Once and for all, cranknumbers....

[Killerwhale]

Ok, i´ve seen a yamaha dealer booklet where all cranknumbers are specified and on the TRX it said 79hp on the crank (deduct ~16% for number on the wheel....right!?)
Dynojet dynos do what??
The dyno my bike was up on today has measured another TRX to ~78hp standard....so that dyno measures cranknumber....right!?

As topic....once and for all...~79hp on the crank...right!?

...also, you who is near or over 100hp, that ain´t on the wheel is it?? In that case it´s a humungous (read great) increase in power!!

[youngy]

Dynojet dynos read anything you like, the more use they've had the higher they read

[dfh]

Ok, i´ve seen a yamaha dealer booklet where all cranknumbers are specified and on the TRX it said 79hp on the crank (deduct ~16% for number on the wheel....right!?)
Dynojet dynos do what??
The dyno my bike was up on today has measured another TRX to ~78hp standard....so that dyno measures cranknumber....right!?

If your bike was on the dyno today what did you ask the operator to measure? As the customer you can ask for what you want, but if I was you I would ask for the rear wheel figure as that is what you actually have powering you along. What figure did you end up with?

DFH

[Killerwhale]

Ok, i´ve seen a yamaha dealer booklet where all cranknumbers are specified and on the TRX it said 79hp on the crank (deduct ~16% for number on the wheel....right!?)
Dynojet dynos do what??
The dyno my bike was up on today has measured another TRX to ~78hp standard....so that dyno measures cranknumber....right!?

If your bike was on the dyno today what did you ask the operator to measure? As the customer you can ask for what you want, but if I was you I would ask for the rear wheel figure as that is what you actually have powering you along. What figure did you end up with?

DFH

I was told rearwheel figure but don´t buy it really...because i don´t think the other TRX owner asked for cranknumbers. Ok, now the % of increase is the important stuff but it´s nice to know from start what one is talking about and what to expect of a big bore etc.

[phuk72]

FFS - you cannot compare dynos or readings.

As has been said, I've had mine measured on one dyno which showed 89 at the rear wheel and a few days later (at a show) on a dyno that showed 90 at the crank.

The only way you can do any sort of meabinful comparison is by using the same dyno to measure effect of miodifications and to sort the mixture.

[phuk72]

Oh - and Yamaha claimed 79bhp at the crank - I would be inclined to use 76 as a reference (which is what I believe is the dyno recommended base figure?)

And you should only lose about 10% from crank to wheel not 16%

[dfh]

I was told rearwheel figure but don´t buy it really...because i don´t think the other TRX owner asked for cranknumbers. Ok, now the % of increase is the important stuff but it´s nice to know from start what one is talking about and what to expect of a big bore etc.

Why don't you buy it?

[Killerwhale]

I was told rearwheel figure but don´t buy it really...because i don´t think the other TRX owner asked for cranknumbers. Ok, now the % of increase is the important stuff but it´s nice to know from start what one is talking about and what to expect of a big bore etc.

Why don't you buy it?

"has measured another TRX to ~78hp standard"

[cheesie]

all I would use a dyno for is fine tuning of the fueling hp numbers dont realy mean much if you can feel a difference wi9th your mods it dont reqaly matter what dyno says

[Killerwhale]

all I would use a dyno for is fine tuning of the fueling hp numbers dont realy mean much if you can feel a difference wi9th your mods it dont reqaly matter what dyno says

I agree fully!

[dfh]

I was told rearwheel figure but don´t buy it really...because i don´t think the other TRX owner asked for cranknumbers. Ok, now the % of increase is the important stuff but it´s nice to know from start what one is talking about and what to expect of a big bore etc.

Why don't you buy it?

"has measured another TRX to ~78hp standard"

In the immortal words of Phuck72... FFS. I does not matter a rats dingle what figure the dyno operator gave the other TRX. Forget the other TRX. Purge it from your memory. It never existed....

What does matter is what figure your bike has as a base line rear wheel figure. Do not go through the silly process of converting using an arbritary conversion figure to find a crank value. This is only of use in a posturing session at the local pub, and having lived in Sweden I know those are few and far between ( pubs I mean, posers are everywhere... ).

Now you have a rear wheel figure for your bike you have a starting point..... use this dyno and operator from now on so you can judge the results of your changes

I suspect a certain amount of 'performance anxiety' is tied up in your reluctance to cough up the figure your bike produced. If you feel your bike is 'inadequate' in the power department the first tuning step would be a full service. Valve clearances, plugs ,oil & filter, air filter and new chain & sprockets. Go back to the same dyno and do another run. If all is well a pleasant surprise awaits. Look at the fuel and CO2 figures. TRX's run rich with age.. do you need a jet kit?

What is possible? Firstly BMW f800s seem to get around 85ps at the rear wheel in magazine dyno tests. Of course 1 magazine dyno test by itself is useless, But a cluster about the same point is a reasonable guide. So 85ps at the rear wheel for a TRX should be a reasonable target. Phuck72 has a well reasoned set of mods to his bike and if you ask nicely I'm sure he can point you in the right direction.

DFH

[Killerwhale]

"in your reluctance to cough up the figure your bike produced"

...It´s all in there mate!

I don´t think my thoughts is coming thru here...
Dyno operator tells me it measures at the wheel.....fair enough....
I don´t buy that because another TRX dynoed by same dude....same bench and bog standard was measured to 78hp (wich by yam standard is about the crank value)

All i wanted to know was if this IS correct or if the TRX has ~79 at the wheel.

SOMEONE is wrong....either it´s the booklet i read OR the dyno operator.
If MY BIKE has 90 on crank or rear wheel....i really don´t care. But i was a bit worried when phuk said it was knackered!

[dfh]

"in your reluctance to cough up the figure your bike produced"

...It´s all in there mate!

Maybe its a language thing but I cannot see in any of your posts the rear wheel figure your dyno operator gave you for your bike. BTW were did Phuk say it was knackered?

As for the booklet, a) there is no statutory requirement for the booklet to be accurate and b) faced with the choice of a booklet or a dyno readout of my bike it would be easy to work out which to place faith in.......

DFH

[phuk72]

[. BTW were did Phuk say it was knackered?
DFH

I was wondering that

[youngy]

Unless you put your motor on an engine dyno, you will not be able to accurately find crank horsepower. So forget about it.

If you know of anyone with a rear wheel figure for a stock TRX then use that as a starting point. Otherwise forget it.

All you can do is put your bike on the dyno, get a number, then try to improve on it. Don't switch dynos.

Look at the fuel and CO2 figures. TRX's run rich with age.. do you need a jet kit?
DFH

No - he's running FCRs.