Could it be that the engine hasn't loosened up properly yet.

I don't suppose theres any error codes in the ECU?

I only ask because if there are, it'd set some default values in and may screw with the fuelling.

I'd say at 900 miles the engine is not loose yet. Its take a couple of thousand miles from my own experiences.

I agree its probably not run-in yet, but its the A/F Ratios that puzzle me....

I should still get the same "gain" from the mods even if the motor is still not loosened up though, - surely?

Hi Daz...I haven't had the ECU checked for fault codes.....

Theres a good article in the latest superbike magazine. They take an S1000R to six different dynos and each one is different. There is a 13bhp difference between the highest and lowest reading. The article goes in to a fair bit of detail which may explain some of your concerns.

I would take the bike to a different dyno center, as I have never seen a XT660 produce the best peak HP at 16:1, something is wrong.

The dyno center said you A/F ratio was running at 16:1 on the fuel map you sent me, I tested it on my bike with the exact same mods & I was running around the 12:1, so something is up.

No 2 dynos will read the same, that is why when carring out mods you do a before & after run & measure the gains on the same dyno, the A/F should read simular from dyno to dyno.

Kev, the map you tried was a "modified" DNA Map Open Ackros. My custom map. (i.e. I came into the Dyno with this DNA Map loaded on my bike, and left the Dyno with the same map, but modified BELOW 40% Throttle, BELOW 4000rpm)

If I remember correctly, when you tested it, you gave me a figure of 100% throttle 5500rpm AF 13.1 on your bike,(perfect!), but on my bike it was 13.9:1 at the end of my dyno, and 16:1 at the start of that session. (remember...un-altered except BELOW 4000rpm).

Kev, now at 100% throttle 5500rpm, my "new revised" map is showing bang-on 13.2:1. (so if your AF readings, taken from your test are 0.8 of a point different at 5500rpm, I would assume that it would now read 12.4:1 on yours). And that would explain why I am 2hp down, from my best figures so far, at those revs.

It has been difficult for me to compare the lower throttle openings to your bike, as my O2 sensor plays havoc at the lowest openings, whereas you don't have an O2 Sensor. But yes, your bike was showing around 12:1 lower down.
Thank you Kev, for testing it for me. (I hope you will eventually be rewarded with a decent map for your bike, on 97ron ...if it ever comes mate!)

It cost me �180 Kev, for an initial power run and a custom map, so it is going to a very expensive move going to another dyno. And difficult to get a refund.

If you see my post above with the results, I have lost power the closer-down it gets to 13.2:1. Therefore, I believe that the AF readings are roughly reading 1 to 2 points out. (i.e. when it reads 14 it is only really 13 or 12.)........I think my best "gain" on their dyno is around their figures ABOVE 14:1.

I'm hoping Dynojet UK will get to the bottom of this problem, (it is an "Approved" Dynojet Centre) and then I can take it back to the same dyno, get it set up properly, hopefully without paying any more. I believe it is a fault with the dyno,or AF reading equipment, rather than my bike, and I will add that the Dyno Centre have been very good about my doubts, even though they think that I'm wrong.

Are there any bike shops that do free runs in your area, theres one near me that do them on a tuesday night to drum up business. Even if there aren't it might be worth going to another one and paying the �30 odd to get another reading.

Great idea, .....but I am not paying anymore!!!! �180 is alot to pay already.
I know a dealer in your area does free power runs on Tuesday evenings....who is it? It would still be about a 150 mile round trip for me...

Maybe if Dynojet UK can make an arrangement with another, more local, dyno to do a "free of charge" power run for me, then I will.