Old Dyno chart

[shoarmadude]

Hi guys,

thought lets post my old dyno chart from a few years ago.

Cause my bike isnt running like it should and now Ive removed the carbs for a clean, maybe its also
the right time to tweak the carb a little

When I did the dyno run, I just had installed the DJ stage-1 kit with BMC filter.
After the run the guy told me that it wasnt to bad, but the bike was a bitt rich.

The setup then and know is:
BMC filter
Laser exhaust, with silencer
180F - 185B - 48
2.5 screws in (if I remember correctly)
Needle 4th from the top

Was thinking to drop the needle, 3rd from the top.

I can't read the chart, but I see a dip of something around 4500-6000 rpm

Any tips are appreciated (Sorry for the poor quallity of the pic..)

[Wicky]

How long ago since it was dyno'd?

Have you cleaned /replaced the airfiter? Adjusted TPS and balanced them at all?

[shoarmadude]

The chart is from 4 years ago.

Changed the filter then, balanced carbs using the how-to and tps got adjusted after I broke the other one.

So if Im right the dyno looks sh1t?

So what does the dyno say, cause I dont understand none of it...

[popkat]

Looks an ok chart. running a bit rich at 5-5500k and a little lean at 4-4500k. I don't see much of a dip.

Fluctuation at the top end could be the filter


100-105hp with jet kit, pipes and a filter is about normal, your a little bit down but that could be the dyno and another dyno might show more.

You could try lowering the needle (raise the clip a notch) which might help but this may make the lean part worse, you could give it a try and see how it feels.


.

[VTRsquid]

What would be the "target AFR" usually? 12.5, 13?

[shoarmadude]

Thanks guys.

The advice the mechanic gave me after the run was to lower the needle, 1 slot up.
What youre saying corresponds.

Ive lowered the needle now, once Ive cleaned everything Ill put it back and see what happens.
Could changing the filter back to OEM en lowering the needle be a better option?

Also I just discoverd that at the I installed the DJ kit, I screwd the FMS 2 turns out from the bottom on both sides, most topics on the forum say something like 2,25 to 2.5 turns.
So could there also be something to gain at?

And how do your read the graph?
Are you using the lower graph, the one for the air thingy...?
AFR = Air Flow Rate?

[VTRsquid]

AFR= air fuel ratio, thats the lower most graph plotted against rpm. If you follow the horizontal axis (rpm) and then look where it lies against the vertiacal axis (AFR) you can see where it runs lean or rich.
Same with the power and torque graphs. Horizontal axis is RPM, vertical axis is power and torque. The line that starts low and ends high is power, the line with the big bulge in the middle is fat juicy v-twin torque.

[shoarmadude]

Ah that makes sence.
Ill try to get a smoother graph with adjusting a few thigs and see how it rides.

[tony.mon]

Why don't you take it a dyno outfit with some idea of hom vtr's work, and have them make the adjustments?
These engines aren't always intuitive, they don't follow the rules very well.

For example, fit a free flowing air filter, do some airbox work and gas flow the heads - more air getting in, so you'll need bigger jets to fuel accordingly, right?

Wrong.
Actually, you'll then need to go a fair amount smaller 9n mains, and depending on your current setup, possibly also on pilots.

You just need someone that has played Vtr games previously.
And who understands that different mnfrs jets don't match....

Oh, and who knows that these run best a little richer than classic stoichiometric ratio.

[shoarmadude]

Thanks Tony,

whats a dyno outfit? You mean go to a shop to tune?
Well I dont have a shop close to where I live that has experience with tuning or that is Honda racing tuning pro or something like that, and I dont have the time or the money to spend hours or days to drive up and down to tune it to perfection.
Thats why Im trying it by myself and using the forum for info and help.

From all the reading Ive done the last few days, I figured that these bikes arnt easy to get perfectly tuned right.
Lucky for me I dont want it to be perfect, I just want it the best it can be, the best I can get it doing it myself using all the info on the world wide web. Perfect doesnt exist.

Why my jets are mixed up or where I got them from, I dont know.
But if Im right, I need to use jets of the same brand in both carbs.

[tony.mon]

Yes re using jets from the same manufacturer, they all use different measuring methods so a 185 of one make is different to a 185 from another.
You can work out the equivalent, I posted up a comparison chart in the workshop knowledgebase years ago, but don't know if its still there.

It's a lot easier if you just stick to one make, eg either Keihin or Dynojet.

[freeridenick]

I agree with Popkat that lowering the needle may make the lean part worse. Dynojet don't recommend different sizes front and rear, iirc, and I found better results with Keihin.

[VTRDark]

Dyno Outfit



Your going by an old dyno chart. This wont be as accurate as it was years back. I would start with giving the carbs a good clean and more importantly the air filter. When was the last time it was washed and re-oiled. Is it the BMC Street or Race filter as they both behave very differently. The Race behaves more like a K&N and the Street is closer to the Standard Honda filter. Just sticking the a standard Honda filter in may improve things for the better. Quick simple fix and easy to revert back if it's not better. You could try shifting the needle but this is then going to have knock on effect elsewhere. It's best to start on the lean side and richen up towards the high end. There is no preset mixture setting as every bike is different and those settings you have are a baseline to start with. It's amazing how much a difference even a 1/4 of a turn makes. But your opening a can of worms here. Once you start changing things it wont be long before you start changing other things to compensate and before you know it your a long way off the chart your trying to use as a guide. Be prepared for pulling the carbs on a regular basis and making small changes one at a time here or there in the aim for perfection by feel and fuel efficiency.

[shoarmadude]

It's a lot easier if you just stick to one make, eg either Keihin or Dynojet.

Ok, Ill try to cop a few new mains from the same brand so I cant mix them up if theyre the same.

[shoarmadude]

I agree with Popkat that lowering the needle may make the lean part worse. Dynojet don't recommend different sizes front and rear, iirc, and I found better results with Keihin.

Thanks Ill look for some Keihin mains.