Author Topic: 77 CB750 F resurrection notes. (update)  (Read 18549 times)

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Offline DarkRider

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Re: 77 CB750 F resurrection notes. (update)
« Reply #75 on: December 16, 2007, 07:22:34 AM »
Just a random thought here man...you said you were thinking of converting the other 77 into a tourer with the parts from this one..why dont you pull the lighting parts you need for this one off of that bke when you install the touring parts onto it? On a side note...me thinks when i search for another 750 it may just be an F
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Offline Terry in Australia

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Re: 77 CB750 F resurrection notes. (update)
« Reply #76 on: December 16, 2007, 11:56:32 AM »
Well get yourself an F2 or F3 mate, those F/F1's are fugly with a capital fug! ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 77 CB750 F resurrection notes. (update)
« Reply #77 on: December 16, 2007, 12:55:19 PM »
Well get yourself an F2 or F3 mate, those F/F1's are fugly with a capital fug! ;D

Oh yeah, I resemble that remark  :D
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline TwoTired

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Re: 77 CB750 F resurrection notes. (update)
« Reply #78 on: December 16, 2007, 08:07:10 PM »
Just a random thought here man...you said you were thinking of converting the other 77 into a tourer with the parts from this one..why dont you pull the lighting parts you need for this one off of that bke when you install the touring parts onto it?

Yeah, I would.  Except the other 77 doesn't have the headlight stuff either, having had a fairing on it in a previous life.
My 78 does have these bits.  But, I'd kinda like to get that one completed, too. It's got most if its bits in total.  And, a helicoil in #4 spark plug hole should tell me if that bike is restorable, or not. ... in the fullness of time.

I'm not going to be able to anything more with these bikes til I get back from Texas next week. Then we'll see.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Thor's Hammer!

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Re: 77 CB750 F resurrection notes. (update)
« Reply #79 on: January 02, 2010, 10:16:05 AM »
After reading and enjoying the last 4 pages, I look at the date of the last post...over 2 years ago  :o ...I need some closure now.

What happened with the bike, did you get it the way you wanted it?  Sell it?  Any updated pics or do you even still have it?

Enjoyed your resurrection story here and in some ways it feels a bit like my 78 750F I just got running.

Anything to add to close this story out?


Thanks,

Mike
1978 Honda CB750F : 2005 Kawasaki ZRX1200

Offline TwoTired

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Re: 77 CB750 F resurrection notes. (update)
« Reply #80 on: January 02, 2010, 11:53:56 AM »
I had pnemonia and a herniated disk in my back.  So, the bike has just sat in the garage waiting for new tires, a new battery, detailing, and some enthusiasm.

Ran well when parked...
 ;D ;D ;D

I have three F models, and I'm trying to decide which will get the sidecar.  It will probably be the one with the K8 engine in it.
But now, I have laminate flooring to address...
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Halvin

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Re: 77 CB750 F resurrection notes. (update)
« Reply #81 on: January 05, 2010, 11:38:49 AM »
I too enjoyed the story of the F2.  I recently purchased a non-running 77 F-2 and it sits in my garage waiting for me to get the time to work on it.  The prospects for its return to useful life after 9 years in storage are good as its pretty clean and all there.  Its the one on my avatar.  Amen to earlier posts concerning the looks of the bike, contoured seats look bad on them, and I am particularly partial to the lines and styling of this version of the Honda 750-4.  It sits in my garage next to a CB200 I am cleaning/tuning up for my grown daughter who wants to learn to ride a motorcycle.  She is reluctant to attempt to learn on her husbands Honda CBR (as you can imagine I have reservations about that too).  As soon at the 200 is out I'll begin preparing the F-2 for summer, which seems quite far away right now since the temps here in Ohio are in the 20s and ice and snow is plentiful. 
Hal

Offline TwoTired

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Re: 77 CB750 F re-resurrection notes. (update 6-7-10)
« Reply #82 on: June 08, 2010, 02:38:13 PM »
So, the bike sat while I had some medical issues and slowly worked through them.  It has become quite evident that I am mortal.  Or should I say MORE evident?
The poor bike became a spider resort out in the shed.  Kinda sad, really.  As I had moved on to some other projects.  ( I have more projects than I can complete in my lifetime.)
But then, events occurred that meant I had to get it to Hollister about 55 miles away via freeway.  I'm not doing that on 25-30 year old tires.
So, I ordered New Metzeler Lasertec tires.  3.25-19 front, 4.00x18 rear.
They came in last Friday.  So, I dragged out the bike, and set upon removing the wheels to have the decrepit tires replaced.   The rear came off without too much of a surprise.  But, the endless 630 chain is a horse to wrestle.  The front speedometer drive screw was completely rounded out.  So, I had to disconnect at the top and let the cable dangle.  Then I couldn't get the axle nut to budge either.  So, I said "screw it" and I'd figure it out at the MC shop.  Tossed both wheels into the truck and off to the shop.  Got the front axle apart with a big pipe wrench and the bench vise.  Annoyed that the pipe jaws left "tooth" marks on the end.  But, the flats were just not beefy enough to budge the axle nut free.  I later used a body hammer and anvil to push the metal back into place, so the marks aren't a fit issue and you can't see them with the axle mounted anyway.  I left the speedo drive screw, for another day.

Its a bit disconcerting to toss tires with lots of tread left on them.  But, the cracking on them probably meant it could all chunk off at 70 MPH.  I don't think I'd enjoy that!  The shop owner has an injured back so I helped him get the old hard tires off the rims. (And, to push bikes and other large objects around his shop, and become general help.)

Found out that the axle spacer under the cush drive was missing, which explains why the axle nut was on so loose.  I drove it this way for about 10-20 miles!    Ordered a new one, $18 and available.  Whoda thunk?

Friday was a long day for me so when I got home I left the newly mounted tires/rims in the truck for the night and the bike out in the front yard on the center stand and the jack under the filter, hoping for only light winds and the neighborhood punks being occupied elsewhere.

Saturday, was get the bike to roll day.  After looking at the wheels which hadn't been detail cleaned since prior to 1985, I decided that while they were off, a good cleaning/polishing was required.  I was really tempted ti take the Comstars apart,  It's probably the bolts staring at me.  But, something told me not to do that.  The "spokes" look to be chromed, but had some rust specks on the them, probably due to stone chips that occurred in the 20K miles of use.  The aluminum rim has a clear coat on it.  But, half the wheel had specs of corrosion.  While scraping the corrosion with a scrap of aluminum used a a scraper (work well on the rust spec, too, I came to the realization that it was the spider's digestive juices that ate through the clear coat.  When they finished with their prey the discarded carcass still has the juice inside it.  That's why only the bottom third of the wheel had the pitting.  There was also a bad spot where animal urine had etched through the clear coat and attacked the base metal.  I can't make these look like new without a refinish job.  But, they look a LOT better now, and are perfectly safe to use.  The 0000 steel wool did a right nice job.  I do miss the specks of finish lost, though.

I also dremeled a slot in the speedo drive and removed the damaged screw with the impact tool.  Front wheel back on, rear wheel ready to go.  But, the work has taken all day.  I still need that spacer under the cush drive, which I am going to "borrow" from the 78 F in the shed.   Gonna have to do that Sunday, ...getting dark.

Got up late.  The dog next door moved out end of last month, in fact the whole house next door is empty of the 5 families that lived there.  So, the neighborhood is pretty quiet on Sunday mornings now.  Moved bikes/projects around in the shed, so I could work on the 78F rear wheel.  Actually, it went way faster than expected, as it wasn't in a running state when I acquired that bike.  Anyway, spacer in hand I head toward putting the rear wheel back on the 77 F  out front.  Oh wait, there's all that grime on the chain and swing arm.  Better scrub on that first.  Tedious, but I feel better about catching up on needed attention that the bike has endured without since the early 80s.  I get the rear wheel on, chain adjusted, lubed, and the rest of the back end assembled and ready for the road.  Check that off the list.

Better put the battery back in.  It's been on the charger/maintainer for quite a while, and lights up the big Halogen car headlight I use for battery testing on the bench.  But, on the bike it just makes the solenoid buzz.  Phoey.  Might still get some use out of it later on a kick start only bike. (But, I'll probably just replace it.)  Luckily I have a new one I bought a few months ago.  So, that one goes in.  Motor spins, but no fire or signs of life.  Throttle is stuck, too. Check the carb drains.  Only # one has fuel.  Oh well, I figured the carbs had gummed up again.  They had.  (It turns out that the fuel selector has a slow leak and all the gas had pretty much leaked out of the tank while it sat.)
Anyway, off comes the gas tank, and out come the carbs which were clean and operable in December of 07.  It has one stuck slide so it was treated with W-40, but still wouldn't come free.  Out came the heat gun.  And, with a little heat, the slide freed up and they all moved again easily.  As expected, all the slows were plugged, two of the mains were plugged and even some of the emulsion tube holes were gummed.  I soaked/ cleaned all the plugged up parts with Honda Pro Carb cleaner after removing them from the carb bodies.  Then put the parts back in. I filled the #2 bowl with gas and put it on the carb bank while still full.  With a few pumps of the throttle the accel pump primed, and all the nozzles had nice streams into the carb throats.
Time to wrestle the carbs back on with 2x4s and wood wedges.  Since the gas tank was empty, I decided to replace the fuel selector with a spare I had previously rebuilt.  I kind of dreaded taking out the in-tank filter, as these are often neglected and rust tends to lock them into the tank bung.  I decided to try an easy out, and was pleased that it worked pretty well.  Yes, there was some rust and the filter had caked rust bits on it.  But, the carb cleaner washed it all off and it was ready to put back in the tank.  I wiped out the tank bung which also had a bit of rust in it.  Although the the tank was essentially empty it was still "wet" inside and was really foul smelling.  If there had been any gas left in it, I'd have used it to spot kill weeds.  I must say that none of the rust/brown stuff found on the filter (I took a picture of it, if anyone is interested) was found in any of the carb bowls.  So, this reinforces my confidence that the Honda in-tank filters work as well as they need to or as is required.
So, the tank goes back on.  And, I put about a quart of gas in the tank from the lawnmower supply jug.  Turn on reserve wait for bowls to fill.  Full choke, a couple of twists on the throttle and hit the start button.  Instant life but short lived.  Seems to only run when the accel pumps provide that extra shot of gas.  So, I put the rest of my lawnmower gas in the tank, probably half a gallon.
Now it will stay running.  It is  grumbling from it's long sleep.  But, it is getting used to it.  It warms up and idles pretty well, but not as smooth as I would like.  Maybe a ride will loosen things up and get all the juices flowing more easily.  So, I shut it off, and go suit up.  It starts right up, and off I go.  Throttle is still touchy, like the slow jets aren't flowing and the accel pump is sluggish.  Rather poor pickup.  I wonder if all 4 are working at idle?  Needs lots of RPM to do anything.  I'm kind of disappointed, but hopeful it will get better with some road behind it.  Don't want to get too far from home...just in case.  So, the 35 mph zones are the best I can do for now.  Then about a mile from home the engine sound changes, cylinders are cutting out.  Need the accel pump to bring them back. I turn onto a side street so traffic behind me can get by, and it quits.  I coast to a shady spot, and the oil light comes on.  Guess I didn't blow a fuse.  Due to my superior planning (HA!), the road I turned on heads toward home and is fairly steeply downhill.  I learn that it will coast down the street in neutral at about 20MPH.  That is far better than walking/pushing!  I run out of hill about 5 blocks from home.  Decide to try the starter again.  It will run if I pump the throttle and keep the R's above 4000.  This works well until I get to a stop sign, which I think about running through, but there is Sunday cross traffic.  You know, where all the drivers are doing the pokey thing and alternating praying with driving.  Anyway, of course, the engine dies again at the stop sign.  It's getting harder to relight the engine every time it dies.  Eventually, with enough accel pump and high RPM I get moving again.  But, I do eventually coast into my driveway, quite relieved.  So, I put the work duds back on.  And go out to see what needs fixing now.  Maybe there still isn't enough gas in the tank? Maybe I didn't rebuild the fuel selector correctly.   I pull off the fuel line and note it is dry inside the line.  Hmmm.  The selector is in off position.  Did I automatically turn it off on arrival or did I never turn it on for the test drive?  Put on test hose and move to RES.  Fuel goes to into gas can freely.  Turn to off, it stops flowing.  Turn to ON and the fuel line drains out then stops. I surmise the fuel level is below the "ON" feed standpipe.  I reconnect the carb fuel line to the selector valve and turn to RES.  Key on, push button, and it starts and idles as it should.  This is when I smack my forehead with the flat of my hand...twice.  All that detail work and I forget the basics!  Turn on the fuel!  This is the fundamental problem with mental checklists.  I know this from piloting airplanes.  But, I am annoyed with myself for not reviewing the check list when there was a problem.  Boogers.  I guess I need more practice.
In my defense.  A shakedown drive on a "new" bike, has me alert and attentive to every sound, bump, and vibration the bike produces, as well as the normal driving in traffic concerns.  At my age, it is probably akin to sensory overload where the mundane gets set aside.  I'm sure there is a "human factor" explanation, there.

And now for the "real" test drive. (This time with the fuel turned on.)
Now that I know the tank feeds just fine in reserve (hey, that IS a good thing to know before it's use is required),  I decide to take the bike to get the tank filled, and do so. $10 and the tank still isn't filled?  Dang!  I used to fill up for $5!  I rode it around for about 5-10 miles.   As was the case back in December 07, the more it runs, the better it runs.  Even low end throttle response is improving and becoming reliable and predictable.  Tomorrow, I'll put some Seafoam in the tank and give it another runabout.
I should probably comment on the new tires.  I like them, of course.  Who doesn't like new tires?  This bike had oversize tires on it when I rode it last.  I recall it didn't handle all that well.  Had to fight the bars to make smooth turn line.  I had assumed that was because the bike was bigger/heavier/taller.  This made it seem more truck like than my 550's, which all handle pretty neutral and nimbly.
Well, I have to say the stock sized tires on the 750F has made quite a difference.  It now handles pretty close to what my 550s do.  It is much more responsive to control than I remember.  And the weight and height of the 750 seem not a factor.  I like it.
It occurs to me that since I also use Metzelers on the 550s, (in essence the same tires), perhaps that's just the feel I'm used to and am comfortable with their characteristics.  Still, I'm not at all sorry for sticking to the stock size for this bike.  I haven't ridden them far enough to have all the mold release agent wear off, so my lean angles are nothing near extreme...yet.


 







Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline ofreen

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Re: 77 CB750 F resurrection notes. (update)
« Reply #83 on: June 08, 2010, 04:22:55 PM »
There's another one saved from oblivion.  I remember when you started this thread.  I looked at the first post, over 2-1/2 years ago.  Geez time goes by fast.
Greg
'75 CB750F

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Offline Retro Rocket

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Re: 77 CB750 F resurrection notes. (update)
« Reply #84 on: June 08, 2010, 06:07:48 PM »
Quote
Turn on the fuel!  This is the fundamental problem with mental checklists.  I know this from piloting airplanes.

I hope you remember to turn the bloody fuel on in the planes ...... ;D

Mick
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline TwoTired

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Re: 77 CB750 F resurrection notes. (update)
« Reply #85 on: June 08, 2010, 11:24:01 PM »
Quote
Turn on the fuel!  This is the fundamental problem with mental checklists.  I know this from piloting airplanes.

I hope you remember to turn the bloody fuel on in the planes ...... ;D

Mick
I have to switch between the Left and Right tanks at 15 minute intervals.  Forget and a wing gets heavy, which you feel in the controls.  I don't use the OFF position.  I think that's there for when you must make a forced landing.  It's to increase the chances that the gas will stay in the wings.  ;D

Anyway, the written pre-take off check list has you select the fullest tank and switch on the boost pump.

Lot's of things are different in airplanes.  Like steering on ground taxi.  The steering wheel like thing on the dash (yoke) doesn't do much for directional control on the ground.    You steer with your feet.  Push the right pedal to go right, left pedal to go left.

Cheers,

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline TwoTired

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Re: 77 CB750 F resurrection notes. (update)
« Reply #86 on: June 08, 2010, 11:30:47 PM »
So, today I put some Seafoam in the gas in hopes that the lumpy idle would improve.  Drove it a few miles and then let it sit a bit.  Then took it out in the boonies up Calaveras road by the reservoir to see where bald eagles had made a big nest at the top of a power transmission tower.  I wish I had brought the Binoculars.  But, I didn't see any Eagles flying around.  Anyway, I think the Seafoam and the running helped.    On the way up to the nest, the idle increased to about 2200 all on its own and it suddenly had better down low pep.  I dialed the idle back down to 1200, any lower and the thing still chugs and rattles.  (I know, I need to go through the whole tune up procedure, but I'd like to have some confidence that the carbs don't have be yanked off again.) On the way back from the nest, I got lazy foot and the trans found another neutral between 3&4.  I didn't want to jam it in gear so I let it idle and planned on stopping to get it into gear without gnashing.   But, the tach went to zero and it wouldn't relight with the starter button.  Oh bother.  This was a fairly steep downhill grade and the speed quickly built to 45 mph.  Oh well, I'm pointed toward home and it is all down hill to about three blocks away, so I just coasted for a while.  The road is all twisty here, and there is no shoulder to stop on anyway, just drain gullies that look quite unfriendly to vehicles.  When the road straightened a bit to give me some time, I gave the accel pump a few shots and got the engine restarted.  Now it needs throttle held open or an idle knob reset.  Revved the engine to mesh the gear and got it engaged again.  At the bottom of the hill it wants to die unless I hold the Rs up around 2500.  I get home and readjust the idle knob, but it still seems that only three cylinders are working at idle.
Number 1 head pipe still seems a little colder than the others.  Thinking back to when I cleaned the jets, I forgot my own advice about "proving" the slow circuits.  (Yes, I know better than to cut corners, but apart from the plugged jets the carb still looked pretty clean inside.)  Now, I'm pretty sure the pilot screw orifice was gummed up on #1.  So, I took them out one by one and squirted carb cleaner into the screw hole while it was running.  After a couple of tries, the carb cleaner made a change in engine running and the idle increased.  I think all four are working at idle, now, and it will motivate itself down the street with it idling at 1100.  It isn't all that smooth, though.  But you can pretty much feel the impulses of all four cylinders with regularity.  (relative cylinder strength is much easier to monitor with a 4 into 4 than a 4 into one.)  I notice this bike has a lumpy RPM range between 4-5000 where you can feel buzzy vibration in the foot pegs.  I don't know if this is a 750 trait, or something funny still going on with the engine.  It has great power above 4000 and is quite eager to climb to redline.  Probably time do the tuneup schedule.  Perhaps the timing is off or there is a clearance issue for the valves?  I rode out to the nest again (it is quite a fun twisty road out there in the hills), and the extra pilot circuit and the increasing confidence with the bike, made the ride a bit more spirited.  No more funny business with erratic idle.  So, that's a good thing I think.  Perhaps there's one less bug to deal with on the bike?

I'm grinning when I get home, only to see oil splashed on my left boot and on the shifter.  I don't know where it's coming from yet, oil pan or alternator cover, I suppose.  I'll have to clean it off and do the foot powder spray, thing.  My other 750F leaks oil from the alternator cover.  I know my 550s don't drip oil like British twins. :-)
 Yeah the 750 is probably faster than the 550s.  And surely the 77 750F has better brakes than the 550s.  But, the 750 does not seem THAT much faster than the 550.  And certainly, my 700SC Nighthawk is quite noticeably faster than the both of them.

Til next revelation...



Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.