1000 SFC Stearing head bearings

Laverdalothar

Laverdalothar

Hero member
Location
Germany
Folks a bit of advice, please:

I think to remember that my 1000 SFC had a grooved ball bearing at the top and a tappered roller bearing at the lower end of the stearing head - am I right? I was a bit confused as someone who had his 1000 SFC restored recently said there are 2 tappered bearings, both on top and bottom of the stearing head...??

I have the assembly with the roller bearing installed, but turning the yokes from left to right shows a bit of a difference in the actuation: to the right, the movement is free, no problem. to the left, it gets stiffer/almost sticky at the end of the movement. You think this will change once the bike is completed and has done some miles or is there an allignement issue potentially?

thanks

 
I agree with Phil
but I use taper rollers top and bottom on 180's
if you can be bothered to arrange a "crush tube" between the two taper rollers, so as to then be able to really tighten the nuts and locknuts, instead of using the adjusting nut for just that, there might be an improvement, but to say that it is tedious is a total understatement, the fitting /removal/refitting of the yolks will have to be done many, many times, as the length of the crush tube is machined a few thou at a time until, until all slack is removed and just the right amount of fit is achieved, I did this on my Egli, which has welded to the legs yolks (twist that you bastard) but the top yolk does not take much weight and is only a single sheet of steel,  but the standard set up,  if they are good and properly adjusted,  are great anyway!
CLEM
 
Here's my 50 cents worth... as I'm a sealed ball race top, taper bottom type guy.

I tend to find that the issue with using two tapered rollers is they need to be installed with the utmost of care as you do need to make sure they are parallel. So there is a lot more than just driving a new set of bearings in and hoping for the best. as without a tool to pull them in dead straight  to ensure that both are parallel then  I would think that there would be the chance of having issues. The amount of folk I have seen drive bearings in with hammers and drifts... grrrr.
Now also with two tapers you need to ensure that the steering stem and both fork legs along with the triple clamps are all dead true as any discrepency there how ever slight can also have an affect on the set up being parallel. 
The net result is that if the bearings are not exactly parallel, or the stem not dead true then they will tend bind at one position and be loose in another in my experience. So you can have tightness when turning one way when comparing to the other.
It may be also that the headstock and triples were good enough to support this when the bikes are new as with the RGS  but given the amount of bikes which have had mods done to the head stock am not sure that this applies these days.
With a ball race at the top I find that they are more forgiving in this respect. With the top being a ball race I find that this tends to be more accommodating and not as stiff plus you can get some preload on the lower tapered bearing which holds the load ...

Which ever set up you choose the key is spend the bucks on good quality bearings and grease liberally though too much grease on a taper can cause issues different though from a poorly greased. Another advantage of using a roller at the top is that a good sealed unit will be more weather friendly that is if you use your bike in times others than when the sun is shining..
 
  If you can't put a bearing in straight - then I'd of thought that the ball bearing type would be a far worse bet. Haven't managed to ever have a problem over the last 40+ years using a drift.  - Regards - Phil
 
The pounding they will take over the first few miles, will seat them into their natural position regardless of how they are driven/pressed into place anyway, only after a bit of use can you then adjust the freeplay and see if they bind or not, if they bind then? I looks like you have a problem only machining will cure.
 
The missing point here is that the steering only needs to be truly 'stress-free' when pointing straight or a degree either left or right, as this is as far as it will ever move once you are on the move (unless you ge a tank slapper!!). Some binding at further angles from centre would indicate something isn't plumb, but it won't have any effect on the bike when it's being ridden.

The two main probs with steering head bearings are: too tight = imprecise or: grooved at straight ahead (ie worn out and self-centering) = bike wanders left-right-left-right etc ... can't get the friggin thing to run smoothly in a straight line, as you're always correcting the self-centering effect of the worn grooves.
 
as Phil,
never had a problem using a drift, sometimes its not even one specially turned for the job, just a socket from a biggish set!
CLEM
 
I just installed new tapered roller bearings in my RGS Corsa as part of my re do of the bike. I put the outer races and the steering stem in the  freezer overnight. I used a long pipe of the correct diameter to install the inner races on the stem. For the outer races I use a flat metal bar across the race until it is flush with the frame, then I use an old bearing race I grind down the OD a bit to tap in all the way to the stop. Dont forget the the little spacer ring that goes in first on the outer races to ensure the race seats correctly. And you will need a new bottom grease/dist cap on the bottom of the steering stem as you will destroy the old one taking out the old bearings. Everything went in good, but you do need a good size hammer, tolerances are tight.
 
Thanks all together. I have decided to try the current setup first (tapert bearing on the lower, roller bearing on the top) and see if it seats after some miles.

BTW: As I have to do 2 more bearings for the Motoplast soon, I decided to buy me proper tools for the total of 4 bearings I have to install (and maybe more to come in the future)...:

https://www.tectake.de/werkzeug-zur-de-montage-von-tonnen-und-silentlagern-27-tlg-401104?gclid=CLGKtbG3_NMCFQ4R0wodUJIANg

worked well, but still you need to make sure they go in not angled...

cheers

Lothar
 
Dave "SPIDER" Holder said:
The pounding they will take over the first few miles, will seat them into their natural position regardless of how they are driven/pressed into place anyway, only after a bit of use can you then adjust the freeplay and see if they bind or not, if they bind then? I looks like you have a problem only machining will cure.
Click to expand...
There was a similar conversation before: http://www.laverdaforum.com/forum/index.php/topic,95211.msg362140.html#msg362140

Need to tighten up the bearings to around 20ft/lb first to bed the bearings in.
 
Laverdalothar said:
Thanks all together. I have decided to try the current setup first (tapert bearing on the lower, roller bearing on the top) and see if it seats after some miles.

BTW: As I have to do 2 more bearings for the Motoplast soon, I decided to buy me proper tools for the total of 4 bearings I have to install (and maybe more to come in the future)...:

https://www.tectake.de/werkzeug-zur-de-montage-von-tonnen-und-silentlagern-27-tlg-401104?gclid=CLGKtbG3_NMCFQ4R0wodUJIANg

worked well, but still you need to make sure they go in not angled...
Click to expand...
Similar concept to bicycle steering head bearing presses. Which would be perfect for motos as well.
 
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