Triumphrat

Programr · 11-09-2006, 08:42 PM

just picked up a 2002 bonneville w/ 17k. it has TOR's on it and I haven't pulled the carbs to see how it is jetted, nor have i pulled open air box yet (not much help am i?). the EPA AI has been removed. i'm 6'2" 230lbs and have been riding the streets of San Francisco for about 4 weeks now and i seldom gun it. (i'm a newish rider [ex lambretta rider] and i'm in no hury to smear myself across pine street.)

i've been going through the gas mileage threads this afternoon and it really looks like i'm at the bottom of the barrel at 23mpg. i'd really like to keep the TOR's on the bike, and wanted to see how others have their bikes jetted at sea level so when i pull the carbs apart (ug) i'll have something to compare against. or i may just take it in to the local dealer to get it a new owner once over by a pro and ask them about rejetting for better economy.

it is running really smooth and seems to have a ton of power (all that gas has to be going somewhere!), but i'll be mostly city riding for the next couple of years while trying to finance law school and i'd like to get my mpg up. i hate to mess w/ the jetting when it is running so strong, but something has to be off, right? needle too rich...something?

i realize i've given scant info for diagnostics, but would appreciate any feedback on options or what to expect when i take it in for service. thanks..

SCbonneville · 11-09-2006, 08:46 PM

MAN! Something just "ain't" right there.... I ride my bonnie HARD (running the revs routinely up to and beyond the 6k range) and I get 40-41 mpg.... When I "throttle back" I get 45-47 mpg...

DrEnglish · 11-09-2006, 08:54 PM

That's low. I wonder how much the urban riding associated with SF and its hills contributes?
Have you taken it on an easier ride for comparison? If it's like that in all conditions, there's something wrong.

Programr · 11-09-2006, 09:10 PM

i am going up and down hills, back and forth from downtown to the upper haight. i haven't had time b/w work and school to take it out to really see what kind of highway miles i'd get. but even so, others running TORs, at their worst, seem to be in the low 30s rather than the low 20s. i wish it were bogging out so i'd know it was rich in one of the circuits, but when i give it gas it just tries to throw me off the back. i can't believe that i'm finding myself complaining about it, but here i am...

markbvt · 11-10-2006, 03:16 PM

Something's definitely off. I have TORs on my 2001 Bonneville and easily get 35mpg when doing nothing but riding around in town. Out on the open roads I get 45-50mpg, even riding aggressively.

Any chance someone's siphoning gas from your tank, or that gas is evaporating or something? I just don't see how the engine could actually be consuming that much gas!

--mark

OhioSpeedmaster · 11-10-2006, 03:28 PM

This may seem a little far fetched but I'm wondering if the mileage indicator on the speedometer is malfunctioning. How many miles are you avereraging on a tank of gas?

Programr · 11-10-2006, 06:03 PM

i think i figured out part of the issue. the previous owner put a new back tire on right before i bought it. i know i should have checked sooner (rookie move), but the pressure was in the low 20s last night. i immediately went and filled it up to around 38-40psi. it was either doing the new tire stretch, or there's a leak. i'll check it later today again to see if it has held pressure overnight. i should check the valve stem too.

i doubt that anyone has stolen any gas, but it isn't impossible as i park downtown and don't have a locking gas cap. but i've gotten the same mileage on two fill-ups, so i doubt that's the issue.

however, regarding the odometer or the trip meter being off, that is possible. when i have some time i'll check it out. i was wondering the same thing.

i wish i had more time to ride and figure all this out. :-D

thanks for the feedback. i'll post again the next time i gas up to see how much the tire pressure was effecting the mpg.

sweatmachine · 11-10-2006, 06:06 PM

I don't check my tires as often as I should, but I do check them. I often get as low as 30mpg, so one could imagine it being worse than that with a low tire.

Probably a combination of things, but the tire certainly was a factor.

ohiorider · 11-10-2006, 08:46 PM

For mixed riding (some Interstate/some two lane) you should be seeing 40mpg minimally. When we took two Bonnies out west this year, we averaged 44-46mpg when running back roads at 55-65 mph. Much less at 70mph into a headwind (perhaps 30-35). I'd think 40mpg would be as bad as I've seen, overall.

I was running an 18T sprocket, with 125 main jets and 42 pilots.

Bob

AVMECH · 11-12-2006, 08:46 AM

I get about 38-40 mpg riding at around 80 on freeways for 34 miles back and forth to work. I will also say that even after tightening my valve stem, I have to add about 4 psi in my rear tire every week. If left unchecked, this could definatly reduce my gas milage and my desire to corner. Try keeping your tires inflated and see if that helps. If not, the carbs aren't that difficult to get the bowles off and check your jet size. If it feels right though, I'd think that it was the tires. Do you hear a growling sound from the rear when you ride it?