NC30 - firing issues

[richhemmings]

Good morning all,


My NC30 seems to have some starting issues... I suspect a naff battery, but after testing, its charging ok (13-14V in at 5k revs), and with the new regulator, I think I can rule this out, although it does depleate quickly when turning the bike over.
On a ride the other day, I completely lost power for a few second (maybe a minute max), after which it was ok agian, and pulled ok.
I have also noticed some hesitance under throttle, around 5-6k revs, I read on another thread that this could be to an over-rich mixture?

The bike is standard but has the 33bhp restrictors in it.
Idles at 2.5k.
Starts on half - full throttle, and heats to over 90 on tick-over, but this is down to 90 on a ride.
Generally ridden well I'd like to think, although I do like to wind it up through the gears, tend to change around 12k.
I also noticed that it is 0-90mph ok (tested on the track obviously), but performace is flat after this - suspect because of restrictors.


Please Please Please Help!!

This is my first bike, and as such my knowledge is a bit limited!
Thanks in advance.

:D

[CMSMJ1]

It should not idle at 2.5k revs...

Sounds like the choke might be stuck on slightly? You shouild really check the carbs out and see what jets are in there anyways..running too rich is a waste of fuel and plugs as they will die faster by drowning!!

Normal starting methods on the bikes are full choke, no throttle at all and let it warm up a touch and take the choke off. it should idle around 12-1300 revs.

[richhemmings]

It should not idle at 2.5k revs...

Sounds like the choke might be stuck on slightly? You shouild really check the carbs out and see what jets are in there anyways..running too rich is a waste of fuel and plugs as they will die faster by drowning!!

Normal starting methods on the bikes are full choke, no throttle at all and let it warm up a touch and take the choke off. it should idle around 12-1300 revs.

Will the restrictors make it run richer?
As I understand these are washers in the inlets on the carbs.
What are the jets? What should I be looking for?

[CMSMJ1]

Yes - the restrictors strangle it a bit and as the standard bike can get more air in per revolution the stabdard carb settings are too rich.

The jets are the carb main jets - they are hollow brass tubes that are a certain diameter and are tuned to the amount of air your bike can breathe. Changing them affects your fuelling and they are majoryl important to have set correctly.

Depending on the model of the bike it will either have 112 jets all round or 115 front and 118 rear.

If someone has been fiddling then expect to see 118 front and 120 rear...that will be much too rich.

It is easy to sort out and check them

[richhemmings]

Cool... I'll look at that then.

Are 112,115,118 related to measurement / size?
It's the 1992 model I think... red/white and blue

http://www.visordown.com/review/images/ ... 0-NC30.jpg" onclick="window.open(this.href);return false;

Supposidly it'll be worth checking the air filter too.?
The plugs were new last season... would they go that quickly if its tuned wrong?

thanks for the pointers!

[CMSMJ1]

Yes - yours will have as std 115 and 118 size jets if it has not been fiddled with.

The sizes are stamped on the bottoms of them in teeny numbers!

it is a mm measeurement afaik - 112 = 1.12mm

New airfilter, standard honda, would also be a good call and help it breathe better.

[richhemmings]

Are there any other obvious things I should look for / test

[richhemmings]

I had the airbox off last night and found that the filter is new anyway... with a bit more digging, I found that it was replaced with the last service (Aug/Sep last year).
Smelt really pertol-ly though.
Checked the choke cable and it doesn't seem to be sticking up or fouling.

How much of a problem are the restrictors if it hasn't had new jets?
I tried to get the carbs off the look for the restrictors (on the inlets.?) but couldnt see an obvious way of releasing the front clamps?

I've ordered an Optimax 4 to solve the battery issue and think that perhaps adjusting the idle may be enough?
I think I may have been letting it idle high for too long which would have run it too rich, correct? But how would this explain the sudden loss of power?

Oh and one more tiny Q... the plugs are NGK ER6EH's? 13mm socket required? Presumably any plug with the same thread/head size will have the same hex size?


Again, a massive thanks for your support!

[CMSMJ1]

the plugs are ER9EH or ER10EH (in race bikes) - 13mm deep socket is what you need.

Ref the carbs - the front clamps can be buggers to see so I use a long screwdriver and get in there form the left hand side of the bike as the thermostat is in the way otherwise.

Am expecting others to chip in..as my yacking is only one opinion..

but basically, you should check the jets out and sort it...it wil run better, cost you less in fuel and you can see the restrictors so when oyur time is up you can get them out asap and put the jetting right...sorted.

[wullvfr]

just a wee note on the plugs cm mentioned.

i have heard that some people run the er10 plugs in the rear two cylinders as they apparently run hotter than the front two.

just thought i would add that



william