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Discussion Starter · #1 ·
Hey my buddy went to school at the wyotech school for motorcycles, recent graduated. Kind of had an interesting opinion on what fuel tuners do. He told me that when the manufacturer builds a bike that they have to do an emission test. When they run the emission test they dont check it thru the entire rpm range just a certain rpm for a certain speed and the manufacture sets it to as lean as it can run at this exact rpm. The manufacturer knowing that most will never run at this specific rpm they will never tell the difference. All the tuner is suppose to do is richen up that rpm range. He says that when aftermarket exhaust etc is installed you get a hesitation at a certain part in the rpm range and it doesnt hesitate all the time etc. Just thought this opinion was interesting or if its actually backed up by something.
 

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Ya just a couple of days ago there was a post about a article about the need or I should say no need for a fuel programer. It was a long, but extremely interesting article. I'm starting to think that I'm going to try the mods without the fuel program and see what performance I get from my bike. I've always seen Dyno's of factory bike and then bike with exhaust, performance fuel intake and fuel programer. The later is always a great improvement, but I've never seen a Dyno with the new exhaust, air intake and no fuel programer. I'd like to see that, but it would have to come from a private test as a company has a stake in the final result.
 

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You will need a tuner when you change the air flow through the engine... A tuner helps out throuout the entire rpm range and when you add exhaust and intake without a tuner your fuel requirements go outside the parameters of what the stock mapping was designed to do. Changing exhaust and intake also changes how the engine produces power (torque curve) so the tuner is designed to adjust for that.
 

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WLFPAK65 said:
Well Said Yose!!
Thanks... I'm also a WYOTECH grad and have been building cars and bikes for the past 14 years. Ive done accouple of custom fuel injection setups. 63 corvette with a SBC 350 with a Edelbrock MPFI unit edelbrock said wouldnt work... and a 2006 chevy 4.8 with a procharger and 15lb of boost & 500 rwhp are the most recent two...
 

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i can attest to the affect just adding the exhaust does. I now have a condition at 25mph in 1st gear and the same at 35mph in 2nd gear where the engine leans out to the point where it cuts in and out. Everywhere else it runs fine. If i accelerate through those two zones there is no issue but if I try to maintain a constant rpm at those speeds in the related gear, I get the sputtering.
 

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I don't know much about all this mapping stuff, but just curious, why hasn't someone come up with a way to change the mapping on the stock system? I would think that it should just be a programming change. I don't understand why this could not be done by a dealer. It sure would save having to go to an after market system, and Yamaha would have one more + in their favor.
 

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Yamaha has "locked" there computers. Ya if someone wanted to they could design a programmer (anything is possible) to reprogram the ROM chips in the ECM. but with how often people make changes vs the ease of designing a stand alone ecm to by pass the factory. Its easier for someone to install a stand alone tuner such as the cobra then have them bring there bike to a dyno shop every time they change something or try something new.
 

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ya that would be nice. but from my experience (my brother use to race karts and used yamaha motors) when we tried for a factory sponsership for a yamaha works motor. they said they would sponser a motor but we would have to pay for the two techs that come with the motor to fly out. they would install it, they would tune it, after the race, the would remove it and fly back with it. every race... they dont like to give out information on how there tuning works or operates. so thats another issue is someone would have to reverse engineer it.
 

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Canadian said:
I don't know much about all this mapping stuff, but just curious, why hasn't someone come up with a way to change the mapping on the stock system? I would think that it should just be a programming change. I don't understand why this could not be done by a dealer. It sure would save having to go to an after market system, and Yamaha would have one more + in their favor.

fuel programmers are basically the same thing as jet kits for carburetors instead it's electronic. Not sure on this bike but some you can have the stock mapping changed example my gsxr-1000 I have a powercommander on it though so I can tweek it for different riding conditions
 

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Discussion Starter · #14 ·
I had a condition with my Cobra Dragsters that at a certain rpm I would get a hesitation but could pull right thru it. I had already bought a cobra powerpro and a air intake and after with all three mods I still have the same hesitation and im running what's arguably the best tuber for our bikes out at the moment.
 

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Discussion Starter · #17 ·
I get the hiccup in 1st at 22-27mph and 2nd 33-37mph sometimes I notice it sometimes I dont. When it does it and if I keep it in that range itll pop back thru the air filter and hiccup. otherwise its an awesome gain running down the hwy.
 

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Discussion Starter · #18 ·
It seems like I read something on here where someone dynoed their stryker. If I recall right there mods was exhaust(not sure but some aftermarker) an aftermarker air intake assy and a powerpak tuner. They had it custom tuned and it made 70+hp to the ground, and 61hp stock form. Thats pretty good considering you loose about 20% thru the driveline. I believe the stock flywheel hp is 73hp and 79ftlbs of torgue. Pretty impressive that definatly put the stryker up against its bigger bro the raider in stock form, but if you mod a raider itll just run away from there.
 

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What I'm wondering is why the manufacturers can't put an autotuner on their bikes from the factory. At any rate, since I've already bought it and paid for it, I will continue to believe that the Cobra Tuner has made a huge improvement. Can't stand even thinking I wasted that money.
 

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Stryker said:
Canadian said:
I don't know much about all this mapping stuff, but just curious, why hasn't someone come up with a way to change the mapping on the stock system? I would think that it should just be a programming change. I don't understand why this could not be done by a dealer. It sure would save having to go to an after market system, and Yamaha would have one more + in their favor.

fuel programmers are basically the same thing as jet kits for carburetors instead it's electronic. Not sure on this bike but some you can have the stock mapping changed example my gsxr-1000 I have a powercommander on it though so I can tweek it for different riding conditions
Technically, you can access the base maps on the stryker through the diag mode on the readout screen. You would have to have a dyno and an exhaust sniffer to get them adjusted properly.
 
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