PDA

View Full Version : EFI performance mod possibililties?



The Tin Man
09-03-2008, 10:41 PM
This is my theory for guys looking to gain extra performance out of their Buells. Please correct me if I am wrong. I have a vast knowledge of snowmobile racing but none with any performance relating to bikes. I have a 08 XB12Ss but have no intentions of trying this mod. The purpose of this thread is to talk it out amongst the Gurus of this site and see where it leads.
Here's where my theory comes from...

On Arctic Cat EFI firecat 700's the fuel can be reduced before it gets to the injection system. The sleds are pretty rich from the factory and being fuel injected can't be leaned out as easily as carbed models. I am not sure how Buells come from the factory but I am thinking rich due the smoke coming out of mine during start ups and the amount of oil I have to keep adding to keep it topped up.
BMP or Bikeman performance makes a mod for the firecat to reduce the amount of fuel read HERE. (http://www.bikemanperformance.com/products/product_info.php?cPath=41_24_195&products_id=138&osCsid=1396bf97618172304bf909bb51c7b913)

This should be pretty much self explanatory. Now what do you guys think of this on a Buell. Any guys like modding their bikes and are interested in trying this or am I out to lunch on this idea?

GatorBuell
09-03-2008, 11:23 PM
Most Buells come from the factory running lean, there are some fuel and spark controls that piggy back on the ecm. Dobeck and power commander allow you to add fuel to different rpm and throttle positions adding performance. Most owners use this when adding a high flow filter and exhaust system that will make the bike run dangerously lean. Then there is the ECMspy program that gives you full control of the ecm. The problem with ecmspy is you have to have a dyno or a wide band 02 controller and a data logger to make the correct adjustments on the bike, too lean and BOOM! you lose your motor and too rich you fowl a plug.
I don't know if reducing the Fuel by restricting the flow is a good Idea. It would be much easier and safer to use a piggy back controller or remapping the ecm.

The Tin Man
09-04-2008, 01:16 AM
Again this is me using my knowledge of snowmobiles and trying to apply it to Buell motorcycles. Works on the firecats and is one of the best mods for them. Adds 2-3 sled lengths on 1000 foot drag races.
What is does to a motorcycle is a bird of a different feather.

The Tin Man
09-04-2008, 08:36 PM
Anyone else have some input into this?

gbalias
09-05-2008, 01:06 AM
the main thing i would worry about on the buells is the fact that with a lower pressure, you run the risk of the fuel not atomizing properly and resulting in a poor burn. in all my experience tuning EFI systems, to reduce or increase fuel, the LAST thing to change is pressure. and then it would only be changed if there was an outside force acting on it (ie: forced induction where a positive intake air pressure would have to be combated with a directly proportional increase in fuel pressure.) to do it properly on our bikes is to leave the pressure and adjust the time the injectors are open. aka ECM tuning.