Dyno Service-Local Help Needed

[SeekGod1st]

Guys,

I live in the local Pasadena, Ca. area and have been looking for a Dyno Service to help me get the bike running tip top. I installed a K&N air filter and a Scorpion exhaust. I have been getting a little backfiring when running the bike at 10k + rpms and then letting the bike decellerate when I stop. I put the orange 700 degree high temp sealer in the 3 connection areas for the exhaust but still have a little backfiring every so often (3-5 times in an hour ride around town).

I enriched the fuel mix by adjusting the c1 and c2 +24 each and the bike runs great, but since I don't know exactly how much to enrichen the mix I'm wondering if I did to much or not enough. I could just leave the bike alone and deal with the backfiring but in the back of my mind I would always be wondering if she could be tuned just a little better.

I called all the local dealers including Yamaha, Honda, Bert's, Temple City and none of them have a Dyno, one even told me that it is illegal to dyno any street bike here in California. That makes no sense to me, they can sell me the exhaust and all the aftermarket parts and then not tune it.

I did find Vance & Hines in Whittier, Ca. to Dyno the bike but he said it would be 2 hours and $170 to adjust the fuel/air mix. He also said he had a special meter that could check for any exhaust leaks. What do you guys suggest, I really value your opinions, especially you seasoned veterans.

I love this forum and even though I'm not always posting am on here 2-5 times daily just to check out what's going on. Is Dynoing my next step? Is $170 the going rate? Do any of you local guys know of somewhere else to go at a better rate? Any help would be appreciated and the cheaper the better.:thumbup:

 

[madmanmaigret]

Vance & hines is pretty reputable. they may be a little pricey (I am not local so this is a guess) due to their heavy involvment in racing and their name. Dyno is always good even if the bike is stock. You may want to call them and see if a power commander would be best before you tune.

Let us know how you turn out.

 

[Wavex]

Personally I think getting your bike tuned on a dyno is not going to make much of a difference (in terms of bike performance) especially if you don't have a PCIII... the occasional popping on decel is to be expected with an aftermarket pipe without a PCIII and Dyno tune. If I were you I'd leave it as is unless the popping is really constant.

However, if you really want to dyno your bike, the price they quoted you sounds about right... Apex Moto in Anaheim are good guys and they have a Dyno too... not sure how much they'd be able to tune with just the CO adjustments from the speedo though...

 

[SeekGod1st]

Personally I think getting your bike tuned on a dyno is not going to make much of a difference (in terms of bike performance) especially if you don't have a PCIII... the occasional popping on decel is to be expected with an aftermarket pipe without a PCIII and Dyno tune. If I were you I'd leave it as is unless the popping is really constant.

However, if you really want to dyno your bike, the price they quoted you sounds about right... Apex Moto in Anaheim are good guys and they have a Dyno too... not sure how much they'd be able to tune with just the CO adjustments from the speedo though...

It's more than just popping, even though she runs well she will backfire.

She definitely also pops though.

 

[Wavex]

Isn't it the same thing? Or are you saying you get backfiring from the intake somewhere??

Edit: IMO again, you put a K&N, and an aftermarket exhaust, which means you allow more air on the intake, and less back-pressure on the exhaust side, meaning you are running slightly lean, meaning you will get decel popping...

 

[Hellgate]

With a Power Commander you can really smooth the bike out and have a much cleaner throttle.

Probably not lean but still rich. These bike are rich stock and use three cats to clean up the exhaust.

Two reasons for popping, 1) less baffle so you are hearing more of what the stock muffler deadens and 2) because the bike is rich and the exhaust us open air is getting sucked into the exhaust system during power pulses and lighting off the any fuel in the exhaust system.

Once my bike was tuned the popping was about zero and it ran so nice.

Try these dudes in Simi Valley,Peak Performance Motorcycles in Simi Valley, CA yeah its a drive. Whatever you do don't got to a Harley shop. Or go to the AFM Roadracing forum and ask who is the tuner to see in SoCal.

 

[Wavex]

I've always read/heard that poppin on decel was due to a lean mixture... not rich...

edit: yep, per Wiki too: http://en.wikipedia.org/wiki/Back-fire

 

[SeekGod1st]

I'm confused now, is my bike too rich or too lean. I've heard both schools of thought, some guys say the bike comes stock lean and others say it comes stock rich.

Either way I enrichened the fuel/air mix because I added +24 to the c1 and c2 values on the bike. Should I richen it up more or lean it out? Should I get it Dynoed or should I get a PC3 and then Dyno it.

What do you guys think, she runs well right now, I have no problems with the powerband or topend.

 

[SeekGod1st]

I also noticed that the Scorpion cans are riveted at the seams and some exhaust is escaping out of the front side of each can, near the clamp. Do you think this is the contributing exhaust leak. Does anyone else have Scorpion cans and has noticed this, or are my cans defective.

 

[Hellgate]

Ahh Wiki...

That article is all over the map.

"Backfire in an automobile engine typically results from various malfunctions related to the air to fuel ratio. Backfiring can occur in carbureted engines that are running lean where the air-fuel mixture has insufficient fuel and whenever the timing is too advanced. As the engine runs leaner or if there is less time for the fuel to burn in the combustion chamber, there is a tendency for incomplete combustion. The condition that causes this is a misfire. The result of a misfire or incomplete combustion is that unburned fuel or flammable hydrocarbons are delivered to the exhaust manifold where it may ignite unpredictably. Another backfire situation occurs when the engine is running rich (with excess fuel) and there is incomplete combustion during the Otto cycle, with similar results."

Incomplete combution is correct. But that is typically caused because the motor is too rich. Many tuner keep adding fuel until popping goes away. What they are actually doing is masking the problem with too much fuel. In other words it is too "wet" to burn in the exhaust if you will.

The only way to "see" inside the combution cycle is via a 4 or 5 Gas EGA. With that tool the tuner can figure out what the combution cycle is doing and then tune for complete combution at various rpms, throttle positions, etc.

With proper tuning a bike will typically make more power, be more responsive and get better mileage.

Attached is my dyno plot. The bottom line is the 4 gas reading, note the difference between the two. Once the bike is tuned the total emissions are much lower and the power is up. What you are not seeing or feeling is the great throttle.

Many tuners blindly add fuel to acheive an air-fuel ratio that they pick out of the air. They assume that 12.5:1 or whatever it the "best" and they tune to 12.5:1 across all rpms and throttle. In reality AFV is dynamic through out the fuel map; from maybe a 12:1 to 16:1. It all depands on what the bike needs to acheive complete combustion. By picking a static AFV the bike tends to be soaked in fuel which actually hides problems instead of resolving them.

View attachment 23414

 

[Motogiro]

Personally I think getting your bike tuned on a dyno is not going to make much of a difference (in terms of bike performance) especially if you don't have a PCIII... the occasional popping on decel is to be expected with an aftermarket pipe without a PCIII and Dyno tune. If I were you I'd leave it as is unless the popping is really constant.

However, if you really want to dyno your bike, the price they quoted you sounds about right... Apex Moto in Anaheim are good guys and they have a Dyno too... not sure how much they'd be able to tune with just the CO adjustments from the speedo though...

:thumbup: Apex is who did my bike and it runs very strong...

 

[Motogiro]

Another reason to dyno is better air to fuel ratios which kinda keeps you motor happier. Unfortunately it really isn't a cheap deal cuz to tell the truth, you want a Power Commander and the dyno. I don't think you'll get any where near the resolution of tuning the CO settings. With the power commander you get it tuned at 250 rpm increments. I went through the same deal. Got pipes but could tell it was off. Got it tuned with a PC and been a happy railer ever since.