stressful nc30
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- Settled in member
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- Joined: Sat Feb 05, 2011 12:47 pm
- Bike owned: honda vfr 400 nc30
- Location: Gloucester
stressful nc30
hello all,
in need of some help badly. my nc30 has decided it doesn't like running atm
had a problem with the solinoid, after buying a new one (which turned out to be the wrong one) i put it on the bike and it burnt out the diode (s3h 02) at the rear of the subframe, it basicly went up in smoke. i have gone out and got a new one.
heres the big problem
the bike has had new spark plugs put in it and it is starting up and lasting about 1 min and its reving itself from 1k -2k by itself. but then it wont start, untill i remove the diolde and plug it back in. i dont know what it could be as weve definatly de-flooded it, new spark plugs, and diode. the only things that were wrong with it.
please someone help me out and give some advice if you know about this or have had the same problem. really wanna be out riding it. thanks
in need of some help badly. my nc30 has decided it doesn't like running atm
had a problem with the solinoid, after buying a new one (which turned out to be the wrong one) i put it on the bike and it burnt out the diode (s3h 02) at the rear of the subframe, it basicly went up in smoke. i have gone out and got a new one.
heres the big problem
the bike has had new spark plugs put in it and it is starting up and lasting about 1 min and its reving itself from 1k -2k by itself. but then it wont start, untill i remove the diolde and plug it back in. i dont know what it could be as weve definatly de-flooded it, new spark plugs, and diode. the only things that were wrong with it.
please someone help me out and give some advice if you know about this or have had the same problem. really wanna be out riding it. thanks
- CRM
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Re: stressful nc30
First of all dont double post unless you want them and the account removed.
when you say diode - what diode ? can you get a picture ?
if the bikes revving on startup with full choke thats normal. DO NOT rev the throttle or you will flood it.
the way to start them is to, full choke, no throttle, press the button and leave for a couple of mins before knocking the choke in slightly blipping the throttle to keep it running before returning the choke to off.
after 3 - 4 mins the bike should tickover easily on its own with no choke.
if your is different to this then the carbs may need a cleanout and ensure the jetting and airscrews are set correctly.

when you say diode - what diode ? can you get a picture ?
if the bikes revving on startup with full choke thats normal. DO NOT rev the throttle or you will flood it.
the way to start them is to, full choke, no throttle, press the button and leave for a couple of mins before knocking the choke in slightly blipping the throttle to keep it running before returning the choke to off.
after 3 - 4 mins the bike should tickover easily on its own with no choke.
if your is different to this then the carbs may need a cleanout and ensure the jetting and airscrews are set correctly.
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- Settled in member
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- Bike owned: honda vfr 400 nc30
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Re: stressful nc30
yea sorry about that only got the account today
http://cgi.ebay.com/ebaymotors/Honda-Ma ... 1703wt_903
couldnt get a pic up but heres one off ebay. exact one.
http://cgi.ebay.com/ebaymotors/Honda-Ma ... 1703wt_903
couldnt get a pic up but heres one off ebay. exact one.
- CMSMJ1
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Re: stressful nc30
Not sure that is going to be doing anything is it? Where exactly are you plugging that in?
So..you flooded it and killed the plugs? Get them outm dry them on a gas flame or in the oven.
Check your vacuum hose from tank to engine is connected (it is the thinner of the 2 hoses from the tap and it should fit on the outer spigot)
I cannot see how that diode is involved at all...either the bike fires or it doesn't. Can you get a pic of it fitted?
So..you flooded it and killed the plugs? Get them outm dry them on a gas flame or in the oven.
Check your vacuum hose from tank to engine is connected (it is the thinner of the 2 hoses from the tap and it should fit on the outer spigot)
I cannot see how that diode is involved at all...either the bike fires or it doesn't. Can you get a pic of it fitted?
IMPERATOR REX ANGLORUM
The V4 is the law..
NC30 - No9 - my old mate
The V4 is the law..
NC30 - No9 - my old mate
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- One Hit Wonder
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Re: stressful nc30
Hi,
I had a similar problem after i got my carbs set up. Very rough idleing and after a while i started to get huge backfires and flames from exhaust. Turned out i had a leak from the Inlet Rubbers and eventually one slipped off. They are about £90 to replace but you could try sealing them to check if that's the problem. If so either replace or glue. I have no intention of removing mine again so i just glued them. 7 months and no problem. [Touch Wood]
[if your is different to this then the carbs may need a cleanout and ensure the jetting and airscrews are set correctly.]
Unless you have been fiddling or changed the set up recently then i doubt it could be pilot screws or choke cables, and unless it has been lying up a while i don't think dirty carbs would be a problem.
Hope this helps.
I had a similar problem after i got my carbs set up. Very rough idleing and after a while i started to get huge backfires and flames from exhaust. Turned out i had a leak from the Inlet Rubbers and eventually one slipped off. They are about £90 to replace but you could try sealing them to check if that's the problem. If so either replace or glue. I have no intention of removing mine again so i just glued them. 7 months and no problem. [Touch Wood]
[if your is different to this then the carbs may need a cleanout and ensure the jetting and airscrews are set correctly.]
Unless you have been fiddling or changed the set up recently then i doubt it could be pilot screws or choke cables, and unless it has been lying up a while i don't think dirty carbs would be a problem.
Hope this helps.

- BillingCBR
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Re: stressful nc30
£90 for carb rubbers?
David Silver Spares lists them at £6 each (£5 + VAT)

'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
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Re: stressful nc30
BillingCBR wrote:£90 for carb rubbers?David Silver Spares lists them at £6 each (£5 + VAT)

Joining 400gb just paid off...
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- Trinirides
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Re: stressful nc30
Cammo wrote:BillingCBR wrote:£90 for carb rubbers?David Silver Spares lists them at £6 each (£5 + VAT)
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Joining 400gb just paid off...
I will put a plus one 2

I know this is the type of question that could be almost anything but something that I have over looked in the past has been to check the "earthed" plate on the lower LHS of the frame where the engine mount bolt goes.. On more than one occasion this has been a issue!! once on my bike and once on a friends, both times causing crap idle and back fires a quick clean and making sure it hasnt worked loose is a easy check...
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Re: stressful nc30
Cheers for all the advice guys.
The bike works perfectly now. I thought it was an electrical problem and ordered a complete wiring loom for the nc30 for £5 and before my mechanic went to put it on, he thought he'd just see how long it would fire up for whilst sounding sluggish.....and it started up perfectly. And stayed on... So after spending £15 on solenoid, £48 on spark plugs and £5 on loom.. It just decided to work, even though the carbs were cleaned a week previous and hasn't worked properly even since that.........joys of a nc30 :)
The bike works perfectly now. I thought it was an electrical problem and ordered a complete wiring loom for the nc30 for £5 and before my mechanic went to put it on, he thought he'd just see how long it would fire up for whilst sounding sluggish.....and it started up perfectly. And stayed on... So after spending £15 on solenoid, £48 on spark plugs and £5 on loom.. It just decided to work, even though the carbs were cleaned a week previous and hasn't worked properly even since that.........joys of a nc30 :)