fork top bolt

[nb1914]

Hi all,

finally got my bile together and the holy grail of an MOT. when riding to the MOT station i noticed front end judder ( even knocking ) on front braking, not necessarily at high speed. The head bearings are solid i installed All Balls tapered bearings and there is no play at all. So i thought i would start at the simple stuff first and check fork oil by emptying and refilling. When looking at the fork top bolt i see what i believe is the dampening adjustment screw, so can you simply undo the top bolt with that screw in situ ?. in case there are any other suggestions i have put new pads in with the old discs and they havnt bedded in yet.The forks are original and most likely very tired, i think the springs are made of marshmallows as the ease of compression is surprising ( I'm not even sure if there is any oil in them )

 

[5twins]

That's not a dampening adjuster screw but rather a spring preload adjuster. It has two stiffer settings than it's lowest one. Each setting will increase the preload by 10mm. Yes, you can just unscrew the top cap and it will come out all together as one complete little unit .....

 

[nb1914]

thanks 5twins, just out of interest how far up should the forks be in the top clamp i.e. currently the top of the fork is flush with the top edge of the clamp with the bolt above it. wondering if pushing the forks up through the stanchion might help with worn shocks.

 

[5twins]

The way yours is set is stock - top of tube even with top of the tree. You can raise the tubes up a little if you like, but not much. You can only go about 1/2" at most or you run the risk of the lowers hitting the lower tree upon full fork compression.

I don't know if this will help much with worn shocks but it is a common "upgrade" to enhance the handling a little. It lowers your front end slightly which more heavily loads it a little. This is said to give better steering "feel" and more firmly plant the front tire. I run mine raised about 1/4" .....

 

[littlebill31]

I have a question, 5twins.
My new to me '81.
I tried to adjust the preload screw and neither move. Tried my darndest and nothing. The po said he replaced the springs, oil, and seals, but they dont want to budge.
Any thoughts are appreciated before I remove them completely.

 

[gggGary]

They can be stuck/frozen but you have to push IN to free the cross pin from the groove before turning. On a stand so the front wheel is off the ground also is a big help.

 

[5twins]

Sometimes they get stuck or freeze up. You may have to remove the caps and free them up. Even when free, the screws are pretty hard to adjust. You have to push down on them really hard as you turn them.

The preload adjuster pin is just plain steel. If some water makes it's way in under the rubber protection cap on top, the pins can get rusty and seize up. A couple drops of oil occasionally on the tops of the pins may help keep them free. The bottoms stay wet with fork oil so they're not a problem. When I free an old one up, I work grease into the cap around the pin. Then in the future, I just keep the top oiled a little.

 

[littlebill31]

Thanks. The po said he did the maintence recently, but I had all my weight on it and tried CW and CCW, with no luck. So either its stuck or he didn't do that work.
Of course the plugs werent even gapped so Im thinking its the later.

 

[gggGary]

Should be able to get a bounce out of it when smacked with a big hammer, but loosen the pinch bolts and unscrew the cap see what's going on inside. Lots of spring pressure behind the cap if the preload is in the longest position.