Starting problem solved but what a way to learn!

[ilyamo-morte]

Hey Guys! For a while now Ive been experiencing starting problems with my NC30. If ran everyday she is fine but if left for a couple of days I would have fouled plugs and starting problems. A set of iridiums helped a bit but problem was still there. I stripped the carb, cleaned everything, drilled slider holes to 1.5mm and changed jets to 118/120s as she still had jap spec 115/118s. Bike def revs a lot better . So yesterday, after the bike had been sitting for almost a week I knew what to expect, out with the plugs, wire brush and a good dose of carb cleaner an she fires up. Guess im lucky I had the air cleaner off because after about thirty seconds of ideling a huge jet of brown liquid came shooting out the crankcase breather pipe. I imediately hit the kill switch. First thought was, sh*t, head gasket had blown but on inspection of liquid I found it to be a fuel/oil mixture. In short, fuel tap is leaking and if left for a while fuel was leaking through carbs and into cylinders where it slips past piston rings and mixes with oil. This was the cause of my foulded plugs and starting problems. On inspection, it is only a slight leak, easily mistaken for run off from pipe. The solution is simple, turn the fuel tap off everytime. Though since I have the brain of a budgie I will be fitting an isolation solenoid. This could be you if you have similar starting probs so worth a check, I was lucky, if I hadnt had air cleaner off things could have got expensive.

[matt_vfr]

Sounds like you're in need of a fuel tap repair kit matey a vacuum hose should open the fuel tap only when the engine is running and you turning the tap off is just an extra little precaution!

Matt

[ilyamo-morte]

yeah, looks that way, just gonna do the mod that removes vacuum control and fit a solenoid cut off valve linked to my alarm system. cheers!

[stevie]

this sounds like a probolem iv been having and am yet to solve, my nc30 has been sitting idle for 9 months due to me having a big off on my winter bike, i discovered that the front cylinders are filling up with petrol, i first thought it was the float switches so i striped the carbs swaped them out set float heights, checked they wrer all working as they should be and the bike started and run well when first put back together, 2 days later i had trouble starting her and when she started every time i went to rev her she tryed to cut out, on taking off the carbs the front cylinders were again full of fuel and im running out of patients and ideas? my fuel tap has been modifyed so is gravity feed and i have a qd coupling from tank to carbs, i run a small k&n crank case breather & nc35 carbs with full hrc kit and air box mods. do you think it could be a simaler probolem? any help or advise would be greatly appreciated as im gutted im missing the great weather were having. thanks.

[phil x]

I sorted my 'permanently on' fuel tap by removing the tiny little alloy plate & rubber seal inside the end cap where the vac tube attaches. It's worked perfectly since
I don't know the alloy plate/rubber seals' real purpose but I guess age prevents it working properly meaning atmospheric pressure is prevented from allowing the diaphragm & spring to close the tap when the engine is turned off.....

Phil

[ilyamo-morte]

Stevie, your problem sounds very similar to mine, least this problem is easy to check, just disconnect fuel inlet to carb and feed pipe into a bolttle or container, if after a couple of days or a week it has fuel in it then tap is leaking. Ive ordered a cut off solenoid from fleebay (item no 160577155605 if anyones interested) though I will still be repairing tap and hopefully remebering to use the bugger.

[stevie]

thanks will give it a try, but shouldent the float switches stop the carbs from over filing and leaking into the cylinders? this is what is confusing me, cos like i said iv done the fuel tap mod, removing the diapham so it is gravity feed not vacume, so unless the tap is in the off position fuel will flow to the carbs, which is the whole point of the mod to stop fuel starvation. So if it isent the tap, which im not realy convinced that it is, the floats must surely be at fault? but again i checked all the float heights and switches and all are good? aaaaaarrrrrggggghhhh this is realy fustrating, and i realy dont want to have to buy another set of carbs, unless anyone has a spare set of nc35 carbs going realy cheep, lol.