last season my bike (01 F4i) was getting 320 miles on a tank ( roughly 3.25 gallons ). This season I been getting 100 miles on a tank! I'm not sure what to think of this at all, I'm losing 200 miles somehow! I did cut 6'' off my pipe so I'm sure there is a small difference in pressure but I cant see it making that big of a difference at all. I'm looking at 15k miles on the bike and from this previous owner the air filter has never been replaced, maybe that could play another small part? I have no idea how I got that big of a jump in mileage.

whats your ideas?

 

Also, when I'm at a light or a dead stop and take off with a full opened throttle the bike sounds like it would if you were trying to accelerate while holding the rear brake. It makes a bog type sound and doesn't have the quick reaction it should. although I have never rode any bike other than mine and have never taken off out of the hole like that often so maybe that's some what normal, being that there is a lot of fuel going to something that is not moving up to speed yet?

 

Well.... 320miles on 3.25gals of gas is insanity. That's almost 100mpg and is never gonna happen.
Now 100miles on 3.35gals is like 31mpg. It's closer, but still seems off... lol..
I would think you'd be in the low 40's, high 30's?

 

I agree, I calculated those numbers last year and it was averaging 85miles a gallon. I thought that was awfully high also but that's truly what the numbers read. So this year when it went to 100 I was blown away and instantly thought something is completely off! Even if 300 is high and 100 is low, something is obviously different and I would like to figure out what the cause is?

 

bad oxygen sensor? too lean last year, too rich this year? would explain the bog I believe

 

I dont think there is anyway an f4i could get 300 miles....my f4 w/ 12k on it gets 300 KM per tank aprox and I that is pretty good compared to my other buddies bikes - no way you miscalculated that?....I mean I guess its possible?

If you are not used to launching off the line the bog may just be your clutch/ throttle control. I know when I was first learning to launch I always got a bog because I got nervous when letting the clutch out and then let off the gas a bit b4 I hammered it. I dont think I even tried to launch until my second season....

 

I think you just mis-calculated your mileage. 100mpg is never going to happen on a 600cc sportbike. Heck, a 50cc scooter is hard pressed to get those numbers. 30-40 is normal. 30 being aggressive riding and 40 just putt'n around.

Look at the 500 ninja, it only gets around 50mpg, and only puts down around 50hp. Your bike is putting out double the hp... its going to be less than that.

If your getting more aggressive with the gas,(which it sounds like you are), letting the bike idle more, staying in a lower gear longer,.. many things can factor into lower mpg.I'd say your bike is right around where it should be.

When you get your bog, if your rpms and speed are not high yet, and you just dump on the gas, its going to bog a little. especially if your clutch is already let out completely and your rolling like 5mph, it will bog. If your going like 15mph, it should take off. If you are slipping the clutch off the line, you can avoid the bog by keeping the rpms higher. Sorta like Platnumbob said, its probably just your clutch throttle control.

 

I'm with trout, squid, and the others saying the 300 miles must be off. Something is amiss there, though I can't say what. On the other hand, 100 mile range seems a bit low. I tend to get around 40 mpg just doing stop and go in the city and riding her pretty good in the twisties...

Something I just thought of with Bob talking about 325 km on a tank... maybe you had the gauges on km's instead of miles? Just a thought, because 100 mpg is frankly impossible.

As for the bogging issue, is it actually bogging or is it revving up and not accelarating? If it's bogging, it could be that you're trying to dump the clutch at too low an rpm like bob suggested. If it's just reving, you may not have the clutch engaging all the way and should probably make sure that the clutch cable is adjusted properly at the engine and at the lever.

 

Yeh the bog is with the clutch fully engaged at low speed. I crank the throttle about a quarter at the same time as letting the clutch grab close to the same time, the tire gets a small spin and then when it grips I let it all out and go. Now that you bring that to my attention it must just be the fact that sometimes I do NOT work the clutch on time with the throttle.

How and is there anything I can do as far as checking and tuning the oxygen sensor to run it at the right mixture? I have a powercommander but have never messed with it, 6'' off the exhaust may have had an affect?

and clutch. any posts or sites I could be linked to that would explain how to check my clutch and tuning? On that topic as well I notice when I'm at the top end of 1st and lift it to 2nd real hard and crank the throttle as fast as I can flick the clutch lever I can hear it kind of wind out as if the clutch is slipping and not gripping fully ( clutch IS all the way out at this point ) Sounds almost like the tire should be spinning buts its obviously not. Does that sound like a clutch or maybe a warn down chain/sprocket? (which I intend to switch out very soon here, its the same since the bike was new I would guess )

 

LOL you sure you didn't have it on KM last year? There is NO way you got 300+mi on your 01 f4i period.