bike is in for a dyno monday

[dillthedog]

tears all the way home
well to start max power was 72.57 max torque 52.49
after adjustment max power 77.88 max torque 54.90
i am distraught

[youngy]

could be you have a problem, could be you got an honest dyno operator.

Do you have a chart to post? Be interesting to see the curve and also the correction factor used.

[philk]

I wouldnt get to hung up on the power figures.
Each dyno is different, so when one will show 90bhp another will show 75bhp.
I would see the dyno as a tool to optimise the set up you have.

More important is what does it ride like?

[Killerwhale]

tears all the way home
well to start max power was 72.57 max torque 52.49
after adjustment max power 77.88 max torque 54.90
i am distraught

As other says, 77,88 could very well be just right...i think i guessed 79??
I would worry about those tourqe numbers though....65-70 would be more accurate me thinks.
Also, what adjustments where made to gain 5hp straight off?? On the carbs? Then they had to be WAY off....

A graph here would be great!

[trixynut]

There is NO WAY fcr's and an acrapovic full system will show those kinda figures: something is wrong, either dyno or major set-up trouble. I've got fcrs and a renegade full system, nothing else, and power is 89bhp at the rear wheel, and the bike was noticably more powerful after I fitted them. Post up the chart if you can: be interesting to see what type of dyno it was too.

[Killerwhale]

There is NO WAY fcr's and an acrapovic full system will show those kinda figures: something is wrong, either dyno or major set-up trouble. I've got fcrs and a renegade full system, nothing else, and power is 89bhp at the rear wheel, and the bike was noticably more powerful after I fitted them. Post up the chart if you can: be interesting to see what type of dyno it was too.

I really doubt that FCR´s and acra full would give 23hp over bog standard....sounds as a crank number as mine are....does not matter in the case but i think that the number he got is a realistic number on the rearwheel (What factory pro call true HP)

[cheesie]

65-70 ft lb torque impossible unless it was bored out to around 1000cc, I wouldnt worry to much either about the hp readings if it feels better than it was before the fcrs then thats what you were after I know mine felt better far better

[youngy]

i'd agree with cheesie regarding torque.

the only way to compare figures between bikes is to put them on the same dyno.

[cheesie]

the only thing I could compare mine with at the time was a bog standard tdm 850 he had run on it before which came out at 69hp versus my 89.somthing

[youngy]

incidentally Yamaha claimed 82.9bhp DIN or 79.7bhp ISO for the TRX.

[dillthedog]

[Killerwhale]

Looks good to me, nice flat tourque curve and they sure did fix it from the first run!

[cheesie]

cant realy see it good did you ask what jets needle pos ect they used

[Killerwhale]

cant realy see it good did you ask what jets needle pos ect they used

Other than tourque and hp should meet a bit higher i think it´s fine...tourque directly up there and holds fine....HP almost linear (although you can see he used smoothing 5)...

What´s your concern??

[idl1975]

i'd agree with cheesie regarding torque.

the only way to compare figures between bikes is to put them on the same dyno.

Exactly! The ONLY relevant figure is the difference between your baseline and your modified figure on the same dyno AND in the same atmospheric conditions. Sure, there should be a true HP figure somewhere, but dynos don't usually show that with any signficant degree of accuracy. However, unless the dyno's very broken, it should be calibrated to itself, and hence back to back figures should show what your changes achieve. So you should only be disappointed if the comparative figures show same or lower modified numbers or, perhaps more usefully, a net loss of "area-under-curve".

Curve to me looks very good - no losses down to 3,000 rpm at all (and we know the TRX engine is no bottom-end powerhouse, unlike the 900SS, so that's basically as far down the curve as anyone would want to look), then a consistent gain with peak about 8,250. Result, I'd say.