After changing my stock pipes to Vance and Hines I now get only 27 mpg...it is a newer trike just broke in...only 4k...was getting 35...37 milesper gallon
Pleas help if u can...donny lovette

 

Unless you are just riding your trike harder to enjoy the new sound, it may be that you need to either get a tuner installed or have your current one "flashed" if that is still possible.

Bikes/trikes are not like cars. Our engines need a certain amount of back pressure in the exhaust.
I once pulled the baffles out of my V&H slip-on's on my '00 Ultra and it was un-ridable!

Perhaps you should try re-installing your OEM's and see if that helps?

 

I have the complete pipes with baffles...I will begin to spin large quantities of money

 

Not sure what you mean by "complete pipes". At first you said slipons, now you say complete pipes????

In any case, with proper tuning for what you are actually running you will get proper mileage again. Naturally if you open the air/gas flow it will cause you to use more gas.

You might want to change the air intake to match the 'complete pipes'

 

Thx for replying...I have read everywhere that just changing the slipons doesnt require a remap...but going from 35 + mpg to 27 tells me that there is a problem...A guy at a local shop here is ordering me a new air filter and he says that's all I need...The problem is I am not a mac mechanic so I am stuck with having to rely on other people's advice...I think I will need some kind of tune...I just have to play that game of chance and hope I am getting the truth from people...I know that when I use to fill up my 6 gallon tank the range would say 230 miles...now it says 201...but I actually get 165 miles on 6 gallons of gas...depressing...but I will keep moving on...Thx

 

I've found that you do need a tuner when changing the slip-ons that are less restrictive.

 

Thank you for that...I will be getting a tune on Monday hopefully when I get the air filter upgrade...All of it makes sense to me...I will get back and let u guys know the outcome...Thanks to everyone...donny

 

LINK to Harley Exhaust- How it Works. Myths & Facts

Dyno charts on M8's, with and without a tuner LINK

 

I switched to Street Cannons and have noticed a little bump in power and if there is a decrease in mileage, it is not noticeable. On my 2001 FXSTS, I had to re-jet my carb when I went to V&H sweeps. I was running way too rich. You might want to do a plug check for a quick answer. If they are chocolate-like and wet, you will need re-tuned.

 

When I put the Fuel Moto full system on my bike I went from 45mpg to 37 with the new FP3 tune. My bike ran great, but wanted the fuel mileage back for a upcoming 6500 mile trip next month. So I sent my tune to V&H for some adjustments to the program and now I'm back at 43mpg without to much noticeable difference in performance.