Honda NC30 misfiring

[crazy man]

just build a new race bike and it misfires at around 6-7000 rpm onwards just changed the plugs and leads ..same thing .. l find if you take the air filter out the bike it improves it buy 50% but starts to die like its running out of fuel after you get into 5 gear.. anyone got any ideas ....cheers

[crazy man]

just build a new race bike and it misfires at around 6-7000 rpm onwards just changed the plugs and leads ..same thing .. l find if you take the air filter out the bike it improves it buy 50% but starts to die like its running out of fuel after you get into 5 gear.. anyone got any ideas ....cheers

[Shaun]

just build a new race bike and it misfires at around 6-7000 rpm onwards just changed the plugs and leads ..same thing .. l find if you take the air filter out the bike it improves it buy 50% but starts to die like its running out of fuel after you get into 5 gear.. anyone got any ideas ....cheers


Are they carbed model bikes?

From what you have said it is fuel related. It sounds like it is running WAY to rich in one zone, and lean in another. The air filter removel response would keeps me focused on fuel area for now

[crazy man]

Are they carbed model bikes?

From what you have said it is fuel related. It sounds like it is running WAY to rich in one zone, and lean in another. The air filter removel response would keeps me focused on fuel area for nowyes it is carbed what your saying does sound right think the carbs have been played around with just a bit somone may of done somthing very silly.. ta

[Shaun]

yes it is carbed what your saying does sound right think the carbs have been played around with just a bit somone may of done somthing very silly.. ta

If you can ride it again? Go out and when it slows up 7K or where ever ( Starving) PULL choke on, Im guessing it will pick up again, so RICH on NEEDLE and LEAN on MAIN

[lostinflyz]

have you got the air filter and airbox lid and snorkel on it still???? if you've taken it off, put it back on.......

[crazy man]

have you got the air filter and airbox lid and snorkel on it still???? if you've taken it off, put it back on.......the only thing l had of was the snorkel should try it with it on but run so bad l would of thought the diffents with it on would not be much . l agree you would would thing with the airbow and filter on it should work fine as l found out 99% of road bike like

[lostinflyz]

airbox is the common one. if your running the stock box there better with the snorkel.

outside the carbs (needles, jets, float height), check/change coils, check plugs (im assuming there new), check fuel tap rubber diaphram, check carby boots.

has it ever run right?

[crazy man]

airbox is the common one. if your running the stock box there better with the snorkel.

outside the carbs (needles, jets, float height), check/change coils, check plugs (im assuming there new), check fuel tap rubber diaphram, check carby boots.

has it ever run right?only bought the motor. l see the carbs have had the few mods done like drill out slides to 2.5 mm bigger jets 120. maybe the needles need a play with

[Wannabiker]

First, check the diaphrams and covers have been fitted correctly. They have a tab on them which goes a certain way (one of the 4 cover screws has a small passage next to it, and the cover has a corresponding passage. It is not uncommon for the covers to be fitted without these passages aligned. There will be little or no vacuum to lift the diaphram in that carby. (and dont forget to put the big spring back in too.!!):innocent:

The NC30 is quite fiddly when altering the airbox / filter / trumpets.

I will have a look in the garage...I think I have a jet kit you can have ( My NC30 is long gone...)

[crazy man]

First, check the diaphrams and covers have been fitted correctly. They have a tab on them which goes a certain way (one of the 4 cover screws has a small passage next to it, and the cover has a corresponding passage. It is not uncommon for the covers to be fitted without these passages aligned. There will be little or no vacuum to lift the diaphram in that carby. (and dont forget to put the big spring back in too.!!):innocent:

The NC30 is quite fiddly when altering the airbox / filter / trumpets.

I will have a look in the garage...I think I have a jet kit you can have ( My NC30 is long gone...)maybe just maybe its the coils giving up ?

[ducatilover]

I'd go with your slides lifting poorly or jetting. I've got some jets in the garage, I'll check to see if I have some a few sizes bigger or smaller.

You're in Palmy? I may be able to pop around and have a looksie

[racefactory]

Dude- you took the speedo out didn't you? :p :p

Every person racing an NC30 stumbles into this bitch. When you take the speedo out it will miss badly from 6k. The bike has a safety feature built into the CDI to stop the spark to 2 no plugs if the speedo is not detected.

Easiest way is to just put the speedo back in! Or you can cut the little circuit board out of the speedometer, plug it back into the loom and wrap it in a plastic bag to make it water-proof if you are removing the clocks. You can also get an M-Max etc box that you plug into where the clocks would be or use an after-market ignition box like the ignitech. Finally there is the 'resistor mod' you can do.

[ducatilover]

Dude- You took the speedo out didn't you?

Every person racing an NC30 stumbles into this. When you take the speedo out it will miss badly from 6k. The bike has a safety feature built into the CDI to stop the spark to 2 no plugs if the speedo is not detected.

Let me guess, little circuit board that sends a signal to the CDI that sits behind the speedo face? Just like the problem I ran into with the 600....


Obviously didn't read your whole post :facepalm:

[crazy man]

no l made this loom up with the 2.2k resistor in it
http://images.trademe.co.nz/photoserver/92/180797292_full.jpg

[crazy man]

I'd go with your slides lifting poorly or jetting. I've got some jets in the garage, I'll check to see if I have some a few sizes bigger or smaller.

You're in Palmy? I may be able to pop around and have a looksiewill let you no how l get on

[crazy man]

Dude- you took the speedo out didn't you? :p :p

Every person racing an NC30 stumbles into this bitch. When you take the speedo out it will miss badly from 6k. The bike has a safety feature built into the CDI to stop the spark to 2 no plugs if the speedo is not detected.

Easiest way is to just put the speedo back in! Or you can cut the little circuit board out of the speedometer, plug it back into the loom and wrap it in a plastic bag to make it water-proof if you are removing the clocks. You can also get an M-Max etc box that you plug into where the clocks would be or use an after-market ignition box like the ignitech. Finally there is the 'resistor mod' you can do.

Oh and also what lostinflyz said is important. Don't go butchering that snorkel and airbox to 'push more air in'. It will only end in tears.think l will look into what you have said there maybe lm having a promblem with the resistor i put in it

[racefactory]

If at 6k it sounds really bad and hits a brick wall like it's running on 2 and is fine below that then yeah most likely your mod needs a little work and the safety mode is still in play.

[crazy man]

If at 6k it sounds really bad and hits a brick wall like it's running on 2 and is fine below that then yeah most likely your mod needs a little work and the safety mode is still in play.yes it does sound like that maybe somone has aready played around in the cdi and the resistor l put in has stuffed it up? thanks for you help think l need a play with it

[DrunkenMistake]

Take out the needles from the carbs, and remove them from the plastic housings they are in, check the washer size, if there are two washers, remove one,
if its 1mm thick get rid of it and add 0.5's in its place.
Sounds like its running rich, I had a similar problem with my bike after adding a 0.5mm washer, the 2.5mm hole only adds to the throttle response shouldn't effect much more.

Otherwise it could be the cdi problem.

[DrunkenMistake]

Take out the needles from the carbs, and remove them from the plastic housings they are in, check the washer size, if there are two washers, remove one,
if its 1mm thick get rid of it and add 0.5's in its place.
Sounds like its running rich, I had a similar problem with my bike after adding a 0.5mm washer, the 2.5mm hole only adds to the throttle response shouldn't effect much more.

Otherwise it could be the cdi problem.

Also the front jets should be .. I think smaller than the rear jets. I think I had 120 and 122, and im running a full race exhaust

[ducatilover]

Also the front jets should be .. I think smaller than the rear jets. I think I had 120 and 122, and im running a full race exhaust

118 and 116 or 120 and 118 I think are stock.
Due to the front being cooler than the rear.

[Taz]

Dude- you took the speedo out didn't you? :p :p

Every person racing an NC30 stumbles into this bitch. When you take the speedo out it will miss badly from 6k. The bike has a safety feature built into the CDI to stop the spark to 2 no plugs if the speedo is not detected.

Easiest way is to just put the speedo back in! Or you can cut the little circuit board out of the speedometer, plug it back into the loom and wrap it in a plastic bag to make it water-proof if you are removing the clocks. You can also get an M-Max etc box that you plug into where the clocks would be or use an after-market ignition box like the ignitech. Finally there is the 'resistor mod' you can do.

Struck the same thing when I unplugged the speed limiter from my Jap import 91 VFR750. Pluugged it back in and moved sensor and zip tied it to the speedo housing. Sorted.

[crazy man]

hi yes its only got 1 thin washer under the needles the jets are 118 and 120

[crazy man]

ok a bit of progrees. the back choke on carb was stuck on just abit fixed the top end power... but running like crap from about 6-1100 rpm found out part of the carb is missing the tee to the vacuum to the carb one is there the other is gone and see they both joint to the back of the airbox. do you think that will fix the midrange when fixed? ta

[racefactory]

Sounds like you have a well and truly butchered NC30. Wonder what else is missing or been tampered with. Typical. Get it back to stock as much as you can. Get another set of carbs off someone.

[crazy man]

Sounds like you have a well and truly butchered NC30. Wonder what else is missing or been tampered with. Typical. Get it back to stock as much as you can. Get another set of carbs off someone.it should be fine its just the price you pay when you buy things in bits

[crazy man]

hi all were are the air bleed screws on the nc30? thanks

[racefactory]

Hard to find is the answer to that. They are on the inlet manifolds. If you don't have the haynes manual to show you where then best thing is to take the carbs off and then locate them. You are wanting to balance the carbs right? The method of least hassle is the 'drill bit under throttle butterfly' method rather than using vacuum gauge. Search on 400greybike.com and you will find it. Yields good results.

[ducatilover]

Hard to find is the answer to that. They are on the inlet manifolds. If you don't have the haynes manual to show you where then best thing is to take the carbs off and then locate them. You are wanting to balance the carbs right? The method of least hassle is the 'drill bit under throttle butterfly' method rather than using vacuum gauge. Search on 400greybike.com and you will find it. Yields good results.

Only problem there is it's not as accurate. The reason for balancing is to get the vacuum the same, as we know. There will be variances in valve clearances, carbon build up (Some bikes do it on the left hand cylinders when warmed up on the center stand and the floats are off) so you're not balancing them to how the engine needs them done.
If my rambling makes sense?

I've used that method before and the verniers method and have found that the only way to get it spot on is with a decent set of gauges.

I'm sure the NC30 are uber sensitive to balancing too aren't they?

[crazy man]

Hard to find is the answer to that. They are on the inlet manifolds. If you don't have the haynes manual to show you where then best thing is to take the carbs off and then locate them. You are wanting to balance the carbs right? The method of least hassle is the 'drill bit under throttle butterfly' method rather than using vacuum gauge. Search on 400greybike.com and you will find it. Yields good results.

have you still got some carbs forsale? got a flat spot at 8-1100 rpm the rest runs very good. l dont think the needles are standard but someone nice on here is sending part of a kit that may help me {-:

[crazy man]

Only problem there is it's not as accurate. The reason for balancing is to get the vacuum the same, as we know. There will be variances in valve clearances, carbon build up (Some bikes do it on the left hand cylinders when warmed up on the center stand and the floats are off) so you're not balancing them to how the engine needs them done.
If my rambling makes sense?

I've used that method before and the verniers method and have found that the only way to get it spot on is with a decent set of gauges.

I'm sure the NC30 are uber sensitive to balancing too aren't they?is there not a screw on the carb that you are meant to have 2 1/4 to 2 1/2 turns out? had the carbs of could not find it for the love of me. l found a pic of some nc35 carbs and they stand out easy

[ducatilover]

is there not a screw on the carb that you are meant to have 2 1/4 to 2 1/2 turns out? had the carbs of could not find it for the love of me. l found a pic of some nc35 carbs and they stand out easy

Can you post a pic of your carbs?
You might have the pilot screws blanked off, you can drill the cap off them very carefully.
They will be on the engine/head side of the carb, on the bottom and should be recessed into the carb body. 243672
You can see on these ZZR400 carbs, the carb on the left has the pilot screw (Bottom of the bowl, slightly to the right) and the one on the right has had epic damage and the oart the screw is recessed in has departed the carb body...

[racefactory]

is there not a screw on the carb that you are meant to have 2 1/4 to 2 1/2 turns out? had the carbs of could not find it for the love of me. l found a pic of some nc35 carbs and they stand out easy

Yeah the NC30 pilot screw looks pretty much the same as the picture ducatilover posted. It won't fix your problems though, that will only effect your idle and starting.

I don't have any carbs. Contact vtec or icemaestro on here- I think they have carbs that they might be willing to let go of.

[crazy man]

cheers guys will pull them of and post a pic if l still cant find them but sounds like they wont fix my promblem . need to find my LambaLink

[crazy man]

l may of sorted it going alot better with no guts in the airbox! even just the gorse in the airbox kills it? strange 90% there maybe just some bigger main jets

[ducatilover]

l may of sorted it going alot better with no guts in the airbox! even just the gorse in the airbox kills it? strange 90% there maybe just some bigger main jets

It might be running far too rich.
Does it pull right up the top?

[crazy man]

It might be running far too rich.
Does it pull right up the top?yes it does. l tryed it a week ago and did fix that 8 to 11000 rpm promblem but felt very lean up top now with some 128 jets in it its fine. going to try some new needles when they turn up as well

[ducatilover]

Once you get it a bit smoother, slap it on a dyno and see what's going.
Sounds like you're making progress though.

[Icemaestro]

Wow, 128 jets, goodness! and I thought my 122's were extreme!:-P. My spare set of carbs are gone sorry mate, to drunkenmistake. Like I said though, AJ has several, just give him a call, his prices are reasonably reasonable, it all goes to his VFR fund! Other than that, there are a couple of sets on ebay.co.uk that you might be able to get shipped over here - there are 4 sets on there at the moment for 65-105 pounds, the cheap one says they'll post worldwide too...

[crazy man]

lucky l got rid of my drunk post

[crazy man]

Wow, 128 jets, goodness! and I thought my 122's were extreme!:-P. My spare set of carbs are gone sorry mate, to drunkenmistake. Like I said though, AJ has several, just give him a call, his prices are reasonably reasonable, it all goes to his VFR fund! Other than that, there are a couple of sets on ebay.co.uk that you might be able to get shipped over here - there are 4 sets on there at the moment for 65-105 pounds, the cheap one says they'll post worldwide too...what do you run in the way of a air box?do you race ?

[Icemaestro]

Me? Race? nooo haha haven't even pushed the limits of my nc30! got more peg down on RF's rvf! My nc30 was a track bike before me though, it's been put back on the road and I've been slowely trying to get it back to stock

Currently has normal airbox and snorkel, though with the ribs cut out of it, and missing the flap/top part of the air scoop. oh and a k&n filter on the rear cylinder

[crazy man]

has anyone run the HRC cam grind in there bike? did it go better?

[crazy man]

the bike runs mint now thanks guys
http://images.trademe.co.nz/photoserver/19/185335119_full.jpg

[ducatilover]

Holly shit, is it an NC30 motor in that?????

[crazy man]

Holly shit, is it an NC30 motor in that?????yip somthing l just wanted to do only 105kgs just need my bro to ride it faster lol

[ducatilover]

yip somthing l just wanted to do only 105kgs just need my bro to ride it faster lol

That is fucking awesome dude :Punk::love:

[crazy man]

That is fucking awesome dude :Punk::love:thanks l feel good now can l now retire lol no my bro wants one more bugger no rest for the wicked lol

[racefactory]

So you gonna tell us what the problem actually was after all that mate?

[crazy man]

So you gonna tell us what the problem actually was after all that mate?ok its just the mater of finding what to do. in the end taken out all the guts out the air box. 1mm washer hold up the the lid of the air box up with 130-132 jets and machined the end of the needles down so not to retricked the main jet. thats it. the washers did the big fix of the 9-11000 kick up

[gatch]

ok its just the mater of finding what to do. in the end taken out all the guts out the air box. 1mm washer hold up the the lid of the air box up with 130-132 jets and machined the end of the needles down so not to retricked the main jet. thats it. the washers did the big fix of the 9-11000 kick up

130-132 is pretty extreme for a vfr with stock heads.

[DrunkenMistake]

130-132 is pretty extreme for a vfr with stock heads.

Open air box thought,
Wouldnt you need bigger jets for more air?

[imdying]

Or bigger jets for less air.

[ducatilover]

Or bigger jets for less air.

My ZZRbarge needed 135s with a foam filter/slip ons, original was 142. :scratch:

[crazy man]

My ZZRbarge needed 135s with a foam filter/slip ons, original was 142. :scratch:are you coming out to he meeting this 24th

[ducatilover]

are you coming out to he meeting this 24th
I'll try to, assuming it's at Manfield?

[crazy man]

I'll try to, assuming it's at Manfield?it iis Manfield

[ducatilover]

it iis Manfield
I'll try get there, could be a fun watch.