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testing , testing.

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testing , testing.

Posted by robert_tuck at August 12. 2017

We took the 99 and Atlas out yesterday for a run round kent lanes, both have had problems of late ,and at times it seems we make things worse by tinkering, we were switching bikes ,spark plugs and twidling carb screws. The Atlas feels ponderous in comparison to the 99 which turns in really fast,  the Atlas seems to understeer , differences are the 99 has taper roller head bearings and panniers which probably change the weight distribution, perhaps the 99 has steeper steering angle from shunts. The Atlas has straight bars the 99  has 2" risers.Be nice to get the Atlas to 99 handling. Atlas braking gone downhill since fitting new linings ,chinese rubbish we think. 99 gearchange now vastly improved after umpteen stripdowns but that kickstart still flips back on acceleration and neutral still hides away. Tank liner residue still finding its way onto the Atlas plugs,(never using liner again).99 clutch wonderfully light,Atlas dreadfully heavy. On the whole the 99 wins hands down, so the Atlas is in the Dog house. At our Pub stop some old boy was in tears of nostalgia at hearing and smelling the Nortons,made my day!.

Re: testing , testing.

Posted by john_hall1 at August 12. 2017

Hi,

Which Kent Lanes, i find Kent back roads and most main roads abysmal, the most downright dangerous I  have found was  last week  near Smarden!

I have a 650SS frame and cycle parts from a 99 and two engines a 1958 99 R14 and an early Atlas engine, without a cylinder head and needing a complete rebuild!

I hadn't quite made my mind up which engine to use but was tending to lean towards the 99 unit, but 31ish  b.h.p against 40/50 plus b.h.p puts a mild dilemma in there, from a usable performance point of view!

 

Figures can be misleading i know!  Is it that strange, that they feel so different though? I have had tyres transform a bike from okayish to almost superb, are the frames and components straight, swinging arms true, component wear comparable?

Perhaps the Atlas performs less well because it knows, it was the bigger more unloved version of the Dominator and that instead of quietly evolving slowly over time, it was a forced "breached birth", into the bigger CC game, with almost all other considerations being dismissed as secondary to a numbers formula!

 

Cheers

 

 

John

Re: testing , testing.

Posted by robert_tuck at August 12. 2017

Hi John, I have long considered fitting an Atlas or 650 motor to the 99 to get the benefit of later more reliable conrods etc, however it would have to be heavily modified  90degree crank etc . At present the 99 is a much better ride at speed and is always out in front . It does have lightened pistons which would probably help the Atlas together with a compression plate to soften the Comdon pistons fitted.The 99 was not troubled by the gravel/mud in Kent lanes but the Atlas felt unhappy.

Re: testing , testing.

Posted by anna jeannette Dixon at August 12. 2017

hello to the both of you  Since it's me that will be doing John's  rebuild  I have told him that the model 99 motor would be best in this import 650ss frame  since the engine  is set up like a model 99ss  with a twin carb adapter manifold  and with a right set of carburettor after its engine rebuild from me it will sing nice songs round the country lanes of Kent but we need some more cycle part to complete this machine and John need to decide what colour scheme he's going for  the 1960s two tone, or black and silver     the Atlas clutch cable should not be heavy so this means you need to investigate the cable should have a good run with no shape bends in it, so  this tank and seat off and see what wrong now good luck to both of you ,  yours anna j 

Re: testing , testing.

Posted by robert_tuck at August 12. 2017

HI Anna, I think the Atlas clutch issue is down to some pattern (everything now is pattern)  clutch springs that have been made too thick and out of the wrong steel (stiff but not springy) ,also it needs the box lever to be re-profiled and the lift adjusted and set using the same dial gauge system that I used on the 99.  I will probably get the alloy pressure plate modified to include a needle roller radial bearing I bought years ago .The gearbox /engine mounting plate will also get drilled or slotted (should have been done by Norton) to allow a straighter cable run to the box.

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