First Bike - NC31 Big One!!

Gidanski · Post by **Gidanski** » Tue Oct 30, 2012 11:09 am

Hi all. Just bought my first bike. A 1997 NC31 CB400 Project Big one.

So far just been fiddling with it to get it set up for how I want to ride it and getting to know it mechanically. First on the to do list ais a major service. Basically oil and air filters, and idle screw adjustments.

So far had no luck finding any info but does anyone know how many tuns out from fully in the idle screws should be? Is 2.5-3 about right? Also whats the easiest way of getting to the 3rd idle mix screw?? I don't exactly have small hands and have had no luck trying to adjust it. Thinking of removing them and adjusting the screws but not the throttle balance screws. Any tips on removing the carbs? Hot water on the rubbers or something to soften them so it comes off easier or something?

Also any major issues I should be looking for? Speed limiter is being bypassed when I get some spare time as free revving it to around 5k rpm has it splutter and pop.

Apart from that there isn't really any other problems I can find. Might look at fitting a custom intake with pods and catch cans but will have to wait till after I get used to it.

Superjack44 · Post by **Superjack44** » Wed Oct 31, 2012 9:11 pm

2 turns out from fully in is a good starting point, to get the carbs off make sure the air/battery box is loose and moved as far back as possible, loosen the carb mounting clips off and work the carbs back and forward and up and down until they release from the bite of the rubbers, I removed mine by using a lever but be careful where you place the lever as breaking a pilot adjuster screw is a real possibility take your time and take care otherwise it could be expensive.
Right angle pilot adusting screw tools are available from that well known internet auction site around £20 or so.

Gidanski · Post by **Gidanski** » Sat Nov 03, 2012 9:43 am

Thanks for that, haven't really had time to go play with it with work and other things interrupting my time to actually pull my finger out and do it. Hopefully I can get some time tomorrow and go do it.

Gidanski · Post by **Gidanski** » Mon Nov 05, 2012 8:52 am

Got the carbs out quite easily today, took it around the back yard to warm it up and then just did exactly as Superjack described. got the airbox as far forward as possible then just rotated the carbs 45 degrees, popped straight off!!

Went for 2 1/4 turns out just to be safe. Is a lot more responsive down low and doesn't have the popping and backfiring out the exhaust anymore on the over run. Also had a look at the float chambers. CLEAN!!! Probably the first time they have come off in nearly 60,000k but were spotless! Seems the bike has only been run on decent fuel.

So next on the list is a decent service and maybe a different sprocket to drop the revs down at highway speeds. Exhaust is loud. More race bike then road bike

First Bike - NC31 Big One!!

First Bike - NC31 Big One!!

Re: First Bike - NC31 Big One!!

Re: First Bike - NC31 Big One!!

Re: First Bike - NC31 Big One!!