 904 Dyno Result
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Joined: Jan 2005
Posts: 122
Adjunct
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OP
Adjunct
Joined: Jan 2005
Posts: 122 |
Hello! Yesterday I had my bike on the Dyno. The result was kind of mixed as you can see from the graphs. The BHP and torque are following Roadworthys latest curves pretty good up until just above 6 000 rpm. Then something strange happens that I have not seen on a 790 with BB; the curve flatens out very quick! Any clues on why? Usally on my previous Dyno runs the curve is going straight up until the rev limits kicks in. Regarding the air/fuel ratio I'm thing of going down from 155 to 150 on Main. Low end was god according to the Dyno man. The mid range dip seams to be built into some of these bikes it looks the same as Roadworthys.   Thankfull for any inputs! By the way the Torque is displayed in Nm and 73.5 Nm is about 54 FtLbs which is not bad. Hasse
Hasse TBA -02 Pre-Fire Cardinal Red, Wiseco 904, Thunderbike pipes, Freak
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Re: 904 Dyno Result
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Joined: May 2007
Posts: 6,432 Likes: 1
Worn Saddle
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Worn Saddle
Joined: May 2007
Posts: 6,432 Likes: 1 |
Something's not right about about this chart and maybe his Dyno needs a calibration, the torque and HP curves don't cross at 5250 rpm where real world physics dictates they must intersect. Still, it's impressive and makes a BB kit the top item on my America wish list.
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Re: 904 Dyno Result
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Joined: Aug 2007
Posts: 10,721 Likes: 5
Should be Riding
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Should be Riding
Joined: Aug 2007
Posts: 10,721 Likes: 5 |
Quote:
the torque and HP curves don't cross at 5250 rpm where real world physics dictates they must intersect.
that really has me confused too.
If you are rich in the mid range, drop a sim or two out from under your needles
Always remember to be yourself. Unless you suck. Then pretend to be someone else.
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Re: 904 Dyno Result
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Joined: Jan 2005
Posts: 122
Adjunct
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OP
Adjunct
Joined: Jan 2005
Posts: 122 |
Yes, you are right there and I thought so also to begin with...but there is 2 things that fools us! First the scale is not the same on both sides. Second the Torque is in Nm not FtLbs and the Nm curves meet the Hp at 7121 rpm. And that is what they are doing if you look at the meeting value for both curves.
Hasse
Hasse TBA -02 Pre-Fire Cardinal Red, Wiseco 904, Thunderbike pipes, Freak
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Re: 904 Dyno Result
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Joined: Aug 2007
Posts: 10,721 Likes: 5
Should be Riding
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Should be Riding
Joined: Aug 2007
Posts: 10,721 Likes: 5 |
So 65hp and mid 50s in torque, real nice! Do you know what you started with, did you get it dyno'd before you did the big bore?
Always remember to be yourself. Unless you suck. Then pretend to be someone else.
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Re: 904 Dyno Result
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Joined: Jan 2005
Posts: 122
Adjunct
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OP
Adjunct
Joined: Jan 2005
Posts: 122 |
Yes, that was what I tought at least but the first thing my friendly Dyno man told me yesterday was that they had just recalibrated the unit so it is not comperable straight off.
Anyway it is a significant increase up until just above 6000 rpm. But then something happens. I expected it to run straight up to 70 before it started to level out and that what is puzzling me.
Hasse TBA -02 Pre-Fire Cardinal Red, Wiseco 904, Thunderbike pipes, Freak
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Re: 904 Dyno Result
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Joined: Feb 2008
Posts: 2,671 Likes: 15
Loquacious
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Loquacious
Joined: Feb 2008
Posts: 2,671 Likes: 15 |
I saw a 904 BB (790-based) dyno chart earlier this week when my 07 SM 865 was in for a run, & that 790-based 904 did peak at 70 HP.
How exactly are the carbs set up, & what filters are you using?
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Re: 904 Dyno Result
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Joined: Aug 2008
Posts: 90
Member
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Member
Joined: Aug 2008
Posts: 90 |
Are you running pod filters Hasse?
What it can't reach it spits at.
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Re: 904 Dyno Result
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Joined: Sep 2005
Posts: 3,816
Freelance Jedi Knight
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Freelance Jedi Knight
Joined: Sep 2005
Posts: 3,816 |
Quote:
Are you running pod filters Hasse?
he does
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Re: 904 Dyno Result
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Joined: Jan 2005
Posts: 122
Adjunct
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OP
Adjunct
Joined: Jan 2005
Posts: 122 |
Status report;
Three things convinced me that I was very rich during the WOT run. 1 the graph of course. 2 The fact that I reached the rev limit fast on 1,2 and 3 gear on ½ trottle with a leaner mix. 3 I went back to my old Dyno runs and found the that at the best earlier CVK run, resulting in a 'normal' increasing BHP curve until the rev limit I had a 145 Main installed.
So the conclusing was that I was very rich and went down from 155 to 145.
Yesterday and today I have been out testing and now it feels like I'm back in business again! Now when I cruise steady in 3 gear at 6000 and crank it WOT it pulls very hard all the way to the rev limit. So I'm pretty convinced now that I have my straight BHP curve ending somewhere around +70. Which remains to be proven but untill then I'm happy.
Regarding the filters, yes K&N that came with the Freak.
Hasse
Hasse TBA -02 Pre-Fire Cardinal Red, Wiseco 904, Thunderbike pipes, Freak
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Re: 904 Dyno Result
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Joined: Sep 2005
Posts: 3,816
Freelance Jedi Knight
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Freelance Jedi Knight
Joined: Sep 2005
Posts: 3,816 |
hope you will finish with CVK son and start to working out CR's 
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Re: 904 Dyno Result
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Joined: May 2009
Posts: 18
Complete Newb
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Complete Newb
Joined: May 2009
Posts: 18 |
Not trying to bust your bubble but HP and TQ must cross at 5250 for a correct dyno sheet.
fast freddy
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Re: 904 Dyno Result
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Joined: Aug 2007
Posts: 10,721 Likes: 5
Should be Riding
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Should be Riding
Joined: Aug 2007
Posts: 10,721 Likes: 5 |
Quote:
Not trying to bust your bubble but HP and TQ must cross at 5250 for a correct dyno sheet.
Quote:
Yes, you are right there and I thought so also to begin with...but there is 2 things that fools us! First the scale is not the same on both sides. Second the Torque is in Nm not FtLbs and the Nm curves meet the Hp at 7121 rpm. And that is what they are doing if you look at the meeting value for both curves.
Hasse
Always remember to be yourself. Unless you suck. Then pretend to be someone else.
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