Stockish FXR Dyno

[John_H]

GPR have taken my FXR Smurf bike away for some 'hotting' and Scott sent me the initial dyno run today, with no work completed on the bike. Only mods are 30mm flat slid carb and pipe.

Dyno recorded it at 16.8 stock which I was surprised at. I knew it seemed to have good power but didn't expect it to be up that high. Dyno pic is below with Rich's (Etherington I think) bike, which they recently worked on as a comparison.

[mr bucketracer]

have a look at the ese boys run , pipe and carb not much in it , its the stardard carb that kills the power big time , with a goodish not to over kill pipe works good with it

[Drew]

Two different dynos, the comparison should be actively ignored.

[mr bucketracer]

Two different dynos, the comparison should be actively ignored.

i set my dyno up of my old dynojet150 so going to be not much in it . we also run the same program as glen and kyle at the start , that was around 3-3.5 hp less witch would make it around 13.5-14 hp just to compair stuff

[Drew]

i set my dyno up of my old dynojet150 so going to be not much in it

It's still bad to promote comparing dyno charts.

Question though. Is a dyno more accurate the lower the power, or the higher? Less slip (or none at 17 ponies) at the lower end, but no chance for the distortion to be overcome in the running surface of the tyre at the lower speed.

[mr bucketracer]

It's still bad to promote comparing dyno charts.

Question though. Is a dyno more accurate the lower the power, or the higher? Less slip (or none at 17 ponies) at the lower end, but no chance for the distortion to be overcome in the running surface of the tyre at the lower speed.

you got me there , all i can say is the maths behind a rolling road dyno(program) been just a weight would be well sorted . no way you would get a low hp engine to slip unless you did not sit on it or tire it down .. standard fxr 14.3 to 14.5 hp as long as its not been messed with

[Drew]

Without having to worry about slip, what sort of pressure are you running in the tyre?

[Sketchy_Racer]

Without having to worry about slip, what sort of pressure are you running in the tyre?

I run race pressures on mine. Can get "more" HP when running higher but consistency is the main thing.

[quallman1234]

i set my dyno up of my old dynojet150 so going to be not much in it . we also run the same program as glen and kyle at the start , that was around 3-3.5 hp less witch would make it around 13.5-14 hp just to compair stuff

Yeah that probably be right. Mine is a 14hp bike on our dyno and is probably the same as john's!

ps I think you only tried the older version of the software (the one in your youtube video?), the later version is completely different!
Anyway, will be good to see another quick bike out there.

[John_H]

Scott reckons with a standard carb it would probably dyno at around 14ish, so a better carb makes more of a difference than I would have thought.

[Rick 52]

have a look at the ese boys run , pipe and carb not much in it , its the stardard carb that kills the power big time , with a goodish not to over kill pipe works good with it

This was my FXR I think, it was a crash damaged bike with low K,s and had been well looked after, clean oil plug filter chain and so on, I got a carb of trade me, they said it was a DR250 but when it arrived it was a XR500 carb, with little time I made it fit and jetted it and it was not bad, just a little harsh off closed throttle.
I made a pipe from a DR 250 header and cut the standard muffler up slotting it under the seat unit, it was always a quick bike, ESE asked to see what power it made, 17bhp !! I was a happy man

[mr bucketracer]

This was my FXR I think, it was a crash damaged bike with low K,s and had been well looked after, clean oil plug filter chain and so on, I got a carb of trade me, they said it was a DR250 but when it arrived it was a XR500 carb, with little time I made it fit and jetted it and it was not bad, just a little harsh off closed throttle.
I made a pipe from a DR 250 header and cut the standard muffler up slotting it under the seat unit, it was always a quick bike, ESE asked to see what power it made, 17bhp !! I was a happy man

amazing what a good carb can do , before i pulled his engine out i put a standard carb on with airbox and made 14.1 hp . if only i new that when dad run the fxr back in 2000 in tim gibbs winter rounds , all we found was changeing the standard pipe lost power

[AllanB]

Haha I thought from the title it was a Harley on the dyno - then I saw the hp and had a goggle.