NC24 jets sizes in Johannesburg (Inland)

[EvanTate]

Hi guys,

So my baby has moved inland with me from the coast. I am not +- 1750m above sea level and the air up here seems to hate all N/A motor vehicles...

Now she was already overfuelling a bit down at the coast (bit of white smoke and slightly underpowered with long flames when pulling away hard). But now she just fouls the plugs up within seconds. I can't get past 3rd gear without losing speed and the 1 and 2 plugs are pitch black and 3 and 4 and sopping wet so I'm currently riding a V-twin haha.

My NC24 has 115 mains all round. Cannot remember what the pilots are but they were standard too. My airfilter is a disaster as it's full of holes and my exhaust has no baffle (compliments of previous owner). So I'd like to find out what jets I can put in to run better up here (assuming proper filter + proper aftermarket exhaust as I'll get them sorted too). I was thinking of trying 110s/112s like the early NC24 setup. Ideally I should dyno her to get it 100% I know but there's no money for that just yet. She also over fuels on idle though. So what pilot jets could I try? Float heights are standard 6.8mm at the moment.

Anyone with experience moving a bike inland like this? Thanks :)

[Neosophist]

overfulling on idle means you have broken carbs.

Most likely you ahve the wrong float heights OR one or more of your float needles are not sealing properly so the carb is overflowing petrol into the engine.

Whats your temperature like? there are proper formulas that will put you in the right jet size instead of just guessing.

It sounds like your carbs and bike are in need of good fix anyway, wet plugs sound like overflowing carbs.

I would go for 108s all around in your carbs. This is based on being between 1750-2000m above sea level with 20c average temp, it'll put you right about where you need to be.

While you have the carbs out to change the jets. replace the filter with a proper Honda one. it wont run right without it.

before you even get them apart to replace the jets connect up a temporary fuel pipe to the carbs and use an empty bottle or funnel for fuel, fill them up with fuel and watch them for an hour for any signs of leaking, if you find some leaking mark which carb(s)... check the float pins are sealing.. they are expensive to replace but it cant be helped.

[tigerclaw]

I live in jhb and my nc30 has 110's.... chat to the guys at racebox in edenvale they seem to know there 400 carb stuff really well and they don't charge silly money. What concerns me a little is that white some usually means there is oil in the cylinders, grey smok is usually over fueling.... But I'm not 100 percent sure I'm right about that.

[EvanTate]

Thanks for the input Neo. Yes I have stripped the bike completely now to rebuild how I want it. There is so much to do on her so I may as well. I do suspect a sticking float in the number four carb, not stuck all the way open but not sealing properly either. I had a long struggle with float heights at one stage and I know they are correct and the seats should still be sealing but who knows lol. Will check it out thank you. And will give 108s a try :)

Tigerclaw: Have spoken to Racebox already. They will dyno my bike for R1500. This includes rejetting and tuning the carbs. I agree they are the best in Gauteng with VFRs :) Unfortunately the guy won't talk to me about jets without a dyno first, doesn't seem to understand that I'm 150km away from him and I'd rather pay for jets here and again there than ride to him on 2 cylinders but oh well. Thing is to dyno I need a new air filter (will definitely use a Honda one) and need the charging issue sorted and exhaust sorted first. Also, she needs to be reassembled haha.

Atm she's just 2 wheels which just enough frame work to keep the motor in place lol.

Neo, where can I find this info on jetting carbs correctly? I have looked but being on my phone it makes it hard to do any real research. I would love to get a hang of this art :) it's a dying skill I'm afraid. Also do you have the part number for the Honda filter? If I give them the number they'll order it for me, but won't go to any effort to help a grey import which sucks.

[Neosophist]

Thanks for the input Neo. Yes I have stripped the bike completely now to rebuild how I want it. There is so much to do on her so I may as well. I do suspect a sticking float in the number four carb, not stuck all the way open but not sealing properly either. I had a long struggle with float heights at one stage and I know they are correct and the seats should still be sealing but who knows lol. Will check it out thank you. And will give 108s a try :)

Tigerclaw: Have spoken to Racebox already. They will dyno my bike for R1500. This includes rejetting and tuning the carbs. I agree they are the best in Gauteng with VFRs :) Unfortunately the guy won't talk to me about jets without a dyno first, doesn't seem to understand that I'm 150km away from him and I'd rather pay for jets here and again there than ride to him on 2 cylinders but oh well. Thing is to dyno I need a new air filter (will definitely use a Honda one) and need the charging issue sorted and exhaust sorted first. Also, she needs to be reassembled haha.

Atm she's just 2 wheels which just enough frame work to keep the motor in place lol.

Neo, where can I find this info on jetting carbs correctly? I have looked but being on my phone it makes it hard to do any real research. I would love to get a hang of this art :) it's a dying skill I'm afraid. Also do you have the part number for the Honda filter? If I give them the number they'll order it for me, but won't go to any effort to help a grey import which sucks.

your bike is running on two not becuase of the jets but becuase there is aproblem with teh carbs.

Its not really a dying skill, you just need professional equipment to get custom setups correct. Other than that set it by the books for stock bikes and you wont have any issues.

Sort your carbs out first and it will run ok but wont pull out due to the rich main jets, if you ride it sensibly at part throttle youll be able to run to the dyno day without trouble

[CybaHag]

I have 110's and my NC30 runs pretty well.

Dudes please send me the number for racebox. I am looking for a starter relay and possibly a reg/rec.

Thanks

[tigerclaw]

I just sent you an email. If it doesn't come through let me know

[CybaHag]

My inbox is empty bud

[tigerclaw]

Oh ate tu 44 tree 1532. Speak to gerhard