Dyno Disappointment.....

[phil x]

I took the '30 to get dyno'd today at Quill (Golborne).

I don't know how to post pics or dyno runs here but;
Power topped out at 53.2hp at 13,000rpm (hit 50hp at about 10,300 rpm then levelled off).
Torque was 25.4ft/lb @ 10,100 rpm
There is a dip in both the power & torque between 5200 & 6800 rpm - this is the sluggish spot that I get - maybe timing/noise emissions related???
At tickover the AF is about 17:1 dropping off to 14:1 by 5000rpm, between 5-7krpm AF ratio richens to circa 12:1 & carries on +/- 12:1 to the redline.....

Now who the feck suggested fitting 115/118 jets....
As I suspected the bike is rich - hideously rich & would have been worse still if I had done the needle raise mod. Drilling the slides - nah feck that.
I'm going to fit the oe 110s back & leave as Honda intended, maybe tweak a little as needs be.
Every dyno that I have seen of an NC30 that has been posted here has been really rich. I'm sticking my neck out here but I reckon that there is lots of bad advice about jetting on this site not backed up by hard evidence.
If you give advice at least make sure that it's good advice.

FYI; The bike is a '90 'K' model with stock airbox & filter, unmolested original exhaust, carbs have had the 110 jets replaced with RO 115/118. Needles floats, pilots etc all correct with stock settings (I haven't checked the valve clearances/changed plugs etc yet (- thats one for the winter)

Phil
ps; Unless the non Keihin jets (as supplied by RO) do run significantly richer that the equivalent Keihin jets???

[CMSMJ1]

Stock system and bigger jets = rich bike.

I have not had jets from Rick but reckon they may be Dynojet ones..and so are not the same.

I agree about the bollocks too - but either way, get a graph up and we can disect it.

Worthwhile getting a dyno graph thread sorted to stop all the blags..

[phil x]

Stock system and bigger jets = rich bike.

I have not had jets from Rick but reckon they may be Dynojet ones..and so are not the same.

I agree about the bollocks too - but either way, get a graph up and we can disect it.

Worthwhile getting a dyno graph thread sorted to stop all the blags..

I upped the jets as I was led to believe that a stock '30 running 110 mains runs very lean, upping the mains size doesn't necessarily mean a rich bike - but it does in my case.

Yes we need hard evidence, modifications, jet make/sizes & dyno results with AF.
Do RO jets run richer than Keihin, if they do we are all pissing in the wind.....

Note, my bike stuttered & struggled to rev out, hence, with advice given here I decided to check the carbs out & up the jetting to those suggested on this site.
My float heights were out, pilot screws all over the place & 2 of the Emulsion tubes were in the wrong location, fed from a fuel tap with a shitty soft vac pipe....... I wish I'd corrected these & left the stock jetting & went from there (I nearly did but decided to fit the jets I got from Rick)!

Phil

[Smev]

I don't want to sound off but why change stuff if you don't know whats going on in the first place?!

Surely the best idea would have been to dyno it first - all standard. THEN decide whether you need bigger jets etc etc....

I understand you are annoyed, but you have no-one to blame but yourself!

Alot of the information on here and most forums, is what has been tried out and is from peoples personal experience. Also, people come from all walksand ages of life - and some aren't technically minded at all (you just have to look at some of the obvious questions that get asked in the workshop) I always bear this in mind when reading about things people have done.

Again, this is all just my opinion and you don't have to act on it!

Good research should lead you away from disappointment.

By the way - this is how to post pics (its easy to find if you do a search)

viewtopic.php?f=5&t=19475

[amorti]

Worth noting - a bike running a little rich will feel lots better than a bike running a little lean. It will pick up quicker when cracking the throttle open for example. It will use more fuel and won't be any faster, but if you are going to be a little bit off perfect then most folk's butt-dynos will prefer a little rich. So that could be where the jetting recommendations came from? Apart from that, I thought they were intended for bikes with at least an end can on?

[Man_Named_Dave]

His Rick-ness suggested the 115/118 combo to me for a standard exhaust and that's what I'm gonna try. Everything he's said has helped me out a great deal.
In short, there may well be people giving dodgy advice on here, but RickO certainly ain't one of them! Chances are he's given you suitable jets, whatever size they are.

Calm down and the nice people here will help you.

[Drunkn Munky]

Yep i think you need to wind that neck in a bit, advice given on here should only be taken as general as all bikes are different and need setting up accordinally.

You mentioned nothing about checking/changing the air filter in your OP, id check that first if its running hidiously rich.

[phil x]

Cheers for the replies.

I went for the 115/118 due to it being unanimously recommended as 'the' thing to do on a stock bike along with the needle raised to get good a/f ratio & good power.

With hindsight, I can never recall anyone putting up a dyno showing before & after results & it's that, that niggles me. Everyone seems unanimous about the 115/118 mains & needle raised but where's the proof?

Sure these bikes are 20=/- years old so theres sure to be some variation between them, I'm not knocking the fact that there are some very knowledgable & experienced folks on here.

The air filter is good by the way

Phil

[royster81]

115/118 came stock on the bike after 1991 so it should run perfectly fine with a stock set of carbs, standard clean filter and a full stock exhaust..... But you say you rises the needles?

Why ?

If everything else is standard why lift them?

Would this be the cause of your richness?

[scooble]

12.1:1 doesn't sound hideously rich though, 12.5:1 give or take a bit is usually the range that gives best power.