NC30 Carbs issue

[Nicks510]

Hi Guys,

My NC 30 has a problem of fuel leaking through into the crankcase which means I have to drain the oil and replace the oil filter-3rd time and now I've had enough. Apart from the fuel tap, the carbs have supposedly been serviced (cleaned and reset twice in a week by 2 different mechanics.

The last one told me the problem was that the needles weren't seating and that the diaphragms are worn. The bike is also running too rich, as soon as it heats up it battles abit to pick up revs-for a second or 2 with a constant fuel smell.

I've now found a supplier that can supply the fuel needles, while I'm busy with ordering them, is there anything else that would cause the problem-jets, etc?

A problem that it has, is that while riding at constant revs, it doesn't run smoothly.

I just need help knowing what to order.

Any help/advice appreciated.

[Neosophist]

where abouts are you? these sound lie some clueless mechanics.

it sounds like your carbs are over-flowing, its the only way fuel can get into the crank case.

this is either floats set widly incorrect or a non-sealing float pin.

most lkely one or more of your float valves are knacered, causing the carb to piss fuel everywhere. if the tap is stock when the bikes not running it will be ok as the fuel is shut off.

When its running one or more of the carbs is pissing fuel, becuase its running its sucking it in rather than overfuelling but probably drowning out one cylidner.

Hook up a temporary fuel tank (ie funnel in some pipe and fill with gas), youll find your fuel level keeps dropping if the float seals are knackered. look at the carbs with a torch (no air box engine off) and find out where the fuels pissing out, this is your problem carb. repace the flaot valve and it shoudl sort it

that much fuel will wash the oil off the bores and maybe the bearings, leading to a ruined engine quickly.

[royster81]

Tap mod ? Don't over look that.

[Neosophist]

Tap mod ? Don't over look that.

worth checking of course but if your float valves are ok though it wont leak fuel.. many of my bikes dont have vaccum tape and i rarely turn the fuel off..

[Nicks510]

Thanx for the replies guys, it makes sense. The fuel tap needs to be closed with the machine running, then kill the motor and open tap again and close immediately. That seems to work but the fuel left in the carbs(faulty one) will run into the crankcase. Without fuel in the crankcase, she starts easily.
Something I forgot to mention is that the airfilter is knackered, I know the dangers of this so I've ordered another which will be here next week.
But what I want to know is, will this cause erratic running while at constant revs.
Another issue I remember, was that when I got my bike back from the first bunch of iddiots, the power band would kick in around 5000rpm, after the second guy worked on it-completely re-did the carbs, sync'd butterfly valves, sync'd carbs etc- the powerband wouldn't kick in at all.

Before anyone touches the bike again, I'll make sure he has intimate knowledge of the VFR's.

Neosophist, I'm based in Cape Town-South Africa, far away from you so no chance of these mechanics messing with your bikes.

[Neosophist]

lol, I almost started my original post with "your not in south africa by any chance are you", it's always south africa, im sure these bikes go there to die, some of the horror stories on here of things being done.

Firstly, they shouldnt really be a powerband, its not a 2 stroke and its pretty torquey so should pick up from idle.

If one of your carbs is pissing fuel it will always be psising fuel, so it will never run right as its constantly flooding a cylinder with gasoline causing the revs to be shitty.

Whats the tailpipe of the muffler look like, is it black and sooty? take out the plugs and check em, will help you find a bad cylinder.

[Nicks510]

Thanx again Neo, these bloody carbs are a headache. I'm going to strip it myself next week and just search this forum when I hit a snag. I don't think I'll find better info anywhere on the net.

If I'm really stuck, I'll post a question.

[iDemonix]

Want to buy some powerbands?