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G15 Questions

Re: G15 Questions

Postby Bernhard » Mon Sep 23, 2013 7:27 am

We have the usual supermarket of misinformation here. First of all the speedo tach bracket in the photo is one that was never, ever put on an Atlas or 650ss featherbed bike for sure. Also, the change in fork centers from 7" to 7 3/8" has absolutely nothing to do with the model of the bike, it was an across the board change for all Norton heavy twins after a certain serial number at the end of 1963 or the beginning of 1964. Atlas bikes first appeared in 1962 and they had the same 7" center forks as all other heavy Nortons![/quote]




Re; “Atlas bikes first appeared in 1962 and they had the same 7" center forks as all other heavy Nortons!”


Do you have proof of this information then- it is well know that the Atlas always had 7 3/8inch fork centres.

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Re: G15 Questions

Postby Rohan » Mon Sep 23, 2013 3:38 pm

I haven't followed this thread much recently.

But what does the parts books say about fork parts for various models.
It was certainly my understanding they all changed to the 7 & 3/8 centres together.

So it was a simple matter of before and after the change.
And trying to mix parts is trouble....

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Re: G15 Questions

Postby BillT » Mon Sep 23, 2013 4:25 pm

The instrument bracket in question is likely an aftermarket part. It is for a 7-3/8" top yoke, which is standard Norton from '63-on. I don't know if the '62 Atlas had 7-3/8" yokes, as I'm not too familiar with them.
I do know that AMC kept the 7" yokes on the bikes they sold with Teledraulic forks, which is what Paul Webb was referring to back when he offered advice on the bracket pictured.
The front hub on the P11 is called the interim hub, which uses a different bearing set-up than earlier hubs. It was introduced in the 1963 AMC model range, except for CSR models - those got the new hubs in '64. Perhaps - and this is just supposition - Norton did the same with their Roadholders? Could they have introduced the wider yokes on the Atlas, then made them standard the following year?

This G15 had been dressed up a bit by the original owner, according to the second owner. The fender that came with the bike is a late G15mkII piece, as was the chain guard. The front forks had the long chrome covers, replacing the headlight ears and gaitors, headlight was a 6" Bates item bolted to the lower yoke on a chrome U-bracket, bars were about a 12" rise, the instrument perch was the piece I posted back in April, and the dampers and instruments had that peel-and-stick chrome-look tape. Oh, and the tanks were painted a sort of latte brown.

Lucky for me, I got a box with the bike that contained some of the parts that had been taken off all those years ago, and the only piece I really had to hunt was the toolbox.
'73 Norton 850 Commando - 3030xx
'69 Norton Ranger 750 - P11/1289xx
'67 Matchless G15CS - G15CS/1235xx
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Re: G15 Questions

Postby beng » Tue Sep 24, 2013 5:11 am

Bernhard wrote:Do you have proof of this information then- it is well know that the Atlas always had 7 3/8inch fork centres.


Well stating "it is well known" sure doesn't count for Jack-Shit. NOR does it count for much that I have inspected a half-dozen 1962 Atlas bikes first-hand. But if you put first-hand inspection of actual bikes together with first-hand inspection of factory literature then you might have something.

In April 1962 Norton put out a four page supplement for the new Atlas laying out it's specification etc.. It specifically states:

" As far as the cycle parts of the machine are concerned - frame - fork - gearbox - etc., these are identical with the other 'featherbed' frame machines and therefore all instructions relating to these parts published in instruction manual P.106 apply equally to it"

The internet is the #1 worst place to get information on Norton motorcycles, this includes the NOC website and forum out of the U.K., as it is no better than those who put up information there, piss-poor.

No one that has any personal first-hand experience or information on early Norton Atlas motorcycles would ever think they had forks any different than any other 1962-63' Dominator.

I will dig around for my copy of the factory bulletin that states at which serial number wide forks were added to the range, meanwhile I have scans of my 1962 Atlas supplement here along with other good information to combat internet idiocy:

https://www.facebook.com/media/set/?set ... 123&type=3

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Re: G15 Questions

Postby Bernhard » Wed Sep 25, 2013 7:10 am

BillT wrote:I've seen those pics, Bernhard. Nothing I've seen so far matches what I've got.


Your original query was “did any G15s come with alloy instrument perches? Here's a pic of what I've got” and “I do know that AMC kept the 7" yokes on the bikes they sold with Teledraulic forks, which is what Paul Webb was referring to back when he offered advice on the bracket pictured.”
The Atlas 750 engine was first produced in the featherbed framed Atlas form in 1962.When Norton moved to Plumstead under the AMC banner the engine was later used in their Matchless and AJS variations.
AMC was renowned for its “badge engineering” motorcycles of all engine sizes. This mix and match approach came in various guises, depending on what was in stock in the parts bin and who they were trying to impress and sell bikes to in that particular year.
The only way that you can determine your particular model is to compare it with that year’s sales pictures from the original sales leaflets, or the pictures from the weekly 1960s Motor Cycle. The Earls Court show and editions containing the AMC spring announcements would be your best bet.
As they also used the AMC Teledraulic forks these came with 7 inch fork yolk centres.
The early Featherbed Atlas with Roadholder forks came with the speedo mounted in the headlamp and the rev counter was an optional extra and was mounted on a single instrument bracket. The twin instrument bracket was first produced by the aftermarket “café racer” suppliers. Norton f/bed ones were always painted black.
To beng, we might have crossed wires here, the "Atlas" model was 100% a Norton in slimeline frame, the fact that the same powerplant was used in at least 3 other differant models may lead to confusion; however, you may be right, if we are talking about the first year of the Norton Atlas, as none of these was sold in the UK in 1962/3 season, as these were for export only, as was the first 650ss, 88ss models. These models are rather thin on the ground in this country, unless one has been reimported and reregistered. My 1965 Atlas did come with 7 3/8 centres and the front wheel was not interchangeable with any other Norton with 7 inch centre yokes on any other featherbed model.
These wider roadholder fork yokes and Atlas engines were also used in the first drum braked Commandos.
Just to add even more confusion a few private owners have fitted a 750cc Atlas/ Commando to the wideline featherbed frames which Norton never produced :!:
Last edited by Bernhard on Thu Sep 26, 2013 5:50 am, edited 1 time in total.

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Re: G15 Questions

Postby grandpaul » Wed Sep 25, 2013 8:38 am

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Re: G15 Questions

Postby dave M » Thu Sep 26, 2013 12:32 am

Bill, I have just arrived in California for a couple of weeks and have been doing a bit of work on my own G15, could you kindly answer a couple of questions for me regarding engine mounting?

The engine plates from this bike have the various spacers welded to the plates, so it is self-evident where each one goes, however having mounted the rear plates onto the crankcases and fitted the gearbox in situ, I note that the gap between the rear engine plates is 3 5/8" whereas the distance between the forged frame mount is 3 1/2", the right side mounting plate has a couple of thin washers welded to the inside of the plates, but are there 2 loose spacers that go in the gap on the left and how thick are they?

Regarding the front mounts, there is a hollow spacer that goes between the front engine mounts at the top where it goes into the frame lugs, is there an identical spacer for the bottom mounting?

Many thanks

Dave

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Re: G15 Questions

Postby BillT » Thu Sep 26, 2013 5:16 pm

dave M wrote:Bill, I have just arrived in California for a couple of weeks and have been doing a bit of work on my own G15, could you kindly answer a couple of questions for me regarding engine mounting?

The engine plates from this bike have the various spacers welded to the plates, so it is self-evident where each one goes, however having mounted the rear plates onto the crankcases and fitted the gearbox in situ, I note that the gap between the rear engine plates is 3 5/8" whereas the distance between the forged frame mount is 3 1/2", the right side mounting plate has a couple of thin washers welded to the inside of the plates, but are there 2 loose spacers that go in the gap on the left and how thick are they?

Regarding the front mounts, there is a hollow spacer that goes between the front engine mounts at the top where it goes into the frame lugs, is there an identical spacer for the bottom mounting?

Many thanks

Dave


Hi Dave,

I got my bike in pieces, so much of the way I assembled it was through trial-and-error. The rear engine plates on mine have washers about 1/8" thick welded on the right (timing) side, and the gap between the plates away from these welded washers is 3-5/8. The frame mount is 3-1/2", the same as the top mount on the transmission. On mine, I had a 1/8" spacer for the transmission which I fit between the mount and the plate on the right side (As I recall, no spacer was needed for the bottom tranny mount). There's a sort of J-shaped bracket that holds the front of the rear fender. I found it works best if held in place by one of the studs going through the frame into the rear plates. One of my studs was 1/8" longer than the other, I assume specifically for this purpose.

On the front mount, there is a middle spacer on both the top and bottom stud.

The center stand also has spacers - one in the center, through the coils of the spring, and one on the right, about 1/8". One end of the spring hooks around the cross-brace of the stand, and the other hooks into a hole in the right engine plate. There's a retention clip for the stand that screws to the base of the frame vertical section with two small screws, I think 2BA

For the long, square stud that runs through the frame, engine plates and footrests, there are 3 spacers. The center one is about 3-5/8, the left (primary) side is about 1/4" and the right side is about 3/8".

You need the footrests in place before you can mount the primary, and to install the outer primary, you have to drop the brake pedal as low as it will go, and slide the stator over the rotor with the primary cover almost vertical, then rotate down to horizontal as you slide it in around the footrest perch.
'73 Norton 850 Commando - 3030xx
'69 Norton Ranger 750 - P11/1289xx
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Re: G15 Questions

Postby dave M » Thu Sep 26, 2013 10:35 pm

Thank you very much Bill, your measurements and spacers match what I have including gearbox mounting with top I/8th washer, I got mine as a rolling basket case with the engine and gearbox in the frame but not mounted.

Am I correct in assuming that the difference between the width of the rear frame mounting point and the gap between the plates from the thin washer, ie 3 5/8" minus 3 1/2 making 1/8th, needs two 1/8 loose spacers on the left engine plate? If this is the case I am surprised that they are not welded in place as the others are.

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Re: G15 Questions

Postby BillT » Fri Sep 27, 2013 5:47 pm

dave M wrote:Thank you very much Bill, your measurements and spacers match what I have including gearbox mounting with top I/8th washer, I got mine as a rolling basket case with the engine and gearbox in the frame but not mounted.

Am I correct in assuming that the difference between the width of the rear frame mounting point and the gap between the plates from the thin washer, ie 3 5/8" minus 3 1/2 making 1/8th, needs two 1/8 loose spacers on the left engine plate? If this is the case I am surprised that they are not welded in place as the others are.


Dave, I didn't have to add any washers between the engine plates, crank case and frame. The necessary spacers were pre-welded to the plates. This is the one instance where the G15 is easier than the P11. The only spacers needed were the 3 long sleeves (2 on the front mount between the plates at the top and bottom mounts, one on the stud running through the foot pegs) and three spacers (one on the right side of the upper transmission bolt and two on the footpeg stud between the rear engine plate and the frame, thinner on left and thicker on right). The only spacers I didn't have in the bits were the two outer ones for the long, square stud that runs through the pags.
This is how I got mine, so my assembly was very much a trial-and error fitment.
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Re: G15 Questions

Postby dave M » Fri Sep 27, 2013 10:38 pm

Sorry Bill, I'm not quite visualising this, Does your primary side engine plate also have spacers welded to the top two mounts where the plate buts up against the frame mount and if so how thick are they. As I said in my previous post, my Timing side rear plate has two 1/8" washers welded to the inside of the plate, but the primary side plate has no washers welded at the top although there are three thick spacers welded to the inside of the plate where it bolts to the crankcase. My problem is that I have a gap because of the difference in thickness between the frame top mounting position and the rear engine plates including the timing side washers. It looks like you measured this same gap in your earlier post ie, 3 1/2" frame lug versus 3 5/8" gap between the two plates including the washers. My assumption is that the assembly either has to but up against the frame lug on the right or left and would need a couple of additional washers of approximately 1/8" on the opposite to whichever side is butted up to the frame. Thanks very much for your patience, I am only here for a short while and if I can solve this problem I am a lot further forward than I was last week.

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Re: G15 Questions

Postby BillT » Sat Sep 28, 2013 6:44 am

Dave, the way I see it, the rear of the crankcase where the plates mount is about 3-1/2" wide, as is the top mount on the transmission and the frame lug. The primary side plate has spacers welded to the front holes to shift the engine toward the timing side. The timing side plate has the same thickness spacer welded to the rear holes to match up with the front. Then, you've got the steel spacer between the crank case and the primary to bring it back in line with the transmission. The trans is shimmed tight to the primary side.

The 3-5/8 I measured the other day is between the plates, not between the spacers.

This frame was designed for this transmission, so no shimming of the trans should be needed on the primary side. The engine, on the other hand, was not designed to fit in this frame, and for whatever reason, the engine plates were shimmed to shift the motor a bit to the timing side. Are you sure the plates are flat, and you've got the front plates on the right way? I think the front plates only go on one way, but I kept careful note of which was which anyway. The frame lugs on the front could also have been modified to work better with the Norton motor - I know that was done on the P11 - so I don't think you can draw any conclusions as to spacer location on the front.
'73 Norton 850 Commando - 3030xx
'69 Norton Ranger 750 - P11/1289xx
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Re: G15 Questions

Postby dave M » Sat Sep 28, 2013 5:39 pm

Bill, I would agree with you except the rear engine plates I have consist of a left (primary side) plate with three approx 5/16" washers welded to the bottom where it mounts to the crankcase and none on top where it mounts to the frame and a right (timing side) plate with no washers where it mounts to the crankcase but a single 1/8 washer for the bottom gearbox mount and two 1/8" washers at the top where it mounts to the frame. The gearbox adjuster has a loose 1/8" washer to allow for adjustment.

The front and rear of the crankcase mounting lugs are 3 5/16" and the gearbox is about 3 1/2" wide, with these plates the gearbox fits perfectly when the plates are bolted to the crankcase, but there is still about a 1/8" discrepancy between the width of my plates and the frame engine mount. I have another set of engine plates that I bought on E-bay and they are identical and I have been up to Rabers Parts Mart in San Jose this morning and they have a pair which are also identical to what I have. You don't by any chance have an extra mudguard bracket holder or something at the frame lug thus widening it by 1/8" do you?

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Re: G15 Questions

Postby BillT » Sat Sep 28, 2013 6:14 pm

Dave, I'm sorry I didn't measure everything before I re-assembled. As I stated before, the engine, trans and primary were still all bolted together and with the engine plates on when I got the bike. The head and cylinder were removed to facilitate getting the entire lower assembly out of the frame. I found out during the strip-down that this was probably done because the previous owner couldn't get the primary open (primary had half-filled with water at some point and corrosion fused the screws until the water ate through the case at some point, allowing it to empty).

Yes, my rear plate on the timing side also has the welded spacer at the bottom trans mount. The one bracket that holds the lower front of the rear mudguard is fixed on the outside of the rear plate with one of the studs the goes through the frame lug. Do you have the engine plate cover (030328), that snaps over the top of the rear engine plates? it has a pair of dimples that lock into the little hole on each plate above the upper trans bolt. This piece is a tight fit, and will tell you if you're missing a shim somewhere.

Mine this evening - too late to start it up, but will be running tomorrow if everything's right or close to it
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Re: G15 Questions

Postby dave M » Sat Sep 28, 2013 11:40 pm

Bill, the problem is solved, the right hand plate had a slight set in it, I removed it and checked it on a flat surface and noted it bent outwards slightly towards the rear mount, having straightened it and bolted it all back together tightly I now have the requisite gap for a perfect fit to the rear of the frame, many thanks for your patience and answering all of my questions. I have already made good progress on this trip and have dropped my cylinder head off at Rabers today for some fins to be welded back on and new valve guides. Thanks again,
Dave

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