The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: Duncan R on 16.09. 2010 15:05
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Could anyone tell me if you need any special tools to replace the headrace bearings? or can you just knock the old bearing cups out of the headstock.
Bit of a numpty question - what is the correct procedure for adjusting the clutch via the screw and locknut on the gearbox? should the cable be slackened right off?
Many thanks
Duncan
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Duncan. The correct way to adjust the clutch operating arm is quite simple. You unlock the nut and adjust the screw until the operating arm is parallel when when the clutch is disengaged. That is to say when you operate the handle bar lever the gearbox arm should be in parallel when viewed from above. When the clutch is engaged the arm should be angled outwards.
http://www.a7a10.net/forum/index.php/topic,2722.0.html (http://www.a7a10.net/forum/index.php/topic,2722.0.html) This is how to replace the head bearings.
Hope this helps John
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Many thanks John, thats a great help
Regards
Duncan
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If you decide to knock them out, get a long chisel or pin punch.
Cut a notch into one side such that when the side of the notch is on the bearing cup the end is just sitting on the base of the bearing cup so you can give it a "healthy" tap without the tool slipping off.
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Thanks Trevor,
I have maaged to get all the old parts out. I used an old engine stud, tapping at 12,6,9 and 3 o'clock, they came out without resorting to any major hammering. The cup on the stem came of with some gentle levering.
The new taper rollers should arrive in the post tomorrow - not sure,but hopefully should be able to use the old cups as drifts to gently tap in the new bearings.
Regards
Duncan
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Duncan,
This my seem like stating the obvious, but when you fit the new taper roller bearings make sure that you do not mix up the cups. The bearings are different sizes ( the bottom one is wider internally). The correct setting for the bearings can be judged by centralising the handle bars and then just tapping the ends. The forks should swing freely under their own weight.
John
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Hi John,
Bearings arrived this morning, they are not tapers but normal sealed ball races. They came in seperate bags marked top and bottom. Gently tapped them in using one of the old cups as a drift and set them up as you suggested. So hopefully all should be ok and I can go for MOT re-test. I need to align the forks when the wheel is back on as I found that one of the pinch bolts on the bottom yoke had sheared, both bolts now replaced with the correct length and new nuts and washers.
I also noticed the wheel spindle was not ligning up - one fork leg was sitting higher, so I loosened the top nut and yoke pinch bolt and tapped it down to align the spindle(tightened pinch bolt and top nut) I can now push and pull it out by hand as before it had to be whacked in with a hammer.
Regards
Duncan
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G'day Duncan,
STOP !!! If I understand right, you lowered one fork tube in the triple clamps. If so now that tube will not be home in it's taper in the top clamp, allowing the tube to move and stressing the bottom clamp.
For the sliders to be un-even there might be something wrong with the bushes. May be an un-matched set, one bush slightly longer than the other side.
Pull that tube back up, things will line up once the axle is tightened. Next job is a fork service with a matched set of bushes.
I was looking at those bearings, a fair bit cheaper than the tapered ones. I can't see how you can adjust them for wear later on.
Cheers
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Duncan,
If the bearings are ball races, did you fit a spacer between them?
I use ball races in my bikes but they need a spacer to stop the bearings from binding when the top nut is tightened.
Trev.
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Hi Muskrat,
Thanks for the advice - just put it back to what it was, the leg was tapped down about 1.5 to 2mm. I will leave everything loose until I get the wheel back on tomorrow and then line everything up. I will go through the forks over the winter, they seem to work ok - no knocking and the damping and springing are fuctional.
I assume there is no adjustment on these type of bearings, they were quite a bit cheaper than buying new cups,cones and balls. Lets see how long they last.
Hi Trev,
There was no spacer in the kit -I set it up as per instructions and all seems ok. What did you use for a spacer?
Thanks
Duncan
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As Trev says, normal ball races would need a spacer. Norton Commandos had such an arrangement. I'm surprised that these were supplied to you - standard fitment would be cup & cone, sometimes replaced by taper rollers.
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It all appears to fit and there is no binding, there is no axial or radial play and the bars move freely lock to lock - soon find out when I road test it tomorrow!
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Duncan,
I use a piece of 1-1/4" hydraulic tube cut to length. The distances between top and bottom all seem to be slightly different so I have to shim to get it right.
Trev.
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Many thanks Trev
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another way i have got old head bearings out the spot weld a bar across then knock it out . taper roller bearings may life much better.
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Hi Nick,
I have heard of this before - you can run a small track of weld along the inner face of the bearing and the heat causes it to contract and drop out. Mine tapped out ok.