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Gas mileage/ horsepower


porterb123

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I am still new to the blackbird..I have had my 2000 model for a month or 2 now. The guy I bought this one from had installed a PC2/ full Yoshi RS3 and set it up to run on 93 octane. He said it Dynod out to 158 HP.

Does this sound correct?

Also I'm getting around 30 mpg around town and 35 mpg on the interstate with 70 to 90 mph cruising.

How does this compare to your experience?

Thanks

Porter

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set it up to run on 93 octane.

WTF does that mean? How do you "set up" a bike to run on 93??? I didn't think the PCIII allowed for ignition advance changes, but I could be wrong. If I am, take it back and have it turned back, since it's well proven that more advance on the XX does absolutely nothing except maybe damage the motor in the long run.

The HP might be optimistic. I ran 147-149 stock with ram air pressurized to 110 MPH, and that was on the high side. A full system (Akrapovic) has been shown to add around 7-8 HP.

The MPG makes me think it is running too rich.

Has your bike been re-geared with a sprocket change?

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Earlier this year when it was cooler, I ran 137hp on the dyno. This month (read: really fuckin' hot) I ran 132hp. All stock with Two Bros slip-ons.

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I thought we had that discussion once before here. On a dyno, advancing ignition on an FI XX did nothing. Not 1/4 HP, nothing. Zippy. It's the only time my bike's had 93 octane in it. That changed nothing either. I spent 9 hours in the dyno room that day with the two founders of Dynojet fucking with everything possible. In the end we learned that we can eliminate the 5200 RPM fueling problem with a little richening, but that's it.

I've been building motors since I was 8 years old. I built (hand made) my first ignition coil at 5 years old. Sure, I had guidance from dad in both cases, of course. Built my first go kart with a welder and scrap iron plus a dead chainsaw motor at 12-ish. That one was on my own.

Just because I haven't fucked with THIS bike doesn't mean I haven't fucked with every other bike I've owned. That was my objective with this bike, nothing to fuck with, just ride it.

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You don't still have a pc installed, do you?

I never tried a PC. I was working with a new product that the Dynojet guys made (they sold Dynojet). Unfortunately, the FI system on the XX is too smart. It sees that their device is holding the injectors open longer than expected and assumes they are defective.

see an improvement is in mid and lower RPM acceleration and driveability--at partial to nearly full throttle.

We were trying to tune out the jerkiness just off idle and the 5200 RPM dead spot. The timing changes did absolutely nothing for either. On the road it felt exactly the same. It was only adding fuel that helped.

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We were trying to tune out the jerkiness just off idle and the 5200 RPM dead spot. The timing changes did absolutely nothing for either. On the road it felt exactly the same. It was only adding fuel that helped.

Maybe a well-tuned exhaust system would have had different results with timing changes? :???:

A restrictive exhaust system will result in intake back pressure, which would lower intake charge volume. I know by just adding slip-ons to mine, I had to lower the idle. If pipes made that much difference at idle, then how much difference could they make at higher loads?

A full system should have even better results.

On any engine I've built, I aim to apply as much part-throttle advance as possible, which helps mileage, midrange power, and throttle response.

Can't say for sure with the XX, though, and will have to believe the guys that have actually tried this. :)

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135 for me on a model 150 Dynojet dyno. 40mpg with "average" rideing.

47mpg really takeing it easy.

Pete, I would sell my soul for 40mpg. And that's just cruzing.

My bird gets an average of 29. I feel like I'm chasing gas stations.

'97 K&N and Jetted 150hp.

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Maybe a well-tuned exhaust system would have had different results with timing changes?

According to them, an exhaust system generally won't make a difference on the timing unless the stocker is pretty bad. They seemed to think the stock exhaust was a pretty decent design. We had originally talked about bringing in another bike to test on, one with an exhaust system, but after seeing mine they said it wasn't relevant.

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I've noted time and time again that I have ALWAIS had shitty millege when compared to any of my ridding buddies. I compared with a 2002 F4i, 2002 SV650, 9? SECA 2, a few 750 Gixxers...

Long rides or top speed runs... I always get the shitty mpg.

The only explanation I have is this:

I sit high up wind in the chest up to 170kph... ALL THE TIME. So... much more drag and I kill any aerodynamics the bike has... hence the shitty mpg. I see nothing else.

My bike is stock.

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I've got a riding buddy with an older Kaw ZX-11. All he has done to his ZX, is a custom exhaust (that he built himself) and some careful jetting on the dyno. When we ride together, he consistantly gets 15% better mileage than I do. If we ride hard, I'm in the low to mid 30's, he is in the upper 30's to 40. If we ride easy, I can sometimes get 40. He gets over 45. It's disgusting.

Mileage is important to me on long distance rides. Lately, he's been bugging me about letting him set up my carbs. I think I may take him up on it this winter. There is no reason why I cannot get the same mileage from my bike as he does. The engine size is the same, and the Bird has better aerodynamics.

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unless you ride like me... I don't think aerodynamics makes that much of a difference (ZX vs BB) ... Are you much bigger than he is? Do you wear syntec gear vs him tight leather? .... I thing your body is the biggest source of bad mpg... ie ridding style.

Hey.. I'm looking to prove my theory!

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Good questions. We have been riding together for years. Our styles are almost identical. (gear selection, how we take corners, etc.....) I ride at a slightly faster pace, so I let him lead most of the time.

We weight about the same, but I am 4 or 5 in. shorter and.......of course........wider.

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I'm always a good 15-20% harder on gas than anyone I ride with.

Gas mileage usually varies the most between riders due to throttle control during acceleration. In second place comes the actual characteristics of your bike vs. others.

I'm a fairly sedate rider, :smokin: and the technique that I most often use is to let the bike catch up to a certain throttle setting. Inotherwords, say you're shifting to 3rd gear....throttle off....then reapply a set level of throttle and let the bike accelerate up to that setting. When you max out at that throttle setting, grab the next gear and start again.

Continuing to twist the throttle back during acceleration is where the mileage is lost. This is also where the fun is at, so figure out what's important to you!

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So my theory does'nt really stand...

I'm intrigued to find a reason for this... I'm always a good 15-20% harder on gas than anyone I ride with.

He spent quite a bit of time on the dino with an exhaust gas analyzer doing part throttle runs.

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