New Commando owner .. in need of help SW London (2016)

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stevemell

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Aug 2, 2016
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Hi after only owning modern fairly hassle free bikes for the last 15 years I became interested in Nortons. My wife very kindly bought me a '73 850 Commando as a surprise 40th present. The bike had just been restored (as a cafe racer) so hasn't really been running much yet. Unfortunately I am fairly clueless. The main problem I currently have is the plugs are fouling (dry black) after only a few miles so I guess it's running way too rich - then hard to start again. It also has a few oil leaks.

I'm based in Twickenham, SW London. Can anyone recommend someone nearby who'd be able to have a look over the bike for me?

Thanks
Steve
 
How West are you Steve?
Norman White is a proper Norton Guru, he's in Salsbury, is that close enough?
 
stevemell said:
The bike had just been restored (as a cafe racer) so hasn't really been running much yet. Unfortunately I am fairly clueless. The main problem I currently have is the plugs are fouling (dry black) after only a few miles so I guess it's running way too rich - then hard to start again.
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Which carbs? Standard Amal Concentric Mk1s?
If so, are you aware the choke lever operates in the reverse direction to what you are probably used to?

Slack cable is choke ON and with the cable pulled tight, is choke OFF.
 
Do you have the chokes fitted, if you do they work the opposite to other chokes ie when the lever on the bike has the wire to the carbs tight ie pulled up then the choke is off for normal running. For starting you turn the choke so the wire goes slack, if you leave it that way as the bike warms up it fouls the plugs and you eventually get 8 stroking. If you are not aware it different its easy to have them on all the time.
 
Hi, thanks for responses.

The bike had the choke removed.

It has Wassell Carbs (which I believe are the same as the Amal Mk1s) pic hopefully attached - first attempt

New Commando owner .. in need of help SW London (2016)


Plug after just 10 miles or so.....
New Commando owner .. in need of help SW London (2016)


Looks nice.. but would be nice to ride more than a couple of miles too!

New Commando owner .. in need of help SW London (2016)
 
In that case you need to take one of them apart enough so you read the sizes of the jets, slide cutaway and the notch the needle is using. Do you have any history of what work has been done on the bike eg cams etc, a Std 850 with an air filter and peashooter exhausts would be 260 main jet. Also assuming the carbs are 32mm bore.

I would get an air filter on quickly, those intakes look good but do nothing for the engine.
 
Just ordered a couple of small airfilters that should just screw on hopefully http://www.classicbikeshop.co.uk/spin-o ... -46mm.html

It's also been suggested to me that I could change the spark plugs to NGK BP6ES which may work better on a rich engine than the BP7ES which are on there so will give that a go too...?

Would still be great to find someone near to Twickenham / London who could show me around the quirks of the Commando.
 
My brother is in NE London and could help you but I guess thats too far away, in journey time rather than distance probably.
 
can you find what the recommended settings are on a Commando for those carbs somewhere?

I would first screw in the air mixture screws on the sides of the carbs until they just seat, count how many turns, and back them out to the Amal 1 1/2 turns setting

take the tank off and take off of the tops of the carbs and pull out the slides to see what the slide number is on the bottoms and also verify the needles are securely in the cir clips and, for now, in the middle notches

to continue the investigation drop the bowls and unscrew the main jets and note what number is on them

we don't know yet what carb circuit is causing the richness but this information will help a lot to get it solved, also one size colder plugs is a poor bandaid approach,
get a new set or two of NGK BP7ES and throw away those fouled plugs
 
1up3down said:
also one size colder plugs is a poor bandaid approach
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Actually BP6ES is a hotter plug and it might be tempting to go that way but it is only a bandaid, and one that could endanger the very life of your engine. There is a thread by Comnoz somewhere which shows what happened to someone who tries it.
 
Make sure the float heights are correct and that the needles and needle jets aren't worn out and letting too much fuel into the intake. You might try lowering the needkes a notch, but if they're worn or incorrect, this will only partly cure the problem.

The air filters will only make it even richer than running open stacks.
 
Those plugs look very black indeed, and sooty for that matter. Perhaps it is the intake valve seals letting oil in past the valve guides rather than too much fuel. I would expect that Wassel carbs wouldn't be worn out yet as they are rather new to the marketplace I believe.
Lance
 
Can I just say I can't help you with your carb problems but I wouldn't mind more pics of your bike.

Plus your wife has amazing taste... in bikes! :mrgreen:
 
Thanks for all the replies although some maybe a bit technical for me after two weeks of Classic bike ownership... taking carb apart etc... think I'd be more comfortable with someone that knew what they are doing showing me at first..
 
stevemell said:
Thanks for all the replies although some maybe a bit technical for me after two weeks of Classic bike ownership... taking carb apart etc... think I'd be more comfortable with someone that knew what they are doing showing me at first..
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Hi mate and welcome to Norton ownership ,do you know any of the history of the bike? I have seen many that are restored or re built that just don't run right maybe never ridden!! it's really not that hard to work on these carbs they are copies of mk 1 concentric as you know, take a look at the carb spec and check what number slide cutaway and needle position / needle jet type/ needle type/ maybe check spray tube type etc those plugs are very black and as said in an earlier post you need to know what circuit is running so rich , marking the twist grip is easy with masking tape or tippex just mark it fully open fully closed then divide quarter/half/three quarters then start and adjust until you get the right plug colour throughout the range take a look at "bushman's carb tuning secrets" nice bike good luck with it Cheers baz
 
I think what he wants is a couple contacts for reputable shops who know Nortons. Is that difficult to provide?
 
The carbs are really very simple, the advice to take them apart is the best starting point, although you could get someone to follow you and see what is going on with exhaust smoke. generally black is too rich, a blue haze is oil.
Black on acceleration is too rich.
Blue haze on acceleration or when the throttle is closed indicates rings or valve seals.
The bike looks great and I suspect its carbonation.
Good luck.
 
Norman White is a good recommendation. Hopefully the bike has the go to match the looks and Norman would be best to advise if the go is there.
 
swooshdave said:
I think what he wants is a couple contacts for reputable shops who know Nortons. Is that difficult to provide?
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There's no mention of dealers in the post he just needs someone nearby for some pointers,b ut if you were looking for reputable dealers in some areas it can be difficult
 
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