HUGE road trip queries and info.. wow (mileage)

[Seaking]

Hi guys, just got back from a wild 3 day road trip that saw my buddy and I leave Halifax Nova Scotia, and ended up all over New England and back on what was basically a wild riding trip.. not a lot of sight seeing but ride and ride and ride.. the RSV makes this an awesome touring machine.. I'd have to say it was my first balls to the walls road trip on this bike and I can still walk today =) We did 16 hours on the bike yesterday from Gorham NH to Halifax through strangest of back roads, highways and a small border crossing out of nowhere.. wild fun.

 

However, it wasn't without a glitch or two that has me puzzled.. In previous messages I had mentioned how bad a mileage I get on my RSV with a tall wide windshield, how I get better mileage with the short windsield and running on premium gas but that I would get inconsistent gas mileage mostly attributable to winds and driving habits.

 

Traveling with a buddy who has a 2008 RSV, I had something to compare my riding to. The only difference between our bikes is that I have K&N filters and Screamin Eagle pipes. We both burn premium and since he's following me on this, his first road trip, our driving styles were basically the same. (my bike is US while his is Canadian hence the difference in numbers coming up)

 

Our first day out this past sunday I ran out of fuel at the 163 miles.. heavy cross winds, and only 2 miles short of our intended gas stop.. 3 bars showing on the fuel gage.. NO yellow fuel low light..

 

I switched to RES on the petcock and nothing.. the engine died and costed to the side of the highway.. Bike wouldn't start. Utoh.. I jump on his bike, get gas and the bike would ONLY start again with the petcock on RUN and full choke.. chuh chug.. vroom... and choke off and it ran normal.

 

When we got to the gas station just 2 miles down the road, I filled up the tank and the whole amount added (jerry can and pump) was 16 litres.. Basically the amount you run to at RES.. so the bike wasn't empty at all.. just that the RES wouldn't feed fuel from the reserve amount.. Strange huh? My buddy's fuel useage was about 14.8 litres, not too far off from my useage.. but the fact is that I had reserve amount but it wouldn't feed to the engine.. this is the second time this year I got caught short like this..

 

What causes this?! Does cross winds have anything to do with it? Does the wind, leaning the bike to one side on the highway deny fuel to the petcock enough to starve the engine of fuel when on RES??

 

The rest of the trip was without incident and road the bike down to 2 bars 180 miles showing and no ill effect.. windy days, hilly roads, cold and hot.. all was good but that one frikken cross wind day has me wondering.. what the heck!

 

I had pulled the air filters before the trip and they looked clean and nice red coloured (K&N) and synch'd the carbs, seafoam into the gas tank a coupla times this spring already (I ride a lot.. not just a weekend warrior).. But this lack of range really got me worried..

 

However, this road trip did show me a coupla things about my mileage though.. Traveling speeds and headwinds make a HUGE difference on how far you can go..

 

Slow ride through the mountains, 40 to 60 miles per hour got me 46 MPG

 

Fast highway speeds 60 to 70, driving hard, 39 MPG

 

Fast highway speeds, heavy winds, cross winds etc 30 MPG

 

But I never went past 180 miles on the trip ODO as it was close to the 2 bars and made me nervous. The fact that my buddy was fuel less into his bike by .8 gallons on average got him better milage with his bike. Nice..

 

But running out of fuel with still the reserve fuel onboard REALLY has me worried.. Any thoughts?

[Naked Rider]

you might want to take the tank off and see if the reserve tube is clog or might be something wrong with it but thats where i would start let us know what you find out. but glad you still had a good time wish i could just go for a long ride.

[Seaking]

you might want to take the tank off and see if the reserve tube is clog or might be something wrong with it but thats where i would start let us know what you find out. but glad you still had a good time wish i could just go for a long ride.

 

I'll be changing the plugs soon and will check that line out as you suggested, thanks..

 

My face is burning from the sun and wind lol.. ouch.. It only hurts when I smile

[royalstarjac]

I understand that the tube in the petcock that feeds the reverve can come loose in the tank and as a result, the reserve stops working. You may want to drain your tank, remove the petcock and examine it.

[McBrush]

Sorry I can't comment on the fuel issue, but wanted to give kudos on a great trip! Really caught my eye because the first long trip I took (a week) after I bought my RSV was to Gorham NH where we had our Virago Owner's Club reunion in '06. I think it was at the Town & Country Motor Inn. Great area!

[skydoc_17]

Hey Seaking,

Sounds like you had a great trip! Wish I couldda'' been there! I think Royalstarjac hit it right on the head as far as the no reserve thing goes. You will need to drain that tank, and check out the petcock closely. I don't know if the Second Gens have filter screens in the tank like the first gens. do but check the parts diagram, order new gaskets, O'Rings and screens (if yours has them) in advance so there is little down time.

Now, About that gas mileage! With those K&N filters and the low restriction exhausts on your bike, you are moving more air and fuel into the carbs. than on a stock bike. If you and your buddy did a rolling start in 5th gear I would bet you would pull ahead of him, (right into the next gas station!) So if more power was what you were looking for when you changed the filters and exhaust then I'm sure you got it, but more that likely you won't see 50 MPG ever again! This last comment is a bit of a "touchy subject" but here goes. The 1300 c.c. Yamaha V4 was not designed to run on "high test" gas. Due to the fact that the combustion temperature is lowered with the "high test" you do not get a complete burn of the fuel/air mixture which leads to poor gas mileage. If you have one of those rare bikes that "pings" on regular gas then by all means, run the high test, but if your bike will run on the regular, put the extra money into some "safety chrome" because it's not doing you any good running the high test. An easy way to check this is look at the ends of your exhaust pipes, are they black and sooty, if you stick your finger into the end of the pipe and touch the sides do you end up with a oily black residue that smells of gas? Thats the smell of unburned fuel going out your tailpipe. The ends of your pipes should be gray and the ash should be dry and dusty.

Check it out and let me know what you find, I might be able to help you with this. (yea, I know, I'm helping a Second Genner, I'm gonna' catch hell for this, I just know it!)

Earl

[V7Goose]

I cannot tell you for sure what happened, but I can give you my comments and experiences from over 70,000 miles on an RSV.

 

First, no riding conditions should have any effect on if your Reserve works or not, at least when you first turn it on. However, steady, straight, flat riding on a smooth highway WILL cause you to loose access to perhaps the last 1/2 gallon of fuel, as it will become trapped in the right side of the tank. The RSV has no leveling tube to connect the sides; under normal riding conditions (leaning, bumps and hills), the fuel sloshes back and forth, and you will normally get to use ALL of the reserve. On both of my bikes and everyone with an RSV that I have run with, this has consistently been 1.5 US gallons (my trip meter and fuel light always comes on with 1.5 gallons left for reserve).

 

For the first year or two of ownership I used the petcock to switch from reg to reserve as needed. My experience has consistently been that the trip meter and fuel light comes on about 5 miles before the engine starves for fuel on normal setting. This has also been the most common experience reported by other RSV riders; however, a few have reported their trip meters switch later, as yours seems to be doing. I no longer ever move my petcock - it stays in reserve permanently. I figure the fuel gauge, the fuel trip meter, and the low fuel light give me MORE than enough warning about hitting reserve without having to mess with changing a lever too.

 

I almost never fill up before hitting reserve. I know for a fact I have a minimum of 40 miles on reserve, even when running at 80 MPH, and if I stay below 65 I can usually get 60 miles on reserve. I have vented my filler neck to make it easier to completely fill the tank, and I have been able to add 5.8 and 5.9 gallons numerous times when I pushed it to the limit (without running out). BTW - I always have at least 20 miles left AFTER all of the bars are gone from my fuel meter - just one more check that I can monitor to guess how low the tank really is while running on reserve.

 

Your fuel mileage seems pretty typical with my experience for the different condition. I do think you are totally wasting money to purchase premium fuel - it does absolutely NOTHING for the RSV. This engine is designed for 87 pump octane (and runs perfectly on 85 octane in the mountains).

 

As for testing if your reserve setting is working, that is easy. Just turn it on now and start riding. If it is not, you will begin to feel the engine starve in a few miles. You should also be able to confirm if the fuel is getting to the carbs simply by turning the key on and listening to the fuel pump, but you will need to turn the fuel off and run it for a short while to lower the fuel level in the bowls first. Then just stop the bike, turn the petcock to reserve and turn the key on. If the pump clicks a short while and then stops, it was able to fill the carbs, meaning it is getting gas.

 

If the reserve is working now, with lots of gas in the tank, then you know the petcock valve is good, and the only other potential problem is if the reserve position has access to the fuel when it is below the normal position. To test that, I would suggest you simply drain all the available fuel from the petcock in the normal position while the bike is in your garage, then simply test the reserve again just like before. There is no external tube feeding the reserve, so I do not know what the above posts are recommending. I also do not have any idea what the fuel feeds to the petcock look like inside the tank, as I have never had a need to check it out. Normally, these would simply be two different fixed input tubes, one sticking up higher than the other, possibly with screens on them. If your testing finds a problem with the reserve feed, why not just take it in to have it fixed under warranty?

Goose

[BOO]

I pretty much agree with Goose.

I did also find out by using the Road King mufflers completely drilled out and the K & N filters I got worse gas mileage then running the regular filters.

At about 80MPH speedometer indicated, my gas mileage goes to crap (30MPG + ).

When you say you are getting 46 MPG is that imperial gallons?

I pretty regularly get 39/42 MPG.

BOO

[similost]

I'm also going to make a comment about running premium....

 

Higher octane fuel needs to have higher compression so you get a more complete burn. Running premium fuel in an engine that doesn't have really high compression will cause a less complete burn, and also more carbon build up, along with lower milage.

 

I would run a couple tanks of seafoam to clean out the carbon with regular fuel. I will bet you'll see better milage once you switch back to regular, and get all the added carbon buildup out of the combustion chamber and off the valves.

[Seaking]

Sorry I can't comment on the fuel issue, but wanted to give kudos on a great trip! Really caught my eye because the first long trip I took (a week) after I bought my RSV was to Gorham NH where we had our Virago Owner's Club reunion in '06. I think it was at the Town & Country Motor Inn. Great area!

 

Ahh so you know the place.. beautiful.. We may be back in August using it as a base of operations as we boot around the area..

 

Cheers!

[Seaking]

I shall be checking out the petcock and reserve tubing as several have suggested.. sound like that might have been the culprit.. Where does the low fuel light get it's signal from?

 

As far as reg and premium gas goes, my exhaust is sooty dry compared to my friend's exhaust and we both run premium.. However.. at my next fill up, I will go several tanks of gas at regular fuel to test this out and see what comes of it. The cost differences from reg to premium isn't that much on a fill up but it's about getting more range and endurance from that same tank of gas.. Premium had proven to have longer legs on my bike...

 

Mine is a 2nd Gen RSV so no worries

 

Thanks for the comments, something to check out when I get a break..

 

 

 

Hey Seaking,

Sounds like you had a great trip! Wish I couldda'' been there! I think Royalstarjac hit it right on the head as far as the no reserve thing goes. You will need to drain that tank, and check out the petcock closely. I don't know if the Second Gens have filter screens in the tank like the first gens. do but check the parts diagram, order new gaskets, O'Rings and screens (if yours has them) in advance so there is little down time.

Now, About that gas mileage! With those K&N filters and the low restriction exhausts on your bike, you are moving more air and fuel into the carbs. than on a stock bike. If you and your buddy did a rolling start in 5th gear I would bet you would pull ahead of him, (right into the next gas station!) So if more power was what you were looking for when you changed the filters and exhaust then I'm sure you got it, but more that likely you won't see 50 MPG ever again! This last comment is a bit of a "touchy subject" but here goes. The 1300 c.c. Yamaha V4 was not designed to run on "high test" gas. Due to the fact that the combustion temperature is lowered with the "high test" you do not get a complete burn of the fuel/air mixture which leads to poor gas mileage. If you have one of those rare bikes that "pings" on regular gas then by all means, run the high test, but if your bike will run on the regular, put the extra money into some "safety chrome" because it's not doing you any good running the high test. An easy way to check this is look at the ends of your exhaust pipes, are they black and sooty, if you stick your finger into the end of the pipe and touch the sides do you end up with a oily black residue that smells of gas? Thats the smell of unburned fuel going out your tailpipe. The ends of your pipes should be gray and the ash should be dry and dusty.

Check it out and let me know what you find, I might be able to help you with this. (yea, I know, I'm helping a Second Genner, I'm gonna' catch hell for this, I just know it!)

Earl

[Seaking]

hey Boo, no all those MPGs were US Gallons to Miles as my bike is US and I was filling up in the USA on this trip.. and most of you guys are yanks so it's easier to keep it simple for you guys Just kidding..

 

Those numbers I sent were in US gallons..

 

I pretty much agree with Goose.

 

I did also find out by using the Road King mufflers completely drilled out and the K & N filters I got worse gas mileage then running the regular filters.

 

At about 80MPH speedometer indicated, my gas mileage goes to crap (30MPG + ).

 

When you say you are getting 46 MPG is that imperial gallons?

 

I pretty regularly get 39/42 MPG.

 

BOO

[similost]

If your pipes are sooty, then you sound to be running too rich... Usually, when you put free flowing pipes and air filters on an engine, you will find you need to lean it out.. not richen it...

 

The more air an engine pumps through, the more efficient it gets to a point.. . The more CFM you can get, the less fuel you need for a complete burn...

 

With my Roadstar I went to a true ram air cleaner. It's strictly a funnel, with a free flowing filter in it. I also at the same time put on a forced air induction collector pipe. It it s straight 2 into 1 pipe, that has a ram air collector right at the point the two go into 1. This scavenges the pipe, so I basically turned the engine on that bike into a hell of an air pump..

 

When I got them on, I figured more air, more fuel... so, I put in bigger jets.. that was the completely wrong thing to do. It would hardly run...

 

Turns out now, I'm running the smallest jets I've ever found anyone to be running in a 1600 roadstar, and when I tell people the size I'm running, they can't believe it's actually running... I also went from about 40mpg to 50mpg, and that's riding it like I stole it all the time...

 

SO.. with that lesson learned, I've learned the better you can get an engine to flow, the less fuel you need.. that ended up taking me about a month to figure out, and running through about 5 different jet sizes to figure it out..

[Dave77459]

Your fuel mileage seems pretty typical with my experience for the different condition. I do think you are totally wasting money to purchase premium fuel - it does absolutely NOTHING for the RSV. This engine is designed for 87 pump octane (and runs perfectly on 85 octane in the mountains).

Goose

 

I have a question about octane. On my recent trip to the Grand Canyon, the RSTD was backfiring like my dad after beans. I'd crest a hill, and let off the throttle in preparation for the switchback. When it got near idle, I'd get a loud POP.

 

I usually run 87 Octane, but most of the stations I saw had 86 Octane, and 89. Not wanting to have too little Octane, I put in the 89. It had no effect on the backfiring.

 

Am I right in thinking the backfiring was incomplete combustion in the engine, resulting in combustion in the exhaust? I definitely have soot in the exhaust tip. Does that mean I was running too rich, and should have used the 86 Octane?

 

Should I be concerned?

 

Dave

[Seaking]

Thanks for all the sage info, Goose.. I'll follow through and let you know what I find out.. going to switch back to regular instead of premium and see what happens with the performance and fuel mileage..

 

I'll try the petcock tests as prescribed and let you know.

 

Cheers, much appreciated!

 

I cannot tell you for sure what happened, but I can give you my comments and experiences from over 70,000 miles on an RSV.

 

First, no riding conditions should have any effect on if your Reserve works or not, at least when you first turn it on. However, steady, straight, flat riding on a smooth highway WILL cause you to loose access to perhaps the last 1/2 gallon of fuel, as it will become trapped in the right side of the tank. The RSV has no leveling tube to connect the sides; under normal riding conditions (leaning, bumps and hills), the fuel sloshes back and forth, and you will normally get to use ALL of the reserve. On both of my bikes and everyone with an RSV that I have run with, this has consistently been 1.5 US gallons (my trip meter and fuel light always comes on with 1.5 gallons left for reserve).

 

For the first year or two of ownership I used the petcock to switch from reg to reserve as needed. My experience has consistently been that the trip meter and fuel light comes on about 5 miles before the engine starves for fuel on normal setting. This has also been the most common experience reported by other RSV riders; however, a few have reported their trip meters switch later, as yours seems to be doing. I no longer ever move my petcock - it stays in reserve permanently. I figure the fuel gauge, the fuel trip meter, and the low fuel light give me MORE than enough warning about hitting reserve without having to mess with changing a lever too.

 

I almost never fill up before hitting reserve. I know for a fact I have a minimum of 40 miles on reserve, even when running at 80 MPH, and if I stay below 65 I can usually get 60 miles on reserve. I have vented my filler neck to make it easier to completely fill the tank, and I have been able to add 5.8 and 5.9 gallons numerous times when I pushed it to the limit (without running out). BTW - I always have at least 20 miles left AFTER all of the bars are gone from my fuel meter - just one more check that I can monitor to guess how low the tank really is while running on reserve.

 

Your fuel mileage seems pretty typical with my experience for the different condition. I do think you are totally wasting money to purchase premium fuel - it does absolutely NOTHING for the RSV. This engine is designed for 87 pump octane (and runs perfectly on 85 octane in the mountains).

 

As for testing if your reserve setting is working, that is easy. Just turn it on now and start riding. If it is not, you will begin to feel the engine starve in a few miles. You should also be able to confirm if the fuel is getting to the carbs simply by turning the key on and listening to the fuel pump, but you will need to turn the fuel off and run it for a short while to lower the fuel level in the bowls first. Then just stop the bike, turn the petcock to reserve and turn the key on. If the pump clicks a short while and then stops, it was able to fill the carbs, meaning it is getting gas.

 

If the reserve is working now, with lots of gas in the tank, then you know the petcock valve is good, and the only other potential problem is if the reserve position has access to the fuel when it is below the normal position. To test that, I would suggest you simply drain all the available fuel from the petcock in the normal position while the bike is in your garage, then simply test the reserve again just like before. There is no external tube feeding the reserve, so I do not know what the above posts are recommending. I also do not have any idea what the fuel feeds to the petcock look like inside the tank, as I have never had a need to check it out. Normally, these would simply be two different fixed input tubes, one sticking up higher than the other, possibly with screens on them. If your testing finds a problem with the reserve feed, why not just take it in to have it fixed under warranty?

Goose

[RedRider]

I have a question about octane. On my recent trip to the Grand Canyon, the RSTD was backfiring like my dad after beans. I'd crest a hill, and let off the throttle in preparation for the switchback. When it got near idle, I'd get a loud POP.

 

I usually run 87 Octane, but most of the stations I saw had 86 Octane, and 89. Not wanting to have too little Octane, I put in the 89. It had no effect on the backfiring.

 

Am I right in thinking the backfiring was incomplete combustion in the engine, resulting in combustion in the exhaust? I definitely have soot in the exhaust tip. Does that mean I was running too rich, and should have used the 86 Octane?

 

Should I be concerned?

 

Dave

 

The backfiring has nothing to do with octane. It is too rich a mixture and/or out of sync carbs.

 

RR

[Dave77459]

The backfiring has nothing to do with octane. It is too rich a mixture and/or out of sync carbs.

 

RR

 

The carbs were sync'd by Gunboat at the Houston MD on 3/21, then allegedly again by the dealership a week before my trip at the 16,000 mile checkup. The bike was smooth at speed (little vibration), so I am thinking it isn't a sync issue. Maybe.

[V7Goose]

I have a question about octane. On my recent trip to the Grand Canyon, the RSTD was backfiring like my dad after beans. I'd crest a hill, and let off the throttle in preparation for the switchback. When it got near idle, I'd get a loud POP.

 

I usually run 87 Octane, but most of the stations I saw had 86 Octane, and 89. Not wanting to have too little Octane, I put in the 89. It had no effect on the backfiring.

 

Am I right in thinking the backfiring was incomplete combustion in the engine, resulting in combustion in the exhaust? I definitely have soot in the exhaust tip. Does that mean I was running too rich, and should have used the 86 Octane?

 

Should I be concerned?

 

Dave

Should you be concerned? Well, yes and no. It is nothing that is going to hurt the bike, but it IS obviously annoying, and it DOES show that something is not just right in the ignition of the fuel (or maybe with the exhaust system). My bet is 98% probability (that percent is jut a SWAG) that you need to replace the two rubber caps on the intake manifold nipples (and also inspect the two vacuum hoses on the other two nipples to make sure they have not been cut or torn while being removed). The caps were cracked and hard on my 05 two years ago, so I'd bet they are bad on your 06 by now. Another common problem for this is a leak in the exhaust pipe at the Y joint.

 

I have gone over the causes of this problem in great detail in older posts, so I won't repeat it all here, but basically this is caused by incomplete combustion allowing unburned hydrocarbons to collect in the exhaust pipes, which then is ignited by the hot exhaust gasses. Lots of things can contribute to that, including a vacuum leak, old plugs, incorrect carb settings, etc. It is ESPECIALLY prevalent when riding in the mountains for two reasons - lots of opening/closing of the throttle along with a tendency to lug the engine a bit on inclines, and the altitude changes the fuel mixture from the supposedly optimal setting you had down lower.

 

Octane had zero to do with it. They sell 86 and 85 octane fuel as regular at higher altitudes because that is all that is needed to produce the same anti-knock results under those conditions as you get with 87 octane lower down.

 

Finally, any carbureted engine that is properly tuned at low altitude will have a bit of soot in the exhaust in the mountains - nothing to worry about. AND, in my experience, many, and maybe all current Yamaha Royal Stars are coming from the factory with the carb floats set way too high. This means they are running a bit rich at mid throttle and higher, no matter how well they are set up.

Goose

[V7Goose]

The cost differences from reg to premium isn't that much on a fill up but it's about getting more range and endurance from that same tank of gas.. Premium had proven to have longer legs on my bike...

I have no doubt that you think so, but technically, the science makes this completely impossible. Premium fuel has NO more energy per gram than regular, so it is totally impossible for it to either give you more power or better fuel mileage (and despite what a few other folks say, it also cannot give you worse fuel mileage). The only thing the higher octane does is resist detonation better, which is the tendency of the fuel to ignite from the heat and compression before the spark. If it does not pre-ignite, once the spark plug fires and starts the burn, the fuel will burn with equal energy and completeness no matter what the octane. BUT! - if you buy gas with alcohol in it, you absolutely will get worse fuel mileage than any gas without alcohol! Again, the science dictates that this will always be true since alcohol has less energy per gram that gasoline.

 

And proof of the mileage is mighty hard to come by outside the laboratory. In fact, it is virtually impossible to get accurate miles per gallon calculations from one tank of gas on a motorcycle, or even five tanks. Too many things will affect the fuel consumption, including road conditions, winds, levelness of the road, speed, braking, etc. etc. To further mess things up, the calculations will be thrown way off by even very minor differences in how much fuel you add each time. Think about it - if you are not going into reserve before fill up, you probably are only adding about 4 gallons, so even a cup or two difference will make a significant change in your calculation, even if all riding conditions were EXACTLY the same.

 

The ONLY way to get somewhat realistic MPG figures from a bike is to do the calculations for every tank of gas over many many many tanks to get a long-term average.

 

However, if you think it is better, no matter why, them maybe the price is worth the value. After all, it won't hurt a thing, so if it makes you happy, do it!

Goose

[Stoutman]

I have a question about octane. On my recent trip to the Grand Canyon, the RSTD was backfiring like my dad after beans. I'd crest a hill, and let off the throttle in preparation for the switchback. When it got near idle, I'd get a loud POP.

 

I usually run 87 Octane, but most of the stations I saw had 86 Octane, and 89. Not wanting to have too little Octane, I put in the 89. It had no effect on the backfiring.

 

Am I right in thinking the backfiring was incomplete combustion in the engine, resulting in combustion in the exhaust? I definitely have soot in the exhaust tip. Does that mean I was running too rich, and should have used the 86 Octane?

 

Should I be concerned?

 

Dave

 

Dave,

 

My experience is that backfiring occurs when there is a need to sync the carbs. Mine backfired when it was new and has not backfired since I bought a sync tool and started syncing my carbs regulary. The tech library has good instructions on how to sync the carbs, and after the first time of locating all the nipples and twisty bits, and reading the instructions, it only takes about 10 minutes to sync the carbs on this bike. I do it every oil change. I'll sync it sooner, say after 2000 miles if I'm heading out for a long weekend, only because I love the way it runs after a carb sync.

 

Best of luck.

[wes0778]

I'm sure there ar lots of really technical terms for octane, but the simple redneck explanation is the higher the octane the more difficult it is to set on fire. (Think gasoline vs diesel fuel) Diesel fuel has an octane rating off the scale when compared to gasoline. Pour a little gasoline on the ground and throw a match at it, then do the same with diesel fuel. What happened?

The difference between 87 and 92 octane are much more subtle, but a spark ignited engine can tell the difference. Years ago my dad's low compression 6 cylinder Chevy would just about not start on the 100 octane Super Shell I had to run in my 1970 400HO GTO. (Wish I still had that car )

 

As for the reserve, thingy, I don't know how Yammie does it, but waaay, (1963) back when I worked at the local Honda shop, the way reserve worked on those bike was there were two inlets to the petcock. The normal inlet had a tube extending about 1-1/2" up into the tank. The reserve inlet was flush with the top of the petcock. So on "normal" the bike would run out of fuel, with 1-1/2" of gas left in the tank. When you switched to reserve, you had the 1-1/2" of fuel to get you to a gas station.

 

I'll sit down now...

[Seaking]

I have no doubt that you think so, but technically, the science makes this completely impossible. Premium fuel has NO more energy per gram than regular, so it is totally impossible for it to either give you more power or better fuel mileage (and despite what a few other folks say, it also cannot give you worse fuel mileage). The only thing the higher octane does is resist detonation better, which is the tendency of the fuel to ignite from the heat and compression before the spark. If it does not pre-ignite, once the spark plug fires and starts the burn, the fuel will burn with equal energy and completeness no matter what the octane. BUT! - if you buy gas with alcohol in it, you absolutely will get worse fuel mileage than any gas without alcohol! Again, the science dictates that this will always be true since alcohol has less energy per gram that gasoline.

 

And proof of the mileage is mighty hard to come by outside the laboratory. In fact, it is virtually impossible to get accurate miles per gallon calculations from one tank of gas on a motorcycle, or even five tanks. Too many things will affect the fuel consumption, including road conditions, winds, levelness of the road, speed, braking, etc. etc. To further mess things up, the calculations will be thrown way off by even very minor differences in how much fuel you add each time. Think about it - if you are not going into reserve before fill up, you probably are only adding about 4 gallons, so even a cup or two difference will make a significant change in your calculation, even if all riding conditions were EXACTLY the same.

 

The ONLY way to get somewhat realistic MPG figures from a bike is to do the calculations for every tank of gas over many many many tanks to get a long-term average.

 

However, if you think it is better, no matter why, them maybe the price is worth the value. After all, it won't hurt a thing, so if it makes you happy, do it!

Goose

 

I hear what you're saying and not disagreeing with your wealth of experience on the matter.. I'm only pointing to my own observations over the course of 15,000 miles since I've gotten the bike as to what I have seen..

 

Just as a note, if I hear another Yank whining about the price of gas again I'll toss them a rubber chicken.. My gosh.. the most it cost me to top up my bike was $10US while that same amount of fuel would have cost me $17CDN.. even after exchange rate you guys have cheap gas compared to us up here.. dayum!! I know where I'm doing all my road trips this summer lol..

 

However, I will be running reg vice premium fuel in the RSV and see how it feels for fuel consumption..

 

Thanks for the info, much appreciated.

[Guest tx2sturgis]

Goose put out some good advise there. Spot on. One thing. Are you putting the fuel petcock in reserve ( by mistake) and then flipping it to ON when the fuel lite comes on? If you do this, thinking the fuel lever should point up for ON, you will quickly run out of fuel , when actually you have about a gallon left.

 

Yeah, your probably not doing this, but the reason I ask is because I rode with a guy one time who thought that the ON position on his bike was with the lever pointed up. He wondered why when he never could get very far when he switched to 'reserve'

[Seaking]

Goose put out some good advise there. Spot on. One thing. Are you putting the fuel petcock in reserve ( by mistake) and then flipping it to ON when the fuel lite comes on? If you do this, thinking the fuel lever should point up for ON, you will quickly run out of fuel , when actually you have about a gallon left.

 

Yeah, your probably not doing this, but the reason I ask is because I rode with a guy one time who thought that the ON position on his bike was with the lever pointed up. He wondered why when he never could get very far when he switched to 'reserve'

 

A good question to ask but I have it on the proper indication.. long end of the pointer down for ON and up for RES.. and set all the way around for RES.. I'll be getting to some work on the bike next week (teaching this weekend) and will get to testing all advices and comments..

 

Thanks in advance.

[Dave77459]

Should you be concerned? Well, yes and no. It is nothing that is going to hurt the bike, but it IS obviously annoying, and it DOES show that something is not just right in the ignition of the fuel (or maybe with the exhaust system). My bet is 98% probability (that percent is jut a SWAG) that you need to replace the two rubber caps on the intake manifold nipples (and also inspect the two vacuum hoses on the other two nipples to make sure they have not been cut or torn while being removed). The caps were cracked and hard on my 05 two years ago, so I'd bet they are bad on your 06 by now. Another common problem for this is a leak in the exhaust pipe at the Y joint.

Yep, I know that either the rubber caps or the intake manifold nipples were getting cracked... these are the ones removed when the carbs are sync'd, yes? Gunboat noticed they were showing signs of rubber death at the Houston MD.

 

That seems a pretty likely cause given the evidence. I'll get new ones and see if that solves the problem. I would infrequently hear minor backfiring on deceleration some time ago. If I don't hear it afterwards, I'll be more confident.

 

Thanks!

 

Dave