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Your air/fuel mixture is not constant throughout the rev range.

really, how do you know that?

do you realized that dyno test is run at WOT up to 6500rpm?

IF it was a carbed bike then it would be a main jet only air/fuel

but it is an EFI bike, which as I said has the Triumph TORS software map

respectfully, just wanted to make sure the correct facts are understood
 

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Sorry Norton828, your service manager is either throwing you a line because he doesn't know how to adjust the fuelling or really doesn't know what he's talking about. You will never get more BHP from a Hinkley Triumph twin running an AFR of 15:1 compared to a more typical 13:1 AFR.

Here's a dyno graph (DynoJet dyno) of a factory spec. Bonnie compared to the same bike with virtually the same mods as yours. As you can see the top end is around 63bhp which is only 5% more than the factory spec bike, but that is to do with the TORS limiting the top end. But more importantly with TORS your mid range should increase by up to 17% which you can really feel when riding.

With a 15:1 AFR at WOT you will not feel this difference and your engine will be running much hotter than ideal.

 

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sorry Pieman, we will just have to disagree

are my eyes bad because I cannot see the air/fuel mixture specified in the two graphs so that I can see how you arrived at your conclusion?

if your charts are presented to prove your belief that a 12.75 mixture produced more hp than a 15 to 1 mixture then I cannot see how exactly you have proved that

can you tell me what I am missing on your charts that proves that?
 

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My mistake, the AFR is on there now.

I can't produce a comparison WOT dyno graph with an engine running at 15:1, because I wouldn't run an engine like that. My concern was for your engine, your service manager is incorrect.
 

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2012 T100

interesting that my air/fuel mixture was 15 parts air - 1 part gas..........
additionally he said that my 15 to 1 mixture produces about 2 more horsepower on his dyno than....... more typical 13 to 1 mixture
apparently a slightly leaner mixture produces more horsepower...... only up to the point of being too lean which he felt was around 16 to 1.....
I wouldn't even take my bike out of the garage if I knew it was running at 15:1!!

I think you need to take your bike to a different service guy and seek another opinion, or take heed of the guys who are trying to help here.

If your really running at 15:1 then even the seat of your pants should be telling you your down on power.
The guys dyno sniffer is likely wrong. Almost as wrong as his opinion on where ideal A/F should be! :)


V.
 

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Norton 828, did you get a print out of the dyno run? Usually a tuner will give you one and that would do a lot in helping everyone understand what exactly is going on. If you can post a copy of the print out here it would really be helpful. Also, you never mentioned what kind of dyno they were using and that's also always good information to know when discussing hp and tq numbers.
 

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I posted this in the tech section before I saw this section.
'Scuse me!

152 main, 42 idle, no changes to '06 needle or needle position, pod filters, 2-1 Mule exhaust, air injection deleted...what do you think is causing that fat spot in mid-range?
 

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Damn! That bike needs some serious tuning.
 

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It's your bike, so do what you want.
 

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Sorry. I just saw your other post on the Twins technical section. When I saw your dyno chart here with no explanation I wasn't aware of what you were doing. Good luck in solving the problem. I also have carbs and adjusted my floats and changed needles and settings until I got it straightened out, but that was 3 years ago and I forget which way I had to go on jets to fine tune it. You're doing the right thing by reading posts on this forum and getting info from the guys who really understand these engines.
 

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Len, to my untrained eye you have 3 different areas that need addressing. From 2,000 - 3,000 RPM, from 4,000 to 5,700 RPM and above 6,000 RPM. If that were my bike I would begin by finding out what changes had been made to the bike from stock. If you can get a copy of Jenks Bolts "Tuning Notes for the Triumph Modern Classic Family of Motorcycles" if would be very helpful because it explains where the pilot screw, piolet jet, needle diameter, clip position and taper, and main jet affect your air'fuel mixture. If you can't find it on the internet. Here's the web site http://www.bonneville.se/nedladdning/Hur man jettar.pdf

This is also a good source of information: http://triumphbonneville.org/my-jenks-bolts-keihin-cvk40-carb-jetting-experience/

Do you know what changes were made from stock? Also, do you have access to a dyno? The local Harley Dealer offers dyno runs (not tuning, just the run and you get the print out) during the winter months for $20. What I did was when I changed my intake and exhaust I changed jets and the pilot screw setting, then did a dyno run to see where I needed to make additional adjustments. I made the adjustments, did another dyno run and found that I was really close, so I made the final adjustments, balanced the carbs and did a final run. So it cost me $60 for the dyno help to get my bike spot on. As you can see from my final dyno run, I got pretty darn close, and I'm happy with the results.

I hope that this helps some.
 

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Stan, if you didn't get to read the response I put in the other thread, I discovered someone had put shims under the needles!

I'm 99% sure it wasn't me but, regardless, it's at least a clear place to make corrections from!

Thanks for your interest!
 

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im wondering why so many of these fuel curves are all over the place. lean to rich and back again........strange that the AFR cant get dialed in and go 13.5 across the board...........
 

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Most on here are running carbs and the carbs can't be dialed in perfectly without a load of faffing. Most have EFI now but the carb bikes make more power..... Even with the fueling off a touch. The EFI is better for mpg etc because the fueling can be controlled better but carbs like FCR39's are very adjustable too and can be dialed in much closer than the stock carbs.

Chris.
 

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im wondering why so many of these fuel curves are all over the place. lean to rich and back again........strange that the AFR cant get dialed in and go 13.5 across the board...........
Read my post above and check out the links that I included. Those links explain how the air fuel screw, jets, and needle affect the fuel at different RPM. Triumph has the bike set up pretty lean when it's stock, (in order to meet environmental restrictions) however, as we make changes and as parts wear changes occur in how everything interacts, so we need to make changes to the different components to adjust the air/fuel mixture at different RPM and different throttle settings.

When I bought my America the fuel injected 09's had just come out and they had my 08 sitting right next to an 09 of the same color. I could have gone either way, but chose the 08 because I felt it would be easier for me to tune the carbs as I made changes to the bike, rather than getting the EFI and having to take it to a dealer for new maps every time I changed components.

But with that said, I believe that with a Power Commander you can use your computer to adjust the fuel injection at any RPM and throttle setting. I now have a Power Commander V on my fuel injected Moto Guzzi and have the capability of changing the air/fuel mixture at 250 RPM increments and at different throttle settings. It's a whole new learning curve, but has great potential for getting the bike running great.
 

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im wondering why so many of these fuel curves are all over the place. lean to rich and back again........strange that the AFR cant get dialed in and go 13.5 across the board...........
well for one thing 13.5 wont give the best power on these bikes on the top rpms.12.5 to 13.0 does
 
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