Topic: Highest mileage on a SOHC?

[andy750]

kpier883 if you are using 3 quarts of oil on a 1500 mile trip then you have problems! I rarely have to top up on oil even on long distance trips - CB750K4 which at the time had 55,000 miles. Now at 66,000 miles it still dosent use that much oil (of course its now had a complete top end rebuild  ).

cheers
Andy

[kpier883]

kpier883 if you are using 3 quarts of oil on a 1500 mile trip then you have problems! I rarely have to top up on oil even on long distance trips - CB750K4 which at the time had 55,000 miles. Now at 66,000 miles it still dosent use that much oil (of course its now had a complete top end rebuild  ).

cheers
Andy

I thought it was the chain oiler, but I loosened the locknut and turned the screw all the way clockwise before the last trip and didn't really use less oil.  I don't get puddles when I stop and it doesn't smoke. It doesn't foul plugs.  It is kind of strange actually.

Maybe I should try another method to plug the chain oiler.

[crazypj]

somehow I missed the poll/thread, its now been rectified.
 My avatar shows 99,999.8 but I did a few more miles (about 5,700) before retiring 550 for a re-build (sometime)
PJ

[ofreen]

The 750 rolled over 110,000 miles today.  No issues to report, still not using enough oil between 3000 mile intervals to need to add any.  The 3000 mile maintenance check 1000 miles ago turned up no problems.  Tappet clearances were unchanged.  The only things I've done to it in the last 5000 miles are 2 oil changes, a new battery, front tire, and front brake pads.  I also had new front brake lines made up as the originals were beginning to show cracks in the sheathing.

Mileage for the year was down a little as I 'retired' last July, so I wasn't commuting.  However, I don't like being broke, so I have a new job with a 62 mile round trip 4 days a week.  That's 1000 miles a month, so mileage accumulation is going to be twice as fast as it was.

There was some discussion in another thread about whether mileage listed in this thread were for engines that were still original.  In this case, the miles are original.  The farthest I've been into this engine was to replace the seals under the cam holders a few years back.

[andy750]

Excellent news Greg and well done on the 110,000 mile mark! Clearly you take very good care of your bike and this is the key. An inspiration to us all!

Good luck with the new job.

Cheers
Andy

[ofreen]

Thanks, Andy.  Really though, it is more of a credit to the bike than anything I do.  These days most of the miles on it are commuting and it has held up very well.  It gets ridden in all kinds of snotty weather and sees some fairly extreme temperatures in both directions.  I'll still take it to redline on the on-ramps occasionally and much of the commute is 75+, so it isn't babied.  One thing I do that I think helps is I try to always be smooth, even when getting on it. 

[jameseb444]

My '74 350 has just over 13,500.

[ofreen]

The 750 rolled over 115,000 miles last Thursday.  All still good.  The only thing I have done in the last 5000 miles that might be considered a repair was to replace the worn carb needle jet sets as reported in another thread.

[HondaMan]

Should I weigh in? Another 120 miles to 130,000.

[scunny]

mine says 75000KM on the clock but I've never heard it run 

[ofreen]

Should I weigh in? Another 120 miles to 130,000.

Out of curiousity, how much have you been in the engine?

[HondaMan]

Should I weigh in? Another 120 miles to 130,000.

Out of curiousity, how much have you been in the engine?

The first 10K miles were a lot of roadracing (ride to the place, race, ride home, that was the rules). Then I pulled the head and ported it, reassembled with just new gaskets on top. At 55K miles (1980), I wanted to bore it first oversize to recover the lost HP these engines suffer from non-round bores, and did. It took it from just under 56 HP to over 62 HP, while the displacement change was only 4cc. Plastigaged the bearings: all were less than .0012" clearance, left them alone. Checked all the rockers and shafts and cam bearings: all very good condition.
At 126,000 miles (2006) it had been sitting 5 years since I'd had cancer, and it felt not-so-smooth when turning it over at the crank. I tore it down to hemi the head and look inside, expecting to find rust in the bores. I had bought new rings in anticipation, only to discover that the new ones had more ring gap than the old ones. (!) So, I replaced the top 2 rings on the pistons, honed the cylinders out .0002" to .0005", plastigaged the bearings (all less than .0018" still), measured all the top end parts like rockers and their shafts, cam bearing clearances, etc...still within Honda's tolerances. So, I put it back together with only one new(er) rocker and cleaned the carbs, new gaskets. The cam sprocket was my racing unit, with cam timing retarded 5 degrees: I installed a new one with stock timing to improve low-end torque.

The current clutch has over 80,000 miles on it, only the 2nd one in the bike. The primary chains and camchain are still within Honda's spec, and the cam rollers were good. I had bought a new slipper tensioner from a fella who sold his SOHC4 and had NOS parts left, I did install that new. I am sorry I replaced the rings, as the compression dropped and has not come back up, and it blows a very slight amount of sythetic oils out the pipes as a result. I will someday have to bore to next size (0.50mm) to cure that little problem. It doesn't even show in a 2000 miles oil change on the dipstick, and the oil takes 1000 miles to show up on the ends of the pipes, but it is real. 

So, none of the major wear parts are new, with the exception of me dinking around with the bore sizes. On my racing bikes, I used to keep sets of different cylinders around for this sort of thing, and was forever installing new this and that. Looking back: what a waste of $$$ ! They would have been fine, knowing what I do now. 

[crazypj]

I changed primary chain at 31,000 when I did full rebuild and 591 kit.( my brother put it in his CB400f  )
 Clutch is totally original except for some oiling holes on inner hub during re-build ( Now at 106,000)
 I'm not heavy on clutches, just brakes 
PJ

[ofreen]

Should I weigh in? Another 120 miles to 130,000.

Out of curiousity, how much have you been in the engine?

The first 10K miles were a lot of roadracing (ride to the place, race, ride home, that was the rules). Then I pulled the head and ported it, ...snip

Thanks for the info.  I thought I remembered you had said before that you done some mods to it.

As I have posted before, my 750F's engine is still original.  The last time I had the rocker cover off was at 82,000 miles to replace the seals under the cam holders.  There was a very slight amount of wear visible on the rocker shafts, but nothing to get excited about, so I put it back together.  Tappet clearances are still holding, oil consumption is low, it never smokes on start-up.  Since replacing the needle jet sets, fuel consumption is back to the low to mid 40s (as long as I don't put ethanol in it).  Since last March, I have a daily commute of 32 miles one way, 27 of which is at 70+ mph.  I'll take it to redline occasionally on the on-ramps.  It is so reliable that I take it for granted it will run forever.  But nothing is forever.  I'd like to see what it looks like inside, but won't while it is making like the energizer bunny.

[HondaMan]

Should I weigh in? Another 120 miles to 130,000.

Out of curiousity, how much have you been in the engine?

The first 10K miles were a lot of roadracing (ride to the place, race, ride home, that was the rules). Then I pulled the head and ported it, ...snip

Thanks for the info.  I thought I remembered you had said before that you done some mods to it.

As I have posted before, my 750F's engine is still original.  The last time I had the rocker cover off was at 82,000 miles to replace the seals under the cam holders.  There was a very slight amount of wear visible on the rocker shafts, but nothing to get excited about, so I put it back together.  Tappet clearances are still holding, oil consumption is low, it never smokes on start-up.  Since replacing the needle jet sets, fuel consumption is back to the low to mid 40s (as long as I don't put ethanol in it).  Since last March, I have a daily commute of 32 miles one way, 27 of which is at 70+ mph.  I'll take it to redline occasionally on the on-ramps.  It is so reliable that I take it for granted it will run forever.  But nothing is forever.  I'd like to see what it looks like inside, but won't while it is making like the energizer bunny.

Isn't it cool? These tickers are like the Ford 200 straight Six engine, often used also in industrial vehicles from 1958 through 1982, as the "base engine" in all Ford cars intil then (i.e., if you ordered a car with nothing special, it came with this engine, there are actually millions of them out there). The difference: this engine can perform excitingly, while acting like it is yawning in the process (the Six makes 88 HP, ZZzzz). My 750's cam is actually worn an average of .022" missing lift across the board, but with no scoring or damage. I got a new one from Terry when I went in to hemi the head, but I both wanted to see how much head performance change arrived, and how much longer the original cam will run, so the new one is still in the box. Less lift equals more low-end torque (like an RV cam in a V-8 engine), and I'm currently relegated to 80% on-street driving, so I appreciate the extra where I'm riding. It still easily hits the redline on the way home, where I get 1 mile of freeway ride, so I 'clean the plugs' once every day for the fun. And the engine yawns, and smiles, and purrs home...

[ofreen]

The 750 turned over 120,000 miles on the way home from work on Wednesday.  Still not much to report.  There have been no real mechanical issues to speak of.  One of the fork seals has been weeping intermittently for the last few weeks, so will replace that.  I replaced both seals back at 75,000 miles, so pretty good service from those seals.  The rear master cylinder sometimes weeps a little as well, so will rebuild it.  The tach has begun to act up.  It reads accurately up to 4500 RPM, then will suddenly rise to redline.

No adjustments to tappets were needed at the 115,000 and 118,000 mile service.  They have never changed much over the life of the bike.

I changed the oil at 116,000 to some Mobile 1 20-50 bike oil I got a good deal on.  I had used nothing but BMW/Spectro oil since around 62,000 miles, but the price of it has become ridiculous, so tried the Mobile 1.  An interesting thing then happened that hasn't happened with the bike since it was new.  Back then, with new oil and a cold engine in cold ambient temperatures, the clutch would grab and make a loud "graunching" ( ) noise when first starting out.  This tendency went away as the bike accumulated miles.  I remember other 750s doing the same thing back in those days.  Well, it did the same same a few times after putting the Mobile 1 in, but after some miles it quit doing it.  Other than that, the Moblie 1 has performed OK.  4000 miles on the oil now, and shifting is still smooth.  I'll change it out tomorrow.  Oil consumption has been a pint over the 4000 miles.

The Westco AGM battery has now been in service since 11/4/01.  Still cranks the bike over strongly, even the other morning at 30F.

The old Windjammer fairing has developed a crack through the hole where the headlight adjuster goes through, so will have to fix that.  I stop drilled it and that has taken care of it for the time being.

That's it.  It still doesn't miss a beat.

[andy750]

Excellent feedback Greg and well done on getting to 120,000 miles!!

For me only 50,000 to catch up to you ;-)

All the best
Andy

[ofreen]

Thanks, Andy.  You may catch up if that new Vstrom doesn't take up too much of your riding.

[HondaMan]

The 750 turned over 120,000 miles on the way home from work on Wednesday.  Still not much to report.  There have been no real mechanical issues to speak of.  One of the fork seals has been weeping intermittently for the last few weeks, so will replace that.  I replaced both seals back at 75,000 miles, so pretty good service from those seals.  The rear master cylinder sometimes weeps a little as well, so will rebuild it.  The tach has begun to act up.  It reads accurately up to 4500 RPM, then will suddenly rise to redline.

No adjustments to tappets were needed at the 115,000 and 118,000 mile service.  They have never changed much over the life of the bike.

I changed the oil at 116,000 to some Mobile 1 20-50 bike oil I got a good deal on.  I had used nothing but BMW/Spectro oil since around 62,000 miles, but the price of it has become ridiculous, so tried the Mobile 1.  An interesting thing then happened that hasn't happened with the bike since it was new.  Back then, with new oil and a cold engine in cold ambient temperatures, the clutch would grab and make a loud "graunching" ( ) noise when first starting out.  This tendency went away as the bike accumulated miles.  I remember other 750s doing the same thing back in those days.  Well, it did the same same a few times after putting the Mobile 1 in, but after some miles it quit doing it.  Other than that, the Moblie 1 has performed OK.  4000 miles on the oil now, and shifting is still smooth.  I'll change it out tomorrow.  Oil consumption has been a pint over the 4000 miles.

The Westco AGM battery has now been in service since 11/4/01.  Still cranks the bike over strongly, even the other morning at 30F.

The old Windjammer fairing has developed a crack through the hole where the headlight adjuster goes through, so will have to fix that.  I stop drilled it and that has taken care of it for the time being.

That's it.  It still doesn't miss a beat.

Very cool, 'O'!

The tach: it may be the cable. When the sheath waers through, the drive cable will snag, wind up a bit, then spring free, "snapping" the tach to a higher reading. That's a common failure ode for the cable: Z1 has nice ones for about $12.

Glad to hear you're riding the Vetter, too: every time I take one of these restored 750s out for its maiden voyage, I'm reminded of why I ride behind one of those, myself. Mine is a Vetter hand-laid fiberglass (some call it a "Vetter I", but it was previous to the 1974 models). I really think it has a lot to do with the still-decent cosmetics on the rest of my 750, as it has deflected much of the rain, stones, etc. over the miles.

My experience with Mobil 1: for many years, my bike has had that cold "graunch" sound in the clutch engagement until the engine had been run about 5 minutes or so. To my surprise, it went away in about 50 miles of Mobil 1 (15w50 Diesel) use! The oil pressure was getting pretty low, though, due to pump wear: when I went to the Mobil 1 (15w base weight instead of my usual 20w base weight), the top end would start getting clattery on hot days during long stoplights. I obtained a pump of 8k miles (thanks to Soos!) and installed it: the noises stopped, the engine has gotten VERY quiet, and now it leaks oil at the cam cover, so I can tell it is moving lots more oil to the top end. The shifting is much improved when the engine is hot, too. And, I estimate the engine is running at least 15 degrees cooler, especially when touching the oil cap (which I have used as my "test" since 1972).

I'll have to pull the engine this winter for the new cam cover gasket: I might just finally bore it to 0.5mm oversize, and install the next size down crank and rod bearings. It has nearly 140,000 miles on it, now. I'm undecided about the bearings at the moment, but the new pistons, bores, and rings are going to be the only thing that will make them seat titghtly enough to hold synthetics in, now. I should not have changed those rings in 2006... 

[CycleRanger]

My '75 K5 has 29000 and some change.

[ofreen]

Very cool, 'O'!

The tach: it may be the cable. When the sheath waers through, the drive cable will snag, wind up a bit, then spring free, "snapping" the tach to a higher reading.

Thanks Hondaman.  Looks like the problem is in the instrument, not the cable, which is fairly recent.  I know what you mean about the cable sticking, then winding up and snapping.  Typically when that happens, the needle will bounce, but in this case the needle goes up to near redline, stays steady, and seems to stick a little as it takes a moment or two to come back down when the revs go below 4000.

One thing I am curious about is the cam chain.  The tensioner is still doing its job, but I've seen a fair number of Toyota 22Rs (even the older ones with double row chains) and various V8s with significant timing chain elongation after this many miles.  I went back and read your posts from last year and you mentioned yours was still in spec with more miles than mine, so I don't worry about it too much.  Good deal on approaching 140K with yours.  Looks like you got a fair amount of riding in this year.  That's what's cool about these old bikes.  35+ years old with high mileage and you can still ride them like they are new because they can take it.

[HondaMan]

Very cool, 'O'!

The tach: it may be the cable. When the sheath waers through, the drive cable will snag, wind up a bit, then spring free, "snapping" the tach to a higher reading.

Thanks Hondaman.  Looks like the problem is in the instrument, not the cable, which is fairly recent.  I know what you mean about the cable sticking, then winding up and snapping.  Typically when that happens, the needle will bounce, but in this case the needle goes up to near redline, stays steady, and seems to stick a little as it takes a moment or two to come back down when the revs go below 4000.

One thing I am curious about is the cam chain.  The tensioner is still doing its job, but I've seen a fair number of Toyota 22Rs (even the older ones with double row chains) and various V8s with significant timing chain elongation after this many miles.  I went back and read your posts from last year and you mentioned yours was still in spec with more miles than mine, so I don't worry about it too much.  Good deal on approaching 140K with yours.  Looks like you got a fair amount of riding in this year.  That's what's cool about these old bikes.  35+ years old with high mileage and you can still ride them like they are new because they can take it.

I am sincerely impressed with Honda's engineering on these particular bikes: even at the mileage it has now, I would not hesitate one second to hop on it and ride clear across the U.S. (in warmer weather!). That's why I'm writing this book, so others can understand what to do with them, and enjoy theirs, too.

The endless cam chains wear quite evenly if the bike is ridden regularly. If ridden infrequently, the rollers tend to get pitted, and then once in a great while, one might crack and might fall off. The pieces end up sitting below the crankshaft, except once I saw one half sitting in the top end by a valve (no damage, though). There's no noise to hint this has happened, but it does slowly chew up the tensioner roller on the arm when this happens. Personally, I feel (can't prove) that the occasional run-to-redline is a good way to informally test these engines: the redline is actually considerably higher than the 8000-8500 seen on the tachs. If a new vibration or noise happens after a run, it usually indicates something may be happening, besides the usual fouled sparkplugs bit. White smoke indicates oil burning. Up until I installed the Electronic Ignition, the points told the story of their condition at about 7K RPM, with a slight unwillingness to run crisply above that if pitted or burned. The Daiichi points, even with the Ignition, demonstrate erratic timing at those speeds, though, due to the poor pivot characteristics.

That tach: I have seen the center bearing get a trifle sticky, which makes the needle not retract well. Of course, it requires disassembly of the gauge to clean, not simple...then lube with very light oil. On just one occasion, I saw a broken return spring, which would only let the needle drop to about 500 RPM when the engine was off, and it read pretty high the rest of the time (like 5k RPM when at 3K, and such).

[ofreen]

The endless cam chains wear quite evenly if the bike is ridden regularly.

Also, if the bike is ridden smoothly.  Making the throttle transitions and gear changes smoothly, plus using the clutch correctly pays dividends with the whole drivetrain.  Some think that fast riding requires a lot of slam/bang, but the reverse is true.  Smooth is faster, and easier on the bike.  I've had a lot of comments that I must be babying the bike for it to last so long, but believe me, it is not babied.

You are right about the tach. I had good luck with the speedometer by shooting some aerosol lithium grease years ago up in that bearing, so will try that this weekend. The speedometer was squealing when I did that, while the tach is still running quietly.  So it may be a different problem and it may have to come apart. 

[HondaMan]

The endless cam chains wear quite evenly if the bike is ridden regularly.

Also, if the bike is ridden smoothly.  Making the throttle transitions and gear changes smoothly, plus using the clutch correctly pays dividends with the whole drivetrain.  Some think that fast riding requires a lot of slam/bang, but the reverse is true.  Smooth is faster, and easier on the bike.  I've had a lot of comments that I must be babying the bike for it to last so long, but believe me, it is not babied.

You are right about the tach. I had good luck with the speedometer by shooting some aerosol lithium grease years ago up in that bearing, so will try that this weekend. The speedometer was squealing when I did that, while the tach is still running quietly.  So it may be a different problem and it may have to come apart. 

Thanks for the tip: I have a squealing speedo on a bike here!
And, you're right about smoothness: the fastest riders I watched in the '60s and '70s (guys like Dick "Bugsy" Mann, Rusty Bradley, et al) never looked like they were going fast, and you never heard them shift, even at 16000 RPM. But they led everyone, all the time.

[Fabricator]

My '76 750 reads 43,200 mi on the clock, and I picked up a "$200 special" a couple months ago with 8100 on the dial ('73 750)....  What's just one more anyway???

Fabricator