My NC30 Dyno Results.

[arsey30]

What is the difference between RW HP and crank HP.
Only one chart on this, and the old site specifies RW, the rest do not say where the power measurement was taken.

Does anyone have a chart showing both measurements, I have seen them, I believe the crank figure is calculated from the RW figure using a formula, as it can't be measured on a roller, only by direct coupling.

How much transmission loss would there be?

Dave.

[fastdruid]

druid.... hes a little bit more clever than that.

LOL, I wasn't thinking I could fool the operator, does this look like a 400 to you?


I meant purely for the willy waving afterwards! :-)

Druid

[greggo]

Hamster. I don't usually venture into the VFR forums. I come from the IL4 darkside over there in the CBR threads...

Anyway, the only important number on the dyno print out is the AF ratio. Forget peak horse power and what everyone tells you. The dyno is a diagnostic tool for tuning, nothing more, nothing less. The peak number means nothing, as any one dyno will differ from the other, even the size of the dyno room (relative to it's ability to 'refresh' the air completely per minute) will affect the power output. Even more telling is the correction factor the operator is using on the dyno, and the level of smoothing they apply to the graph. It is best if he can overlay your graph with another stock VFR graph from his dyno. That will tell you if you are really down on HP. The final test is what your wrist and arse tell you. A dyno is NOT a real road.

The story your dyno graph tells me is this:
1. You are running a little rich at the top end, there is some playing you can do here to get it a little better, cleaning air filters (when was the last time it was cleaned or replaced?), changing main jet, placing(or removing) the washer from under the needle etc. Your tuner will no doubt point you in the right direction. At least the AF ratio is consistent (flat), you just need it to move closer to the ideal line, and that should be easily manageable.
2. While the overall shape of the curve is okay (similar to others posted here), it is still rough, this suggests that your engine isn't running at it's optimum. I would suggest this is an accumulation of a number of small factors, rather than any one big thing. It would be worth checking compression, shims, spark plugs (cleanliness and gap), coil output, lube and adjust chain, correct tyre pressure and then go back to re-dyno. (even if you say everything is nearly new - if you had new plugs and an overly rich engine, they won't look new now!)

I'd shout you a beer if the difference isn't chalk and cheese, but I'm in Aus and it might be a big shout!

The difference between a freshly serviced engine and a saggy one someone has hasn't bothered to service can be quite significant on these smaller engines.

[The Hamster]

but you want to be seeing at least 10 more bhp than that

Afraid Your wrong.

Your bike is very underpowered and must be running poorly somewhere

Nope. Your wrong aswell. The Bike is running beautifully now.

The Honda figures are actually RWHP

No There not. See Below.

hi hampster sorry to be another naysayer but stock nc30's make around 58 ish bhp at the rear wheel,

Not according to Mr. Honda. See Below.




I emailed Honda Motorcycles Technical Support with the following simple question...

My bike recently ran peak power at 47.4bhp on a dynomometer and am worried that this is considerably lower than the Manufacturer stated 58bhp. Are you aware of any common faults that could cause this? Also, is the Honda stated power output of 58bhp measured at the Engine or at the Rear wheel?


I got the following response this morning:

Dear Mr XXXXXXXX,

Thank you for your enquiry.

The factory standard output figure is measured at the crankshaft, which accounts for your low dynometer figure which is measured at the back wheel.

Kind regards

Honda Customer Service team
Motorcycles


So, to end this thread, Im now quite satisfied with the power of my bike. The power curve is massively improved after the 10 Dyno runs today and the contless number of changes we did. In general, throughout the Rev range the bike is producing 6bhp more than what it was when I first took the bike to him. I am quite confident that I could easily keep up with you all on a rideout, with only skill making the difference between our machines.




Also, Kevin has said this:

He now wants to organise an NC30 specific Dyno Day to really see how these machines can vary. If he can get 10 bikes booked in for the day, the price will be £15 per bike and will include a bacon sarnie and a cup of tea. now that is not a deal to be refused!! So Get your names on a list and i will organise it with him!


1. The Hamster

[Spike16]

im up for that, my bike needs setting up and thats £20 cheeper than a dyno run at my local place, mines stock engine 120 jets f&r scorpion can new filter new er10 plugs and definetly running rich

I recon that dyno just under reads compaired to others, if it ride like you describe then I doubt theirs and majour problem with it

were abouts is this place located

[The Hamster]

http://www.projex-uk.co.uk" onclick="window.open(this.href);return false;


All the details can be found on there. Best bet is for you all to sort it out wiith me and I will pass on all the details to Kevin and see what dates we can get together to suit everyone.


What Kevin was hoping for, is another 100% Factory Standard NC30 to go on the dyno, so that we can compare the results with what we have obtained from mine.
It is going to be hard though, even Kevin says he doesnt think he has ever seen another 100% Standard on apart from mine??

[fastdruid]

Well I can give a totally bog standard NC35, with 20k on it as a comparison.

Done 0 miles since last serviced and had carbs cleaned too.


Just as soon as I receive the other two caliper bolts (and it stops bloody raining) it'll be on the road too.

Druid

[simmo]

other people on here have dyno printouts of their standard bikes reading 58 + hp.

so they will also be rear wheel horsepower as they were dyno readings the same as yours.

so with that in mind, your bike is very underpowered

[CMSMJ1]

Dave,

Don't get stressed too much - the numbers are low. no doubt about it and with everyone else running high 50's on their rear wheel BHP then there is no doubt about it.

The person responding to your mail will be toe-ing the company line but it is clear as day that the 59PS (VFR) and 53PS(RVF) factory figures are for rear wheel output...

It is all word play...so as long as you are now happy with it then the job is a good'un. If something gets sorted, I might get my ass down to show you how a 45k miles old skooler works...

[arsey30]

My dyno chart is crank hp, what would that be at the wheel? 55?
Honda used to give power at the crank in PS at the time NCs were about.

Only one of the graphs in this and the old thread specifies wheel hp, the rest do not indicate where the power was measured, so how can anyone say they are all wheel hp, the dyno can convert from wheel to crank hp if required.

The previous owner of my bike complained of a 5000rpm flat spot, that is now removed, and the 8 to 12 range is stronger.
My old RN model never did pull as well as this one, so whatever the final figure, setting up on the dyno where fuelling and other settings can be optimised must be a good thing, and the before and after results are most important, to see gains and losses for each adjustment.


A local dyno shop had to recalibrate his low? reading dyno because customers complained that friends bikes on other dynos gave bigger numbers to shout about at the pub.
I used to own the Honda UK RC30 used for the 1989 road tests, and the magazine dyno outputs for the same bike during the summer were 92, 98 and 103.

Dave.