Page 1 of 3
NC24 Vacuum pipe flexing
Posted: Wed Jun 30, 2010 3:25 pm
by Old Painless
Just been looking at the bike again today and im having awful trouble starting it and it wont idle low down at all.
Looked at the vacuum pipe by chance and its flexing to half thickness in time with the engine. lmao
This bike is pure evil, i swear. No wonder it was so slow, its not getting proper fuelling !!

Re: NC24 Vacuum pipe flexing
Posted: Thu Jul 01, 2010 4:09 pm
by Terri400
But as long as the vacuum pipe remains, even partially open, thus retaining your semi-vacuum, the fuel delivery shouldn't be interrupted. Change the bugger just to be sure though
Might be worth checking out the in-tank filter, assuming you've not already gone through this process.
Ian
Re: NC24 Vacuum pipe flexing
Posted: Thu Jul 01, 2010 11:00 pm
by Old Painless
The tank filter is clean as a whistle. Ive changed the line to be on the safe side.
Still a bugger getting it started.
Re: NC24 Vacuum pipe flexing
Posted: Fri Jul 02, 2010 12:54 am
by spooky
have you tried cleaning out the tap itself, there is a small catch bowl under the tap which could be blocked!
Check the wires going to the coils too. other than that clean out the carbs, try new plugs etc.
good luck.
Re: NC24 Vacuum pipe flexing
Posted: Fri Jul 02, 2010 5:10 pm
by Old Painless
The fuel tap assembly has been stripped and cleaned, the diaphragm is sound, the vacuum hose has been renewed, the fuel pipe to the carbs is good, the carbs are cleaned, jetted and set correctly, the coils are good, the wiring is all good, the relays and switches work well, the spark plug firing areas have been sanded and cleaned, the HT leads are good, the reg/rec has been replaced, the battery has been replaced, the engine compression is okay, the ground connections to the frame have been sanded and re-crimped ......
The only thing i can think of is that the pilot screws are too rich as the o-rings i used were *possibly* thicker than OEM.
Its taking the piss out of me on purpose. lmao
Re: NC24 Vacuum pipe flexing
Posted: Fri Jul 02, 2010 8:04 pm
by Neosophist
erm
Have you balanced the carbs?
Are they sealing on the rubbers propely?
What does the bike do when you slow the idle down?
What do you have the pilots set at?
Re: NC24 Vacuum pipe flexing
Posted: Fri Jul 02, 2010 8:32 pm
by Old Painless
Wont run to balance the carbs since i took the fairings off to balance the carbs. lmao
Carbs are sealing perfectly.
Idle at 2500 is okay, any slower and it slows then cuts out.
Pilots @ 2 turns exactly.
Im wondering if im going to have to shell out for new plugs tbh.
Re: NC24 Vacuum pipe flexing
Posted: Sat Jul 03, 2010 12:43 pm
by Old Painless
Well, carbs are balanced, i needed to set the fuel tap to reserve as it was low on petrol, easy fix. lol
The carbs are perfectly balanced now and it still lhas a lumpy idle. Im wondering about the pilot screw settings tbh.
The heads of the screws are pretty much flush with the body of the carb, should they be slightly recessed ?
Re: NC24 Vacuum pipe flexing
Posted: Sat Jul 03, 2010 3:05 pm
by Old Painless
Pilot screws moved in a bit to compensate for thicker o-rings, idles a lot better now.
Re: NC24 Vacuum pipe flexing
Posted: Sat Jul 03, 2010 3:54 pm
by Neosophist
There you go then :)
Might be time to get a dyno run on the go, they'll give you a good fuel / air mix graph so you can see how it's fueling.. and make adjustments (if necessary) accordingly.
Otherwise your stabbing in the dark :)