My bike is spluttering in every gear around the 5k mark and someone suggested taking a look at the speedo wiring,
the previous owner mentioned that it had come loose inside the speedo and he had to re-solder it, so i took the speedo off and took it apart... not only is the wiring intact... but ive also managed to somehow move the resting position of the needle :s

so two problems, the running extremely lumpy and i desperatley need to find out how to get the speedo needle to sit back at the 0mph mark!!! help!

okay nevermind the speedo resetting ive sort of managed to do that i just hope it isnt too far off
but does anyone know why the bike would splutter and not want to rev higher than 5k bearing in mind that the speedo cables are all good and connected? :s

It's an electronic restriction. When the speedo unit is removed (or unplugged), or the speed limiter wire is cut, the bike will go into a 'limp home' mode by cutting spark to 2 cylinders after 5000 rpm.

So... either your speedo wiring is unplugged, or the wire has been cut, removed or wrongly modified.

If it's all plugged in properly it might be easier getting hold of another speedo unit rather than fixing yours.

that seems to be the problem, its all plugged in properly and ive even checked that the wires that go from the plug to into the speedo circuit board are all intact, the only thing that concerned me was a minor amount of corrosion build up on the circuit board where the wire solders on...

to make things worse as i was riding to and back from work today the spluttering is starting from 3.5k :O
i think i may have to stop riding it until i can find the problem and sort it...

could it be a possible fueling issue?

...also the bike only splutters when in gear and under load

if that makes a difference?
im going to try swapping the speedo from my friends nc30 just to see if the speedo is the problem

makz2008 wrote:that seems to be the problem, its all plugged in properly and ive even checked that the wires that go from the plug to into the speedo circuit board are all intact, the only thing that concerned me was a minor amount of corrosion build up on the circuit board where the wire solders on...

to make things worse as i was riding to and back from work today the spluttering is starting from 3.5k :O
i think i may have to stop riding it until i can find the problem and sort it...

could it be a possible fueling issue?

Sounds like it's not the speedo restrictor.

Fuel / electrical are first things to check.

Has it been standing for a while? If not then it's unlikely to be build up of crap in carbs.. could be casued by a shitty tank of gas though, check the obvious first.

The fuel flows from a vaccum tap.. the pipes are known to split, make sure its' conencted properly without splits.

Check the electrical system next, there known to go shitty and can cause bizzare running issues.

Measure battery voltage at idle and at 5000rpm

ok so i swapped the speedo with my friends NC30 and the problem still persisited...
so i spent the day today trying to figure out what the problem was...

i discovered the air filter was filthy
spark plugs were covered in engine oil
one of the ht leads seems to be damaged
there was alot of green powdery build up on most connector blocks
and the starter ignition fuse needed replacing

so ive done nothing about the air filter
cleaned the spark plugs off
spray wd40 on the connectors which had the powdery stuff
and replaced a 10a fuse

the bike now runs alot better however it does sometimes splutter if i ride it hard
think i might need 2 change the pulgs and filter

not sure if the bike has a fuel filter? if so does anyone know how i can replace/clean it

*bike is a NC30 jap import

No fuel filter as standard, there's a small 'sieve' in each carb body though.

A really clogged air filter could be causing these problems. So could fouled plugs, and faulty leads, etc. You could try cleaning out the filter a bit by blasting it from underneath with compressed air, though a new one should be on your list (get genuine honda only!).

I think you're on the right track checking all of this stuff out.

A thorough dismantling and cleaning of the carbs and jets would also be a wise move. If you follow the carb jetting guide sticky you should have no problems cleaning them.

I've got a used (But still in good condition) stock airfilter you can have if you want. just cover postage and a beer...

jetblack wrote:I've got a used (But still in good condition) stock airfilter you can have if you want. just cover postage and a beer...

i may have to take u up on that offer as genuine filters fetch a fair sum...

on the other hand the bike seems to be riding 100x better now
but as soon as it started running well...
another problem has come up and this one is worse than before...
put the key in the ignition, turn it to on... and nothing! no neutral light no oil light no headlights no response from starter switch no horn basically nothing...
had the same problem yesterday but after checking all the wiring and playing with some fuses the bike decided to behave, unfortunatley it doesnt want to behave anymore...

i have checked the main earth cable from chassis to the battery -ve terminal is on and in good condition, made sure all connections are properly connected and removed any corrosion from block terminals, ive even replaced all the fuses with brand new 1s... the only thing that works on the bike seems to be the alarm

this bike seems to be more hassle than it is worth at the moment