high compression engines

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Nov 29, 2009 | 06:44 AM

#11

FastHarley

Former Sponsor

Joined: Apr 2007

Posts: 5,360

Likes: 453

From: Davie, FL

Just putting my motor back together as the top ridge between the piston top and 1st ring blew off about 3" in diameter edge and up to the inside of the ring edge. I picked up some bad fuel in Clewson, FL (bottom of lake Okeechobee) and started pinging along RT. 27 (South, in farm country). Upon careful inspection there could not be any other explanation. I have a 113 CI TP evo.

Nov 29, 2009 | 07:42 AM

#12

maineultraclassic

Elite HDF Member

Joined: Mar 2006

Posts: 4,722

Likes: 5

From: Biddeford, Maine

Quote:

Originally Posted by trickin addixion

Hoping some of you guys with high comp engines might be able to answer some questions for me. I am having trouble with detonation and fuel milage. Am getting crappy fuel milage and if I try leaning the fuel or adding more timing I get detonation. I run 91 octane which is the highest octane I can find. Would running an octane booster allow me to add more timing or lean my fuel or maybe both? or would I just be throwing money away? I'm only getting 30 mpg and doesnt seem to change much no matter how I drive. Is this just a trade off for having a engine that makes good numbers? 95" make 100/100 numbers and I am pleased with performance just dont like the milage. Would appreciate any help you guys can give. BTW I think this is an awesome forum with some awesome people.

Thanks
Brian

30 mpg is a bit low, you still should be around 40-45mpg if your tune is right. But you always have to trade something for added performance and power.............if you wanted 50mpg you should have left it stock.

Octane Boosters are just a waste of money, there was a study done on them in a magazine and it turned out most of them had no effect at all on octane ratings, and some of them actually lowered the octane rating.

I would recommend getting to a true dyno tuner and let him tune your bike for you. Make sure the guy comes highly recommended, there are a lot of idiots out there with dynos.

Steve