MK3 Seat Alignment issue

I just finished restoring my MK3, very happy how it came out, but when I mounted the factory seat, it won't sit level with the bike. I believe I have the mounting assembly correct. Here are pictures of the Seat and the Seat Hinge

I bought this bike last year, could be a replacement seat with a defect. I might be able to lower the fender in order to get it to rotate a few degrees clockwise so it sits flat. That may introduce other issues so before I attempt it, I'd thought I see if anyone else has seen this issue?

Have you fitted the rubber 'bumpers' to the seat base? It looks too low on the left side, almost resting on the side cover.

Seeing as it's low on the left, you could loosen of the hinge bolts to the frame and try raising the seat before tightening back up

The hinge assembly looks correct except for the 06.7612 lipped washer that the parts book lists as '4' but should only be 2 on the opposite side in my opinion.

2WheelsUp said:

I bought this bike last year, could be a replacement seat with a defect. I might be able to lower the fender in order to get it to rotate a few degrees clockwise so it sits flat. That may introduce other issues so before I attempt it, I'd thought I see if anyone else has seen this issue?

Click to expand...

Could you post pictures with the seat raised so showing a view of the seat pan and fender also closed (or as much as it will close?) on the lock side.

For reference, here's how my seat sits:

2WheelsUp said:

Here are pictures of the Seat and the Seat Hinge

Click to expand...

Whilst looking through the other pictures there for an answer to the question I couldn't help noticing the peashooters are attached with (original Mk3 black cap) silencer/muffler bracket sets which can pull the peashooters out of correct alignment with the pipes and also set them further back so there's less/no engagement between the pipes and mufflers.
The triangular muffler mounting plates appear to have a second set of holes drilled, presumably to mount the peashooters closer to the correct position or just to slip onto the pipes which seems like a half-measure.
Peashooter plate set (6).
None of which are interchangeable with the black cap set (6).

Bilko said:

Have you fitted the rubber 'bumpers' to the seat base? It looks too low on the left side, almost resting on the side cover.

Click to expand...

Yes, they touch the frame and fender when the seat is closed which doesn't allow it to close completely.

Bilko said:

Seeing as it's low on the left, you could loosen of the hinge bolts to the frame and try raising the seat before tightening back up

Click to expand...

Tried that, in order to tighten it, the bracket has to be flush with the frame mount which brings the seat out of alignment.

Bilko said:

For reference, here's how my seat sits:

Click to expand...

Beautiful... that's what I want!

L.A.B. said:

The hinge assembly looks correct except for the 06.7612 lipped washer that the parts book lists as '4' but should only be 2 on the opposite side in my opinion.



Could you post pictures with the seat raised so showing a view of the seat pan and fender also closed (or as much as it will close?) on the lock side.

Click to expand...

L.A.B. said:

Whilst looking through the other pictures there for an answer to the question I couldn't help noticing the peashooters are attached with (original Mk3 black cap) silencer/muffler bracket sets which can pull the peashooters out of correct alignment with the pipes and also set them further back so there's less/no engagement between the pipes and mufflers.
The triangular muffler mounting plates appear to have a second set of holes drilled, presumably to mount the peashooters closer to the correct position or just to slip onto the pipes which seems like a half-measure.
Peashooter plate set (6).

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

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None of which are interchangeable with the black cap set (6).

Click to expand...

The original cross over pipes where in bad shape so I replaced them with non-balanced pipes. Yeah, the peashooters and brackets were on when I bought it... on my list to resolve, thanks for pointing me to the correct brackets.

In the pictures I just posted, you can see that the rubber pads are touching the frame in the front and the fender in the rear. The underside of the seat doesn't look bent/twisted. If I loosen the lower plate assembly so I can raise the left side a bit, it will fit fine but not if it's flush with the frame mount.

I just removed all the seat buttons and with that it almost looks level, but the seat still has an uneven look. I'm beginning to think the seat pan is twisted. Probably wouldn't take much to cause a problem. The seat wasn't attached to the bike when I picked it up, could have been lying around in the seller's garage covered with who knows what stacked on top of it. I can't think of anything else other than the rear fender being a bit high which if lower would allow the seat to rotate clockwise a bit further. I don't see any adjustments to the fender height... it's pegged by rear mudguard support bracket (06.2169).

2WheelsUp said:

I just removed all the seat buttons and with that it almost looks level, but the seat still has an uneven look. I'm beginning to think the seat pan is twisted....
.
I can't think of anything else other than the rear fender being a bit high which if lower would allow the seat to rotate clockwise a bit further. I don't see any adjustments to the fender height... it's pegged by rear mudguard support bracket (06.2169).

Click to expand...

I can't see anything wrong with the seat. It could be twisted as you say.

The fender does perhaps look a little high in your pictures and the (enlarged) picture below shows the front lower mounting bolts at the bottom ends of the slots so the front end of the fender could be repositioned further down as far as the slots allow (or further with a little filing)? The 06.2169 might then need to be 'readjusted'?


There should also be some adjustment range at the rear (also slots) mounting?

L.A.B. said:

The 06.2169 might then need to be 'readjusted'?

Click to expand...

I think this is the biggest thing that is stopping the fender from moving down near the front. Didn't see a way to adjust it other than using a smaller diameter bolt and maybe open up the hole a bit. That said, perhaps I should loosen the fender, remove the bolt for 2169, and see if I can get the seat to sit correctly. That will at least provide me some clues on where to start working it.

All good now!



Attempts to adjust the fender didn't yield anything. I finally grabbed the front and rear of the seat and twisted it into alignment. I seat foam might be degrading so I may buy a new seat now that I know it works. Thanks for your help!

Now I can move on to fixing my peashooter brackets. I don't believe that's why the right silencer is higher/wider than the left rather it's affected by how close I run the header pipes to the frame... closer makes the silencer go wider/higher.

I'll post my pictures of my build at some point, meanwhile folks can view it on my Flickr steam.

2WheelsUp said:

Now I can move on to fixing my peashooter brackets. I don't believe that's why the right silencer is higher/wider than the left rather it's affected by how close I run the header pipes to the frame... closer makes the silencer go wider/higher.

Click to expand...

If the (non-original unbalanced) pipes are the flared Mk3 type with spherical seatings then it should be possible to reposition the pipe (or both?) to (mostly?) even up the misalignment. The incorrect (black cap/bean can) brackets probably aren't helping matters. The black cap mufflers being substantially longer and heavier were mounted further back no doubt to support the extra weight...


With peashooters mounted onto black cap brackets...


...the mufflers don't even reach far enough to attach to the pipes on my Mk3.


Instead of buying the complete peashooter bracket set, adaptor plates can be made to replace the triangular black cap muffler plates (examples below). If you choose to do that then I suggest you make them to your own measurements.

L.A.B. said:

If the (non-original unbalanced) pipes are the flared Mk3 type with spherical seatings then it should be possible to reposition the pipe (or both?) to (mostly?) even up the misalignment.

Click to expand...

They are the flared MK3 type with spherical seatings. I don't remember an issue when I put them together other than the left and right don't line up evening.