Britbike forum

Classic British Spares Klempf British PartsBaxter Cycle BritBike Sponsor SteadfastCyclesSRM Engineering Lucas Classic Motorcycle Industrial tec supply Hepolite Pistons The Bonneville ShopLowbrow Customs

Upgrade your membership: Premium Membership
New Sponsor post
2022 Classic Triumph Motorcycle Calendars
by C.B.S - 09/28/21 6:22 pm
New FAQ post
How To: Add attached images in between text
by Morgan aka admin - 10/03/21 9:46 am
Manuals on DVD - Buy 4 for 3
All 4 DVD Manual
Member Spotlight
ricochetrider
ricochetrider
Pennsyltuckey
Posts: 11,542
Joined: May 2007
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
Rohan 82
Top Likes Received (30 Days)
koan58 20
Newest Members
Pratty, AndyW, ChrisTriumph3, GLENN'S PLACE, Smartfella
11,876 Registered Users
Who's Online Now
9 members (RPM, Blown Income, Chip H, Lannis, trig, rick e., The Bonneville Shop, gunner, L.A.B.), 22 guests, and 67 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Joined: Mar 2013
Posts: 392
Likes: 2
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Mar 2013
Posts: 392
Likes: 2
There isn't much happening on this forum, either the marque is very reliable or the owners know everything!
Here is a change of scenery, it is my 1962 AJS Model 31 CSR with optional Speed Kit.
[Linked Image from i.postimg.cc]

2 members like this: JagLite, Magnetoman
AJS & Matchless on eBay
Joined: Apr 2005
Posts: 2,094
Likes: 18
A
Britbike forum member
Offline
Britbike forum member
A
Joined: Apr 2005
Posts: 2,094
Likes: 18
Perhaps some info about a bike and how does it feel during riding, perhaps some comparison with A65 / T 120 / 650SS? smile

Joined: Mar 2012
Posts: 260
Likes: 6
F
Britbike forum member
Offline
Britbike forum member
F
Joined: Mar 2012
Posts: 260
Likes: 6
Rob, that is one nice looking ride! Very much the same as my 1959 AJS 31CSR. It is really a joy to ride, goes reasonably well, and wholly British. Mine leaks oil so bad I have had to park it. It is embarrassing, lots of small puddles that coalesce into one giant puddle if given enough time in one spot. It only leaks when running. Just sitting in the garage it is fine. I hope to find time to fix it soon. That is the main problem, trying to find time to work on the bikes along with the rest of life stuff.
I see you haven't solved what to do for an air filter either. There is precious little room to fabricate something behind the carb mouth, the oil tank/side covers, and the frame tube. Any ideas?
Mine has the narrow steel tank with bulbous sides, and decal emblems instead of the badges yours is sporting.
Thanks for sharing the photo. I enjoyed seeing it.
Fullminator

Joined: Mar 2013
Posts: 392
Likes: 2
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Mar 2013
Posts: 392
Likes: 2
I did fit air filters at one time, they were cylindrical foam 'socks', but I ditched them. The engine is standard bore and has original pistons but they had been machined for metric rings by a previous owner. I found that BMW circa 1960's fitted!
There were not many of this model made and as far as I can ascertain, this is the only one in South Africa. It still manages to do the magic ton and the feeling when riding is that it is very easy to change direction quickly.
Regarding oil leaks, have you done the modification to fit an o-ring between crankcase halves around the oil gallery? Originally there was a thin paper ring in this area.
My CSR wet sumps, but as long as I run the engine every 2 weeks it's ok. You could drain the oil if it stands for longer periods.

Rob C

Joined: Oct 2006
Posts: 4,234
Likes: 83
I
Britbike forum member
Offline
Britbike forum member
I
Joined: Oct 2006
Posts: 4,234
Likes: 83
Rob, what does the "optional speed kit" consist of?

High-performance factory parts always interests me.

Joined: Mar 2013
Posts: 392
Likes: 2
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Mar 2013
Posts: 392
Likes: 2
Here is the list of parts, the extra carb is the "chopped off float bowl" Monobloc. The bike also has alloy rims and siamese pipes (which I think were on the standard CSR). My friend had a standard 650 and there was a big performance difference. The pistons are claimed to be 10.5:1, but I calculated them to be 9.5:1.

Rob C

[Linked Image from i.postimg.cc]

Joined: Mar 2012
Posts: 260
Likes: 6
F
Britbike forum member
Offline
Britbike forum member
F
Joined: Mar 2012
Posts: 260
Likes: 6
Rob, I haven't had my engine apart, so I am unaware if it has the O-ring mod you speak of. I will be very interested in this mod when it comes time to fix my flood of oil. I found your speed kit list interesting. There isn't much here that would increase speed or performance, except maybe higher compression pistons. The list states that the pistons are standard. It also shows part numbers for the camshafts, but how they relate to standard camshafts is unknown . I don't have the standard part numbers of the top of my head. I suppose adding a second carb would add some high end performance. but it would make tuning more complex. I am reminded of something I read someplace by Hughie Hancox, a test rider for Triumph. He stated that a single carbed T110 TR6 Tiger could be just as fast as a dual carbed T120 Bonneville with careful tuning, and it would be less cumbersome. I suspect it would be the same with the 31CSR. I am having enough trouble finding space for one air filter, let alone two!
Fullminator.

Joined: Mar 2013
Posts: 392
Likes: 2
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Mar 2013
Posts: 392
Likes: 2
The STD in the piston description means standard bore (72 mm) and the camshafts are higher lift and longer duration. Another friend has a 650 BSA Thunderbolt and we have ridden together and swopped bikes - the CSR has a slight edge on his bike.
In 1958 the AJS was the first production bike to average 100 mph for one hour. In 1960 the AJS won the Thruxton 500 mile race at an average speed of, I think, 89 mph.
When/if the time comes to open your engine, give me a shout if you need any advice.
Cheers
Rob C

Last edited by robcurrie; 07/11/20 4:43 am.
Joined: May 2009
Posts: 387
P
Britbike forum member
Offline
Britbike forum member
P
Joined: May 2009
Posts: 387
Hi Fullminator. I do not own an AJS or Matchless but I’m an interested lurker. You mention that your bike leaks only when running and not when parked for a while. That suggests to me that you have a build-up of crankcase pressure which isn’t being released adequately. Have you checked your breather?
Kind regards,
Paul.


Paul

'74 Commando - Interstate
"74 Commando - Hi-Rider, possibly
'65 Atlas, mostly anyway
'15 R1200 GS Adv
'51 Vincent Rapide
'58 Ariel Square Four
Joined: Mar 2012
Posts: 260
Likes: 6
F
Britbike forum member
Offline
Britbike forum member
F
Joined: Mar 2012
Posts: 260
Likes: 6
Yes I suppose it could be breather trouble. At this point I am unsure of what type breather is used on the 31CSR. As I said, the bike has taken a place in line to be looked over, but it seems to take a while as life gets in the way of bike time. There is a long list of stories I could regale you with, but I will spare you.
Thanks very much for the offer Rob. When I am ready I will get with you with plenty of questions I'm sure. I have at least two bikes that are ahead of the 31CSR, and the one I'm working on now isn't going too well.
Fullminator

Joined: Mar 2012
Posts: 260
Likes: 6
F
Britbike forum member
Offline
Britbike forum member
F
Joined: Mar 2012
Posts: 260
Likes: 6
So, the bike I am currently working on is a 1948 AJS Model 18. It is in very rough condition. It will require a full restoration. A DPO fitted incorrect footpegs that had him bore out the engine plates and castings of the frame from the original square holes to an oversize round hole. I have sourced some square hole tubing that I will use to repair the frame. I need someone to look at their frame and tell me how the square hole is oriented in relation to the frame tubes. Anyone have an example they could look at and point me in the right direction?
Thanks.
Fullminator

Joined: Oct 2017
Posts: 510
Likes: 122
G
Britbike forum member
Offline
Britbike forum member
G
Joined: Oct 2017
Posts: 510
Likes: 122
Originally Posted by Fullminator
I need someone to look at their frame and tell me how the square hole is oriented in relation to the frame tubes. Anyone have an example they could look at and point me in the right direction?
Here is an engine plate. Ignore the square hole to the far bottom left which is an extra bit welded on to enable foot pegs to be mounted further back for competition use.

The frame holes are round on the '50's bikes and I would suspect they are too for 1948

[Linked Image from live.staticflickr.com]

John.

Joined: Mar 2012
Posts: 260
Likes: 6
F
Britbike forum member
Offline
Britbike forum member
F
Joined: Mar 2012
Posts: 260
Likes: 6
George, so it appears the square hole is square with the edges of the engine plate. Thanks very much for this it helps a great deal!
Also, you believe the hole through the casting brazed in the frame, that the square bolt for the footpegs goes through, is round not square? So the only square hole that this square bolt bears on is the two engine plates?
Fullminator

Joined: Aug 2001
Posts: 4,177
Likes: 52
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Aug 2001
Posts: 4,177
Likes: 52
Originally Posted by Fullminator
So the only square hole that this square bolt bears on is the two engine plates?
Fullminator

That is correct. I have both a 49 Model 18 and a spare 48 frame and plates, and they are thusly.

I reinforced the square hole in the engine plates with some weld, since they were drifting towards being less than square,
and the footpegs didn't seem too solidly anchored. If you overdo this, the lengths of the spacer(s) need to be adjusted.

Also, I don't know about the 48 model, but the 49 square footpeg bar only had a nut at one end.
This means if you have a fall and the bar gets distorted enough, it is near impossible to extract it from one direction only.
Ask me how I know this - The PO must have scrambled this or something similar ...

Joined: Jan 2014
Posts: 1,662
Likes: 186
N
Britbike forum member
Offline
Britbike forum member
N
Joined: Jan 2014
Posts: 1,662
Likes: 186
That is a very nice looking bike.
You don't see many around with the twin carb etc set up, even in the UK.
They could go better than a lot of people thought, glad your one still hits the ton.

1 member likes this: robcurrie
Joined: Mar 2012
Posts: 260
Likes: 6
F
Britbike forum member
Offline
Britbike forum member
F
Joined: Mar 2012
Posts: 260
Likes: 6
Looking back at this thread, I think I may have hijacked the originator, robcurrie, sorry Rob, I hope I haven't offended you. Your original post with picture of your fine AJS got me thinking of my own AJS bikes, one of which I am working on now, and these questions have come up.
Thanks to George Kaplan and Rohan, for your picture and experience. I think I know what my frame and engine plates now need.
Fullminator

1 member likes this: robcurrie
Joined: Oct 2006
Posts: 88
C
Britbike forum member
Offline
Britbike forum member
C
Joined: Oct 2006
Posts: 88
did they use Norton gear box on that bike ?

Joined: Mar 2013
Posts: 392
Likes: 2
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Mar 2013
Posts: 392
Likes: 2
The gearbox is AMC and is also used for Norton.

Rob C

Joined: Aug 2001
Posts: 4,177
Likes: 52
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Aug 2001
Posts: 4,177
Likes: 52
With the proviso that the AMC gearbox shells for AMC bikes have the mounting lugs for the gearbox
at different angles to the mounting lugs on Norton bikes.
Nortons have them at about top and bottom, for AMC use the top lug is much further forward.
This means that although the internals are about identical, the boxes themselves are not really interchangeable.
Unless you start modifying stuff, or they sit at funny angles, or impossibly close to the engine.

I didn't comment before this thread was derailled (!) about what a good looking bike your Model 31 CSR is.
In an era when it was all still AJS/Matchy.
Are there many of these about, I don't recall ever seeing one in the metal. ?

Someone here has/had a Model 33, I understood it was quite uncommon.
But quite a Norton component to it ...

Ha, Matchman62 is in the spotlight, I don't recall precisely what bike he has, but in his avatar it looks to be a Matchy
of a similar type/style (?), and presumably a 62 ...

Joined: Feb 2006
Posts: 1,098
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Feb 2006
Posts: 1,098
Originally Posted by robcurrie
There isn't much happening on this forum, either the marque is very reliable or the owners know everything!
I think more Matchless and AJS owners are active in the forum at https://www.jampot.com//

And make sure to check out their fantastic archives, I can spend an evening reading their old brochures, http://www.archives.jampot.dk/


1982 Suzuki GS650G
Joined: Nov 2006
Posts: 271
Likes: 5
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Nov 2006
Posts: 271
Likes: 5
My 1958 matchless csr had a bad oil leak. separating cases the thin paper gasket was absent. replaced thin paper gasket and no more oil leaks

Joined: Mar 2012
Posts: 260
Likes: 6
F
Britbike forum member
Offline
Britbike forum member
F
Joined: Mar 2012
Posts: 260
Likes: 6
Russ, perhaps you could expound on the "thin paper gasket" you speak of. Is this the same gasket between the crankcase halves around the oil gallery that was mentioned by Rob Currie earlier in this thread? He said a better mod was to replace the paper gasket with an o-ring. You said your bike doesn't have either! I would like to know as a teardown and rebuild of a 1959 model 31CSR is in my future.
Fullminator

Joined: Mar 2013
Posts: 392
Likes: 2
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Mar 2013
Posts: 392
Likes: 2
Fullminator,

The thin gasket ring is the original, the O-ring is a modification. The problem with the original gasket is that although it is very thin, it still does have thickness and this will cause a gap between the casing halves in this area which will eventually leak oil. There is no other gasket between the casing halves so a sealant like 3 Bond should be used. Note that the bolt above the oil filter gallery must have a fibre washer because that bolt hole is also an oil gallery.

Rob


Moderated by  Matchman62 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5