Gear cam
Grand HDF Member
Joined: Jul 2007
Posts: 3,741
Likes: 8,537
From: Bates County MO
Typical gear drive needs less than .003" total indicated runout, .000 to .001" is preferred- typical late model pressed together crank from HD has two to three times that runout- factory spec states up to .012" ( 4 times acceptable) is within spec.
Darkhorse or S&S flywheel would be the choice if gear drive was preferred.
Or use the hydro chain setup, and be happy...
Darkhorse or S&S flywheel would be the choice if gear drive was preferred.
Or use the hydro chain setup, and be happy...
Banned
Joined: Jan 2012
Posts: 3,098
Likes: 474
From: Location location.
Typical gear drive needs less than .003" total indicated runout, .000 to .001" is preferred- typical late model pressed together crank from HD has two to three times that runout- factory spec states up to .012" ( 4 times acceptable) is within spec.
Darkhorse or S&S flywheel would be the choice if gear drive was preferred.
Or use the hydro chain setup, and be happy...
Darkhorse or S&S flywheel would be the choice if gear drive was preferred.
Or use the hydro chain setup, and be happy...
Or that it will improve it because it's out of spec ?
Cheers man.
Seasoned HDF Member
Joined: Sep 2009
Posts: 17,148
Likes: 6,171
From: SE Michigan
Personally I don't think there's any real benefit to gear driven cams in the M8 despite the grief I'll get for saying it. Too much senseless fretting about old issues with tensioner shoes that are not an issue any more, and haven't been for years. You could also introduce new issues with the oil pump
Last edited by Keithhu; Feb 17, 2018 at 10:29 PM.
Banned
Joined: Jan 2012
Posts: 3,098
Likes: 474
From: Location location.
He's saying you need to check it.
Personally I don't think there's any real benefit to gear driven cams in the M8 despite the grief I'll get for saying it. Too much fretting about old issues with tensioner shoes that are not an issue any more, and haven't been for years.
Personally I don't think there's any real benefit to gear driven cams in the M8 despite the grief I'll get for saying it. Too much fretting about old issues with tensioner shoes that are not an issue any more, and haven't been for years.
Club Member
Joined: Aug 2008
Posts: 22,865
Likes: 17,922
From: Lafayette, Louisiana
Originally Posted by badcooky
My understanding is that your timing is more precise with a gear drive , whether that's true I'm not 100% on it's what I've been told , no vehicle I've had has used one, but for me the sound is cool from a gear drive..
I think a lot of twin cam guys forget that the camshaft was gear driven for many years.
I don't hear gear whine in the single counter balanced M8 used in the touring bikes but I find it very pronounced in the M8 Softails which have two counter balancers. With time, I am sure the gears will wear to each other and the whining will subside.
Since they are driving counter balancers with gears, it seems like they would have driven the cam with gears as well.
Timing is more precise with gears, but isn't a noticeable difference that can be felt in this application. On an automobile engine making hundreds of horsepower, it makes more of a difference.
Trending Topics
Thread Starter
|
Tourer
Joined: Oct 2006
Posts: 295
Likes: 12
From:
Thanks for the info. so far. I may do some pinion measuring to see where I'm at. Also I have an 17' FLHR with the 107.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
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
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Grand HDF Member
Joined: Jul 2007
Posts: 3,741
Likes: 8,537
From: Bates County MO
It's a shaft- if the runout is 0, the pinion shaft turns in a circular motion. If there is .003" TIR, then it turns in a tiny oval. If the TIR is .012", then the oval is more pronounced. Think bent shaft. As the bend moves toward the cam, clearances are reduced towards binding, and "gear whine". As the bend goes away from the cam, clearances increase; then, the force of the valve springs can push the cam forward or backwards, thus the "clacking" sound. HD went away from the gears, and their required tighter tolerances, to speed up production, and reduce sound- DOT has noise restrictions, and HD had already replaced the chain with a belt to reduce sound levels.
Gear drive requires a "hand fit" style of assembly, and tight tolerance components- chain drive allows for much wider tolerances, and is faster to assemble- good for production pieces, and once they figured out the hydro chain setup, very durable.
Gear drive requires a "hand fit" style of assembly, and tight tolerance components- chain drive allows for much wider tolerances, and is faster to assemble- good for production pieces, and once they figured out the hydro chain setup, very durable.