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Help needed
Posted: Thu Dec 31, 2009 7:14 pm
by scotjell
I have a 94 NC30 which I have just rebuilt the engine cleaned out the carbs and still having problems so after a little advice if possible!!
Problems I'm experiencing are tick over is erratic varying from 1500 to 2500 and when you shut off the throttle the revs don't seem to drop off as quickly. The bike is completely standard with 115 and 118 jets tempted to take carbs off my 89 and try them to see if it makes any difference.
The other is overheating too thermostat out and that was tits and after finding out how much a new one was decided to put the housing back together without one!! £42 they are having a laugh Honda! So took it out today and still overheating any ideas or imput on way ahead would be great.
Happy New year members.

Re: Help needed
Posted: Thu Dec 31, 2009 7:24 pm
by abrmoto
Are you slides on carbs coming down freely, had problems like this a few times and is usually sticky slides, carb strip may be way forward.
Over heating......are rads OK or shagged?
Re: Help needed
Posted: Thu Dec 31, 2009 7:42 pm
by scotjell
The pistons/slides seem to be a little slow to be honest had the carbs stripped yesterday. Not sure about the rads ran for 25 miles then all of a sudden gauge shot up!
Re: Help needed
Posted: Thu Dec 31, 2009 7:51 pm
by abrmoto
Make sure slides are spotlessly clean and give a squirt of WD40 when rebuilding, leave to soak/settle in over night before firing.
Rads, poss air lock, sorry never really had that.

Re: Help needed
Posted: Thu Dec 31, 2009 8:12 pm
by scotjell
May try the swapping of the carbs from my better old nc and see how it goes just to prove the problem.
Drained the rads yesterday so no blockage would the rad cap cause overheating?? Just a thought.
Re: Help needed
Posted: Thu Dec 31, 2009 8:29 pm
by abrmoto
scotjell wrote: would the rad cap cause overheating?? Just a thought.
Cant think of any reason why it would.
Re: Help needed
Posted: Thu Dec 31, 2009 9:04 pm
by Neosophist
Firstly, are your carbs balanced? if they are then you may have an air-leak too if its runnign shitty.
Is your vaccumn pipe connected to the tank and have no splits in it?
The old carb rubbers go brittle and split and let in air after a while.
If you get a carb balancer on it, sync the carbs, rev it up and bit and see if their still in sync, if you have an air leak it'll be very hard to get them balanced properly.
Re: Help needed
Posted: Thu Dec 31, 2009 9:43 pm
by scotjell
carb balancing is on the list to be done!!
Re: Help needed
Posted: Thu Dec 31, 2009 10:43 pm
by CMSMJ1
abrmoto wrote:scotjell wrote: would the rad cap cause overheating?? Just a thought.
Cant think of any reason why it would.
If the rad cap does not seal then you'll get lots of fluid out your overflow and not a lot of cooling, so it could be an issue.
Re: Help needed
Posted: Sun Jan 24, 2010 5:31 pm
by scotjell
State of play so far........ Tickover sorted after removing front and rear heads found two slightly bent exhaust valves and replaced them. Relapped everything in set up all the shims and plug gaps. No exhaust popping or erratic tickover, but still overheating. I have read in the Haynes manual that the plugs could cause over heating? I must admit tickover it sounds sweet and when the throttle is shut off sounds nice, but under load not so sure just not as smooth as my other NC. Just trying to check the fan and switch, but not having much luck there either. Open to ideas!!!!!