NC30 fuelling

[matt_vfr]

Eh, whats the kill switch trick??

When i first got the bike it had a huge flat spot between 5 and 8k rpm so i thought it was running lean then, but it never did anything like this, i just couldnt really use the midrange too much. Im assuming my mechanic upped the jet size as he said 'ive put 117.5 all round and some washers to try and remove the flat spot' or words to that effect, which doesnt sound like he lowered the size. I did have the carbs apart once but i didnt note the jet size Anyway, i called him up and its going in again on friday to get sorted... otherwise i can see me spending a small fortune on parts that it 'could' be... if it does turn out to be running lean then i doubt he'll ask for too much to fix it as thats what i asked him to do the first time, and hes a pretty decent bloke!

Matt

[wullvfr]

when the flat spot happens between 5-8,000rpm and you suspect it's running lean put the choke on and see if it clears!!!!

if it does then you know it is more than likely running lean,if it gets worse it could be making it run even more rich.

you said it plays up when the bike is warm,this could be because it's over fueling/running rich.

runs fine on start up and when the bike is relatively cool,because for the engine to run fine at this point it requires a slighlty rich mixture,hence the reason for the choke.



william

[wullvfr]

when the flat spot happens between 5-8,000rpm and you suspect it's running lean put the choke on and see if it clears!!!!

if it does then you know it is more than likely running lean,if it gets worse it could be making it run even more rich.

you said it plays up when the bike is warm,this could be because it's over fueling/running rich.

runs fine on start up and when the bike is relatively cool,because for the engine to run fine at this point it requires a slighlty rich mixture,hence the reason for the choke.



william

[Sligeach]

kill switch trick is accelerate hard from standstill untill just before redline, then roll off the throttle and hit the kill switch, leave it for 2 seconds and turn it back it back on again, if theres a loud loud bang then good, if not, its a lean mixture.
any one else got opinions on this?

NB this is dangerous, prob illegal and may damage your bike

[matt_vfr]

Hmm, yeh i dont think ill be trying that As i say, if its lean it will be a pretty easy fix for my mechanic. I just dont understand why, if it is the mixture, it was fine for a week?!? I wasnt exactly going easy for the whole of that week cos we had a couple of sunny days and i wanted to make sure the flat spot was gone so i took it for a bit of a blast

Matt

[matt_vfr]

Just a quick update on this... just got my bike back and it turned out the tank breather was blocked, and the petrol tank and carbs were full of water and shit.... my mechanic showed me a jug of what came out and it looked like swamp water, had loads of sediment and shit, was separating and was a kind of green/black colour... was no wonder it wasnt running properly with that shit at the bottom of the tank :p Its something i could have easily done myself but at the time i was bogged down with so much other stuff! Reckon it was caused by the rainwater getting in when i opened the tank a few times!

Anyways, its now immense, got a lot more grunt low down and sounds beautiful :D It was only gone a couple of weeks and i started gettin withdrawal symptoms but thankfully its running perfect just in time for summer!

Matt

[Sligeach]

good stuff mate, they V4 does tend to run better on refined petroleum and not swamp water

[Le_Blur]

good stuff mate, they V4 does tend to run better on refined petroleum and not swamp water

No way! Maybe that's where I'm going wrong...