Not so smooth

[Pappy]

I did the 6000 mi maintenance 1000 miles ago on my '04 RT. I did a valve adjustment, TBS and changed all 4 plugs (Bosch) for good measure. Everything looked and adjusted well. The bike has approx. 7000 mi on it. I still burn a little 20w50 Castrol, so I guess it's not run in yet.

 

Still, I'm concerned about gas mileage and surging.I have a 5-tank average of 36 mpg. I have a top bag, so that might account for a mpg or so. The shield has been barely raised around here because of the heat. About 60% of my riding is city, 40% is slab and I keep it around 4-5000 rpm. Unless I'm on the throttle, I can feel it surging. When I am on the throttle, it pulls steadily and strongly. The bike start OK every time. I think the surging has always been there, but it was worse before I did the service. Now, it seems to be getting worse again. I have a riding buddy that has a big Harley bagger that wants to swap out with me on one of our rides, and I'm ashamed to do it because of the surging.

 

So. I imagine you guys will give me some heat, but there's gotta' be something wrong here. Realizing there's many variables here, what should I look for? Is anything common to this problem such as a vacuum leak? If so, how do I go about finding it? Should I do the valves and TBs again? Mucho gracias for any discussion/hints/tips to get me smoothed out.

[tom collins]

that milage figure has me wondering. if i ride easily and below 70 mph, mine gets around 50 mpg. on the race track last week, it dropped to 40, but there were many 125 mph passes and controlled agression all day. just hard riding or between 70-90 on the slab usually gives about 45 mpg. so, my thinking is that the milage is an indicator of a problem that has not been fully addressed yet.

good luck.

 

tom collins

04 r1150rt

[Couchrocket]

I'm with Tom, my 04 RT averages about 46 mpg, with highs being in the low 50's.

 

Mine has zero surge. I'm a "big guy" and solo I'm probably what some svelter riders are two-up! I also ride about 90% of the time with both side bags, and the top box, though fairly lightly loaded.

 

Something is amiss w/ your bike, me thinks and it might be worth the $$ to have the LD take a close look at it.

 

Good luck, and keep us posted if you find a "culprit" to explain the low MPG and surge.

[kingpinofdisks]

I am having similar mileage on my 1150rt. However, I have a +4" Cee Bailey windshield, weigh 235, and my superslab riding is done around 80mph average, with lots of slow-speed lane splitting. I always have the luggage on, with about 40lbs of stuff in them total.

 

That gives me an average of 38mpg.

 

The bike idles around 1000rpm, 2500 with the choke, and over 3000 holding the fast idle lever up.

 

I thought it was the stupid gas in California. I use mostly 76 and Shell gas (cause its free), always 91 octane.

 

My twinmax shows dead 0 on the meter at any RPM, valves are adjusted, and the engine runs as smooth as a turbine.

[ShovelStrokeEd]

36 city really isn't all that terrible. I don't know what to tell you about the surge. Nothing I have ever ridden has surged. So much of fuel milage measurement is dependent on fill technique as to make all but the most careful observations worthless. Minor changes in traffic pattern or throttle application can have a large effect on fuel milage as well.

 

One thing you might try is resetting your Motronic and then making sure you go for a long, steady throttle kind of freeway ride every couple of tanks or so. All of my bikes will start to show a marked drop in fuel milage if I stay around town too long. On the way out of town, it starts to pick up again. The S will typically get in the high 30's around town. First tank on the road, ditto. Second tank, low 40's and the third tank will be in the mid 40's which is as good as it gets on that bike. PS, I run 80-85 mph on the road and I push quite a bit of air.

 

Reason being there is a long term, for lack of a better word, memory in the motronic than kind of tracks your throttle usage and makes blanket mixture adjustments. Around town driving, with its multiple throttle transitions tends to generate a richer overall mixture and, it follows, greater fuel consumption.

[TracerBullet]

John,

I have the same bike,

windshield hardly ever up, no top box, I am 185, 5'10". Mix of highway and city driveing, but mostly highway.

Ever since the bike was new I consistently get 40 mpg.

Around town 40 mpg. 500 miles on the highway at 80, 40 mpg

I just figure that is my bike.

Still way better than my truck

 

no surge though

 

 

sal

[Pappy]

...One thing you might try is resetting your Motronic and then making sure you go for a long, steady throttle kind of freeway ride every couple of tanks or so. All of my bikes will start to show a marked drop in fuel milage if I stay around town too long. On the way out of town, it starts to pick up again. The S will typically get in the high 30's around town. First tank on the road, ditto. Second tank, low 40's and the third tank will be in the mid 40's which is as good as it gets on that bike. PS, I run 80-85 mph on the road and I push quite a bit of air.

 

Reason being there is a long term, for lack of a better word, memory in the motronic than kind of tracks your throttle usage and makes blanket mixture adjustments. Around town driving, with its multiple throttle transitions tends to generate a richer overall mixture and, it follows, greater fuel consumption.

 

Ed, I think you hit on it. Because of work and the rain, I haven't been through a full tank since resetting the Motronic, but it "feels" better and I'm not noticing the same intensity of surging I had. Maybe I'll put "Motronic reset" on my 3000 mile maintenance schedule! Thanks.

[BFish]

same bike as you and just turned 10k miles. spend most of my time on non-city roads. run above 4k rpms and speed varies but between 60-75 on most trips, that average 200+ miles. been averaging 46mpg for a while. very little variation, altho 2 tanks ago was 44.8 due to time in and around daytona beach and vicinity. follow ed's advice and see what happens.