NC24 starting and flatspots

[dave_c24]

havent checked earths,where are they all,may as well do whole bike.

new carbs have 112 jets with 4 hole emulsions in front and 115 with 5 holes in rear this right?

cheers dave

[dave_c24]

i think ive cracked it , it was a cobination of some of these:


1.dodgy new honda rubbers (will be returning these)
2.pilot settings were 1 1/2 on new carbs forgot to check them! now 2 1/4 but might be rich still
3.plugs
4.exhaust valve clearances slightly tight on cylinder 3 and i mean by .05mm
5.emulsion tubes mixed up
6.carb balance
7.earths to coils on rear cylinders

hopefully it will stay cured and i can enjoy riding it! its only taken 2 months of head scrathcing lol!

bike doesnt always start without a tickle of the throttle but at the moment is ticking ova super smooth and behaving and no flatspots at 10k so im well happy!!!!

thanks for all the replys
cheers dave

[Neosophist]

ok cool.

But 115's should be all round >.<

the NC21 had 112/115's.

If it's running ok though I wouldn't bother till the winter.

[dave_c24]

ok cool.

But 115's should be all round >.<

the NC21 had 112/115's.

If it's running ok though I wouldn't bother till the winter.

i spoke too soon

bike started stuttering badly at high revs on the way home when fuel was nearing resvere bout 20miles off,didnt improve when switched over but seems ok now filled up??? i got around 13 litres in? only thing i can think of is the tank filter being dirty. only put one in there bout month ago but its had around 5 tankfuls through since then so may have some crap in.

bike ticks over nice and stays at the right revs starts and goes on choke nice, around 2 k on choke. mixture screws are 2 turns out, could occasionally smell fuel at 2 1/2 and 2 1/4 more so at 2 1/2.

i have always have had a slight pause around 10k that cant get rid of, me being well fussy though,doesnt affect progress.this is nothing compared to before.

any ideas.

cheers dave

[Neosophist]

I'd put the 115's in the front, while your at it blow through the jets again, you might have some rust or crap in the tank thats gotten into the carbs.

Fuelling on full throttle is all about main jets and needles. Do you have any sticking sliders? push them up and see if they drop down easy enough.

After that try raising / lowering the needles. Deffo get the tank checked out though just incase therse still crap in it.

[dave_c24]

I'd put the 115's in the front, while your at it blow through the jets again, you might have some rust or crap in the tank thats gotten into the carbs.

Fuelling on full throttle is all about main jets and needles. Do you have any sticking sliders? push them up and see if they drop down easy enough.

After that try raising / lowering the needles. Deffo get the tank checked out though just incase therse still crap in it.

thought it might be that,gave old carbs to a mate to play with, so will have to wait for jets. sliders were all good, thats one thing i always check, all lovely and smooth.

how much difference does the needle adjustment make, could i get rid of it with just that? also which ones do i raise and how or do i do all four the same?

one thing i did wonder,done a new thread in v4 general, could it be electrical as its been constant throughout 2 sets of carbs?

cheers dave

[Neosophist]

Oh right... I didn't realise that. It could be.

It's more than likely the vaccumn pipe to the fuel tank has perished... under high revs / accelleration theres a great deal of 'suck' on the pipe from the engine... if theres any holes in it it draws in extra air, shuts off the fuel tank, bike runs crap till you back off the throttle.

Check that first as its often over-looked / missed out and i've seen it on several vfr's now.

It'd be a good start to check all your needles are the same height (middle setting will do), and you have the correct jets, just to rule anything out.

[dave_c24]

Oh right... I didn't realise that. It could be.

It's more than likely the vaccumn pipe to the fuel tank has perished... under high revs / accelleration theres a great deal of 'suck' on the pipe from the engine... if theres any holes in it it draws in extra air, shuts off the fuel tank, bike runs crap till you back off the throttle.

Check that first as its often over-looked / missed out and i've seen it on several vfr's now.

It'd be a good start to check all your needles are the same height (middle setting will do), and you have the correct jets, just to rule anything out.

hi thanks agin for yet anouther reply.

i have replaced the vacume pipe with a bit of 1/4 rubber fuel injection hose, unless its colloapsing under heavy acceleration?? that is a very good idea! what pipe should i of used? old bit was about 2/3 pipes bodged together!

apart from that i will have to take my carbs off and check needles and also change the 112 to 115 jets.seems strange that theyed have them in. i will try the vac hose 1st though . do you think rubber hose is too soft???

cheers dave

[Neosophist]

well you could out your finger over one end and suck on it yourself see if you can get it to collapse, it's worth a try ^_^

If they had 112's in it there either NC21 carbs or somebody has changed them.

[dave_c24]

well you could out your finger over one end and suck on it yourself see if you can get it to collapse, it's worth a try ^_^

If they had 112's in it there either NC21 carbs or somebody has changed them.

could but i dont think i can suck that hard without passing out lol!!

ive got hold of a piece of plastic pipe to replacve it anyway.gna try andf get time to check the needles and nopefully blag 2more 115jets off a mate to try this weekend if i get time.

will keep you posted

cheers dave