Cool no.4 pipe

thmjo1 · Post by **thmjo1** » Thu Jan 29, 2015 8:44 pm

Hi all,
Need some opinions on what is happening with my nc29.
Bought the bike in December as a race bike and have been slowly sorting it out since then. I've never owned one before so its all a bit new to me! I have not been in the engine but have had it out of the frame to give everything a good clean. Anyway, bike is pretty much back together now and has been run several times during the rebuild to ensure I haven't knackered anything or forgot to connect anything up. I am now fitting a GF ram air system and so have relocated the coils to the outside of the frame rails which involved some wiring. When I fired the bike up again to check all was well I noticed the no.4 exhaust was not getting as hot as the others, in fact you could keep your hand on it long after the other three were burny hot! Got new plugs in and seems to be running ok (pulling the lead off the no.4 coil makes a very obvious difference to engine running) but the exhaust on no.4 cylinder takes ages to warm up. The carbs have been off and on 3 or 4 times so I'm wondering if I've unsettled something there. All carbs were ultrasonically cleaned so shouldn't be any gunk in there BUT when I've been test starting the bike it has mostly been with no air box.
Anyone any ideas where to start with sorting this out?

Cheers

Post by **dobbslc** » Fri Jan 30, 2015 7:37 am

Do you have a spark on no4 ? if you do it's probably your carbs idle circuit.
Will the pipe heat up on part throttle? If it does, again it could be the idle circuit in that carb is blocked.
Try swapping plugs just in case one is duff.
Check the pilot air screw settings as well.

thmjo1 · Post by **thmjo1** » Fri Jan 30, 2015 12:06 pm

Yes, got a good spark. As I say, the bike starts no problem and seems to rev up ok but no.4 pipe stays cool. Now the coils are easy to get to I can pull the lead off for no.4 pot and the bike really labours so I think its 'running' ok but the pipe isn't getting hot. Think I'll have to pull the carbs again and double check the rubbers and maybe the pilot jet?

thmjo1 · Post by **thmjo1** » Fri Jan 30, 2015 2:27 pm

Sorted!!

Turns out there was a tiny bit of snot in the pilot jet. I suppose the moral is, use an air filter!!
Thanks for the advice dobbslc.

Cool no.4 pipe

Cool no.4 pipe

Re: Cool no.4 pipe

Re: Cool no.4 pipe

Re: Cool no.4 pipe