Big bore and reliability question(s)
Extreme HDF Member
Joined: Apr 2006
Posts: 10,449
Likes: 46
From: Roswell, GA
RE: Big bore and reliability question(s)
Darren: Before HD started "splitting the cases" with the 96" stroker motors in '07, I too had reservations--but no more, especially after watching Kevin pull his and seeing what's inside. Also, if you do the kind of builds Kevin, Dalton, Phil and others are doing with replacement cranks, balanced by Dark Horse, your bottom end will actually be a precision machined and better piece than what you are currently riding which consists of mass-produced components assembled on the line with whoknows how much runout and scissoring issues.
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Ultimate HDF Member
Joined: Dec 2006
Posts: 8,294
Likes: 33
From: Po-Dunk Looziana
RE: Big bore and reliability question(s)
In my own analogy and reasoning Ialso feel like the majority spoken that a well built big bore could/should exhibit the same/better reliability than stock if built correctly. The clarification I personally needed was that it wouldn't be just the fact that a bigbore build is stressful in an of itself, but instead as you guys have pointed out, pushing the envelope in wringing out all the HP/TQ possible with select components intended for this use. I also need some feeback so I can either put this to rest in my own mind and move on, OR continue to toss and turn at night, think about it all day, wondering if I'm up for the task, as a couple of local builders have shown an interest in helping me since this is a rarity around here and they'd like to be a part of it.
Now if I could just cough up the cash.[&o]
Also, as mentioned, since I may end up in places with less than desirable Octane ratings, what are you guys doing to rectify this in these 10:5.1 builds? I'd hate to knock holes in my pistons and/or bend valves in my new money pit project.[&:]
Now if I could just cough up the cash.[&o]
Also, as mentioned, since I may end up in places with less than desirable Octane ratings, what are you guys doing to rectify this in these 10:5.1 builds? I'd hate to knock holes in my pistons and/or bend valves in my new money pit project.[&:]
Tourer
Joined: Sep 2006
Posts: 359
Likes: 0
From:
RE: Big bore and reliability question(s)
Remember the good ol' days when a 95" was a monster big bore.........
I am not even done building my "Philly Special" and I already have bigger bore envy reading about all you guys going, 103, 107, 133, 120...... Dang.... I am thinking aboutbuying an HD Destroyer and putting bags on it!!!
As far as the 10.5:1 build, pinging was my major concern. 91 octane is about as good as we get on a regular basis. I told them I would gladly leave a little performance on the table to insure a ping free motor. Doug, Phil, Kevin all encouraged me to go 10.5:1 and assured me that pinging was not going to be an issue with my HQ build and proper tuning. They were not the least bit concerned. Doug's only comment, if you get a bad tank of gas, just user the shifter to ride without pinging.
Go for it UK!!! It will be PHast and PHurious!
RJ
I am not even done building my "Philly Special" and I already have bigger bore envy reading about all you guys going, 103, 107, 133, 120...... Dang.... I am thinking aboutbuying an HD Destroyer and putting bags on it!!!
As far as the 10.5:1 build, pinging was my major concern. 91 octane is about as good as we get on a regular basis. I told them I would gladly leave a little performance on the table to insure a ping free motor. Doug, Phil, Kevin all encouraged me to go 10.5:1 and assured me that pinging was not going to be an issue with my HQ build and proper tuning. They were not the least bit concerned. Doug's only comment, if you get a bad tank of gas, just user the shifter to ride without pinging.
Go for it UK!!! It will be PHast and PHurious!
RJ
Outstanding HDF Member
Joined: May 2006
Posts: 3,273
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From:
RE: Big bore and reliability question(s)
proven fact; engines that are raced and ridden hard don't last as long as those that aren't! if you have a stroker motor you should have a decent life out of it as long as you aren't running it at its limits. my current stroker is 3 years old and 40,000 miles.
Outstanding HDF Member
Joined: Jul 2007
Posts: 2,241
Likes: 7
From: Daytona, Fla.
RE: Big bore and reliability question(s)
I think most of the "poor reliability" myth was created by people that don't know motors or how to ride them. It does take a little thinking & some restraint to ride a stroker the way it should be ridden, but they'll repay you with years of fun. A lot of inexperienced people get excited about the power that's imediately available in a newly stroked motor. The first thing they do is go see how fast this new thing really is, without regard to break-in time or rev-limits. In fairly short order they have problems.
Do the piston speed math for whatever stroke you intend to use & you'll know what your rev-limit should be. If you/or your builder puts together a good tight bottom end, take your time breakin' it in (read S&S's break-in recommendations), & ride it the way it's meant to be ridden & it'll last as long as any other size motor. My FXR was stroked in '99 & is as reliable today as it was new, & a lot more fun!
Do the piston speed math for whatever stroke you intend to use & you'll know what your rev-limit should be. If you/or your builder puts together a good tight bottom end, take your time breakin' it in (read S&S's break-in recommendations), & ride it the way it's meant to be ridden & it'll last as long as any other size motor. My FXR was stroked in '99 & is as reliable today as it was new, & a lot more fun!
Road Captain
Joined: Jul 2007
Posts: 601
Likes: 12
From: Texas
RE: Big bore and reliability question(s)
Okay - stupid question, when you up the output, surely the heat gets up too, right? So for everyone that's punched it out (103 - 120) what, if anything, did you do about the added heat?
Tourer
Joined: Jul 2007
Posts: 286
Likes: 0
From:
RE: Big bore and reliability question(s)
Not real any hotter than stock . Your tune controls this more than anything .
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Outstanding HDF Member
Joined: Oct 2007
Posts: 3,437
Likes: 15
RE: Big bore and reliability question(s)
hopefully the heads will be set up to breath better which helps with the heat and a good tune will help. Oil coolers are important on a big motor. the only bike that broke down in our group was a 117 incher and the starter crapped out. He was not running compression releases and had a 6 year old starter. Can't hardly blame the build for that break down.
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
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From: Bluffton, South Carolina
RE: Big bore and reliability question(s)
Lets talk about why some large engines were called unreliable. First: most large engines weren't built so the rider could put around doing under 3500 RPM's. They were built to be ridden like someone stole it. Secondly: back in the day parts weren't as good as they are today. Third: cases were bored out too big and reliability suffered. Lastly big inch engines were new and some of the combinations weren't the best.
Obviously there are other reasons that could be stated, but for the sake of brevity I kept it to a minimum.
Obviously there are other reasons that could be stated, but for the sake of brevity I kept it to a minimum.