Harley Upgrades that Increase Gas Mileage

[arthureld]

I've been thinking about doing some upgrades that will increase gas mileage.
I want to try a new cam and I want to have my heads ported. I want my bike to run better, but I want better gas mileage too.
I hear a lot of talk about a 6th gear, but my Stage I setup would be awful with a 6th gear. My bike moans going uphill with my fat ass and all the other weight I bring with me on long trips. Even when I'm doing 55 in 5th, if I decide to speed up a little, if I don't shift to 4th, my bike doesn't like it.
So, I want more torque, and more gas mileage.

Anyone have ideas? Is there info available about this?

I'm sure I'm not the only one thinking about this.

[Sandman]

i wouldnt mind gettin a bit more outta my scoot. maybe i'll go down to kagan's way next weekend when i got a 2 day'er. last time i seen the 'tech' pull the plugs, they were a bit white. yo kag, ya think u'd be able to richen it up juuuuuust a tad? seen those pipes 1 guy posted, and i'd rather not have any trouble if its runnin too lean ya know?

[Mungo]

Interesting post Authureld. I'll be interested in seeing what people say out here.

Based on the way the TC88 is designed, I imagine it would be maximizing the efficiency of the burn in the cylinders. This would involve effiencies in ignition and a better, more through gas/air mixture in the cylinders. So I can see portin the heads, but not polishing them. Maybe even one of those turbulators in the intake to mix the fuel better.

But that will only yield so much. Driving habits go along way.

I read an article/question in AIM where a pilot had written in. As a pilot, you learn what the most efficient glide slope is for your plane in the event of an engine failure or fuel crisis. This is the longest amout of "hang time" you have without power. The guy applied this thinking to a Harley and asked at what speed did the TC88 get the best gas mileage. The answer was 53 mph.

So, maybe that 6 speed isn't such a bad idea?

Otherwise, slow starts, adn 55 mph max where ever you can.

Although - if you're like Coolmaker - you can't drive 55.

[Stoney]

I've been thinking about doing some upgrades that will increase gas mileage.
I want to try a new cam and I want to have my heads ported. I want my bike to run better, but I want better gas mileage too.
I hear a lot of talk about a 6th gear, but my Stage I setup would be awful with a 6th gear. My bike moans going uphill with my fat ass and all the other weight I bring with me on long trips. Even when I'm doing 55 in 5th, if I decide to speed up a little, if I don't shift to 4th, my bike doesn't like it.
So, I want more torque, and more gas mileage.

Anyone have ideas? Is there info available about this?

I'm sure I'm not the only one thinking about this.

sounds to me like you aint got it tuned right to begin with.my stock 80 inch evo pulls like a MF in 5th gear.

[gdkenoyer]

I'm sure I'm not the only one thinking about this.

damn straight you're not!

The current series of Donny (ln?) performance articles in American Iron began with a comment aluding to increasing performance and mileage, but I'll be damned if I have seen any mileage considerations...

[arthureld]

sounds to me like you aint got it tuned right to begin with.my stock 80 inch evo pulls like a MF in 5th gear.

I did the stage I upgrade. The common problem with stage I upgrade (free flowing exhaust and air filter) is loss of low end torque. It's not enough to effect ridability with standard gearing, but I don't think it would work well with a 6th gear. I know I could gain some low end by switching to a 2 into 1 exhaust, but I love my Rienharts so that probably isn't going to happen.

[gdkenoyer]

I can see portin the heads, but not polishing them.

note that this is said with no practical experience, only reading:
my understanding is that the intake should be "smoothed" and shaped to increase flow but should maintain a rough texture to encourage the air-fuel mixing process, on the other hand the exhaust should be shaped and polished to minimize any flow restrictions.
The AIM articles discuss the TC88 being a much more efficeint head design (squish area) than EVO or Shovel, but being lacking in flow.

[Oli1200]

I've been thinking about doing some upgrades that will increase gas mileage.
I want to try a new cam and I want to have my heads ported. I want my bike to run better, but I want better gas mileage too.
I hear a lot of talk about a 6th gear, but my Stage I setup would be awful with a 6th gear. My bike moans going uphill with my fat ass and all the other weight I bring with me on long trips. Even when I'm doing 55 in 5th, if I decide to speed up a little, if I don't shift to 4th, my bike doesn't like it.
So, I want more torque, and more gas mileage.

Anyone have ideas? Is there info available about this?

I'm sure I'm not the only one thinking about this.

Just a thought, if you're going 55 mph in 5th you're lugging it, which is bad. Probably why you can't feel any pull. To increase speed and really feel it you've got to be doin' like 70 to feel a zip from 5th gear.

[arthureld]

Just a thought, if you're going 55 mph in 5th you're lugging it, which is bad. Probably why you can't feel any pull. To increase speed and really feel it you've got to be doin' like 70 to feel a zip from 5th gear.

I don't lug my motor and I know that is one of the worst things you can do to a motor. It causes detonation which can burn your pistons and break your crank.

I was just trying to say that I want more bottom end. And that if I can get more bottom end, maybe a 6th gear would be a good way to increase mileage. But from what I have heard, reducing rpm in the top gear is asking a lot from a 2 cylinder aircooled motor. It's likely to cause lugging and decrease the life of the motor.

My crusing speed is above 70 mph. And that isn't going to change. I'm not going to ride slow to save gas. I see a lot of Harley guys riding the right lane doing the speed limit and that is great for them, but that isn't the way I ride. I ride in the fast lane and do as fast or faster than the flow of traffic in the fast lane.

[xxxflhrci]

Authereld,

No offense, but your bike sounds sick. It needs a tuning job. It should pull just fine on a throttle roll in 5th at 55 mph. You didn't say what it was, but I'm sure it is a later bike with 3:15 gearing. That hurts roll ons a litte, but not the way you are describing, IMO.

What kind of mileage do you get? My bike with the lower 3:37 gearing will get 40 mpg riding two-up, heavily loaded, and running 70 mph. That is without being easy on starts and rolling on the gas heavily to pas cars. If I try to ease it up to speed and go easy on the gas, it will get 42 or so. It did that before and after the Andrews 26G cams.