Bad gas mileage

B

brandocommando29

Registered
Hey guys, I'm a new Busa owner and new to the forum. After riding my bike and working on it for these past couple of weeks the tripometer says I'm getting about 25 mpgs. According to threads I have read a good running busa with a gentle throttle hand should be getting at least 30mpgs in the city and up to 50mpgs hwy. Here's a little about the bike:

- K2 w/3,600 miles
- Just changed oil to castrol 10-40 synthetic
- Has the stock air filter, recently checked it and its spotless
- Checked spark plugs, they are a little black (will be replacing them with NGK iridiums when I get home from work today)
- Put injector/top end cleaner with my current tank of gas
- Pumped up tires to ~42psi
- Cleaned chain/sprocket
- Has Yoshimura RS3 slip ons
- Does NOT have a powercommander
- Exhaust occasionally pops when I decelerate or hold steady throttle at lower rpms(<5k)
- No PAIR valve mod
- I ride mostly city, but do not ride hard
- The bike sat around since 2004, being started up and ridden very occasionally (I've only put 1.5 tanks worth of gas in it since I bought it)

Even though I have yet to change the plugs, I don't believe they will give me that extra 5-10 mpgs in the city the others are getting. I am beginning to think I will need a powercommander, but I have read that even without a powercommander and with slip ons I should be fine, but since the spark plugs are black that is an indication that it's running rich, correct?

My real question is has anyone experienced this and how did you fix it? Am I going to need to take it to a shop and get a powercommander/dyno tune? Or did I miss something that is an easy fix at home? (just got the haynes manual btw). Or am I just being silly and I should expect 25mpg city from the 550lb 1.3l busa even though my 2400lb 1.8l miata gets me 28mpg average... :banghead::dontgetit:



PS sorry if this has been addressed before, I tried searching for an answer but all I could find was that people would go without a powercommander and slip ons and still get in the 30-50 mpgs... even with a little exhaust poppage... :)
 
25 city is pretty normal to me its the stop and go and accelerating from a stop that gets you... and i would love to see a miata get 28 city since a smart car only gets 34 city on perfectly flat roads lol. Biggest thing with your mpg on your busa is your riding conditions and riding style also what grade fuel are you running... the bike is tuned for regular
 
well my miata gets 28 average... if I drive all city then ill get around 26, got the reciepts to prove it, but when I drive I try to get the best mpgs I can. Best I've done is 33mpg average for a tank, all hwy though. Anyway, I have been using premium in the busa, maybe next tank i'll have to try out regular and see if it helps. Always thought it was ok to go up in octane, just not down.
 
Was gonna ask about the battery. Change the plugs and put a thousand miles on it. I always got a dip in mileage when I first changed plugs on my '06. I figured the ECU had to retrain itself with the new plugs. If the mileage goes back up you're good to go. Check all vacuum lines and connectors on the airbox.

The slip-ons from everything I've read really shouldn't make a significant difference. If you have the previous owners contact info you could make sure he didn't go into the motor and sneak cams and pistons in on ya. It's highly unlikely that he would not have shared that with you, but you never know.

Best of luck, when I was trying for fuel mileage the bike would indicate 50 hwy and around 47 city. I don't have a lot of stop and go or heavy traffic in my area. So, yea, you have an issue or modification.
 
brandocommando29 said:
well my miata gets 28 average... if I drive all city then ill get around 26, got the reciepts to prove it, but when I drive I try to get the best mpgs I can. Best I've done is 33mpg average for a tank, all hwy though. Anyway, I have been using premium in the busa, maybe next tank i'll have to try out regular and see if it helps. Always thought it was ok to go up in octane, just not down.
Click to expand...

just a lesson learned spending the extra money for premium is more expensive than the mileage your going to lose.
 
card16969 said:
just a lesson learned spending the extra money for premium is more expensive than the mileage your going to lose.
Click to expand...
Unless the bike is modified, you're really wasting money on premium fuel in a Gen I IMHO.
 
Oh, and even though I'm not an anything I imagine you would say that the engine build, purpose, amount of boost, etc. would all go into that. People have even been known to tune for different services and swap to one map for this and another for something different, but i wouldn't know.


You're trying to get me in trouble I see :rofl:
 
dadofthree said:
Oh, and even though I'm not an anything I imagine you would say that the engine build, purpose, amount of boost, etc. would all go into that. People have even been known to tune for different services and swap to one map for this and another for something different, but i wouldn't know.


You're trying to get me in trouble I see :rofl:
Click to expand...

nope not trying to get you into trouble just went to school for this crap lmfao.. you tune for what you have and what your doing
 
Thanks for the info guys! I've been reading about how the 1st gen busas like 87 octane. I didn't get the owners manual with the bike but the previous owner said he used 91 and I assumed such a high performance bike would require 91 anyway so thats what I've been putting in it, but I'm gonna try 87 next fill up for sure. Well I just changed my plugs with the iridiums and the bike starts up a little quicker. Gonna take it out for a test ride with my buddy in a little to make sure all is well. Btw before I bought the bike I asked the owner if it had any mods besides the exhaust, he said no. Hopefully all these changes help, if not I'm probably gonna take it to a shop and/or get a powercommander.
 
If I was you I would be riping into that throttle for a good week or two. Get all that carbon out of it:D I get around 25-30 city 46 highway and 36-40 mixed.
 
What are these mpg's that you speak of... Is this a mod??? So I need to buy 50 of them??? Can someone post pics and a how to install these so called "mpg's"....:rulez:
 
Update! Went for a good 25ish mile ride last night to make sure it was running alright after the new plugs and I felt like I was on a whole new bike! Put 87 in it and the computer was showing me up to 37mpgs... Wasn't expecting that big of a difference from new plugs/gas. I feel pretty confidant I can get into the mid 40s on the highway. I am a very happy camper now. Thanks again folks!
 
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