Topic: engine life

[cadler]

how many miles will these engines do before they die.
I have 23000 miles on mine and had to rebuild the top end because the thing siezed from sitting too long.
I am just wondering if you take care of the engines how long will they last?

[KB02]

The Key part of that question is "If you take care of them."

If you care for them well, they will potentially last forever...

...as long as you can get or make parts for the ones that wear out.   

[theunrulychef]

Exactly.  Ask Hondaman how long he expects his motor to keep running.   

[cadler]

 I mean with normal maintance and no wheelies and stuff like that.

[theunrulychef]

Wheelies - I wish my F2 was capable of doing a wheelie  . 

But seriously, these bikes are 30 years old.  They've lived completely different lives, with different riders.  Some have sat for years & years, some have been daily riders since they came off the line in Japan.  The expected engine wear life would be different for each story, and would have different problems relating to how they were treated in the past and future.  Also, different engines have different problems and characteristics.  For instance, my 750F2 at 14,000 needs valve guides etc, where a K might just keep going and going.  An engine that had been riding daily and well maintained might need all sorts of stuff once it finally goes kaput, but alot of that would depend on exactly what maintainance and how hard the rider was - stored inside or out - running lean or rich for years at a time.  Like KB02 said, you can make one of these things keep going forever & ever with the right parts, tools, and know how. 

You've just had a top end rebuild done.  Some people start leaking out of the head gasket after a 1,000 miles, some people can ride it for another 20k.  It all really just depends on so many factors.

[Bob Wessner]

theunrulychef (always get a chuckle out of that one  hit it on the head.. all depends. You might want to take a look at this poll on the topic of longest mileage bike.

http://www.sohc4.us/forums/index.php?topic=6895.0

[phylo101]

I know of FIVE 750s that have gone round the clock, in my extended circle of friends, including my own K7 which is on 105,000 mils now

phylo

[mwvachon]

My own experience is with a 1971 CB750 that has been in our family since new. My Dad rode the heck out of it the first few years, racking up over 15K miles with nary a problem. I took it over in 1978 and proceeded to add another 19K. At around 24k (in the early 80's), I noted a bit of oil weep around the head. I pulled the motor and had the top-end serviced. The mechanic actually chewed me out for wasting his time - there was nothing wrong with the engine that he could see, but the new gaskets did take care of the leak. I continued to use the bike as my regular ride up until 1989. A used '81 GoldWing got the majority of my attention after that. I still rode the 750 occasionally, and kept it stored out of the weather when not in use.
Fast forward to 2006. My regular ride these days is a '99 Valkyrie Interstate, but the 750 still has a special place in my heart. For the past few years, I've been gathering all the major parts I was going to need to do a full-on restoration (exhausts, seat, fenders, etc.) I just recently tore down the motor's top end (the weeping had returned) and was amazed to see how fantastic the inside of this engine looks. No hint of wear on anything! I measured the cylinder bores and checked for roundness - all well within spec. Even the clutch (original) shows no sign of wear! I had the head serviced at a local machine shop and the tech was impressed by the overall condition.
Yeah after 20+ years or 30K miles you may well expect to replace some seals, or gaskets - but it's great to know the major components stand the test of time & miles! It's a shame the engine has to come out to do this work, but it's a good opportunity to check over all the other non-engine components...

[seaweb11]

That's like asking the Canadian Military "how long will this helicopter last?"

Or how long is a smile?

next................
 

[phylo101]

Should have also detailed my maintenance regime in my contribution above. In the 75000 miles *I* have put in the Black Pig, it has received three oil changes one filter change, and have NEVER adjusted the valves. I have NO idea why it keeps on going but it does.

phylo

[ofreen]

Should have also detailed my maintenance regime in my contribution above. In the 75000 miles *I* have put in the Black Pig, it has received three oil changes one filter change, and have NEVER adjusted the valves. I have NO idea why it keeps on going but it does.

And I get static for only changing the oil filter every 6000 miles...

[mkramer1121]

Wow...My bike's a baby compared to everyone elses.  With 998 original miles, and a recent once over, my cousin sold it to me for $500.  If I take care of it, maybe it'll be around for another 30 years based on what everyone here says, 

[byidesign]

My cb650sc"82" is just over 140,000 mi . top end and rings done once,
    Replaced,    2 oil pumps/cam+trans drive chains, oil changes every 1000-1500 mi depending on season
   and driving {I.E. hwy or city}. It will need a cam next yr. {getting worn} still runs every day.
       bought it new ,still in the crate.It has been good to me..
        Some of my project bikes hadn't been cared for,
           It makes things that much worse to start with.....
             Take good care of your machines
              It will pay you back.
                   Hope it helps
                        Bruce