1958 Matchless G3

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Re: 1958 Matchless G3

Postby clive » Fri Mar 15, 2019 7:58 am

John looking at your photos again are you sure you have the correct Spring? The twin ones were a different size to the single ones I think. The centre of the bought cap does not look a very good fit for the spring. Does the spring fit neatly on the recessed part of the splined cam?
clive
if it ain't broke don't fix

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Re: 1958 Matchless G3

Postby George Kaplan » Fri Mar 15, 2019 7:35 pm

Hi Clive, I purchased (or at least I thought I did) a 500cc spec spring, part number 000703. The ID of the spring is about 1.550", the OD of the spring seating on the splined cam is 1.460" and the OD of the part of the cap that fits inside the spring is 1.395".

The cap is a very loose fit inside the spring.

The OD of the spring is 2.050" and the OD of the flange on the cap from AMOC is 1.770"

I am pretty sure the spring is the right diameter because I have a broken spring that came with my other 350 bottom end and it is the same OD as this replacement spring. My guess is that the pattern cap is a bit on the small side on its diameters.

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Re: 1958 Matchless G3

Postby George Kaplan » Sat Mar 16, 2019 8:58 pm

I managed a bit more progress today after taking care of some other stuff this morning.

I made another cap, this time with correct dimensions. I left the base of the replacement 0.140" thick, the base of the pattern one is 0.090" so I need to take another 0.50" off to get the nut fully on.


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I swapped the cams around to enable me to fit the front facing timing case. I need to check if the cams are the same or not. I have a press so could swap the shafts over if need be. I think I have seen something on here about it so will look into it.

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I put the mag platform into place to see how the SR1 lined up and it seems that the platform that I have is not correct. I think I will just make one. I had a look at the metal I have in stock and everything I have is either too thick or too thin so I will pick some up next week of the right thickness.

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Then I offered the exhaust up to the head. The head has a layer of what looks like silicone sealer inside where the exhaust fits. Is that what folks usually do to seal it? Again I am sure I have seen something on here so I need to have a look around.

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I also had a think about cleaning out the tanks. What I usually do is put some old ball bearings and nuts in side along with some paraffin and then wrap them on cardboard and wedge them in my cement mixer and leave it spinning for an hour or two. However I have lent the mixer to my Nephew and it is currently 100 miles away so I need to do something else. This is what I decided on for the oil tank, the mill has a vfd so I can get it to run as slow as I need it to. I still need to work out what to do with the petrol tank.

Image

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Re: 1958 Matchless G3

Postby George Kaplan » Sun Mar 17, 2019 8:05 pm

Today I had another look at the nut on the shock cap and noted an un-threaded portion at the inboard end. It was a simple matter to reduce it a bit to get it on the last couple of threads.

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I cleaned the oil tank inside and out. Once the crud was off I noted that the back had been epoxied up in the past. I will leave it for now but will deal with it properly at a later date. Inside the tank is pretty good.

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I had a look at the fuel tank and it looks a bit scabby but seems sound. The threads on the mounts dont seem right. It came with one BSF bolt which I am not certain is right as it only screws into one mounting. I will order a set of bolts and run a tap with the right thread through.

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Re: 1958 Matchless G3

Postby 56G80S » Sun Mar 17, 2019 8:55 pm

HI

In a rush so two things - the SR1 platform looks correct to me. There are slots for the mounting bolts the fit up into the mag and you could always lengthen these slots a bit if necessary. Do you have the spacers that help locate the platform? Pop the A/R unit and sprocket assembly on and see what the chain run looks like. There is a rubber ring that goes between the rear of the mag chaincase and the mag itself and that's not always a consistent gap; I had to cut down the new one I got from AMOC spares in order not to deform the rear of the chaincase.

When I fitted a new chain I also had to cut the barrel to allow adequate adjustment of the mag to provide necessary chain whip; do not make this too tight it will wreck the mag bearings. My 500 barral turned out to be the wrong year (although it was on when I bought the Matchless in the mid 1970's) and did not have relieved fins to move the mag rearwards - this may not be a problem on a 350 and others will advise on that.

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Re: 1958 Matchless G3

Postby George Kaplan » Sun Mar 17, 2019 10:00 pm

56G80S wrote: There are slots for the mounting bolts the fit up into the mag and you could always lengthen these slots a bit if necessary.

I did think of that. The magneto needs to move roughly 0.800" and here is what I have to work with.

Image.

56G80S wrote: My 500 barral turned out to be the wrong year (although it was on when I bought the Matchless in the mid 1970's) and did not have relieved fins to move the mag rearwards - this may not be a problem on a 350 and others will advise on that.


Thanks for the tip. The mag is very close to the fins and I am using a 500 top end. I may need to adjust my fins too.

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Re: 1958 Matchless G3

Postby Duncan » Sun Mar 17, 2019 10:30 pm

Hi John
I put the mag platform into place to see how the SR1 lined up and it seems that the platform that I have is not correct.

The forward mounting platforms did not change from N1 to SR1, it could be the mounting points on the magneto that differ.

The mounting bolts (or set screws) have a reduced thickness head and are fitted without a washer, if you use a usual thickness or washer the platform will not have enough movement and the chain may run tight.

The head has a layer of what looks like silicone sealer inside where the exhaust fits. Is that what folks usually do to seal it?

I use silcone every time to seal the exhaust to the head and to fit the silencer its good at stopping air leaks and backfiring, I use cheap clear stuff and have never had a problem with it burning, its relativly easy to remove as well when you need to remake a joint. Others may have a different experience but it works for me.


Are you using dynamo sprockets on the engine?

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Re: 1958 Matchless G3

Postby George Kaplan » Sun Mar 17, 2019 10:42 pm

Duncan wrote:The forward mounting platforms did not change from N1 to SR1, it could be the mounting points on the magneto that differ.

I have an N1 and thought it was the same mountings. I have my PJ's on now but will check it all again tomorrow evening to be 100% certain.
Duncan wrote:I use cheap clear stuff and have never had a problem with it burning,

Since posting I have also heard the same from elsewhere about the cheap stuff. I will try that first.
Duncan wrote:Are you using dynamo sprockets on the engine?

Yes.

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Re: 1958 Matchless G3

Postby Mick D » Mon Mar 18, 2019 7:54 am

Hi

Not sure if this is a year specific change, but I don't have that, 'mounting point?', where the epoxy repair is. If it's an 'addition' it may be the reason for the damage in the first place.

Regards Mick

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Re: 1958 Matchless G3

Postby George Kaplan » Mon Mar 18, 2019 8:12 pm

Mick D wrote:Hi

Not sure if this is a year specific change, but I don't have that, 'mounting point?', where the epoxy repair is. If it's an 'addition' it may be the reason for the damage in the first place.

Regards Mick

I was wondering what it bolts to because its not apparent, maybe it is a modification?

Next, its official. I am an idiot!

When I got the mag platform I bolted the SR1 to it to see if the holes lined up OK (incidentally they are about 30 to 40 thou too wide apart) and I left it bolted on by two bolts. In between then and now I had forgotten that there were two sets of holes. Doh!

Here is the SR1 on the right compared to an N1.

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Also the N1 mounting holes are an exact match for the mag platform so the SR1 (or at least the one I have) has slightly different hole spacing.

Using the other set of holes the mag is close enough to fit using this platform although the slots needed lengthening by approximately 0.250"

Image

Image

Now that I have fitted it in the right position it looks a bit low. Thats obviously not such an issue.

Image

Image


56G80S wrote:There is a rubber ring that goes between the rear of the mag chaincase and the mag itself and that's not always a consistent gap; I had to cut down the new one I got from AMOC spares in order not to deform the rear of the chaincase.


I have looked in the parts list for this rubber ring or seal but cant find it, any idea what its called in the book or the part number?

John

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