nc30 engine problems

[mini_me]

May not be as bad as a new motor. Oil coming up the cylinders certainly looks like holed psiton. But i've known that happen and all that's needed is a new set of pistons and rings (and gaskets etc). Of course, there may be other damage, ring chunks can score up the bores etc. You'll know once the heads are off.

yeah, but there is a big catch 22 in the whoe thing, i need a bike to get to work on and if i dont work i cant pay for the repairs and I *could* spend thousands fixing that motor and i think it works out better to throw a new motor into it and then pull the old one to pieces to have a look at whats wrong with it and if pos fix it up and sell/keep for spare

[Sketchy_Racer]

well dont spend any money yet just pull it down and see what has gone wrong.... it may have blown the gasket near the oil trace and is pumping oil into the cylinders... if its well screwed bugger but sometimes they are better than thought

[Ixion]

I'd second that. Y'r not going to know what you're up against until you pull the heads. And most of the work to do that you'd have to do anyway to switch engines. So pull the heads, then make the call. If it is a new engine you've not lost anything, just carry on with the removal. And if it is a simple and cheap fix (and really, you just never know either way until you get into the innards ) , then you're laughing.

[wendigo]

I'll third RG100. Blew a piston in my NC23 after ~130 k (due to buildup of deposits on the valves raising the compression enough to cause detonation), which cost the price of 1 piston + 1 headgasket + 1 set of rings to repair. Can't remember the exact price (couple of hundred I think), but it was certainly shitloads cheaper than going of and buying a new engine. At 38 k there's still plenty of wear left in the motor.

How many cylinders is oil coming out of & what state are the plugs in (ie any signs of little balls of alluminium or the plugs being excessivly worn)? The impression you give is that it's more than 1. I find it hard to believe a honda motor would let go 2 or more cylinders at once.

I blew really hard down the fuel line and it seemed to get a little easier after a bit

If its a diaphram pump like on the nc23 (which in likelyhood it is), I found this means SFA. It's nigh on impossible to blow through the pump. Best plan to test the pump is to pull the fuel hose of the fuel rail, point it into a container & turn the ignition on. Fuel should get pumped out. If none does & there's no clicking noise of the pump working, pump is fucked. I bring this up, coz again I had this problem (at a different time) on the cbr - in my case it was actually caused by one of the screws that go through the end cap (where the power lead goes into the pump) having worn away some insulation internally in the pump & shorting out the pump. It was quite an interesting problem really, because it was only intermittent, and manifested in a number of different ways. To start with the engine would mysteriously die after a couple of k (in hindsight however long it took the float bowls to empty themselves). Leave it for a couple of minutes start her up & of I'd go. At first I though it was carb icing (it was December in Ireland at the time), coz it would only happen when starting the bike from cold, and I could hear the pump clicking for a few seconds whenever I turned the ignition on. It was only when it blew a fuse that I twigged something more was amiss. Again like you I was bloody miles from nowhere & ended up jamming the entrance hose from the pump into the exit hose & limping home.

The moral of this story is to double check that pump. Would be a damn shame to go off & either get the motor repaired or bung in a new one & have exaclty the same thing happen a few hundred k down the road.

Good luck with it anyways.

[sAsLEX]

If its a diaphram pump like on the nc23

I am sure the thing dont have a fuel pump, see http://www.kiwibiker.co.nz/forums/at...8&d=1125915428, which shows no power to a pump, plus I havent seen one when taking the carbs off mine

[Kwaka-Kid]

alex your like a dog with a bone!

no,they never ever had fuel pumps, but it only takes 10 mins to put on on it which is a semi-common race trick.

[Raven]

Been readin through this thread and I have come up with the only possible explanation I can think of which would explain your lack of cpmpression in all pots like you've got and would also explain your oil problem. I don't know where you have parked your bike but sugar etc in the fuel would explain all your symptons including the misfire. Fouled plugs due to glazed bores and rings allowing blow by. Hope I'm wrong and best of luck.

[Raven]

More along the same lines as before. Check your fuel by putting some on a sheet of glass or anything for that matter that won't absorb it and let it dry. See if you get any residue. I've heard of some real stupid things people have done and some things can be added to fuel to the same effect that are undetectable and will continue to stuff engines until the tank is thoroughly cleaned. I'm not really sure you'll be able to detect anything but it's worth a shot and is cheaper than getting a chemist to check it.