My new 850 and my first Norton

Hello everyone. Been reading this board for a while but I just bought my first Norton from the original owner last week. Its an all stock (as far as I can tell) 74 850. I rode it about 60 miles home this weekend and it was a less than ideal ride. A few issues arose about halfway home that I believe are the result of age and lack of use. Mostly, the bike all of the sudden required the use of the choke to run, and would also bog down at wide throttle opening (I suspect that the tank wasnt fully cleaned and some debris is obstructing the pilot circuit and main jet). Secondly, the primary, or gearbox starting leaking and spraying oil over the rear wheel. Lastly, the reserve petcock began leaking from the face/knob and would not shut off.

I awoke the demon.

Despite these issues that were either not disclosed to me, unknown, or just bad luck, I really love this thing. I'm pretty sure my ride home was the most it has been ridden in a while so that may be why these problems showed up. I now just need to hunt down the cause of these issues. The oil leak is particularly concerning to me as its a safety issue. I was thinking that maybe the inner primary may be leaking? Perhaps the gearboxn seal at the sprocket? Any advice is greatly appreciated.

Patrick M said:

I awoke the demon.

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Yeah, you did! Nice looking bike, by the way...

Patrick M said:

I'm pretty sure my ride home was the most it has been ridden in a while so that may be why these problems showed up.

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Watch for the front brake action. These are very prone to having pits corrode in the cylinder wall, renedering the brake worth even less than when they were new (which was pretty bad). If not done already, have the M/C resleeved. this will restore the wall condition, and, more importantly, give you better brake action through the increased hydraulic advantage of the smaller M/C bore diameter. Lots of threads on this very issue. Other option is to replace with an aftermarket 1/2" or 13mm cylinder. That's the route I went with on mine, and it works well. Cheap, too...

Patrick M said:

I was thinking that maybe the inner primary may be leaking? Perhaps the gearbox seal at the sprocket? Any advice is greatly appreciated.

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Without knowing what color of oils are in the primary and transmission, it's hard to say. There's a rather flimsy felt seal behind the clutch, then a proper lip seal on the countershaft sprocket. Either could be the culprit. Check out http://www.oldbritts.com/nor_comm_73.html and pages http://www.oldbritts.com/1973_g10.html (items #2 and 4) and http://www.oldbritts.com/1973_g7.html (item 9) for a good visual.

As for the possibility of carb jets being plugged, you'll soon wish you hadn't asked. And, as so sagely remarked upon, "If it acts like carbs, it's ignition". And, vice-versa... Here's a nice run-down of the Amal http://amalcarb.co.uk/rebuilding-mark-1 ... arburetter This next one gives good cut-away images http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html You may find it's easier to search topics through Google search engine that then take you back to Access Norton.

Welcome to the club! Trust me; it'll be worth the long road ahead.

Nathan

Once you have sorted the tuning problems, the just take it easy, enjoy the bike and fix one thing at a time. A small oil leak isn't going to hurt. If you do decide to fix oil leaks, check here first because sometimes it may be better to replace more than one seal when doing certain jobs. Eg, do the engine main seal at the same time as the gearbox main seal because of the effort to get the primary trans apart.
Check the level of you primary every month and if the level keeps rising, you know your rear main seal is weeping. Seals go rock hard after a time and stop working. We have all been there and done that.
Dereck
ps its not a demon, its a Leprechaun.

Lots of luck getting it sorted. It looks really good.

That's a proper looking Roadster! Somebody took pretty good care of it. Welcome aboard.

Brad

Hi Patrick, welcome. Did the oil on the rear tire SMELL like gear oil?

Snorton74 said:

That's a proper looking Roadster! Somebody took pretty good care of it.

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Took care of it externally (cosmetically).
It does look good, an exceptionally stock looking 850,
and all polished up too.

But if it wasn't being ridden, then the mechanical side of things wasn't quite kept up, by the sound of it...

Rohan said:

Snorton74 said:

That's a proper looking Roadster! Somebody took pretty good care of it.

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Took care of it externally (cosmetically).
It does look good, an exceptionally stock looking 850,
and all polished up too.

But if it wasn't being ridden, then the mechanical side of things wasn't quite kept up, by the sound of it...

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I did say 'pretty good care of it'... Most of us can spot a polished turd a mile away. This one owner bike looks to be the goods though. I wish mine had been that clean and unmolested.

Thanks guys and for the tips Nathan, and Dereck

Concours, It didn't particularly smell like gear oil. Though my hands smelled mostly like gasoline when I checked (because of the bad petcock) so I will have to look at it further.

Cosmetically, the bike isn't bad at all. There's the typical rusting fasteners here and there, but overall its clean. Original paint which shows its age close up. I like the originality and that the previous owner didn't mess with it too much. Mechanically, as I've mentioned, it could use a little work. Mostly with the dried out and aged seals. It fires up after a kick or three but I'll be adding a Tri-Spark someday soon.

I'd say the oil could most likely be coming from the primary for one or two reasons. Both have happened to me. (1). If the bike sat & wet sumped for a while, oil can weep past the crank seal & into the primary overfilling it & the result is it coming out the felt seal in the back behind the clutch basket. Check the primary oil level & see if it's over filled. This happened to me years ago & now I always check it if it's been sitting a while. (2). The wire coming from the stator comes out the back of the inner primary cover and is sealed with a rubber grommet that gets hard & leaks after a while. I just had this happen with one that was new a couple years ago. Easy to replace & seal with RTV from the inside & out.. (3). Oil could be leaking from the primary cover but both of the above will have you thinking it is when it's not. Great looking bike & welcome. Hope your tank is metal not fiberglass, if rusty use the search here & deal with it. Learn about cleaning your Amals pilot jets & such. Good luck. Glenn T.S.

do a search for PCV valve, it may cure your oil problems and if not its a good upgrade regardless

Snorton74 said:

I did say 'pretty good care of it'... Most of us can spot a polished turd a mile away. .

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I didn't say that. If its been polished but not actually ridden lately, at all, then the mechanicals could well have been a bit neglected.
Seals drying out etc, as the OP mentioned.

Snorton74 said:

This one owner bike looks to be the goods though. .

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Indeed. Cosmetically, it is great. An excellent example of a stock looking 850.
Apart from dealing with rusty fasteners etc, it would be disappointing if it was 'restored' any further.
Don't often see them this original.

Looks very nice. Wish I had that to start with.
Work the safety stuff first a little at a time.
Good luck!

Excellent advice guys. I really appreciate all the experience here. The PCV valve idea sounds good regardless of what's leaking and where. To start, I'll monitor the levels and check the grommet mentioned. The bike has an anti-sump valve and the oil level has been consistent in the short time I've had the bike (3 days). As far as the carbs go, a fresh set of Amal Premiers looks quite tempting but that'll have to wait. I'm going to break into them this week and have a look.

I'd like to get it sorted just enough for the season for rips around town while my confidence in the bike grows. I have another restoration taking up my heavy focus but I'm sure I'll be up to my neck in projects with this bike in no time.

Engine oil can also get into primary via one or more of the 3 inner case mount bolts by leaking or missing. In Wrong side shifting 850s via the cross over shifter shaft.

Welcome!