Engine size, rpms, and engine longevity

[dsmith41]

Does engine size and/or configuration have anything to do with overall engine longevity? For example, we have all heard of the vehicles (automobiles) on BITOG and all over the internet that have made it to 300k or more miles. I am wondering if it would be possible, or likely even, that a motorcycle engine of less than a liter of displacement to make it that long with proper maintenance. I know most people would never ride a motorcycle that much but that’s not my point. I am wondering if car and truck engines have a better chance of making it that long because they generally don’t rev as high and have more displacement. Car engines rarely seem to break 3000 rpm unless accelerating from what I see.

My Honda has a 750cc V-twin that runs 4500 rpm at 76 mph. Sometimes when I am riding longer distances on the Interstate, I worry that I am revving it too much even though I have never hit the rev limiter and I have had it up over 100 mph at 6000 rpm. My old scooter had a 250cc in it and would do about 9000 rpm on the highway.

I try not to think about the poor cam lobes when I am riding down the highway because the engines are turning so fast but is it really putting as much stress on engine components as it seems like or am I worrying about nothing? With cars and trucks we always consider lots of highway driving to be fairly easy on the engine but would that same rule apply to my motorcycle which cruises on the highway at 4500 rpm?

 

[Robenstein]

I have seen several motos with over 100,000 miles on them. A guy I ride with has a couple BMW bikes with they much on them. He uses BMW oil or Mobil 15w50 in them.

As with any engine a lot has to deal with design and materials. I dont think you are going to get 300k miles on a bike, but you can get into 6 figures on some cruiser engines with good maintenance and not abusing them.

 

[bonjo]

I was once told by an engineer that a 4T engine works best at 2/3 of its rev range. (Efficiency, torque ...)
I don't know about your in detail; but longevity depend a lot on how highly tuned an engine is. Of course maintenance & riding technique also play a big part.
On a modern bike engine (2000~), I would tend to vary the cruising speed so that I don't sit at the same engine revs for hours.
IMO it is also important to push the engine every now & then.
I think the big problem is engines getting clogged with deposit due to lack of high speed running when hot.
With low revving old bikes, taking it easy was indeed a good way to extend its like.
Like the previous post said, high mileage should be possible. Have heard of VFR's with 100k+.

 

[Lurch]

Originally Posted By: Robenstein
I dont think you are going to get 300k miles on a bike, but you can get into 6 figures on some cruiser engines with good maintenance and not abusing them.


IMHO the bike I have right now would be a great candidate for high mileage - the inline four that's been made by Honda, Kawasaki, and Suzuki and others for well over 30 years. I'd say these inline fours would last longer than cruiser V-twins but I could be wrong. An inline four or even an opposing four such as the Gold wing engines are better balanced than a V twin. The rear cylinder on a V twin gets hotter than the front cylinder because it gets heat from the front cylinder going down the road.

Longevity has a lot to do with oil change intervals, oil types, and basic maintenance (getting the valves adjusted once in a while, new air filter every __k miles, etc.) and type of riding (not beating on it, not constantly running the motor in the red line area, not trying to find out if the bike will do 140 MPH even though the book says it's top speed is 120 MPH).

I was talking to a man that put 175,000 miles on a Gold Wing and changed the oil every 5k miles.

 

[QMartinez]

There are many yamaha fz1 998cc bikes with over 100,000 miles. There is a girl from oklahoma that has an 01 fz1 with 160,000 miles changing the oil every 4000 miles with mobil1. The bike doesn't seem to be stopping anytime soon.

My old xj650 dohc inline-4 had close to 100,000 miles and it was air-cooled. Still ran great when I sold it, although the rest of the bike was starting to rot. I was running 6200 rpm with a redline of 9400 while cruising at 75 mph. I did this daily commuting to work. I wouldn't worry about the high rpms in an inline [censored] motor. Can't really comment on twins though.

 

[cven]

IMO.....You have to look at piston speed. My TL1000 with 70,000 miles on it "only" revs to 10,500 rpm but the piston speed is as high or higher than a inline 4 cyl turning much more rpm and it does this with a heavier piston.

I also agree that 2/3 of the rev range is a good rpm for bike engines...lugging a small engine is not good for it from what I've read.

There are many bike engines that have 100,000 or more miles on them from low rpm V-twins to high rpm inline 4 cyls. Yes car motors may last longer but the ones tuned to a high degree (Ferrari,AMG,ect..) would most likely not make it as many miles.

 

[boraticus]

A well balanced engine, properly maintained and sensibly operated will last a very long time. I wouldn't doubt the possibility of 300K miles on the engine. The rest of the machine, on the other hand will likely require much more maintenance. To last that long, you'd be looking at complete chassis bearings and wheel bearing changes, swing arm bushing replacement, a few brake jobs, sprockets & chain replacements, probably some electrical work and cosmetic repairs.

A good rule of thumb for engine life is how you manage your fuel mileage. If you're getting good fuel mileage, chances are that your engine is enjoying life. If you're flogging the engine to the point where there is significant fuel consumption, you're potentially reducing engine life.

Most Japanese engines are very well balanced and well built machines capable of very long service life. I've read of examples of even big singles (KLR650s) getting over 100K miles on them with virtually no work done to them other than basic maintenance. I'd suspect that multis would be even more capable.

 

[beanoil]

Originally Posted By: Lurch
Originally Posted By: Robenstein
I dont think you are going to get 300k miles on a bike, but you can get into 6 figures on some cruiser engines with good maintenance and not abusing them.


IMHO the bike I have right now would be a great candidate for high mileage - the inline four that's been made by Honda, Kawasaki, and Suzuki and others for well over 30 years. I'd say these inline fours would last longer than cruiser V-twins but I could be wrong. An inline four or even an opposing four such as the Gold wing engines are better balanced than a V twin. The rear cylinder on a V twin gets hotter than the front cylinder because it gets heat from the front cylinder going down the road.

A friend of mine is on his second Kawasaki Concours. 1000cc, in line 4, water pumper. 1st one went 150k, second owner still rides it. His second one is at 120k, still runs like new. The head was never off of either bike. Rotella white bottle and Emgo filters for the majority of both bikes lives. I wont say it is better balanced than my 60 degree SV though. In line fours "buzz" with higher frequency vibes, while my V finds a sweet spot at 60 or so where it smooths out to the point that there is no tingle in the bars or pegs. That's at 5200 RPM, a little over half of redline. Your statement on the rear cylinder being hotter only applies to air cooled bikes. And 300k on a bike is easily obtainable with good maintenance, and a well designed and constructed engine. Ask any BMW owner, many Concours owners, and even a (very) few HD folks.
http://www.bmwmoa.org/ridetour/mileage_awards/roll

 

[FLHRGator]

Are we talking about longevity without rebuilds? Any modern bike should get 100k without a rebuild, I would think. If you're willing to refresh the top end every once in a while and the bottom end every once in a great while the sky is the limit.

 

[Lurch]

I was talking to a bike man today that said the 6 cylinder Gold Wings often get to 300k miles. His own bike has 144k on it now.

I'd say most bikes will/can get to way over 100k with a little TLC. Most bikes don't get to that because many riders ride on weekends only, if the temp is between 70* & 80*F, and if their wife lets them.

Most bike odometers don't even have 6 digits, so if they went over 100k they'd start all over again like the old car odometers used to be.

 

[RonH]

I rode a 1978 Kawasaki KZ650 160,000+ miles in about 16 yrs time. I think and hope oil is "better" now than it used to be because the engine was shot beyond definition of the word with 1/2" or more sludge everywhere by that time. Castol GTX every 2000 miles since new.
That's old news though. There's a couple Yamaha FJR1300s I know of that have over 200k on them. Steve Short's 2005 Goldwing had 280k last I heard. Of course luck of the draw, GL1800 newsgroup is currently debating what action to take on a new goldwing with 211 miles on it with a terminally shot engine and yes he had oil in it.

 

[boraticus]

211 miles and the engine is shot? What's the debate?

 

[dsmith41]

Anyone know the redline on an 04 Honda Shadow 750 engine by any chance?

 

[RWEST]

Originally Posted By: boraticus
211 miles and the engine is shot? What's the debate?

Shouldn't be one - seems pretty simple; I'd think the dealer would be tripping over himself getting a new bike or new engine ready. Stuff happens sometimes, even to Hondas.

 

[Kiwi_ME]

Water cooling alone would allow significantly extended engine life. I don't any reason why perceptions of "smoothness" or "balance" would factor into this, nor piston speed for that matter. Engines rarely deteriorate from mechanical stress, it's the usual suspects - rings and valves.

 

[boraticus]

Originally Posted By: Kiwi_ME
Water cooling alone would allow significantly extended engine life. I don't any reason why perceptions of "smoothness" or "balance" would factor into this, nor piston speed for that matter. Engines rarely deteriorate from mechanical stress, it's the usual suspects - rings and valves.


Vibration causes metal fatigue and premature wear.
Balance and smoothness will reduce vibration.

A shoddily built engine will self destruct much sooner than a well balanced engine. Why do you think people have performance engines balanced?

 

[Robenstein]

On a couple Virago pages and forums, owners in Australia and New Zealand are getting about 30k miles on their engines. Since my 250 spends its life on the highway at about 5700 RPM, thats not too bad, especially if in Australia where an air cooled engine can really really suffer.

 

[boraticus]

Originally Posted By: Robenstein
On a couple Virago pages and forums, owners in Australia and New Zealand are getting about 30k miles on their engines. Since my 250 spends its life on the highway at about 5700 RPM, thats not too bad, especially if in Australia where an air cooled engine can really really suffer.


It's not just heat in Australia, it's also the dust. Dust and heat on a continuous basis will wreak havoc on any engine.

 

[Kiwi_ME]

Originally Posted By: boraticus
Vibration causes metal fatigue and premature wear. Balance and smoothness will reduce vibration.
The various internal parts inside an engine fight each other anyway, irrespective of whether the sum of that vibration experienced by the rider appears to be "smooth." It's simply ridiculous to connect this to engine wear otherwise no one would make a single cylinder engine! Performance engines are carefully balanced to minimize crank loading because that loading is closer to the failure point.

 

[Zedhed]

Originally Posted By: beanoil



A friend of mine is on his second Kawasaki Concours. 1000cc, in line 4, water pumper. 1st one went 150k, second owner still rides it. His second one is at 120k, still runs like new. The head was never off of either bike. Rotella white bottle and Emgo filters for the majority of both bikes lives.


And this is on an engine (Concours 1000) that has known cam wear problems and cam chain tensioner problems. Think what they could do without these issues. One reason that you see these bikes with this kind of mileage is because they are well maintained and rode many miles per year for many years. I agree that any well-designed engine should last at least 150k miles. IMO, a liquid-cooled, 4-cylinder engine would be the best candidate for 300k miles.