small amount, but it should still be air gap we are measuring rather than volume.
If you can be bothered laboriously searching through the difficult forum KTMtalk has a fair few old threads talking about working and tuning these forks.

I have wondered aloud in this thread somewhere before about how the air gap/oil volume should change when we shorten them. I am not sure if we came up with a proper answer.
To me, when shortening a fork, it would make sense to to also proportionately shorten the air gap, so
180mm travel: fork shortened 10mm..... do the math... reduce air gap by around 6-7mm...
but then air gap is a tunable thing anyway.


I hope that helps a little.
Please post some photos of your fork swap and explain a bit more of what you have done and are doing,
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