Rethinking Bottom End
Road Captain
Joined: May 2014
Posts: 673
Likes: 252
From: Alberta
I had a crank fail on a 2010 FLHTCU with a stage 2 installed by Harley dealer. It failed just over 50,000 Km on the bike. I think the stage 2 was installed previously to 18,000 Km when I bought the bike used from dealer.
There was brass or bronze chunks and flakes in the oil. When shop opened up the engine one of the bronze thrust washers was pretty much eaten up, one con rod had been hitting the fly wheel and the wrist pin bushings were spun. Me I think the crank went out of alignment (scissored??), which caused the rod to contact the flywheel and disintegrate on thrust washer and then maybe the being so far out it caused undue stress on the wrist pins and spun those bushings. I don't know.
The result was a costly engine rebuild from the crankshaft on up.
From my experience, if I would be putting mods for power I would do the crank.
There was brass or bronze chunks and flakes in the oil. When shop opened up the engine one of the bronze thrust washers was pretty much eaten up, one con rod had been hitting the fly wheel and the wrist pin bushings were spun. Me I think the crank went out of alignment (scissored??), which caused the rod to contact the flywheel and disintegrate on thrust washer and then maybe the being so far out it caused undue stress on the wrist pins and spun those bushings. I don't know.
The result was a costly engine rebuild from the crankshaft on up.
From my experience, if I would be putting mods for power I would do the crank.
Ultimate HDF Member
Joined: Jun 2009
Posts: 6,899
Likes: 3,412
From: OH
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Outstanding HDF Member
Joined: May 2012
Posts: 2,385
Likes: 1,442
From: Brentwood
That is what I was trying to convey. The 48 with a good tune makes the 96 run like it should. displacement and head work with the right cam and things get even more fun. I don't think a 107 making 125/130tq is all that much more stress on the bottom end providing you don't beat the hell out of the bike.
You'll have that thing built up way before the 3-4 year time frame you've given yourself!
Stellar HDF Member
Joined: Aug 2015
Posts: 3,425
Likes: 1,418
From: pensacola fl
If you beat the hell out of it, dumping the clutch, burnouts, something will break for sure.
Granted I read some of the crank issue threads before I did my 106 kit. Knowing how I am, I didn't even measure the runout, if it wasn't perfect I would have constantly worried about it. Ive put over 20,000 miles on it since the kit install and all has been good. I don't beat on it though. Some roll ons sure, but it doesn't go above 4500rpms very much. Im knocking on wood as I type this.
Im sure some of these stock cranks are made, assembled, better than others. For every crank that has gone bad how many have not?
Granted I read some of the crank issue threads before I did my 106 kit. Knowing how I am, I didn't even measure the runout, if it wasn't perfect I would have constantly worried about it. Ive put over 20,000 miles on it since the kit install and all has been good. I don't beat on it though. Some roll ons sure, but it doesn't go above 4500rpms very much. Im knocking on wood as I type this.
Im sure some of these stock cranks are made, assembled, better than others. For every crank that has gone bad how many have not?
Cruiser
Joined: Jan 2014
Posts: 147
Likes: 61
From: Mulkeytown, IL
I'm suffering from the same dilemma. I am at a "Stage 1" 96 (extremely low mileage) and am planning to add a Woods 222 cam and a tuner. Eventually I want to go up to 107", but a friend of mine is an Indy and builds a lot of hopped up Harleys. He has had no problems with stock cranks up to 103", but at 107" he has had a few scissor. Granted these bikes were beat on, but I am leaning toward a built bottom end. If I do that, I might as well go BIG (?) cu in!
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Outstanding HDF Member
Joined: May 2012
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From: Brentwood
Im really pretty content with it right now and have no problem running this top end until it starts acting up.