Triumphrat

Pauljo · 03-11-2008

I've read a few previous threads on this. I see guys claiming that they get anywhere from 45 to 50+ mpg. I've seen guys claim that they got 50 mpg since new. I've seen claims that some folks can go 120 miles or more before hitting reserve. Then there is the person or two saying they are hitting reserve at 70 to 90 miles and getting no more than 30 mpg on new Bonnies. Losers, I thought. Something wrong there, with the rider or the motorcycle. Everyone else seems to be doing much better.

Well, it finally got warm enough to go on a couple of long rides on my new 2007 Bonnie T100. Guess what? Loser.

I am consistently going on reserve at 90 miles (or slightly less). I am getting 30 to 31 mpg. I spent most of the day cruising at 60 - 65 mph out on country 2 lane highways. I did hit the gas twice to pass trucks, running her up to 80-90 mph at the end of the pass. Ran her up to 5500 rpm or so between shifts a couple times. But very little stop and go, mostly steady cruising. Should be getting pretty decent mileage results riding like that. Got 30 mpg.

OK. The bike was delivered with AI removed, TORs, airbox opened up and carbs rejetted, UNI filter. I was told that the mods would be good for a few more horsepower, smoother performance, AND probably a slight improvement in gas mileage. The bike does run good. It is still in break-in phase, a bit over 300 miles on the clock. I do have the Triumph Summer screen on it, smallish saddlebags, and a T-Bag roll pack on the rear rack. Fairly minor additional wind drag. I know most bikes give better mileage after initial break-in. But a 50% improvement? That doesn't seem likely.

Mileage isn't my biggest concern, I ride for enjoyment. But at $3.30 per gallon gas prices, it does matter some. Worse, touring range IS very important in the lightly inhabited wide open spaces out here in middle America - and 90 miles to reserve isn't comfortable. I'm frankly disappointed in what I'm experiencing for mileage even with a new "tight" bike.

I know some folks, quite a few I guess, have gone to the 19 tooth front sprocket. I was hoping to avoid that, but maybe that mod will be necessary. I'd like to get maybe 1500 miles on the bike (see if mileage improves by then) before deciding. At least that is what I'm currently thinking.

If you got this sort of range (90 miles or less to reserve) and gas mileage (30 mpg) on your new Bonnie, and experienced a significant improvement after putting on some miles - or converting to a 19 tooth sprocket, I'd like to hear about it.

If you got 50 mpg right from the beginning, I'm happy for you, but it doesn't apply to my situation. I'm trying to get from a consistent 30 mpg to something tolerable (mid 40's would do).

Derby Boy · 03-11-2008

You mentioned some pretty radical mods to the airbox,carbs and exhaust. I would be curious to know what jets they installed. You can't flush a toilet and get good milage. Your right about the break in. I have 2500 mi on my 07 in 4 months. At stone stock and new I was dissapointed at 42-44mpg. See my mods below. I think they helped performance and milage especially the 19 tooth which only takes 30 minutes and $20.00 to change. I am now consistently getting 54mpg on 150 to 300 mi. day trips and that's a lot of 75-90mph ridding. I would question the dealer to find out exactly what they did to the bike.

mecscc · 03-11-2008

Sorry for your troubles, Paul. When someone changes something to do with the air/fuel ratio and increases the volume of both most of the time more gas is used. It would be really helpful if you could find out what jetting changes, and carb settings the dealer made. Derby Boy seems to have found the golden combination of changes and good mileage. Most don't. And, regardless, you should get a lot better mileage after break in and when the weather gets warmer.

I get 50 mpg but my bike is a bone stock 790cc, except for removing the AI, and I do not ride hard.

Some add'l data will help the responses here to your problem.

Good luck.

Pauljo · 03-11-2008

Quote:

Originally Posted by Derby Boy

You mentioned some pretty radical mods to the airbox,carbs and exhaust. I would be curious to know what jets they installed. You can't flush a toilet and get good milage. Your right about the break in. I have 2500 mi on my 07 in 4 months. At stone stock and new I was dissapointed at 42-44mpg. See my mods below. I think they helped performance and milage especially the 19 tooth which only takes 30 minutes and $20.00 to change. I am now consistently getting 54mpg on 150 to 300 mi. day trips and that's a lot of 75-90mph ridding. I would question the dealer to find out exactly what they did to the bike.

Actually the mods are pretty typical, not very different from yours. I wouldn't call them radical. This is a single line Triumph dealer with an experienced mechanic who did the work. I do not know the specifics on jet size, shims, or airbox modification (I assume a bellmouth was used). I do intend to find out, and I do intend to discuss my current mileage situation with him. I agree with that suggestion. From a performance standpoint, the mods are on the money. The bike starts easily, runs smoothly and has good power. If I can get up to the mileage you started with, I'd be OK with that I think. I don't expect to get over 50 mpg, mid forties would be fine. My only concern with going to a 19 tooth is the effect on acceleration. I'm not sure how noticeable that would be.

trboam · 03-11-2008

a couple things come to mind here.
not to be totally insensitive but how large are you?(i know, i'm a pig.)
how tight is your chain?(too loose or to tight robs power and messes up your mpg.)
how large are your jets?(too big and there goes your mpg again)
how heavy is your right hand?(too much volume and there goes your mpg.)
lets see... one more thing, are your tires at the proper pressure?
ok, one more ... what size is your tranny sprocket?may need to go larger.
all little things but they add up to scrappy mpg.

geolpilot · 03-12-2008

I get about 120 to 130 mph before hitting reserve. That is for mostly going somewhere riding and not loads of stop and go. That is also without radical acceleration or hard braking. Tors, Unifilter, no snorkel, 125 mains, 42 pilots, 2 shims. I think you should be getting better mileage. I have the original 17 tooth sprocket as far as I know. I have decided to keep that sprocket.

CommandoRdster · 03-12-2008

I've got to wonder if your bike is over jetted a bit too,although others have said that their stock bikes were getting 30 mpg also.And then some of us are getting over 50.I just find a 20 mpg swing a bit much to swallow.At least on stock machines,there just shouldn't be that much variance.There is either something very wrong with some bikes,very right with others,or somebody's math is suspect.

Since day one,my Scrambler has gone on reserve at between 130,and 135 miles.No matter whether I baby it,or thrash it,it seems to return a little over 40 mpg.I was disappointed at first,considering my old Ironhead Sportster averages better than 55 mpg,unless I'm really whacking on the accelerator pump,but I guess middle of the pack is just fine,in this case!

I definitely understand your concern.There are lots of places in Arizona that going on reserve at 90 would be decidedly uncomfortable.

By the way,although I haven't tried this experiment myself,according to some very reliable members of this forum,there is a half pint,or so,of fuel trapped on the non-petcock side of the tank.If you lean the bike over,and slosh it around,you can get it over to the petcock side.That just might get you to the next station.

Cheers!
Bruce

badpenguin · 03-12-2008

WOW! I hit 155 miles before hitting Reserve today. It was primarily freeway driving up to 85 MPH. The only mods I currently have is the TORs, I was thinking of the Airbox removal kit, but I don't know now.

drharveys · 03-12-2008

I know it's obvious, but how are the brakes? Any drag? Take the bike around the block a few times, then stop it using only one brake -- take off your glove and feel the OTHER disc. Is it warm? Once the brake you used is cool, repeat and switch brakes.

And do you cover your rear brake? Are you sure your heavy boot isn't resting on the pedal even a little??

Pauljo · 03-12-2008

Quote:

Originally Posted by trboam

a couple things come to mind here.
not to be totally insensitive but how large are you?(i know, i'm a pig.)
how tight is your chain?(too loose or to tight robs power and messes up your mpg.)
how large are your jets?(too big and there goes your mpg again)
how heavy is your right hand?(too much volume and there goes your mpg.)
lets see... one more thing, are your tires at the proper pressure?
ok, one more ... what size is your tranny sprocket?may need to go larger.
all little things but they add up to scrappy mpg.

I am 6'6", 210 lbs. Yes, there is likely some additional wind resistance from my height. My weight is fine for my height, but a 150 lb person would get better mileage. So there is some mileage penalty here, but I doubt it explains the 12-15 mpg I seem to be missing.

I'll post jet size after I talk to the mechanic. Hopefully tomorrow.

I do enjoy twisting the right grip a bit. I like to feel the engine pull some when accelerating. I'm not extreme though. I don't ride in a way that would attract legal scrutiny. One exception is passing. I don't like to hang out there on a pass, I like to get that done. But in about 150 miles of riding today I cranked out 2 high speed passes - that would be one per tankful.

I checked my tires before the ride. 36 psi front, 40 psi rear. I keep a close eye on that. (Manual says 33 front, 38 rear - I prefer a bit firmer which should be better for both tire wear and gas mileage.)

Sprockets are stock. I realize that a 19T front might be in my future.