Road: On the dyno

 I got asked to pop over to my racing teams new den on a cold January evening to get some photographs of the team dyno for a bit of publicity.
The plan for it is to allow us to run diagnosis with various jetting and pipe set ups on our Classic race machines including; Yamaha RD250/400s, Suzuki X7s and a couple of Honda MT125s including my own RD250 as well as any other bikes we may be racing or simply playing with.
The subject of the day was Andy's RD250 which was in the process of being prepped for next year (much like the rest of our bikes) but still looks presentable enough to demonstrate our new piece of diagnosis kit.

After the shoot we slung the new CBR400RR on to see what she would do.
As I had only really run the bike for a brief time, at fairly sedate speeds and engine RPM's,
I wasn't sure what to expect.
I didn't even know what the bike was supposed to produce.
A search of the internet came up with various numbers but most seemed to sit around 50-55 bhp with the odd optimistic 60 cropping up.
This machine, at this stage, was basically unknown except for a micron race can, a clean (if a bit old) chain and missing ram air ducting.
Once the bike was on, front wheel locked in and an HT lead found; we let her warm up and got ready for the first run.
The bike took a good while to warm up but I had noticed that the gauge never really showed the bike fully warm the last time I was on the bike so we got things going at a third needle deflection.
Now I was unsure of what I was doing, having never done a dyno run and it is bloody loud in there so receiving instruction is a bit tough. Either way Andy saw me through and we managed a few  power runs with fairly consistent results.

She is kicking out around 50bhp at the rear wheel during each 5th gear power run. Apparently these FUCHS dynos aren't as optimistic as Dynotune's so they do read lower figures but I was very happy with the results regardless of optimisms.

The bike is producing good power having not really been touched since I bought it and more importantly at pushing for 30 years old soon!
As you can see from the curves above; the torque (blue) comes on strong and early where it stays, for the most part, till 96mph where it swaps for power.
The horse power "curve" (red) is a pretty straight line up to 96mph where it flattens off to cut off at 14000 rpm.
Hp and torque both dip around 60mph, not by a lot, but noticeably. This could have a fair bit to do with cold conditions and fairly general jetting. As we don't have a lambda sensor yet, we don't know what the mixture was doing but it is a good indicator of leaning out in the mid range.

It was also interesting to note that the bike rapidly cooled when the fans were turned on. I will need to see if the coolant is good and if the thermostat is working correctly.

So what?

well this is a helpful base line for this machine. She is fairly healthy by the looks of things and could happily be run as she is.

I will be stripping back some parts to make sure there are no gremlins hidden away.

A simple clean could well see more power appear and this run doesn't take into account any ram air effect (if the ducting was even fitted to my bike) so it will be interesting to see what she produces after I have had a good fettle.