[AgentX]

Been working on this G15-CS over the past few years...finally fairly road-ready...shortest story is I got it from the original owner in a kind gesture.  Ran when parked after a minor refresh in the 90s.  Mag wasn't sparking, clutch had some issues, and a few other things stood in my way when I got it into my hands.






Significant work done so far:

-Got the mag refreshed with an Easycap
-Got the ceriani rear shocks rebuilt
-Got the Monoblocs sleeved and rebuilt them
-Reversed the shift pattern to match my 1-down-on-the-right Enfield
-Installed a Bob Newby belt drive and clutch (with some modification to the primary to allow better mag access), which was easy except for needing a spacer for the outer primary cover
-Rebuilt the fork with Lansdowne cartridge dampers, fresh stanchions, and JSM turcite bushings
-Swapped the timing cover for one with the tach drive oriented vertically; previous owner had swapped for one with the high-pressure feed to the head, but the tach drive cable was pointing right at the pipes and running hard over them
-Got the tach unfrozen and rebuilt the drive unit using epoxy over the covers which previously liked to expel gears at high RPMs.  Also frankensteined together a working speedo drive.
-Swapped out the stock air filter cage for some Unis

Just re-timed it to 28 degrees (vice stock 32) because I confirmed it had high-compression pistons.  Much snortier now.  The mag is cool, but was a real pain to access for adjustment; less so now with my dry primary into which I cut an access port to the front of the mag.  Less need to remove either the inner primary or the mag from the bike for most work.  Alas, still need to open the timing cover to re-set the ATU on the taper if you have to do any real timing adjust.

Trying to keep the bike as rideable as possible without messing up its classic-ness.  Love the way it feels on the road...heavy center of gravity down low almost feels nimbler than my Enfield.  Little gutsier than my Fireball, especially with a passenger, but the little Enfield would give it a run for its money.  Brakes lead something to be desired and I might convince myself to put a TLS plate up front.

(little more of a write-up of the work here: https://www.dotheton.com/index.php?t...-g15-cs.77009/ )

[Adrian II]

A serious-looking bike from the days of AMC Matchless/Norton factory bitsas, extra bonus points for keeping the magneto! 

Just needs a pair of these to finish it off.

A.

[AgentX]

I have those.  I hate them so very, very much.  Fitting them is a royal pain in the ass, especially with the longer metal shrouds on the forks vice the stock short ones for rubber boots.

Put on the ceriani repops to save my sanity as I had to take it apart and reassemble so many times in rebuilding the fork to its current state.

Might put the stock ears back on next time it's apart, though I do think this looks more "desert sled," in the spirit of the bike's original intent.

I'd kind of like to go back to the stock rubber boots, too.  Previous owner was tired of them rotting and changed over to the metal shrouds.

[Bilgemaster]

Sweet. I've still got my old Norton-badged N15CS $100 "daily driver of yore" in the shed to attend to. It's the ratty old "bitsa of bitsas" what with its shocks from some old Honda abandoned by a Texan creek bed, oil feed and return system looted from an ancient Lady Kenmore washing machine, and other broke-ass "enhancements" like handlebars that resemble some '70s IUD birth control device.

Where are you getting your parts nowadays? I used to rely on Domiracer, but they lamentably went belly-up years ago. Now and then I've been pouncing haphazardly on the odd eBay bit to squirrel away for "later", but I'm sure I'll be needing a more reliable source than that. If you've got some old no longer needed downpipes, especially a right-hand one, shoot me a PM. In fact, whatever bits you pulled off and have sitting in a box in the rafters are likely better than what may be on mine.

Seriously though, those are sweet beefy rides, ain't they?

[AgentX]

WOW.  We must know more.  Make it work again!

I have been scavenging from many different sources.  The best source for Norton hybrid bikes like the G15/N15 and P11 is Walridge Cycle in Canada... Mike there is somewhat of an authority on these, and would also be interested to hear from you about the provenance of your ride.

RGM and Andover Norton have selections of Atlas parts, as does Norvil. Britcycle.com, Baxter Cycle, oldbritts.com, and Classicbritishspares.com are all useful as well.

Unfortunately, most of the spare bits that I got along with mine are many, many states away and I don't have much access, especially with an international move imminent (and all to be disrupted by the .  I think there was a set of headers that looked a little like rumpled tin foil...I think I recall seeing appropriate pipes for relatively little money.

[Richard230]

Here is a 1961 road test of a CSR.   

[Adrian II]

That one still has the Matchless engine and forks rather than the Norton parts used on AgentX's bike. Anyone got a Norton P11A?

A.

[AgentX]

Lots of P11 owners (of various models/years) over on Access Norton...


I will say that when I first started doing work on the Fireball, I bought a number of classic bike magazines and saw a photo of a guy standing between a P11 and a G15-CS, having NO idea what they were. 

But I fell in love with them immediately from that one photo.  Probably more the P11 than the G15.  When one of these got thrust into my lap, it was almost eerie.  I will say I still love the look of the more angular P11 frame/oil tank and the high pipes...but in the end, the low pipe G15 is much better due to the passenger capacity, and I've come to enjoy the look just as much or more than the higher setup.  My favorite pillion agrees:




And yes, the P11 has those Matchless fork internals (despite being entirely Norton-badged, which I always found interesting.)  The Lansdowne setup, however, has been spectacular in my test rides round town.  Hoping to put it to the test on some rougher roads some day:



The manufacturer had to make some longer damper bodies for me, and I had some minor fit issues with my repop stanchions (partially cured by going to the $$$ turcite bushing setup, as I think the wear pattern on my sliders was part of the issue), but it was  *well* worth the effort.  Forks had a top-out issue that I couldn't solve by traditional means (masking holes in the stanchion etc) without shortening the extended travel of the G15-CS fork.

[Richard230]

Well gee, you guys are finicky.  OK, here is a road test of a Matchless G-15 CSR with a Norton 750 Atlas engine.  You ask and you shall receive.

[Bilgemaster]

Yep! That's the ticket!

[AgentX]

My tach drive won't stop exploding despite various methods of holding the covers in place.  (Nickels as thick cover plugs, epoxy poured in, etc.)  Also tried spacing out the drive from the camshaft nut that turns it, in case there was overmuch interference between the two...I even shaved a MM off the drive spade on the 'box to ensure it was running clear.

Trying it one more time with very minimal grease inside, because I suspect I over-packed earlier iterations and created too much pressure in there.  Otherwise, it's time to order a repop from Speedograph because I'm stumped.

[AgentX]

Well, tach rebuild finally worked...discovered the drive spade was bent, probably from the original tach's orientation that stressed the cable.  Used thinner grease more sparingly.

Swapped an Emgo ring gear into the original Smiths speedo drive, too.

Swapped handlebars for one with less back-sweep, installed new repop Amal style brake and clutch levers because the originals flexed visibly and alarmingly in use.

Carbs seem to finally be balanced and it idles strong.  Brake cable adjusted to a better length...the performance difference was palpable on a ride today, both going and slowing.

Only thing is a nagging throttle issue I can't nail down.  Lubed cables.  Slides snap back perfectly and strong, every time, with the engine off.  But the slides will stick when it's running...playing with the cable can make them get better, or even worse.  I've had to kill the engine when it's run away too far.  Cable routing seems fine.  Maybe it's the cable ties (old rubber style) having migrated somewhere they shouldn't be while I was messing with things.  I'll check tomorrow and hopefully get a long test ride in.

[gizzo]

Only thing is a nagging throttle issue I can't nail down.  Lubed cables.  Slides snap back perfectly and strong, every time, with the engine off.  But the slides will stick when it's running...playing with the cable can make them get better, or even worse.  I've had to kill the engine when it's run away too far.  Cable routing seems fine.  Maybe it's the cable ties (old rubber style) having migrated somewhere they shouldn't be while I was messing with things.  I'll check tomorrow and hopefully get a long test ride in.

Is it possible that the slides are worn out, causing them to not fit the bore properly, engine vacuum holding them against the bore so they can't drop completely? IDK much about Amals but they are famous for wearing out. My old Ducati did the same thing years ago. The slides on the Dellortos were worn on the vacuum side. Swapped them out for a good S/H set and problem solved.

Beautiful bike!

[ace.cafe]

Amals also are famous for distorted bodies which can cause binding slides.
And as Gizzo said, worn slides.

Amal Premier are supposed to not wear out so fast, but you still have to watch that you don't overtighten the flange nuts when you put them on the head. They distort the carb bodies very easily.

[AgentX]

Hi, Ace/Gizzo...these are the original monoblocs, re-sleeved when I got the bike with almost no miles on them.  They were an amazing combo of rattly and sticky when I got them,but the resleeve made them slide perfectly.  I've also ensured flatness in the flanges and spacers.

I have considered going to a manifold and single TM34, but that's a project for another time.  Mid-range and throttle response are what are important me on this bike, though, and that could help while simplifying things.  Then again, I do like the originality of the amals.

The Amal slides move perfectly in the bores when manipulated by hand or cable right now, as mounted, so there's no distortion causing an issue either.  I think I had a eureka moment last night, though.  The problem may be in how the cables, the splitters in particular, are riding under the frame tube and tank.  I think they were secured to the tube and now are not.  This might account for everything.

Ed: After securing them more tightly, I really do think I got it knocked, but need to wait till open-pipe hours in my neighborhood before giving it a try.