I would like to take a poll. I've talked to four Harley dealers so far and every one runs from this question so I guess I can get the truth from the people that own them. I find it strange that a Harley dealer would avoid this question like the plague.
This is a question about miles before a rebuild. i need a average. Not the top miles before you did a rebuild contest but average miles before a rebuild.
Question - How many average miles do you think Harley engines will take before they need a top end rebuild ?

 

I would think it is dependent upon maintainence and how one rides. I do my 710 changes at 3000 miles religously, I adjust valves when I start to hear niose, I don't do burnouts, I don't drag race or dyno race. I have 40,000 on a big inch engine. I expect to get close to 100,000.

 

You didn't say which "Harley" engine you were talking about. I answered the poll assuming you were talking about a TwinCam 88. I've heard from several people that the TwinCam's are designed for over 100k before a rebuild. I've heard that the Evo motors were only good for 40k. Not saying I'm right by any means, just what I've heard from people i tend to trust.

 

I know people with 80" Evos that have 100k without having had major work done. I've heard rumors of 50k Shovels.

I'm guessing 150k should be possible, but so much of the bike would be out-of-whack that you'd need a ground-up rebuild anyway.

 

I hear 100,000 miles alot and even more. As stated maintence makes BIG difference!

 

I didn't think you needed to do valve adjustements. Or are you talking about a non-Harley engine?

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The older ones need valve adjustments

 

Now you've got me even more curious.... In all my reading of Harley history (I think I own every coffee table book ever written), it was my understanding that Harley engines as far back as the knuckleheads had hydraulic valves lifters. Are there still valve adjustments that would be necessary (aside from after an engine rebuild) for these older engines?

 

I had a chat the other day at Starbucks with an older gentleman who had over 100K on his harley. The bike was an older touring version bagger that was in beautiful condition. He told me that he had just sent his old engine back to Harley for remanfacturing. That would be the way to go.

He did say that you have to take the heads off a couple of times to scrape the carbon off the pistons and valves and do a valve job if necessary. I don't remember the frequency of that work but it makes good sense. So most likely you will have an upper end valve job or two between now and that 100K point.

 

I honestly believe no one really knows about an average. So a vague answer from the dealer may be the most honest answer possible.

MOST Harleys are modified in some way related to the engine. That is highly unusual for any type of vehicle (even unusual for other motorcycles) and it makes durability and longevity extremely difficult to determine. Many are tuned by the owners, some know what they are doing and some don't. They are air cooled and run pretty hot. That is super rough on fluids so delaying service can really take a toll over the life of a bike. So the impact of a lazy owner is MUCH greater than most other vehicles.

The real problem though is that most of these bikes are used for recreation and it can take 10+ years for a lot of us to reach 100K miles. Many have performance engine work done on them before that point which throws everything off. Plus after a decade, component age starts to become more and more of a factor (as opposed to mileage only).

The guys you NEED to hear from are the ones you are saying you don't WANT to hear from. Only guys with high mileage bikes can tell you what you want to know and they are the minority. I think some people hear a guy say he got 120k miles before having a top end rebuild done and it is assumed this is unusual. That is legitimate data and shouldn't be assumed to be a fluke.

What you probably should do if you really want to learn something statistically here is ask for everyone who has a STOCK bike that needed a rebuild to report at what mileage that happened. You could also ask all over 70k to report their mileage if they have a STOCK bike and have never had a rebuild or any top end performance changes. I know that's kinda what you were asking, but the poll is about opinion and our opinions are meaningless because most of us don't know.

I'm not trying to make excuses for the dealers for dodging that question . . . I'm a mechanical engineer and in my opinion, the MoCo should give the dealers an estimate of longevity. But I do have an appreciation for the fact that HD makes a product that isn't used like conventional products are so longevity is hard to establish. I would suspect a bone stock, properly maintained Harley with a modern twin cam engine will run a LONG time without needing a rebuild. But if the first thing you do is put on Screamin' Eagle air cleaner and a performance exhaust and have the conservative tuning replaced with aggressive tuning, then you can't really expect them to tell you you're going to get 100K+ out of it.

Bottom line for me is that top end rebuilds are pretty cheap. So if I get 90k or 120k+, it isn't going to affect my enjoyment of this bike in any way.

Kevin