As of monday evening my NC30 has been running extremely funny, it started spluttering and coughing whenever i got it above 7k revs, which lowered down to 6k then 5 then 4 then 3 and now its just refusing to behave at all.

I have since tried to figure out what was wrong with it, so i ran it on idle for a good 10 mins then checked the downpipes and the two pipes which run along the right side of the bike by the rear brake pedal where cold whereas the other two where hot, so i assumed it was the limp mode thing to do with the speedo wiring, so i took the speedo off and checked the wiring all the way downto the box at the back and all appeared to be fine

put it all back together and ran it, all exhaust pipes are now warm, took it for a spin same problem.
so took the fairings off whipped the tank of, cleaned plugs which where covered in engine oil and cleaned carbs and it seems to have got worse.

i really dont know what else could be wrong any help and advice will be much appreciated
thanks
maks

Rear coilpack possibly?

i hadnt thought of that i do have a set of spares I might give it a go on friday

does anyone know why i would find plugs drenched in engine oil? and if it will damage the bike? what to do about tht?

Well if the back plugs aren't sparking they are going to be drenched I suppose.

Whip the back plugs out and see if they are sparking.

Check that the the carbs have sealed properly. If they arent then will throw cylinders off. Happened to mine once.

Could be coil, but I would expect rear pipes to be cold not warm.
Doubt if it is restrictor related if it won/t even pull 3 or 4 k rpm.

Put a clean plug in a rear lead to check for spark, you can swap front/rear coils to prove out.
Is the vacuum hose to the tap sound, no split/rot.
The front carbs sit lower and may take the fuel away from the rears if flow rate is low.

Remove the fuel hose from the tap to check flow rate from tap by spinning over engine on starter with kill switch off.

i'm thinking along the lines of arsey30 on this one.

Sounds like it's run / running out of fuel.

Easiest first check is undo the float bowl drain screws (have some rag ready..)

If the carbs have fuel it should run out... if not then you've found your problem.

Easy thing to check and takes no time at all (carbs dont need to come off.. just side-panel and long screwdriver)

right ive replaced the entire wiring loom (old one had too many breaks to trace), replaced coil packs, new plugs, topped up oil... but its running even worse now, the fuel lines seem ok but the bike feels and sounds like its starving

i really should have checked the site before i started work on it
i will try all the suggestions tomorrow evening after work see if i can get a friend who is more carb friendly then i am, as i have next to no knowledge about carbs and how they work

on a seperate note i have noticed alot of oil and muck built up around where the cam cover gaskets would be...
also there seems to be alot of oil gathered inside the bellypan...
but i dont think an oil leak could cause this problem?

makz2008 wrote:on a seperate note i have noticed alot of oil and muck built up around where the cam cover gaskets would be...

How do you mean? Are they missing?

It should have rubber gaskets on the top of the rockerbox.

First thing i'd do. (you've checked the small vacuum pipe right?)

remove the tank and block the end of the vaccum pipe as it'll run lean otherwise (small screw etc will do)

Use a small funnel as a temporary fuel tank (shove it in the fuel line)

Either cabletie it secure or get somene to hold it and fill it up until you can see fuel.

Run the bike and see how it goes, will elimanate tank / tap / vacuum hose if it makes no difference.