Thanks Jason - all is clear....
Robin
9 Sep 2010, 12:11pm
Clonks and Bonks...
12 Sep 2010, 6:55am
Well I fitted the lock nuts - so I did get the size right!
While I was at it though I think I may have found the root of the problem. When I removed the springs there were some signs that they have been binding - that is collapsing enough for the coils to touch. Fortunately when I moved the lower spring plates I also made the lower bump stops adjustable. So for a quick fix I can tweak these up a bit so that the bump stops come into play before the springs bind.
Robin
While I was at it though I think I may have found the root of the problem. When I removed the springs there were some signs that they have been binding - that is collapsing enough for the coils to touch. Fortunately when I moved the lower spring plates I also made the lower bump stops adjustable. So for a quick fix I can tweak these up a bit so that the bump stops come into play before the springs bind.
Robin
So you mean the springs can compress so much that the they touch before the bump stops hit?
I'll have to take a look at mine and see if that possible.
I'm using Apex aftermarket lowering springs for an BMW e30 which is much heavier than a Sportster so i'd be surprised if that is the cause of my occasional 'clonk'.
But my clonk does only occur when I go over a big bump followed by a dip in the road so I guess this could be the cause. It is quite rare.
Was the thread standard M24 and do you think its worth put on some lock nuts?
cheers
Peter
12 Sep 2010, 4:34pm
So you mean the springs can compress so much that the they touch before the bump stops hit?
Yes - that's exactly what I believe is happening. Because my springs were new and are powder coated you can easily see where the coils have touched. (Marks in the coating). I think I confirmed it today. I stiffened up the dampers (so the springs don't compress so readily) and I only had one clonk on an 80 mile trip.
So as a first step I will increase the height of the lower bump stop (Mine is a large nut with a bolt screwed into it. Then I think I will get some new "proper" springs and get Marlin to make me some of the new fangled upper spring plates and shorten the springs as Jason's are done.
Nuts are M24 with a 3mm pitch thread which I believe is standard for M24. Got mine off ebay.
Cheers
Robin
25 Nov 2010, 11:06pm
Robin,
these might solve your clonk problem?
http://www.orange-tuning.de/shop/supersport-3series-bump-stops-p-16513.html
...peter
these might solve your clonk problem?
http://www.orange-tuning.de/shop/supersport-3series-bump-stops-p-16513.html
...peter
26 Nov 2010, 8:26am
Thanks Peter - I ordered some. Worth a try and a lot cheaper than new springs!
Robin
Robin