What year/model? What am I missing?

marshg246 said:
#1: OK, that's original. The oil tank picture is a little hard to tell - does the breather connect to the side of the froth tower (the part sticking up) or to a hose connection in the top of the tank. If the top of the tank, then no problem. If the froth tower, then you can't install a reed valve without adding a connection to the top of the tank.

#2: When installing a reed valve, the current breather hose connection to the front of the engine is eliminated.

#3 When you rebuild the engine, you should leave out the timed breather parts. Parts 84, and 85 here: https://andover-norton.co.uk/en/shop-drawing/451/engine and make sure 83 can't come out.

#4: If I were rebuilding that bike, I would install the crankcase breather from JS Motorsport which includes eliminating the original breather. And I would either find a oil tank with the two hose connections to the top or add one for the breather to the top of the oil tank.
Click to expand...

#1: Correct, but his last set of pictures clearly show he has the later model central oil tank with the port NOT in the froth tower, so he's good to vent a reed valve in that port

#2: I didn't eliminate that camshaft breather port because the early bike frames can't use crankcase sump breathers because the lower frame rail of the early frames block the use of the sump breather mechanisms.... (If Jim Schmidt's sump breather fits by the frame rail, that would be a new development that I wasn't aware of, but the Comstock designed sump breather does not fit past the frame rail) I use a camshaft port breather that uses the early model camshaft breather port, so it's not eliminated in my case. I have yet to hear of anyone with an early frame bike using a sump plug breather... Have you?

#3: If you are going to rebuild the engine, you should leave those parts out... because you can plug the threaded port from the outside if you can figure out a different kind of reed breather application or actually use that threaded port to mount Jim Schmidt's camshaft port breather... (like I have done)

4: Do you know for certain that Jim's sump breather fits past the early bike frame crossmember?? His oil tank is fine as it is. I have no idea why you think he , or anyone else needs 2 hose ports on top of the oil tank... I have one port in a central oil tank just like his and I have 2 reed breathers on my bike....


I have an early bike and have dealt with these differences regularly. I'm not sure why we disagree so much...
 
o0norton0o said:
#3: If you are going to rebuild the engine, you should leave those parts out... because you can plug the threaded port from the outside if you can figure out a different kind of reed breather application or actually use that threaded port to mount Jim Schmidt's camshaft port breather... (like I have done)
jsmotorsport.com

One way reed valve crank case breather

Pumping out positive crank case pressure and leaving a slight negative pressure is a great way to eliminate oil leaks. This simple breather uses the proven stainless steel reed valve from the BMW twin…
jsmotorsport.com
Click to expand...
 
I don't think that was available "for sale" when I modified my bike in spite of Jim's site saying that his breather dates back to 1985. The early bikes didn't have a sump breather option back then Cool that it's available now. Does anyone know a person who has one on an early frame with the crossmember??

As I've said, I have an early bike, so I keep up on the things that relate to them. I've still never heard anyone before Greg said today that this was an option for an early bike..... I wonder when Jim started selling these sump version of his reed valve. I'd bet it was only recently...
 
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This is the kit we are talking about? The description says it fits

jsmotorsport.com

Sump reed valve breather

Replace your sump plug with this one way reed valve breather to reduce oil leaks and pump out excess wet sump oil on start up. Fits all Norton Twins with a large screened sump plug.
jsmotorsport.com
 
macvittiemotorcycles said:
This is the kit we are talking about? The description says it fits

jsmotorsport.com

Sump reed valve breather

Replace your sump plug with this one way reed valve breather to reduce oil leaks and pump out excess wet sump oil on start up. Fits all Norton Twins with a large screened sump plug.
jsmotorsport.com
Click to expand...
It would be awesome if it does fit the early frame bikes... that part wasn't on Jim's site last time I looked.

The first I saw of a sump plug breather was made by Jim Comstock and it didn't fit the early frame bikes because of the cross member... So Jim Schmidt's sump breather is new to me... I don't think it's been on the market very long and I don't know a single early bike owner who has one... (not that I know all that many early bike owners but I pay attention to early bike technology because it effects the options for my bike..
 
ninja

Thread 'Jim comstock breather'

Anyone got any info on the Jim Comstock breather for 71 Commandos.

---------------------------------

E

Thread '1970 Commando crankcase breather options'

I am looking for a crankcase breather option, other than the very nice but pricy NYC one. I have seen some mention of "New reed breathers" on this forum, but all the links are no longer active. Older posts. anyone have any suggestions for a nice easy bolt on.
 
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o0norton0o said:
It would be awesome if it does fit the early frame bikes... that part wasn't on Jim's site last time I looked.

The first I saw of a sump plug breather was made by Jim Comstock and it didn't fit the early frame bikes because of the cross member... So Jim Schmidt's sump breather is new to me... I don't think it's been on the market very long and I don't know a single early bike owner who has one... (not that I know all that many early bike owners but I pay attention to early bike technology because it effects the options for my bike..
Click to expand...
Here is more info w/ photographs
 
Thanks Pete, I took a look at the link a little while ago today. Do you have that breather on your early frame bike?
 
Alrighty. Started to get the engine apart today. Head came off easy, looks to be in good shape. I was missing the front four head bolts.

The pistons are seized, which I figured they would be. I’m still working on it but I’ve gotten them about as far as they will go. Now I have to think on what sort of contraption to to get them out. I’ll check around the forum but also open to any tips.

My main concern is that is looks like the right side bore is cracked and broken at the bottom. See pictures. Can these cylinders be re-sleeved or should I try to source some new jugs/used jugs? Any sources at a decent price?
 

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Success! I used some thick steel bar and wrench sockets to compress the pistons while pulling up the cylinders and taping with a hammer. The pistons successfully moved a few inches!

Looking under the cylinders I can see the crank has a few small chips on one side (not cracked) will get more pictures tomorrow
 

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macvittiemotorcycles said:
Success! I used some thick steel bar and wrench sockets to compress the pistons while pulling up the cylinders and taping with a hammer. The pistons successfully moved a few inches!

Looking under the cylinders I can see the crank has a few small chips on one side (not cracked) will get more pictures tomorrow
Click to expand...
Yes they can be resleeved .
 
nortonmargie said:
Checked Andover Norton - new barrels for your model are out of stock. Also 750 pounds sterling if they were in stock. You could probably get an entire basket case with good barrels for less than that
Click to expand...
Yeah, patience is your best friend here for a barrel and trawling through Fleapay & other sites. Took myself six months but I got one (for an 850) free of damaged fins etc and either stock or +020 over IIRC with intact cylinders & tappets. You can choose to sleeve a crap second hand one if you want. $$$'s anyway, just a question of how bad you want it in the end.

Regards
Sean aka Ctefeh
 
75 norts came with 'vernier' quick adjust engine mount isolastics, particularly handy for rear adjustment, which prior to that, was a pia (lotsa xtra work) in comparison

especially if pulling the engine, or primary cover & internals, clutch stuff etc, something to look at, or anytime having to go there & adjust the rear.

a few other folks also came up with prior 75 vernier iso upgrade kits/options

 
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L.A.B. said:
Eh, why?
Click to expand...
As us Canucks ( over here across the pond ) , we use Eh to close or end a sentence or statement , not to start it .
An internet search shows my presumption of Great Britain using Kms. ( as we do , being the Dominion of Canada ) , to be incorrect . Distances are counted in miles it seems , other measurements use metric . Correct me if wrong , I've never been to England .
 
Torontonian said:
As us Canucks ( over here across the pond ) , we use Eh to close or end a sentence or statement , not to start it .
Click to expand...
Well, there you go.

Torontonian said:
An internet search shows my presumption of Great Britain using Kms. ( as we do , being the Dominion of Canada ) , to be incorrect .
Click to expand...

Torontonian said:
Distances are counted in miles it seems , other measurements use metric . Correct me if wrong , I've never been to England .
Click to expand...


Yes, we still use miles for roads.
 

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