1989 Gas MPG

[uhfradarwill]

1 up riding the last two days. 19 Miles in fourth gear doing around 45MPH, then Highway for another 31 miles doing around 70 MPH; my work route.

Gas MPG for a 205 lbs, 6'1" rider is 34.9 MPG.

4th gear for the 45 and 5th for the 70.

 

She sure ain't no economy bike lol

Will

[luvmy40]

I've seen a few boast 40-42 Mpg.

 

I've had one tank that hit 38 Mpg.

 

I average 35 Mpg with a very similar riding profile to yours except I'm 5' 8" and 180lb.

 

I don't see much variance in fuel economy whether I ride like it's a Gixxer or a Harley. I do see a decrease in economy when I'm loaded and two up.

[CaseyJ955]

If it were a car it would be a 72 Eldorado. I get about 40 if 1-up with some cargo. I had to do some tuning and tweaking to get there, before I got it sorted I was getting a high of 29-30.

 

Sounds like your doing alright at ~35. Other than a synch, new plugs and current maintainance may getcha a lil more, but its a pretty herking bike. Economy scoot she is not, comfy and reasonably capable she is. Oddly enough I get about the same MPG with my Vmax with a third more power and a third less weight.

[s.tyler58]

Seems like I rarely get as good as 32. The Road King pipes may have a little bit to do with that though. I do enjoy leaving people at lights that look at the old man on the old bike as boring. ;-)

 

Sent from my SM-G935V using Tapatalk

[Flyinfool]

My engine, drive train and breathing are all bone stock. My commute to work is all city with the top speed limit 45 and 22 miles each way. This compromises 95%+ of my riding. I get 39-40 MPG consistently for the last 10+ years. It is all 1 up (I'm 6'1" 250) with around 30 lbs of junk in the trunks. I get gas at the first station after the warning light first comes on steady, which is always right at 160 +/- 3 miles on the trip meter and put in 4.05 - 4.15 gallons.

 

I can not compare my interstate MPG because that is usually fully loaded and pulling a loaded trailer at speeds faster than I should.

[Patch]

I'll share these thoughts with you all.

 

Mileage to a tank is just a result of... In motorcycling it isn't usually the highest priority.

 

The closer you are to stoichiometric the more efficient the burn, the quicker the ignition of fractured vortexes, the lesser remaining after burn.

 

A fare question would be to ask Jeff what spark plugs no. type and heat range or any other simple changes.

Also a fare question would be main jets, shims and needles. Jeff mentions "bone stock" but are they newish?

 

If mileage is or becomes a concern then an easy option is diaphragm springs, up by one number. Stretching them will not help. Drilling is irreversible so I wouldn't.

 

Luvmy40s bike is a 1200 cc and displacement matters. If I recall Luv has a shim but also I think a pilot jetting issue? Trying to recall Luv, didn't you post pilot adjustment past 4 turns?? Seems to me you mentioned this and I didn't bring it up because my thoughts were around the compression part of the conversation? Something I rarely would suggest for anybody but for Luv perhaps one step up in octane while the compression is still high, and one step down in pilot jet, or just start the tune at 1 &1/4 turns, with, as small an adjustment in 8 to 10 second intervals and based on rpm only! You may just find that this tighter pattern will also solve the low rpm heat issue as well..

 

This suggests that stoichio will give you best bang per gram of fuel for your buck but, can only be achieved when all the combustion parameters are close to being met..

Patch

[luvmy40]

Yes, my needles are shimmed with Skydoc's thinner shims. I have no idea how many tuns my pilot mix screws are turned out. I tuned to clean burn at 1000 rpm(on the dash tach)with the ColorTune.

 

I will go to a higher octane next tank to see if it has any effect. As of now the bike is running great though I do need to either let it warm with no enrichment for about a minute or open the enricher just barely for 30 seconds or so on a cold start before she'll jump out of the hole. She'll start right up with out enrichment but just won't pull under load for a minute or so.

[Patch]

Yes,

I will go to a higher octane next tank to see if it has any effect. May and likely still be dogish at low cold rpms but is better capable for handling the high compression temps.

As of now the bike is running great though I do need to either let it warm with no enrichment for about a minute or open the enricher just barely for 30 seconds or so on a cold start before she'll jump out of the hole. She'll start right up with out enrichment but just won't pull under load for a minute or so. Well described and tricky because of the carbon build insulating effect. So as mentioned she goes through rich (Lambda) 1.1+ then >1.0 lean

Good stuff to share.

 

Thanks Will for letting me combine the comment.

[Flyinfool]

Oh now I'm gonna get yelled at............

 

Plugs are the stock recommended NGK, they are 5 years old and have around 20K miles on them. I have a new set on the shelf but the bike is running so good why replace perfectly good parts. I do a sync every spring and it needs very little adjustment. The carbs have never been off the bike (at least in the 12 years I've had it) and they even still have the plugs over the adjustment screws.

 

When I did my valve clearances, I set them all to max gap so there is more room to wear before I have to do it again 9I have a surface grinder and made some custom shims to get them all perfect). This also means that I have very slightly less lift and duration on the cam. It is surprising what a few thou on the lifters can do to the way an engine runs. When I was racing valve lash is one of the things we played with every week to tweak the power band of the engine to suit track conditions.

[SpencerPJ]

I check MPG with every tank. My 83, cruising mostly 55-60, country twisties, rarely on HWY, some hot rodding, I religiously get 40MPG.

[SpencerPJ]

Yes, my needles are shimmed with Skydoc's thinner shims. I have no idea how many tuns my pilot mix screws are turned out. I tuned to clean burn at 1000 rpm(on the dash tach)with the ColorTune.

 

I will go to a higher octane next tank to see if it has any effect.

 

It actually hurt me a couple MPG. I'll be curious for you. Someone pointed out that higher octane may have meant less energy??? They lost me, but I did get a little worse MPG, and as previous post states, I always get 40 MPG.

[Patch]

Oh now I'm gonna get yelled at............

 

 

When I did my valve clearances, I set them all to max gap so there is more room to wear before I have to do it again 9I have a surface grinder and made some custom shims to get them all perfect). This also means that I have very slightly less lift and duration on the cam. It is surprising what a few thou on the lifters can do to the way an engine runs.

There usually is a reason and of course compromise. In a case like this we have chosen to not make full use of potential displacement. Even if its a minor its certainly not common practice.

 

When I was racing valve lash is one of the things we played with every week to tweak the power band of the engine to suit track conditions.

Yes and likely before dino tuning was just next door, more like seat of the pants tuning.

Running in the red zone there's no choice. I used a spray chem with a black light to check for cracks in the springs, but I can't remember the name.. a blue dye??? made by Moly?

 

[Patch]

It actually hurt me a couple MPG. I'll be curious for you.

Someone pointed out that higher octane may have meant less energy???

Octane has to do with ignition and duration of the fuel, so fuel timing (simply put)

Luv has an unusually high compression and therefore we assume that the combustion temperatures are also higher.

The reasons for that are listed in his thread.

They lost me, but I did get a little worse MPG, and as previous post states, I always get 40 MPG.

 

Fuel ignition and duration are a phase during the compression and expected timed combustion where all the focus is on heat and expansion. This takes place after spark ignition! There is a term used to denote this phase but I'll leave that for another time.

 

And of course the octane increase may cause an unavoidable effect to the 3rd phase of ignition which is after burn. But that is more on the math side of efficiency..

[luvmy40]

I wasn't getting any preignition running 87 octane but it did sound like a reasonable tactic to run a higher octane gasoline for reference. I had just filled up with 87 yesterday, so I added 3oz. of Lucas' octane booster today. I really don't know how much of a boost the Lucas is supposed to give but they claim "3 times more than any other octane booster."

[Patch]

I wasn't getting any preignition running 87 octane but it did sound like a reasonable tactic to run a higher octane gasoline for reference. I had just filled up with 87 yesterday, so I added 3oz. of Lucas' octane booster today. I really don't know how much of a boost the Lucas is supposed to give but they claim "3 times more than any other octane booster."

 

Certainly I know the product and have used it out of necessity a couple of times. I can't remember the ratios but I'll look them up. If I may add this and you'll know what works best (of course I'd like to hear back) but remember that too much will confuse your analyzing of the results. Also consider phase 3 if it gets to high you'll be popping again.. Anyways Luv I enjoy your enthusiasm..

 

By the way, Jeff mentioned his tamper caps are still in place, talk about giving up racing.. Hmm

But connect a dot and we know he's running more lean then most of us on that circuit.

[RDawson]

Bone stock 07 RSV riding 2 up with about 425 lb of riders and gear we got 38 mpg running 78-80 today. I haven't touched the enrichment screws either. Got in 308 miles this evening going for supper.

[Patch]

Bone stock 07 RSV riding 2 up with about 425 lb of riders and gear we got 38 mpg running 78-80 today. I haven't touched the enrichment screws either. Got in 308 miles this evening going for supper.

 

Well you had a favorable wind on your stern pushing you, I'm pretty sure I saw your wife flying a handkerchief as a down wind sail as well..

[Jayceesfolly]

I have an 89 Royale and went for a ride today of 106 miles and got 43 MPG. Mostly country roads at 45 to 62 MPH, with the last 15 miles at expressway speeds of 70 MPH. I routinely get in the low 40's riding the local freeways at 65+ MPH. Riding all country roads (45 to 60 MPH), I can get 50 MPG. I also have the shim kit installed from Earl.

 

Jim

[Freebird]

[/color] Yes and likely before dino tuning was just next door, more like seat of the pants tuning.

Running in the red zone there's no choice. I used a spray chem with a black light to check for cracks in the springs, but I can't remember the name.. a blue dye??? made by Moly?

 

 

I don't suppose it was MagnaFlux? I never used it to find cracks in the springs but have used it for many other things.

[stanG]

I consistently get 42 ish when commuting to work 44 miles round trip. 2 up on longer trips I get 45 to 48 consistently on my 83. I have the Skydoc shims installed and keep the carbs super tuned.

 

Have fun out there!

[RDawson]

Bone stock 07 RSV riding 2 up with about 425 lb of riders and gear we got 38 mpg running 78-80 today. I haven't touched the enrichment screws either. Got in 308 miles this evening going for supper.

I was butt numb and tired when I figured that, I used odometer miles instead of actual. Actual miles showed 35.88 mpg. I kept the cruise at 78-80 using gps speeds. I always get my best mileage 2up, guess I play too much when alone and bored.

Edited August 5, 2018 by RDawson

[Patch]

I don't suppose it was MagnaFlux? I never used it to find cracks in the springs but have used it for many other things.

 

That was the name bouncing around my head Don. Thought it came to easily funny enough, so I simply discarded it.. yikes