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should an NC30 start without choke

Posted: Mon Sep 12, 2011 1:02 pm
by philfingers
just got my bike. previous owner said it always starts without need for the choke. is this correct, it's an import and from what i've read they run a little leaner. It does indeed start without choke, will tickover right from the off and doesn't smell rich. std can. Seems to run ok through the rev range tho does feel a little rich/wooly
I've yet to remove the tank, i will in due course strip and clean the carbs as a matter of course and reset the balance. I have an ultrasonic tank and compressed air for a good clean out.

Re: should an NC30 start without choke

Posted: Mon Sep 12, 2011 1:39 pm
by Chrissy_J
The short answer is NO. Most petrol motors need some choke when starting from cold, except in hot weather when the bike's been in the sun, the fuel and air (in the airbox) are already warm and a less rich mixture is needed to start.

A choke works by richening the fuel/air mix, this is done by closing some of the air passages.
A dirty or blocked air filter would do the same thing so I'd look at that first.

You should always regard any previous owner as being monkey-fingered buffoons from hades, with less mechanical skill or sympathy than a housebrick, because quite often they are ... so a quick check on the consumables is always a good thing, when you purchase a new vehicle.

Re: should an NC30 start without choke

Posted: Mon Sep 12, 2011 3:02 pm
by philfingers
i will be checking out various bits in the coming weeks, including giving the carbs a full check over. Oil filter has a little surface rust on it but as the bike has only done 1000miles in 6 years the oil is still a little golden in coolour. brake fluids need changing and will give the brakes a cursory clean.
I will check the airfilter out. It was justa quick question, to make sure they don't all do it!
Out of interest do valve clearances need doing often? My mille for instance, they rarely need doing at the first 9k unless they're seen a lot of track or race use.

Re: should an NC30 start without choke

Posted: Mon Sep 12, 2011 8:54 pm
by JIGGLYB4LL
Chrissy_J wrote: You should always regard any previous owner as being monkey-fingered buffoons from hades, with less mechanical skill or sympathy than a housebrick, because quite often they are ...

lol lol :lol:

Re: should an NC30 start without choke

Posted: Mon Sep 12, 2011 9:33 pm
by arsey30
None of my NC30, NC35, RC30 will ever start from cold without choke.

They may fire, but not catch.

Re: should an NC30 start without choke

Posted: Tue Sep 13, 2011 7:42 am
by Lane
Motorcycles do not restrict the air passages, but enrichen the mixture using an additional fuel circuit.

An open throttle butterfly in the inlet provides too much restriction when extracting as much power as bikes do from small engines.

Re: should an NC30 start without choke

Posted: Thu Sep 15, 2011 6:38 am
by johnnie5
Lane wrote:Motorcycles do not restrict the air passages, but enrichen the mixture using an additional fuel circuit.

An open throttle butterfly in the inlet provides too much restriction when extracting as much power as bikes do from small engines.
this all depends on the bike

some use a conventional choke which restricts air

a lot use an enrichment circuit