I know, you are wondering why this is here. I couldn't figure out where else to post it.

I had a problem with my bike being hard to start when warm or hot. So manual compression releases installed. Starting problem cured.

Prior to the install my low fuel would come on at 147 miles and I'd run to 165 miles or so and tank up with usually about 4.2 gallons. About 39 mpg.

Now with the compression releases I get low fuel indicator at 133 miles, run to 150 and fill up with 4.5 gallons. About 33 mpg.

This happened immediately.

So a 15%+ reduction in gas milage. I thought 39mpg sucked but 33mpg really bites.

2007 Ultra
103 SE stage II kit
Mufflers that came with the kit
V&H true Duals
No aftermarket FM system.

 

Wow that's strange, maybe your compression release has a leak

 

That would be my guess too. One of them could be leaking but I would think you would hear a different kind of sound coming from one of the cylinders.

 

I read in another thread the OP had the same basic set up and is only getting 33.

 

Do a compresion test, No other logical reason I can think of for a compresion release to affect mpg. Maybe the gas station you use just hapend to add ethenol to the mix around the same time?

 

Prior to compression releases when I hit an ethonol blend my low fuel light dropped to 127 miles. If all I'm hitting are ethonol stations then it went up 6 mpg which I doubt.

 

Interesting post... i've got compression releases on my bike (10.25 pistons) and my mpg's are only 36-38 mpg at best. Never thought of the releases being a culprit. My bike had them when I got it so dont know what it got before the upgrade.

 

Its my guess that if the release was not sealed correctly, you would be able to hear it......sort of like a exhaust leak. Were your heads just placed in the jig, and drilled and tapped for the compression releases or did you buy new heads with the releases already in them?

 

Jig, drilled and tapped. The front one stick open a bit so you 'blip' the throttle and you can hear it snap shut.

While its open there is a distinctive sound. Once throttle is applied its gone.