Diiss won voz avter the engine voz a big bore
 

It was much better to ride than to talk too:lol: On the previous graph which was running the ITG filter and 45/50 open termis you can see the bike spike on the bottom end which was causing problems and we never really got rid of. this run is with the blue base line as the bore without the commander running on Alans 853 chip and the red line after the commander was mapped also from Alan, both with the 54mm system

You can see how the bottom end has cleaned up
 

with the commander mapped. I needed glasses to read it but it says 110.6 summit up from 105.4 without the PC2. the air fuel line is lurverlly. but the top end is crap:o. You expect the torque to go mad and it did, from 55 on the old 748 engine to a max of 65.5 but with a 54mm full system where are the rest of my ponies :ninja: Hence gasflow. All figures were measured at rear wheel. Enjoy:P

Crikey didn\'t expect this
 

Well the gasflows done ! The following graphs show the results. for those with glasses here's the low down. Bike now puting out 116.3bhp at the back wheel at 10'500 rpm but it actually does 116 from 10'000 and stays over 115 all the way to 12'000. From making 50bhp at just before 6000rpm the sps cams kick in a it fecks off to 110bhp by 8300rpm. But thats not the good bit:devil:

The torque is unbelievable. it's puting out a peak of 68.0ft at 8500rpm and over 60ft from 6 to 10'000rpm awesome.

Now for the crap bit. The bottom end fueling is somewhat suspect. without fail the bike will cut out while idling even when it's warm and sitting at traffic lights, :( oh dear or trailing the clutch at low revs. checked all the fuel lines and adjusted the idle speed, no luck. Hoping to get some dyno work today.

Am I pleased ? Yes, and broke £990 pounds please. It's the closest I'll ever get to a race bike that won't need rebuliding after a day out, i'm chuuffed and a little scared first time back on the banana in a month and a half and taking it easy, whoa there boy:lol:

graph two, torque
 

The blue lines are the gasflow before the commander was mapped, apart from the last one where HM racing kindly compared it to an 853r that makes 118.3peak hp but gets mullered by mine right through the range, nice:P

graph 3 gearing thingy
 

I'm now running a 36 tooth renthal and it's still trying to rip my arms off, had a 'trial run' yesterday and power stays solid until about 145mph then carries on but i didn't get that far:lol:

Job done
 

Slight hicup at 9000rpm, but you dont feel it. bye bye 853r. :roll:

Do you have locations and phone numbers for these tuners? There is nothing I can see in the links page.

Ta,

Rob

It's interesting that you got a dip in the horsepower curve at 9,500 rpm after you gas-flowed the heads. I suspect this is a resonance effect associated with the airbox volume. For example, the 748R comes with a larger (14 liter vs. 8 liter), two piece airbox. To accommodate the larger air box the 748R frame is also slightly different, so they're are not interchangeable with a standard bike.

You can test my theory by temporarily increasing the airbox volume, by lifting the fuel tank away from the lower section of the airbox on a future dyno run, or perhaps make one of your future dyno runs without the ITG filter (since it fills-up some of the airbox volume.)

As to the low rpm stalling problem, a too-smooth intake tract can limit the creation of air vortices that help in the mixing of the incoming air and fuel droplets. Unburned fuel that drops out of suspension acts as a damper on combustion. At higher rpms the intake air velocity is higher so it's less of a problem.

Keep in mind too, that intake air velocity and efficiency in filling the cylinder is also affected by the throttle body diameter. 748's use 48mm, 916 use 50mm, 996 dual injector use 51mm, and shower injector models use 54mm (with the 748R being restricted down to 48mm at the bottom of the manifold.) The early 748's came with 50mm throttle plates, but were restricted after the plates down to 44mm which is why a number of 853 big-bore owners have back-fitted 916 50mm throttle bodies.

Thanks shazzam .
 

YOU both have ooo 2 ooo :)

Mods, so far................
 

Well,

So far the bike has carbon termis + chip. A full monty service, 853 kit and a minor bit of head work from Sigma performance. :devil:

Much more to come.:roll: Oh yes!