F800 head-set bearing how to
I couple weeks ago I noticed that my bike wanted to steer straight ahead and didn't like to have the bars moved slightly left or right at slow speed. I actually thought it was the oddly wearing MT21 front tire causing this. I swapped to my K60 rear and MT60 front but the issue persisted. Hmm, looks like my head set bearing are on their way out.
My bike is a 2009 with 65,000km and there's never been any issue with it's head set bearings to this point. Never loose, never clunking.
The swap is real simple and straight forward requiring only one dust cap, 2 bearings, grease and basic tools.
$60 x2 from BMW P/N 31427663941
$42 x2 from Napa Napa P/N BR32 (thanks dsrydr)
SKF part number is: 320/28 X/Q (didn't price them out)
NSK part number is: HR320/28XJ (didn't price them out)
*All prices are Canadian*
The bottom "cup" is a BMW part only... $7.50. Some have said they were able to get the bearing off without damaging this piece, I was not able. Best to buy it before hand and return it if un-needed.
First things first: I am NOT a bike mechanic, or a mechanic of any kind, nor do I play one on TV. Do your own research and if your feel you can tackle this project go for it. If you are unsure about your abilities please do everyone a favor and take you bike to a mechanic to have work done. If you F this up, it could lead to lose of control of your bike and you may get hurt, die, hurt or kill someone else, blah, blah, blah.
Depending on whether or not you have bar risers or a steering stabilizer the first couple steps may or may not be required. I had to remove the bars and stabilizer:
You need access to the BMW logo in the middle of your triple tree, remove bars, stabilizer etc if required. Pop cap off with screwdriver:
Loosen pinch bolt on triple tree:
Loosen the 4 pinch bolts for the forks on the upper triple tree:
Remove brake calipers and ABS sensor and wire or zip tie them out of the way *do not leave them hanging from the brake hoses!*:
With the high fender conversion and non-cross over brake lines, I was able to simply set the calipers on the tank:
Un-plug horn or in my case remove it since it broke and was krazy glued back together and no longer unplugs, remove it completely:
Put a jack under your skid plate. Loosen and remove the top center 10mm hex bolt:
If you have a stabilizer you will have to remove the ignition security bolts and remove the plate and pin:
Then lift up on the upper triple tree sliding it off the forks:
Zip tie or wire the bars/triple tree out on the way if required.
Remove top dust cap, the top bearing is now exposed:
The front fork/wheel assembly will now start to roll ahead and will drop right out. Take care that it does not fall and damage the forks or steering stem:
Prop the front forks and wheel up somewhere safe:
The lower bearing, note the rust:
Lower bearing outer race, note grooves (that's what causes the notchy, unsmooth steering motion):
Find a suitable punch or piece of tubing to tap the outer races from the frame. Work your way around the race, just tapping it out. DO NOT just whack one spot as you can damage the bike frame!
Remove lower bearing from steering stem by tapping with a small hammer and chisel between the triple tree and bearing race. Try to save lower dust cap:
*Update: See post 19 and 21 for a better way to the lower bearing off*
My lower bearing was a real bitch to get off. I had to lay it down flat and work for about 20mins to get it off. No saving the dust cap in this case:
Slide new dust cap on:
Grease new bearing like you would an automotive wheel bearing (ie, put a glob of grease in your palm and cup the bearing until grease starts to come out the top). I'll try to find a good YouTube video of that and post it. Slide greased bearing on to the steering stem:
It's a snug fit. I didn't have a piece of tubing the right size to drive the bearing on so I found a suitable punch. The punch should be large enough to catch the lip on the inner race but not be resting on the stamped steel bearing cage on the outside:
Install new outer race in lower frame tube by LIGHTLY tapping around the edge with a small brass hammer. The race will become flush with the bottom of the frame tube before it it totally seated. Note gap at the top:
Take one of the old races and flip it upside down and use it to drive the new race in completely. Again, TAP with a small brass hammer. If you beat on the race you will damage it. I got carried away taking pics and clearly didn't do a good job of this but make sure you clean the area well before you install the new bearings.
Same situation up top. Place the new outer race in the frame and TAP to seat:
Once it's started evenly you can place a piece of metal over that whole race and smack the middle on that metal to evenly drive the race in.
Same deal here, the race is flush with the frame but IS NOT seated fully yet. Again, use old race to drive the new one in until fully seated:
Roll fork/wheel assembly back into place:
Stem is now sticking up through frame tube:
Slide new upper bearing over shaft and chock wheel to keep it from rolling forward:
Wiggle forks so the bearing drops into outer race then slide new or clean used top cap over steering stem:
Set upper triple in place:
Don't forget the washer:
Start 10mm center hex bolt:
This adjust procedure was posted on another board. I don't have a manual and can't say how accurate this process is. it seemed to work just fine for me.
Here it is:
1- Tightened the 10mm hex-head steering head bearing adjustment bolt to the recommended 25 NM.
2- Swing the handlebar through 3 full arcs (I guess to seat the bearings)
3- Backed off the steering head adjustment bolt 60 degrees (one flat's worth).
*Edit* Step 3.5- Tighten 10mm hex-head adjustment bolt to final torque spec of 10Nm
4- Tightened up all five clamping bolts to 19 NM as directed
Re-insall BMW logo on triple tree, re-install the bars if required, re-install the brake calipers and ABS sensor, plug horn back in.
Go for a test ride. If there is a clunk over bumps you may need to tighten the 10mm hex another 60 degrees which of course required bar and logo removal and loosening of the 5 pinch bolts on the upper triple.
You will want to check them again in a couple hundred miles.
My head bearings needed replacing at 1000 miles
For the Adjust procedure quoted above there should be one more step:
3.5- Tighten 10mm hex-head adjustment bolt to final torque spec of 10Nm
Nice set of pictures & write-up - THANKS!:clap
Any idea why yours rusted out?
The "dust seal" is probably not waterproof is it?
There didn't seem to be much grease in there either. There was some but less than I expected.
Realizing that they aren't sealed and thinking about all the rain I've ridden in over the last two years, I'm not surprised the bottom bearing was F'd up.
Oso, nicely documented. I've been hearing about steering head bearings for a while and had some concept of how it was done. Nice to see the process illustrated.
When you get a chance toss this into the Thread Index & Links post! Good stuff here!
As listed with adding in step 3.5 (10Nm) is the procedure outlined in the service manual.
This is a great thread that gave me confidence to tackle the job.
I have a 650GS twin.
The hardest part is getting the lower bearing off the steering tube. My fork has 2 holes that allow a 4mm rod ( a drift or pin punch) to push on the under side of the bearing and get it off. You have to hit it pretty hard and I could not do it without the correct drift or punch. I had to buy the drift and slightly sand it down to fit the hole but it worked perfectly - I guess it would be possible to not damage totally the lower dust cap - it would likely have 2 hoes punched it it but I guess you could rotate it a little and reuse it. I heated the bearing with a hot air heat gun as well.
To seat the new bearing rather than use a punch I used the inner race of the old bearing after first cutting through the old bearing with a Dremel type rotary tool with a cutting disc - it cuts the hardened steel remarkably easily - this makes the bearing loose on the shaft and easy to remove once the new bearing has been seated.
I removed the cups from the frame with a bearing puller - it cost me $40 and was called a "pilot bearing puller" - google that and you will get a picture . 2 posts sit on the bike frame, a central thread cause 3 arms to spread and engage strongly with the small lip of the bearing and a threaded collar allows slow easy removal of the bearing cup. Once I had the gadget adjusted it was easy.
I had just paid $550 for the 20,000km service and being told the bearing needed doing ( what, after only 20,000???) which would involve another 2 hours labour I was motivated. Apart from saving a heap of cash I am much more educated about headset adjustment. It looks to me to be a weak spot and I would not be surprised if I have to do it again. I suspect it only takes 1 bad pothole in a slightly loose headset to do the damage.
Thanks again for a great thread. I think I may upgrade the fork springs now....
I think the 800 GS is the same - the repair manual seems to omit the description for the 800 but the adjacent diagram shows using a 4mm drift in the same manner as the 650. The test mentions a 4mm drift but doesn't tell what to do with it.
One last thing - I think the bearing adjustment / torque procedure should be done with the front wheel on the ground.
Not a difficult job, all you need is an uncluttered piece of sidewalk outside the bearing store, here is my friend's bike.
All parts over the counter and dirt cheap compared to BMW or any other automotive type retailer.
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