HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
kex

Daves Mods Done ,and So Is My Gas Mileage

36 posts in this topic

I have just completed daves mods on my 04 xr 650l ,also installed kn filter and fmf Q2 slip on muffler ,and now my gas mileage is terrible . went from 82 miles per tank before res. to 63 does anyone have the same problem or is there someway to better this ? cant complain about the power increase , what a diffrence. :thumbsup::lame: also whats your mileage ? thanx

Share this post


Link to post
Share on other sites

I am also getting ready to do this mod and looking for similar info!

The power increase was THAT noticeable huh?

Thanks

Share this post


Link to post
Share on other sites

That mileage sounds about right, I have the same bike withe similar mods & a 4 gallon tank. I hit res. at about 112 miles. Changing the jetting & opening things up drasticly improves performance :thumbsup: but you are gona loose gas milage

Share this post


Link to post
Share on other sites
I have just completed daves mods on my 04 xr 650l ,also installed kn filter and fmf Q2 slip on muffler ,and now my gas mileage is terrible . went from 82 miles per tank before res. to 63 does anyone have the same problem or is there someway to better this ? cant complain about the power increase , what a diffrence. :thumbsup::lame: also whats your mileage ? thanx

There's no "free lunch."

Where does performance come from? A tuned system and an energy source.

Dave's mods help tune the L to a decent performance level, and the energy source is, as we all know, gasoline. The performance increase uses more gas, plain and simple.

Outside of drastic re-engineering (a two-barrel carb--small main venturi for economy and average riding, and a bodacious secondary for power and antics), if you change one or some of the elements in the system, others will be affected. In this case a better breathing engine uses more fuel.

One suggestion after Dave's (or other) mods, is to validate that your combustion mix is in order...check your plug often for a clean, efficient burn. If too rich, your mileage (and engine) will suffer. :p

Share this post


Link to post
Share on other sites

63 miles to reserve sounds a bit low- I get to about 75 in most cases.

I have the stock muffler, though.

Are you keeping the front tire on the ground?

Dave

Share this post


Link to post
Share on other sites

My XR610R (96) supermoto has a pipe, 610 kit, jetted a little rich and a UNI filter, airbox mods. On a 5 gallon Clarke tank I get about 190 before reserve then another 35 on reserve before I get off and push.

Share this post


Link to post
Share on other sites

I have a '94 with Dave's mods, FMF Q slip on, UNI filter, desmogged and desnorkeled and I get low 40's. I was hoping for a little better mileage but the power and overall rideability with the mods is worth it. I have an SRX600 Yamaha streetbike that has essentially the same engine as an XT600 that will get 60mpg pretty easy. I think the knobbies and barn-door aerodynamics on the XR really drive the mileage down. I run a 4.0 gal Clarke tank, I don't fill it quite all the way full and have to go to reserve around 120 miles depending on how much has sloshed from one side to the other.

Share this post


Link to post
Share on other sites
There's no "free lunch."

Where does performance come from? A tuned system and an energy source.

Dave's mods help tune the L to a decent performance level, and the energy source is, as we all know, gasoline. The performance increase uses more gas, plain and simple.

Outside of drastic re-engineering (a two-barrel carb--small main venturi for economy and average riding, and a bodacious secondary for power and antics), if you change one or some of the elements in the system, others will be affected. In this case a better breathing engine uses more fuel.

One suggestion after Dave's (or other) mods, is to validate that your combustion mix is in order...check your plug often for a clean, efficient burn. If too rich, your mileage (and engine) will suffer. :thumbsup:

I would think it may even out though? Sure you may use more fuel but since you have more power you don't have to open her up as much to accomplish the same job as before.

You see it all the time with automobiles.......... every few years some get a bigger motor slapped in, gain more horsepower , yet get better gas milage.

Share this post


Link to post
Share on other sites
I would think it may even out though? Sure you may use more fuel but since you have more power you don't have to open her up as much to accomplish the same job as before.

You see it all the time with automobiles.......... every few years some get a bigger motor slapped in, gain more horsepower , yet get better gas milage.

I see your point, but I beleive with the phenomenon you see with cars, there is alot more changing than just a less-restrictive airpath, and a larger jet. For example, roller rockers, fuel injection, fuel maps, OHC vs pushrods, etc.

Now if the 650L engine was redesigned... :thumbsup:

Share this post


Link to post
Share on other sites
I see your point, but I beleive with the phenomenon you see with cars, there is alot more changing than just a less-restrictive airpath, and a larger jet. For example, roller rockers, fuel injection, fuel maps, OHC vs pushrods, etc.

Now if the 650L engine was redesigned... :thumbsup:

.............and I see your point too! :lame:

Share this post


Link to post
Share on other sites
My XR610R (96) supermoto has a pipe, 610 kit, jetted a little rich and a UNI filter, airbox mods. On a 5 gallon Clarke tank I get about 190 before reserve then another 35 on reserve before I get off and push.

That's 225 miles for 5gals. of gas.225/5=45mpg...45mpg@2.5gal. stock tank should take you 112.5 miles before workout It all comes to driving style,If I wake up late for work the mileage will surely suffer :thumbsup:

Share this post


Link to post
Share on other sites

Man, when you think about it, that's really crappy mileage toward a 2 ton car now a days. There are a lot out there that get 30-35 mpg (more on a trip) feeding a 4 or 6 cylinder motor and yet the bikes are ONLY 300 pounds or so feeding one cylinder and get just a bit better gas mileage. It's terrible when you look at it from that perspective.

You think a fuel injected one may have a substantial increase in mileage, that is if they come out with one?

Share this post


Link to post
Share on other sites

thanx for the info fellas ,i guess that ims 4gal tank is coming sooner than my wife thinks. with all that new power i just cant stop twisting .

Share this post


Link to post
Share on other sites

You may want to consider looking & the Clark 4 gallon tank, fit & finish is very good. It is also cheaper :devil:

Share this post


Link to post
Share on other sites

my 96 with the mods gets around 40 above 70 mph. If I slow down to around 60 I have gotten close to 50. That's with stock 15-45 gearing. Subtract 5 MPG when running the 14 countershaft on the hiway.

Share this post


Link to post
Share on other sites
Man, when you think about it, that's really crappy mileage toward a 2 ton car now a days. There are a lot out there that get 30-35 mpg (more on a trip) feeding a 4 or 6 cylinder motor and yet the bikes are ONLY 300 pounds or so feeding one cylinder and get just a bit better gas mileage. It's terrible when you look at it from that perspective.

Look at it this way,a one hour conmute on a car with heavy stop and go traffic can be done in less than half that time on a bike.I think were even then...

Share this post


Link to post
Share on other sites
Man, when you think about it, that's really crappy mileage toward a 2 ton car now a days. There are a lot out there that get 30-35 mpg (more on a trip) feeding a 4 or 6 cylinder motor and yet the bikes are ONLY 300 pounds or so feeding one cylinder and get just a bit better gas mileage. It's terrible when you look at it from that perspective.

Look at it this way,a one hour conmute on a car with heavy stop and go traffic can be done in less than half that time on a bike.I think were even then...

How the heck do you arrive at that, unless your riding the bike in a aggressive illegal way to get around traffic?

Why does a bike take so much gas towards a car? I know they (enduros) are not near as areodynamic as a car but with only weighing 300 lbs how comes they don't get a lot more then 40-50 per gallon?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0