Bad cams?
Road Master
Joined: Apr 2012
Posts: 1,096
Likes: 17
From: San Jose
What did hey check? If it were me trouble shooting this problem, I would be putting a degree wheel on there and confirming correct valve timing.
I have the FM 107, TW777 cams 10.7-1 and in California it's only 91 octane and using a PV. Mine runs awesome, never pings, just keeps hammering on.
It's not the package, it's the set up.
I have the FM 107, TW777 cams 10.7-1 and in California it's only 91 octane and using a PV. Mine runs awesome, never pings, just keeps hammering on.
It's not the package, it's the set up.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,957
Likes: 8,048
From: poway
As other have stated 178 is a little low if checking the CR at 900 ft level (Bow NH). If running flat tops as a 110 and 85 cc stock ported heads the compression ratio should be about 10.6 to 10.8 to 1 which should net you about 200 to 210 psi at sea level.. Motor will likely not need much timing to run. You may want to find someone else to tune your bike.
When doing the compression check, are you holding the throttle wide open? Is throttle system fly by wire?
When doing the compression check, are you holding the throttle wide open? Is throttle system fly by wire?
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
6 Weirdest Harley-Davidsons Ever Sold to the Public
Verdad Gallardo
7 Times Harley-Davidson Chucked Tradition Out the Window
Verdad Gallardo
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
Thread Starter
|
Advanced
Joined: Jul 2011
Posts: 51
Likes: 1
From: Bow NH
As other have stated 178 is a little low if checking the CR at 900 ft level (Bow NH). If running flat tops as a 110 and 85 cc stock ported heads the compression ratio should be about 10.6 to 10.8 to 1 which should net you about 200 to 210 psi at sea level.. Motor will likely not need much timing to run. You may want to find someone else to tune your bike.
When doing the compression check, are you holding the throttle wide open? Is throttle system fly by wire?
When doing the compression check, are you holding the throttle wide open? Is throttle system fly by wire?
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,957
Likes: 8,048
From: poway
If this motor is built right, my bet would be that you got way too much timing and the guy tuning only has experience with stage 1 bikes... I've run 10.8 with 42 degree close. CCP was 220 psi.. Once dialed it it rarely pinged.. Did get some when I was trying to bring up the gas mileage tho..