I've had low mpg (<=33) for a while... changed my plugs (new NGK iridiums), checked the vacuum hose on the FPR (no leak).
Bike's functionally stock except for scorpion slip-on. ~12k mi

Another problem: coolant level is going low. Temperature of coolant seems fine, tops out at 225 when the fan blows it cool, and that's only at long traffic lights. I cant see where it is leaking from... no drops/pools form under the bike... Could this be related? [tear]

It has started idling higher than usual on cold starts too: >3k rpm instead of usual <2.5k. I'm guessing this is more a secondary symptom.

If I cant figure it out I will take to the stealership... and hope they dont give it to their latest intern. (the last time some guy turned down the idling before the bike settled, and it choked off when it warmed up)

Any ideas on checks I can run? This could be related to a (<20mph, stator cover) lowside from several months back, although I noticed it quite a bit later.

Thanks in advance

 

Coolant has to go somewhere, the temperature thing doesn't matter, the radiator works as well as the fan, so it will stay cool but the coolant has got to go somewhere. If it ain't leaking out, it is being consumed.

If this was my corvette I'd say headgasket...is the exhaust kinda whiteish? I think that is the water in the cylinder color (black/carbon/fuel and blue/oil).

What did the old plugs look like? A headgasket leak would make one or two of them a little different. Did you save them?

What does your oil look like. Frothy/milky? That would be bad too.

I don't know if the F4i has a coolant path into the motor besides the headgasket, I have never gotten into one before. I hope it isn't that, mabe someone has a better idea, good luck.

 

I hope I dont have to mess with the motor...
Any ideas on the mileage problem anybody? Come on guys, I have until next Friday... then I get to take it in. And I called the dealership guy and he was quite frank that he had no idea what he would be checking

 

fishfryer is right, if its not physically leaking out it's going in the motor..maybe headgasket, coolant port, block cracked.......if your getting a small amount of water into one cylinder it's going to misfire that cylinder and not burn correctly..that would explain your coolant mystery and your mpg.......my advie take it to the dealership and have them pressure test your coolant sytem, sometimes you wont have coolant pouring out of your motor but it will only leaak under pressure...once the bike is completly warmed up, and it could be just a small pin hole somewhere on a hose, a gasket somewhere on the motor.......so without a doubt if your losing coolant get that thing pressure tested ASAP before you have to replace the motor

 

Thanks... I'll ask the dealership to do a pressure test.
Another dealer advised that I should dyno the bike while checking exhaust, to find any detailed power-loss symptoms... does that sound useful? Anybody know good dyno places around Seattle?

 

don't get too freaked it could be somthing very small......I would just get it checked before I rode it anymore.......I used to be an auto tech.....I have seen very small pin holes and gaskets that had the exact same problem...the shops would usually sell them a head job and I would change out a thermostat housing, gasket, hose whatever.....problem fixed.....butusually wherever I worked they still charged for a head job....I quit working on cars..don't like the industry

 

Update:
I asked for a pressure check of the coolant system and the service dude said my coolant cap seal was ok and that I shouldnt worry about the level in the reservoir as long as there's coolant in the radiator...
And no they couldnt solve the mpg problem [:@] so it's 85 bucks down the drain so far. The dude said if I did a full service he'd be able to go over the whole bike and figure out if there's other problems, specifically he'd check the valves to start with... but that's quarter of a grand just for labor.
Wonder if I should do the service when my tax return comes in... what say?

 

why do you think you have a problem? i get roughly about 35-40mpg. I ride hard, i keep my bike over 8k rmps a good amount of time. if you run your bike all the time at 5krmps and you get 33mpg than i would say that you do have a problem but if you rev it up once in a while than expect your gas milages to go down!

 

My friend is having the same problem with his bike. It used to get much better gas mileage and we cant find anything wrong with it. Whoever told u that it is okay for your coolant tank to be empty is a dumb ***. Once that is empty the radiator will go down slowly until there is nothing left and your bike overheat then u will have some problems. Sounds to me like you should make sure 100% there are no external leaks... i dont care what it takes... take all the plastic off and run the bike and check it out. If the level keeps going down then buy a service manual and rip some **** apart. Then once that is fixed and you still have ****ty gas mileage then the problem is something else. But i know for a fact that coolant problem isn't going to fix itself.