maybe better fuel mileage?

[kawboyCAFE]

i had a thought about how to make our bikes get better fuel economy. i dont know if this would work or not, maybe i will give it a try this winter. anyway, here it is. i thought if you made the bike into a 2-into-1 exhaust, using the stock right side muffler, then put barely smaller jets in the carbs, and also retarding the timing about 2-5 degrees, then putting different sprockets to make it a higher gear ratio it might get pretty good MPG. i know it would kill the acceleration a little bit, but not that much. besides, these days i am not about horsepower anyway. i will admit i was when i first got the bike, but not now. if i could do this and gain 10-15 MPG, i would be thrilled. like i said, i may try it this winter just to see what would happen. by doing this i would have a full size economy bike. it may work, then again it may not. dont know. what are you guys thoughts on this? i had a brainfart and got curious, just thought i would share. what do you guys think? would it be worth it to you to trade 5 HP for 10-15 MPG? just curious.

[fastpakr]

So you want to make it run artificially lean, then try to increase the load on the engine with taller gearing?

[kawboyCAFE]

dude, it wont be running lean. if you make a 2-1 exhaust header, then put one size smaller jet in the carbs, they make up for each other. it wont be lean. and taller gearing wont hurt our bikes anyway, they are geared too low to begin with from the factory. there is no reason whatsoever for my 6 speed VULCAN to run the same or more RPM's as my 5 speed VSTAR did at highway speed. and if you retard the timing a little it will also help with the new exhaust and jets. the bike will run just as good as it does now, just not quite as fast.

[Triangles]

I thought advancing the ignition helped with mileage? Oh wait you're talking about retarding the exhaust? I was gonna say good luck hacking the ignition box. If I have time this winter I'm going to fuel inject my '94. I know it will be ridiculously expensive, I'm just going to do it because I can. If I could figure out how to rig up a cam position sensor the microsquirt controller also can control the ignition. I still might figure out a way to jury rig it. I would imagine adding the capability to vary ignition timing based on load as well as RPM should help fuel economy.

[fastpakr]

You're going to make yourself crazy trying to create hacked solutions to a problem that doesn't exist. You've already bought wholeheartedly into the scam of putting a Tornado like blockage in your intake. Now you've decided to install an aftermarket exhaust, assume that it will actually be a restriction on airflow without doing any testing, and concluded that you will therefore need to reduce the size of your main jets. You've also made the curious leap of assuming that just because it's restrictive, it will improve your fuel economy. In addition, that the higher engine speed you're seeing is reducing your fuel economy significantly. It's a fundamentally different engine design from the relatively low revving V-2 from your Yamaha. It's possible that you can tweak the mileage fractionally with sprocket changes, but not enough to make a difference over many, many thousands of miles. The engine was designed from the ground up to be used in a sport bike. The OEM gearing was designed to put it in an efficient point at highway speeds in sixth gear.

How do you plan on retarding the timing, and why on EARTH do you think that will improve your fuel economy? If anything, advancing it slightly might help a bit, but in all likelihood only if you were also willing to spring for higher octane fuel that would offset any limited gains you might see.

[kawboyCAFE]

the 2-1 exhaust would be a little more restrictive, because i would use the stock right side muffler, therefore i would have to tune down the carbs just a little. the ignition i probably wouldnt mess with anyway, just a thought. barely taller gearing will help with my fuel economy strictly because i do most of my riding at 65-70 mph. and my little turbulators i made might not be helping that much, but they do help a little. they certainly dont hurt anything. i am sorry you have such a problem with them, but oh well. i may not do any of this anyway, it was just a brainfart to begin with.

[burkbuilds]

Sounds like a lot of work with potentially "ify" results. I agree with you that the bike is geared lower than necessary. I changed my sprockets and picked up about 10mpg highway and about 5 mpg around town. You seem to be getting about 5 mpg better than I was with the 17/42 (I had the 17 tooth installed right after buying the bike, so no way for me to tell you what I was getting with the stock set up. I was getting right around 50mpg with the 17/42 set up). I'd be willing to bet that changing your sprockets to the 17/40 from stock (assuming you are running stock now) would probably put you into the mid 60's highway mileage. I think I'd recommend just doing that first and see what you think, it's pretty inexpensive and not to labor intensive and easily reversible if you don't like it. By the way, I generally try to keep it right at 70 mph on the highway, and it's pretty "hilly" here in N.W. Georgia where I ride. I'm about 215lbs and I have two big saddle bags and a trunk and they are usually loaded fairly heavily when I'm riding.

[kawboyCAFE]

thanks burkbuilds. i will probably try that first anyway. the honda rebel i had i changed the front sprocket and noticed a slight difference on it too. like i said earlier, i may not mess with any of this, except the gears of course. it was just a brainfart i had and thought i would bounce it off you guys. most of the bikes i have owned over the years have been bone-stock except for maybe bags or something like that. mine is stock gearing now, and i have been thinking about the 17/40 combo to put on this winter. tell me, do you like the combo? how much did it reduce your RPM's? any noticeable change for around the town riding? i dont do jack rabbit starts anyway. i have been pretty easy going on bikes since my son was born. anyway, thanks for the comments, keep them coming.

oh, and FASTPAKR, keep trying to rip up my posts . doesnt bother me at all.

[fastpakr]

Oh dear, please forgive me for trying to post accurate information backed up the laws of physics. If you don't believe me regarding the 'Turbulator' (or Tornado, as one of its more common trade names), just do a google search on 'Tornado Scam'.

I assure you, I'm not the only person to be a little skeptical. Here's a good one:
http://www.fuelsaving.info/turbulence.htm


Here's another one:
http://www.popularmechanics.com/cars/al ... ge/1802932

I'm not doing this to be argumentative or make an ass of either you or myself. The whole point is to try to point you in the right direction and keep you from falling prey to any more scams or from causing long term damage in the name of improving efficiency. If all you're after is efficiency, ditch the Vulcan and go pick up a Honda Rebel or any of the other small cruisers on the market. They're excellent machines that consistently get 70+ miles per gallon and you'll pocket money on the trade.

[burkbuilds]

Kawboy, I really like the sprocket change to 17/40. My rpms dropped to about 4900 at 70mph which apparently got me out of a very fuel inefficient rpm range, and thus my mileage went up noticeably. I haven't been able to tell a significant difference in around town other than that I shift less and rarely go into 6th gear unless I'm up to highway speeds. Today I had to pull out, left turn, into heavy traffic here in Atlanta and I gunned it and it shot out like a rocket. If it had been any more aggressive I probably wouldn't have kept it under control. This is a great bike. Well, getting ready to ride back towards Chattanooga, lots to do over the next several days, so everybody have a great weekend coming up.

[kawboyCAFE]

hey FASTPAKR, if you think you have accurate info based on something you read on the internet, well you can that with a grain of salt. i have accurate info based on real life experience. i really dont care whether or not you believe me, doesnt really matter. it works for me, and me is all that counts to me. i will write this here for everybody to read. FASTPAKR, i will no longer answer your posts at anytime from now on. this will be the last time i write something for you. you seem to think it is your mission in life to try and piss people off in your answers. you do this on the other vulcan forum also. if your life is so shitty that it makes your day better to shit on someone else, well, i feel sorry for you. i did not join this or any other forum to have someone try to tell me how stupid i am when i know that something works from first hand experience. you say the articles you read are the true fact? well, i read articles about UFO's and BIGFOOT wrote by people who say their articles are true facts also. again, last time i will answer you, so i guess keep up the good work of trying to put down other peoples ideas by calling them stupid.

[kawboyCAFE]

hey BURKBUILDS, thanks for the reply. i am definately going to change sprockets this winter the 17/40 combo. i would do it now, but i would rather wait until riding season is over, that way it will be ready for next spring. of course, my riding season doesnt end until its about 35 degrees outside.
below that and the car heater starts calling my name .

[gregm]

Hi. I am new to the forum, as I am new to my recently bought used 2006 kawi vulcan. I was reading through your post about changing the sprockets, seems like something worth doing. I live on the big island of hawaii, gas is expensive, and highway (not sure I'd even call them that) speed limits are more than 55mph. I believe my gearing is stock. I want to add on the 17 up front. I was wondering if you ever made that switch, and if so, how did it work for you? my first gear is so short, it would be really nice to get more out of it, and to lessen the RPMs at "highway" speeds here on the big island.

Greg

[Turbojoe]

Greg,

I consider the 17t sprocket one of those "must do" upgrades. First gear actually becomes useful, rpm on the freeway drops and gas mileage can increase pretty significantly. I'm 6'3" and 250 pounds and I've gotten as much as 61.2 mpg. The lowest I've gotten lately is when I've had to ride 75-80 mph because of traffic flow. Then I get about 55+. I do my best to ride the 65mph speed limit but it's hard to do without getting run over.

It can be a bear to get the sprocket broke loose but it's worth the effort. You should be able to find the JT sprocket on ebay for well under $20.00. It'll pay for itself in no time with fuel savings.

Joe

[Triangles]

Then I get about 55+. I do my best to ride the 65mph speed limit but it's hard to do without getting run over.

Also keep in mind that when your speedo says 65 you're actually going 60-61ish.