20HP on 160cc engine! OORacing

[Despise]

Old thread I know but I thought I would bombshell this question once and for all.
This is an email from adrian at ooracing about 2 years ago about how they conduct there dyno runs

Hello

Ok we take readings from the final drive on the engines but we class it as
at crank. Why we don't use the big rolling road i.e Dynojet 250 is the Eddie
currant roller weighs around 150 kg and will not register well under 25 bhp
+ it tends to iron out a lot of spikes in the torque curve.
This is why we had a one off dyno with a 40 kg roller/fly wheel that
connects to the final drive.
__________________________________________________________________

Notice that doesnt account for anything when taken by the crank, no wheelsize,sprockets etc.. to account for, just pure delivery of engine output

In my opinion this is the same as what china do, as base test (1 in a 1000) of every engine as a benchmark of hp, would this be right? I hate to argue about hp figures but fleabay (ebay) aclaimed yx140's at 14hp rear wheel has never been correct in my opinion

cactus said in his previous post, its pretty spot on but this shizzle has been blown out the water already right

-comments-

 

[thump*140]

yeah Egay hp figures are full of it...

example: YX140's advertised as putting out 14hp at the rear wheel...
I run a Lifan 140, stock capacity, oko28mm, 32-44mm H-bomb pipe, port matched, 7mm cam, IRK and cleaned up head, manifolds and cases...

On the dyno, this combination ran up 9.9HP at the rear wheel, running a 12'' rear, with 17/37 gearing...
Now i ran this up against Satchy's YX140 which has almost identical mods, with a slightly different exhaust, and i believe his has the stock YX140 cam...

Now i weigh about 90kg... Satchy at a guess, would be somewhere in the low seventies... the Lifan hosed the YX both in acceleration and topspeed...
Now for arguments sake these two bikes are identical aside from the badge on the motor... Both Twin Trellis Monster framed midsizes, running the same suspension... so they weigh the same...

So a 69kg Monster-framed 140 Lifan, with considerable mods, dyno'ed at 9.9hp, was outperforming a YX140, with similar mods, but undynoed...

I think we can thus see, that the Stock YX140 does not produce anywhere near 14hp at the tyre... if a modded one is pulling somewhere in the vacinity of 8.5-9 hp, then a stocker is going to be close to 6.5-7hp at the back tread...