NC30 only idles with super unleaded
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- BillingCBR
- Site Supporter
- Posts: 1043
- Joined: Sat Oct 10, 2009 10:36 pm
- Bike owned: '88 NC23, NC30, '98 R1, NC35
NC30 only idles with super unleaded
Hey guys, this has been bugging me since I did an oil change and put the new battery on my NC30.
When filled with normal unleaded the bike runs great, and when on full choke sits bang on 4k without so much as a twitch, but when left to idle without choke it occasionally coughs and very slowly starts idling lower and lower until when it coughs the revs drop too far and it stalls. However it sits perfectly happily at 1600rpm when filled with super unleaded without a problem, no matter what the conditions (2am, or in the middle of the day with a blazing sun)
The only reason I ask is it seems to be fuel related, and as I said has ONLY done this since having new oil (10W40 SL grade) and a new Gel YTX7A-BS battery, which strikes me as a little odd, I'd expect if the carbs needed adjusting it would do it all the time, no matter what fuel I used, and may well run like a dog down low.
Running 120DJ's, stock + .5mm needles, #35 pilot jet and screws out 2.25 turns.
When filled with normal unleaded the bike runs great, and when on full choke sits bang on 4k without so much as a twitch, but when left to idle without choke it occasionally coughs and very slowly starts idling lower and lower until when it coughs the revs drop too far and it stalls. However it sits perfectly happily at 1600rpm when filled with super unleaded without a problem, no matter what the conditions (2am, or in the middle of the day with a blazing sun)
The only reason I ask is it seems to be fuel related, and as I said has ONLY done this since having new oil (10W40 SL grade) and a new Gel YTX7A-BS battery, which strikes me as a little odd, I'd expect if the carbs needed adjusting it would do it all the time, no matter what fuel I used, and may well run like a dog down low.
Running 120DJ's, stock + .5mm needles, #35 pilot jet and screws out 2.25 turns.
'89 CBR400RRJ and '91 VFR400R NC30 project
Neosophist - The NC30 doesn't go very well when it's on fire
Neosophist - The NC30 doesn't go very well when it's on fire
- Cammo
- Site Supporter
- Posts: 4505
- Joined: Thu May 01, 2008 12:35 am
- Bike owned: NC30
- Location: Melbourne, Australia
Re: NC30 only idles with super unleaded
That's what I would expect also!BillingCBR wrote:I'd expect if the carbs needed adjusting it would do it all the time, no matter what fuel I used
Have you tried normal unleaded from other major suppliers? Might be a bad batch of fuel?
"It's just a ride" Bill Hicks
- BillingCBR
- Site Supporter
- Posts: 1043
- Joined: Sat Oct 10, 2009 10:36 pm
- Bike owned: '88 NC23, NC30, '98 R1, NC35
Re: NC30 only idles with super unleaded
I've used it from about 4 different places 2 supermarkets and 2 well known fuel companies regularly and recently filled at 6 more around the country on a trip to Hastings, sometimes it'll be fine then out of nowhere it'll do it, I've been through maybe 20 tanks of fuel now, and it only does it with regular unleaded
Any other ideas? I'd like to get it sorted if possible, as it's a minor niggle that will eat away at my very soul! Plus Super isn't a vast amount more (3p a litre where I am, over a tank full it's about 30p extra) so might just continue to run it on that

Any other ideas? I'd like to get it sorted if possible, as it's a minor niggle that will eat away at my very soul! Plus Super isn't a vast amount more (3p a litre where I am, over a tank full it's about 30p extra) so might just continue to run it on that

'89 CBR400RRJ and '91 VFR400R NC30 project
Neosophist - The NC30 doesn't go very well when it's on fire
Neosophist - The NC30 doesn't go very well when it's on fire