More frame loop droop

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MikeG

MikeG

Mikeg
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Just wondering if rear loop droop can cause the tail lamp housing to fit poorly and crack? the loop does not look drooped to me but I have not measured yet. This housing was new two years ago and now the front anchor bolt has pulled out.
20230130_190001.jpg
More frame loop droop
 
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MikeG said:
Just wondering if rear loop droop can cause the tail lamp housing to fit poorly and crack? the loop does not look drooped to me but I have not measured yet. This housing was new two years ago and now the front anchor bolt has pulled out.View attachment 103291View attachment 103291
Click to expand...
If the tail light is somewhat pointing downwards, then it almost certain the frame loop droop. It's real hard to fix. The picture is not great. The bike was held down and I lifted with the engine hoist. Then a couple of strong blows with a small sledgehammer against a piece of wood across the frame right behind the top shock mounts and all was well. Of course, if possible weld on the gussets AN has for the purpose.





1675129047009.jpeg
 
www.accessnorton.com

Rear Frame Hoop De-Drooper

With the mudguard off for other work, decided to have a go at my droopy rear hoop. Noted the underside of mudguard was showing signs of tire rubbing. Design requirements were to not require lashing bike down to floor since I do not have any lift or tie down points etc. Pics worth a thousand...
www.accessnorton.com www.accessnorton.com
 
Thanks.it does not look to me like it's drooped but I don't have another to compare to. I'll set up a straight edge off the Z plate mounts and measure.
 
MikeG said:
Just wondering if rear loop droop can cause the tail lamp housing to fit poorly and crack?
Click to expand...
The second picture shows the tail lamp harness section running over the frame loop into the housing where there's no clearance for it to do so and has possibly put additional stress on the front mounting?
 
marshg246 said:
If the tail light is somewhat pointing downwards, then it almost certain the frame loop droop. It's real hard to fix. The picture is not great. The bike was held down and I lifted with the engine hoist. Then a couple of strong blows with a small sledgehammer against a piece of wood across the frame right behind the top shock mounts and all was well. Of course, if possible weld on the gussets AN has for the purpose.





View attachment 103292
Click to expand...
Been looking for these gussets on AN website , can't find them? I remember Old Britts having them. Got a link by chance?
 
L.A.B. said:
The second picture shows the tail lamp harness section running over the frame loop into the housing where there's no clearance for it to do so and has possibly put additional stress on the front mounting?
Click to expand...
It looks like it might be holding it LAB, but the wires can be wiggled back and fro easily.
 
MikeG said:
Been looking for these gussets on AN website , can't find them? I remember Old Britts having them. Got a link by chance?
Click to expand...
Yes, annoyingly AN have dropped the Frame repair section from the site, or hidden it.

You need 2 of these which have the rear extended to support the rail, last frame I had them added to I had them welded over the top of the existing short ones for extra strength.

andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

More frame loop droop
 
MikeG said:
It looks like it might be holding it LAB, but the wires can be wiggled back and fro easily.
Click to expand...

But is that because the front mount has pulled out, however, the harness would normally run along the underside of the loop into the housing.
kommando said:
Yes, annoyingly AN have dropped the Frame repair section from the site, or hidden it.
Click to expand...

It's still there in each model section.
andover-norton.co.uk

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk
 
Thanks. I found the Old Britts tech article on mounting theirs. Will this one clear the existing welds?
 
MikeG said:
Thanks. I found the Old Britts tech article on mounting theirs. Will this one clear the existing welds?
Click to expand...
They will need a bit of dressing. Trick is to get them flat and the shock bolt hole directly in line with the hole on the existing bracket and to if needed use a bolt and nuts to keep it in place while tack welding
 
MichaelB said:
www.accessnorton.com

Rear Frame Hoop De-Drooper

With the mudguard off for other work, decided to have a go at my droopy rear hoop. Noted the underside of mudguard was showing signs of tire rubbing. Design requirements were to not require lashing bike down to floor since I do not have any lift or tie down points etc. Pics worth a thousand...
www.accessnorton.com www.accessnorton.com
Click to expand...
Looks to me like the loop has drooped about and inch. I cured my droop quite easily using the apparatus shown on the link.
Nothing like the power of a good screw.
 
I'm sure mine must have drooped after thousands of miles with 75kg luggage + passenger + me on there, but apart from appearance, it doesn't feel like there is a problem with a bit of droop on a 50 year old bike. Am I missing something?
 
Not to take away from the drooping loop theory as the cause, but the housings are often ill fitting and fragile, so how they are installed is critical. Unfortunately there isn't a good photo of the tail light housing showing the crack you refer to. In the first photo I see significant chafing on the loop from the housing. Installed properly, the housing shouldn't rub on the loop. You mentioned the front anchor bolt pulling out. This could be caused by a drooping loop, but the bonding for the inserts is fragile and if they are overtightened they will fail. I have installed a few of these, and often had to reshape the housing in the vicinity of the loop to achieve clearance. And had to rebend and shim the bracket under the housing that wraps around the loop, or it puts an excessive load on the housing.

Because they are made of fiberglass, they are repairable. Done right you will end up with something better than new. You can rebond the inserts with epoxy. And grind down the cracked surfaces and relaminate with either polyester resin and fiberglass cloth and matt. Or use epoxy resin if that is your preference. Don't waste your time trying to V out the cracks and fill them, as they will just return.
 
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Stephen Hill said:
Don't waste your time trying to V out the cracks and fill them, as they will just return.
Click to expand...
There are modern fillers that have carbon fibre strands in them that will fill and stop that crack returning, the trick is to lower the surface around the crack so the CF strands grab on to more material that just the crack edges.
 
The chafing is from a previous lamp assembly. I put the original style back on 2 winters ago and the fit was OK. Did not have to put any amount of strain on it to get it to fit properly but it has always pointed downward. Lucky for me the housing did not crack, just the nut pulled out. I'll pull the loop back up and go from there.
 
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