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slimline featherbed center stand/ proper tire size?

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My 62 Atlas center stand requires quite a struggle raising and lowering the machine. placing a slab of wood under the tire seemed to improve such. (took years to figure that one out) , decidedly the tire size must have been too small. i just fitted a 400 18 new tire, still requiring more lift that my 72 body likes to put out. what manufacturer and size tire would help correct this?. if in fact that is the problem? the center stand is the correct one having compared it to others on hand.

does anyone have an easy use center stand on a similar model or is this just another rabbit hole?

thank you

 

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Atlas came with  19  or 18 inch rear  wheels . Must have been 2 sizes of stand?.  Our Atlas has 19 inch and its still almost a 2 man job to get it on the stand .  Its a bad design , usually made worse with wear to the stops under the frame that allow the action to go too far over center. Get a decent prop stand. Helps too with climbing on and off.

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I once bought an Atlas which the previous owner had fitted with Manx stanchions on the front end. Losing around 1.5" comapred to those normally fitted on Short Roadholders made using the mainstand an interesting challenge. 

Hi Phil, good to see /read you !  i did not consider the front compounding the issue. i am  fairly certain 18" wheel is standard on the Atlas, but the new tire sizes confuse me. i do not know that they are the same as the old TT100's . so im still hoping someone knows of a tire size that works, my stand hardware is all new or like new, nothing wallered out. 

looking in the green Plumstead  book  publication P106/P i see i am wrong to some extent. American Machines had 400x18 but all others show 3.50x19. would the wheel height be the same? 

and then too what new size tire is the same? 

front spec is either 300x19 or 350x19 american  pg 4 and 5  Maintenance Manual and Instruction Book for the Unapproachable Norton Motorcycle

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I once put 2  19" wheels alongside each other. One had an Avon SM with its very deep sidewalls, the other a modern  low profile  tyre.  There appeared to be a couple of inches difference in overall height.  Not very scientific but  food for thought. At the time I was more interested in the effect on rolling radius and overall  gearing and was prompted by this   to fit a bigger engine sprocket . This also had the unexpected result in lowering the kickstart  ratio  a  little and helping me to kick  the beast over compression.

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Hi Steve.........check out the recently released Heavy Twins Compendium Version 2.2. Link above left in the News column. There is an excellent article about Wheels & Tyres starting on page 180. This comprises of a blend of contributions from various NOC members with years of riding experience on various Norton models. 

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The Compendium is a really good resource . With regard to tyres , a  shedule  of actual fitted tyre widths would be most  usefull ,  Pointless saying a 90 90 is the equivalent to a 3.00 x19  etc  if when you buy it its  far too wide to fit the bike.

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Hi All,

Avon tyres have a useful area on their website that gives key dimensions for their tyres, including fitted widths and diameters (when on their recommended rim sizes for the tyre width).

See: https://www.avontyres.com/en-gb/tyres/roadrider-mkii as an example for their Roadrider2 range. Similar data is available on their site for all the tyres that they do.

Obviously this is for Avon tyres, so won't apply to other makes.

Of interest to me was the matter of tread depth. I have an 18" WM3 rims front and rear on my 650 and if I were to buy a rear specific tyre, I get 7.5mm tread depth, whereas if I were to buy one suitable for front or rear, I would only get 5.6mm tread. 

Putting on the stand, I have 100/90x18 on the front, 110/90x18 on the rear, and putting onto the stand is reasonable for me. Having 7 3/8" yokes opens up your tyre choice immensely.

If you wish to retain the 19" rims for a UK spec,650 or Atlas, Avon also sell a modern construction 'GP' tyre in 3.50x19 size that would have been original factory fitment on the rear wheel.

Best regards to all,

George.

great stuff there , i was not able to find the correct link to purchase the compendium hard copy however, as shown in the news section. ill keep trying, i struggle with keyboard stuff.

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I have just ordered a new Speedmaster for the front £68 delivered , and happily  due to this thread I got a 3.25x19   (the correct size)    instead of the 3.00 x19  I was planning . After 7 years  the old one was too hard. I have been buying the wrong size for years .

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It might be worth checking that you have the correct length shock absorbers fitted.

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Hi,

Paul has a point - rear suspension should be just under 12”, my ‘63 Atlas had wrong, about 13” (Commando?) absorbers fitted when I first got it. Worn main stand pivots and maybe another thing to check? I am on 4.00x18 rear and 3.25x19 front Dunlop K70 and she goes on the main stand with a wee tuck and my weight (l am 10 stone) easily enough, no difference with Avons before.

Holger

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My bike has its factory fitted shocks still , have never changed any on any bike ive owned , do they wear out? The Commando shocks are adjustable, old Atlas too? Ill have to look, if they crank down it could help out,less lift? everything is nice and tight still. will take a  look underneath at the frame stop plates, for the stand too far forward thought mentioned. 

not certain if i should feel enlightened or very dumb. the shocks (armstrongs?) are adjustable and i have them relaxed for solo riding, i rarely if ever rode double so my shocks are always relaxed. after raising them the bike does seem to lift onto the stand easier. Ive only a 90/90 avon roadrunner up front, its old so when i order new i can go taller to say a 100/90?  Or possibly another manufacturer and get a 3.25 19  which is specified?

Magneto putting out a nice blue spark and with the machine on the center stand i can use my left leg for starting, will need to get used to that... I still need to go over everything, its been laid up since my last surgery, over a year now. 

thanks again, the forum is wonderful.

 

 

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My Early Atlas is back on the road! Thanks to the help found here and in the compendium (which i have enjoyed cover to cover more than once) I was able to solve the center stand problem and with John  Hudsons advice on setting plug gap to ..012 on hard starting machines solved the starting problem as well. Able to continue to use my K2FC magneto after setting and cleaning the points , filing them slightly and cleaning out the excess lubrication i put on the cam, the bike now starts 2 or 3 kicks.I did replace the fuel filter and new gas lines too. I run a single Amal 930 with 220 main which may be too small. My old Plumstead book has a red stamped ADDENDUM to run the Mercury 650 on a 280 main. 

Does anyone know the reasoning behind increasing jet sizes when using a single carb? 

Thanks to all 

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I took the trouble to check and Uk  Atlas spec was 19" rear wheel ,  It would seem logical that a shorter stand would be made for US spec bikes with 18" wheels   but  perhaps they just "winged" it. For sure building up the frame stop plates  has reduced the effort needed to get the bike off the stand.

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Atlas had 4x18 tyre, not 3.50x19. So half inch bigger tyre balanced half inch smaller radius as far as stand ( and speedo) was concerned.

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I bought a new wm3  rim for the Atlas  rear  as a wm2 just looked wrong . Thats why I checked  the Spec. Perhaps they supplied some  of either size, or changed the spec at Woolwich.

I still have a struggle to get off the stand but able to get it on with shocks cranked down and bigger 400 x18 tire. its so much better for me to start it on the center stand with my 73 now year old knee. I have to get off the machine to raise the stand. I did not build up the frame stops they are not worn . i thought maybe the front tire was too small which affected the geometry?? will investigate adding material to the stops. still learning. My bike still has factory paint (and almost gone decals) so i am reluctant to weld metal to the stops. how else to accomplish that?

My plumstead book lists: front 3.00 x19 /rear 3.50x19 UK

                                        front 3.00x19/  rear 4.00x18  american

Publication P106/P Maintenance Manual and Instruction Book 

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I have learnt to cast a critical eye on ground levels when parking as pulling off the stand uphill  is a thankless task.  The prop stand is your friend  and getting your leg over  from the nearside is much easier . I have even considered  fitting a 2nd prop stand  to the offside .

 


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