I recovered a beaten up LWT 250 Model G2 from a landfill site many moon ago thinking it might be a useful spares source someday. I was about to use the swing arms off it in the current restoration of another AMC 250 but have just noticed that the jaws that hold the the rear wheel spindle, measure about 1/16 inch.wider gap at the rear than at the front. It's plain to see from a side view that the jaws have opened out. Is this a common fault to look out for on the Lightweight swing arm or is mine just the case of a particularly, badly, abused example?
Rod
Lightweight swingarm jaws opening out
-
- Member
- Posts: 168
- Joined: Mon Jan 01, 1990 12:00 am
- Location: WEST YORKSHIRE UK
-
- Member
- Posts: 1439
- Joined: Sat Oct 09, 2010 9:17 pm
- Location: ABERTAWE UK
Re: Lightweight swingarm jaws opening out
Seeing that you have no replies I shall say that a 1/16" is nothing to worry about, you could clamp it up in a vice and give it a squeeze.
Colin
Colin
only dead fish go with the flow
-
- Member
- Posts: 8559
- Joined: Wed Sep 01, 2004 1:00 am
- Location: WEST SUSSEX UK
Re: Lightweight swingarm jaws opening out
I agree with Colin and I'm not sure I would be able to 'plainly see' such a tiny (1/16") difference. It could've been like that from new.
I'm not familiar with L/W's and may have misunderstood the issue, but surely the 'spread' in the s/arm jaws will close up anyway when the wheel nuts are fully tightened?
EDIT.
Hmm, maybe you mean the 'slot' for the spindle each side of the end of the swing arm opens up by 1/16" over its length?
Here: (Not a L/W swing arm.)
I'm not familiar with L/W's and may have misunderstood the issue, but surely the 'spread' in the s/arm jaws will close up anyway when the wheel nuts are fully tightened?
EDIT.
Hmm, maybe you mean the 'slot' for the spindle each side of the end of the swing arm opens up by 1/16" over its length?
Here: (Not a L/W swing arm.)
You do not have the required permissions to view the files attached to this post.
'There is a tide in the affairs of men
Which taken at the flood............'
Which taken at the flood............'
-
- Member
- Posts: 168
- Joined: Mon Jan 01, 1990 12:00 am
- Location: WEST YORKSHIRE UK
Re: Lightweight swingarm jaws opening out
Yes, I'm talking about the slot for the spindle.
On the British bikes I'm used to, like the AMC Heavyweights, this is usually a lovely cast bracket brazed onto the arm tube. In this case it looks instead like it has been formed by pressing the end of the swingarm tube flat & machining out the slot. Cheaper but can't be as strong as the Heavyweight jaw/slot & looks like it might be prone to distorsion if abused. Then again maybe quality control when it was made is the explanation & that's the way they left the factory. I hadn't another similar to hand to compare it with to check.
I was about to spend money on replacing the swingarm spindle on it but hesitated when on cleaning it I noticed that the jaws opened out and now I am wondering if I should try to find another.
Rod
On the British bikes I'm used to, like the AMC Heavyweights, this is usually a lovely cast bracket brazed onto the arm tube. In this case it looks instead like it has been formed by pressing the end of the swingarm tube flat & machining out the slot. Cheaper but can't be as strong as the Heavyweight jaw/slot & looks like it might be prone to distorsion if abused. Then again maybe quality control when it was made is the explanation & that's the way they left the factory. I hadn't another similar to hand to compare it with to check.
I was about to spend money on replacing the swingarm spindle on it but hesitated when on cleaning it I noticed that the jaws opened out and now I am wondering if I should try to find another.
Rod
-
- Posts: 2884
- Joined: Mon Mar 24, 2014 5:44 pm
- Location: Aberdeenshire
Re: Lightweight swingarm jaws opening out
Hi
I have no direct experience of lightweights but I'd be very surprised if your swinging arm is unusable.
A 1/16" taper would ease installation of the spindle so may actually be by design.
The only way I can imagine to distort your forks would be to try and fit a larger diameter spindle with considerable force - is your current spindle per design?
From memory the swinging arm forks on both my AMC HW and Triumph have a slight taper.
Regards Mick
I have no direct experience of lightweights but I'd be very surprised if your swinging arm is unusable.
A 1/16" taper would ease installation of the spindle so may actually be by design.
The only way I can imagine to distort your forks would be to try and fit a larger diameter spindle with considerable force - is your current spindle per design?
From memory the swinging arm forks on both my AMC HW and Triumph have a slight taper.
Regards Mick
- Martin.S
- Posts: 443
- Joined: Sun Mar 18, 2018 12:02 pm
- Location: Bristol UK
Re: Lightweight swingarm jaws opening out
Mine were tapered - I thought that wasn't right so I welded them up and filed them to size - perhaps they were supposed to be like that?
Here they are before I welded them.
Here they are before I welded them.
You do not have the required permissions to view the files attached to this post.
- clanger9
- Posts: 1163
- Joined: Sat Jun 20, 2015 9:38 am
- Location: Chester, UK
Re: Lightweight swingarm jaws opening out
I suspect they're all like that. I just checked my spare swingarm and it's 1mm wider at the end of the fork.
You do not have the required permissions to view the files attached to this post.
1989 Moto Morini Dart 350
1993 Ducati 750SS
1993 Ducati 750SS
-
- Member
- Posts: 168
- Joined: Mon Jan 01, 1990 12:00 am
- Location: WEST YORKSHIRE UK
Re: Lightweight swingarm jaws opening out
It may well be the result of past, brutal over-tightening of the rear wheel spindle nut on the Lightweight pressed steel swing arm which is softer than the cast or forged bracket on the AMC Heavyweights. I am not saying it's impossible the widening has been there from the beginning but I have not myself come across a case of jaws opening slightly to aid spindle assembly on any other make of old Brit bike I've dealt with and that's not a few. The one I know were always parallel as you might reasonably expect. I notice one of the jaws on one of these swing arms is also bent slightly slightly sidewise too. I can't imagine that on a Heavyweight.
I will try straightening & then increasing the diameter of the adjacent washer.spacers when assembling the spindle/wheel into the swingarm assembly.
Rod
I will try straightening & then increasing the diameter of the adjacent washer.spacers when assembling the spindle/wheel into the swingarm assembly.
Rod