Can't keep the oil in

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
Deceased
User avatar
Posts: 3924
Joined: Thu Jan 01, 1998 12:00 am
Location: KENT UK

Can't keep the oil in

Postby Biscuit » Thu Aug 28, 2008 9:36 pm

I haven't studied this area in depth, but on the lightweight I worked on, ( yes only one!!!!!!) there seemed no way out for the oil that accumulated in the timing chest, apart from through the timing side shaft, could it be your suffering from oil build up here?




User avatar
Posts: 47
Joined: Wed Aug 17, 2005 12:00 am
Location: SURREY UK

Can't keep the oil in

Postby model26 » Thu Aug 28, 2008 9:56 pm

Hi Locust,
I think it would be worth measuring the bore/piston, as I note you have changed the barrel and kept the piston. For a precise fit, the correct method is to re-bore to match the piston.

The other area is to check that the valve guides are not excessively worn.

User avatar
Posts: 1645
Joined: Wed Oct 12, 2005 9:45 pm
Location: SOUTH AUSTRALIA AUSTRALIA

Can't keep the oil in

Postby paul knapp » Fri Aug 29, 2008 2:39 am

Why was the cylinder re-bored and fitted with a new piston in the first place?
Was it because the engine was smoking back then, before the re-bore?
Perhaps the problem goes way back!
___ďAs a hobby for the technically minded, motorcycling provides great scope.Ē

J.B.Nicholson

Don't worry about the world coming to an end today. It's already tomorrow in Australia!


_____________________________________________




Posts: 98
Joined: Fri Jan 16, 2004 12:00 am
Location: KENT UK

Can't keep the oil in

Postby Locust » Fri Aug 29, 2008 8:22 am

Hi everyone

This bike has had a total restoration, the engine was rebuilt with new bearings and crank etc, yes the bore was not bored to the piston (the proper way) so is looking like a possible cause.
Today ( Friday ) a nice member has offered me a barrel and piston to try, so it will be comming apart again.
As a matter of interest anyone who has the Real Classic look at page 15 Smokin' Bullet, this is something else.
Will let youall know how it goes soon.
Haven't had any offers for the bike yet.????


Locust

Posts: 98
Joined: Fri Jan 16, 2004 12:00 am
Location: KENT UK

Can't keep the oil in

Postby Locust » Sun Aug 31, 2008 3:28 pm

How about this.

I have taken the head off, there is a nice shiny piston but in the valve cutouts is nice clean oil.
That is wrong it should be dry, yes???
So before I take the barrel off, I have looked at the cylinder head.

I have taken the valves out and the exhaust is caked in carbon, again wrong.

My cylinder head is the later type with no oil adgustable feed screw in the side, the oil comes up the cylinder into the rockers then out into the valve gear.

I have renewed the guides and valves but I have noticed that the oil lubricates the guide down a groove in the guide, which is about a 3/32" hole in other words there is too much oil going down the guide. Have I found the answer.?????

If that is the answer the only thing I think I can do is take the guides out and turn them round so that the oil groove is not at the top.

How much oil should the guides need.?????

Your thoughts on this please gentlemen.


Locust

User avatar
Posts: 288
Joined: Mon Jan 01, 1996 12:00 am
Location: OSTERGOTLAND SWEDEN

Can't keep the oil in

Postby chris kelly » Sun Aug 31, 2008 4:57 pm



Hi Graham,
My engine, 250. was 1966. It had an adjustable pointed screw in the cylinder head.

I think I remember someone on this Forum writing that the Factory forgot them on some cylinders ( )

Anyway, the Instruction Book states, '' Adjustment of Oil Feed . The internal flow of oil is controlled by fixed restrictions, with the exception of the oil feed to the Inlet valve guide, which is regulated by a needle pointed screw located in the cylinder head, etc , etc

The final sentence states, ''An excess of oil to the inlet valve guide will cause a smokey exhaust and heavy oil consumption ''

Under ''Excessive Oil Consumption '' the Handbook also states, ''maybe due to Badly worn , or stuck up , piston rings (Causing high pressure in the crankcase ) or

Worn valve stems ''

One more thing, for information, the oil filter should have the felt inside the cylinder body ( discussed on this forum ). At one time I received filters from the club like this...but I believe the club has put this right now. Doubt that this would contribute to your problem though.

'The oil pump forces oil through...A, B , C If you want me to quote this from the Handbook then tell me.

Best wishes,
Chris.
'My cat can beat up your cat!'

Posts: 7725
Joined: Tue Nov 22, 2005 6:01 pm
Location: UK

Can't keep the oil in

Postby itma » Sun Aug 31, 2008 4:58 pm

Taking my usual glum cynical and miserable view, but drawing on past experience, I would say that your problem starts and ends with the words...

" total restoration."

sorry.

Posts: 98
Joined: Fri Jan 16, 2004 12:00 am
Location: KENT UK

Can't keep the oil in

Postby Locust » Sun Aug 31, 2008 7:11 pm

Itma can you elaborate, are you with me or against.???

Is the head I am useing no good, do I need the adjustable feed to the head.???

Chris
Are you refering to the Workshop Instrution Manual All Models 1957-1964 if so can you give me page numbers please

Locust

Posts: 7725
Joined: Tue Nov 22, 2005 6:01 pm
Location: UK

Can't keep the oil in

Postby itma » Sun Aug 31, 2008 8:19 pm

Its hard to say anything about the head over the ether.
All AMC singles have this feed, it is trouble free in my experience.
My point is, as always that is the standard of assembly that matters, I have lost count of the bikes I have seen ruined by "restoration"
If it were my bike it would all be in bits by now being double-checked.

User avatar
Posts: 3686
Joined: Mon Jan 01, 2001 12:00 am
Location: BLACKPOOL UK

Can't keep the oil in

Postby Merlin » Sun Aug 31, 2008 8:34 pm

My point is, as always that is the standard of assembly that matters, I have lost count of the bikes I have seen ruined by "restoration"
Quite correct itma I was indeed fortunate to buy a restored machine from a club member before I had any knowledge of you lot,what a treat it has turned out to be both the bike and you lot.
Cheers
Merlin.
ps keep cheerful.
Chemists do it with test tubes

PreviousNext

Return to G2 / Model 14

Who is online

Users browsing this forum: No registered users and 2 guests