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D Comet

Peter Holmes

Well Known and Active Forum Website User
VOC Member
I purchased a D Comet conversion last year, I think it has a Spax rear shock on it, I have no idea what strength spring it has but it does have a small adjuster screw for the damping.
My problem is that there does not appear to be a happy medium adjustment, it either bottoms out or it is rock hard and uncomfortable. I purchased an Armstrong of Ebay last week and the damping seems OK, I am missing the top metal shroud and also the top rubber bushing and bushes, I am unable to find these parts as spares, any ideas anybody?
I did give Hagons a try in the hope that they might have made a shock to suit in the past but no joy there, they do make a nice looking shock for a Yamaha TR1 which was regarded by some as a stab at a Series E Vincent and as I own one I offered it up but it is a bit to long and I do not possess the skills to modify it, and even if I could it is about £300 to start with, any ideas anybody. Is anyone using the Thornton D Shock, perhaps that's the way to go.
 

Tom Gaynor

Well Known and Active Forum Website User
VOC Member
The Thornton shocks, which I've had now for four years on my C, are worlds apart from the Vin shocks which they replaced. They are also, professionally tested on a "shocks dyno", streets ahead of Armstrong and Koni.
There is a reason that Vin springs are so stiff, not unconnected with damping that, while state-of-the-art in 1949, was largely ineffective. Stiff springs to an extent do their own damping. I have Petteford springs, came with the bike. It can be bounced on its suspension. It handles very well. I still get the occasional "ouch" over bumps, but suspect that converting to a D seat would markedly reduce the ouch count. Softer springs would be even better, because what you need are soft springs and stiff damping. (Colin Chapman of Lotus thought the same.) Thornton provide one of these. I did try removing one front inner, which noticeably improved the compliance over bumps, but led to a weave, terrifying to onlookers, mildly disconcerting to the rider, on fast sweepers. Removing both inners was too much, but would have stopped the weave.
My big-bore Comet, now building, will use a Thornton coil-over rear unit, and a Thornton front, front springs yet to be determined, but the lightest I can get. I wouldn't countenance anything but Thornton dampers.
 

chankly bore

Well Known and Active Forum Website User
Non-VOC Member
Throw out the SPAX damper,they nearly killed Pete Johnson see 40 Years On I,m using a Thornton coil over, too
 
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Deroberson

Active Forum Website User
VOC Member
At first blush, check out this website or similar one for the rubber/urethane bushings.

http://www.suspension.com/shockeye.htm

I have a D model that I replaced the rubber grommets on with this supplier, I had to "thin" the supplied grommets, but if you cannot find another closer alternative, I think you will find it a very viable option.

pm me or deroberson@me.com if you want something of more detail

Dave

I would be interested in hearing other D owners solutions, sound off!
 

Peter Holmes

Well Known and Active Forum Website User
VOC Member
Chalky, Is it the Series D Thornton coil over you are using or the shorter C coil over unit, I am looking info on either repairing or replacing the longer Armstrong Series D unit, my Comet is a proper D conversion using D UFM and D RFM. Having said that I am interested in any info on the C coil over Thornton for my Rapide
Peter
Throw out the SPAX damper,they nearly killed Pete Johnson see 40 Years On I,m using a Thornton coil over, too
 
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timetraveller

Well Known and Active Forum Website User
VOC Member
For the rubber bushes to fit into the ends of 'D' type dampers find a local Land Rover, or possibly Rnge Rover repairer and have a look at the bushes used at the bottom of the dampers used on some of those. Take along your old bushes to show the storeman (person). A competent person will recognise the old bushes at once and will be able to find some which need the minimum of modification before fitting to the bike. Good luck.
 

Bill Thomas

Well Known and Active Forum Website User
VOC Member
Hello Peter, I have a top metalastick type bush, From a D Rear spring unit that I snapped a long time ago. Don't know what make it was. It has a 1/2" hole, The inner tube is 1 1/2" long, The outer tube is just over 7/8" long and 7/8" in dia'. I am about 1 1/4 hours from you in east dorset. Cheers Bill.
 

Tony Cording

Well Known and Active Forum Website User
VOC Member
Hi Peter, when the Armstrong damper on my Prince failed, I replaced it with an AVO damper, as described in Jeff Bowen's excellent MPH article "Bespoke Rear Suspension". I found that it suited the Pirnce very well, and since then it has been transferred to my newly completed Seedy D Comet. In addition Jeff wrote another article entitled "Details of My Damper", also in MPH concerning the fitment of an AVO front damper. I have now ordered one of these and will be picking up shortly. The pricing is very reasonable, and as mentioned the rear worked very well. My expectation is that the matched pair will be the business. Unfortunately I do not know which month or year the articles were written, perhaps someone out there can provide this information. However, Peter, if you would like copies just e mail me at tonydreview@hotmail.com and I will forward, plus a picture of the Seedy to a fellow D Comet owner!! AVO website www.avouk.com.

All the best


Tony Cording
 

vibrac

Well Known and Active Forum Website User
VOC Member
I have had an AVO I modified myself (to fit the top of the girdralics) for the front of the racing comet very fine damper with multi adjustment good company
 
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