Topic: Beautiful 1972 cb750 with dagnabbit stuck engine

[Hondawggie]

That gold bike on ebay is worth more than 2600 mate, it didn't sell, it also won't cost you that much to fix the engine. DON'T part it out, its a surviver in great condition, if its too much for you too fix then sell it complete. If it has as little mileage as you say and was running 12 months ago then it can't be that bad, have some patience it will come unstuck.....

I really did not buy it to part it out.  However I also didn't want to tie up my time and money on a big project -- when he said 'it was turning over last year' I really believed him.   If he would have said 'it has been stuck for quite a while' I would not have bought it despite the condition.  The thought of disassembling and then selling parts to a gazillion people is something I have never done.  Heck I have had trouble giving valuable stuff away for FREE on craigslist.   However I see that I can make some money if I do have to part it.  The good news is -- everyone's early cb750 goes up in value every time a complete bike is parted out.

[d9canada]

Hondawggie, listen to me.  Big projects are simply a stream of smaller bite-sized tasks.  You need to be organized and determined.  Sometimes you can do several things simultaneously and other times there are bottlenecks where you must have A, B and C done and ready before you do D. 

You have a lovely bike that is crying out for someone to have the determination to fix it right.  Too many people these days are lazy, they gotta have everything now, cheap and easy.  Think of how proud you'd be to be running that beauty knowing you fixed it properly. 

I'm not blowing smoke here, if that thing is so stuck, it WILL have a big fat ugly ridge of rust on the cylinder walls after it get's unstuck.  You must fix it right.  Your rings WILL be damaged to some extent and dragging them over that rust ridge IS going to cause a catastrophic failure.  Then you will have to part it out.  If you live in BC or Alberta, PM me.  I don't know how I'd get that past the wife but I'd figure something.

Be proud to be one of the oddballs whose self-determination more than money leads him to be driving down the road one sunny day on a fabulous old bike.  Or, sell the thing in one piece to someone who cares.

[chickenman_26]

-- when he said 'it was turning over last year' I really believed him. 

I feel your pain, but just tuck that lesson away for next time. If the engine is stuck, then it's stuck. Regardless of hopes and dreams or what the owner might imply ("shouldn't take much to get her running") you have to assume the engine needs to be dismantled and repaired, and be pleasantly surprised if it actually breaks free and runs well. As someone already said, if rocking in 5th won't budge it, you'll only damage something by going after that crank nut with a cheater bar. BTW, that eBay bike looked to me to be a wolf in sheep's clothing, and it appears the bidders realized it. If yours is all original and super clean, it's worth a lot more.

Stu

[Eydugstr]

I really did not buy it to part it out.  However I also didn't want to tie up my time and money on a big project.

Please forgive me when I ask this...If you weren't willing to commit some time and money to a project...why buy an old bike?  Older bikes, even ones in perfect condition, require way more routine maintenance than modern bikes do, let alone all the stuff that it takes to get them in good running order.

Please consider carefully what d9canada has just said.  Because it WILL take money, time & effort to make a runner out of that bike.

If you decide "Hey maybe this isn't for me..." sell the project bike, and look for something else, no big deal.  If you cleaned that bike up, posted an honest ad on ebay, stuck motor and all...Would probably fetch a good amount for it as is, without having to part it out.  If you posted a pic of the complete bike on the forum, wouldn't be surprised if someone here made a good offer for it.

But if you decide to take the project on, and are willing to spend some $$'s, wrench time, and want to learn about old bikes..Old Hondas are a good way to go.  But it WILL take some sacrifice & effort.  To me, it's worth it in the long run, but that doesn't mean that everyone else will feel the same way.

Please post a complete pic of that bike!

[Retro Rocket]

The good news is -- everyone's early cb750 goes up in value every time a complete bike is parted out.

And there's one less for future buyers, i wouldn't call that good news....

[Hush]

My bike was in much worse condition than you decribe and it has only cost me $3500 all up to have it running/legal/look'n good.
My son and I bought a bike recently and the seller swore it was running "just the other week" well I'm not sure which year that "week" was in but when I finally pulled the carbs the main jets were like full of cement, there was no way that bike had ever run in the last few years, it takes a lot longer for "cement' to set in the jets (an E string from a guitar minus the wrapping wire worked wonders on those jets).

[Hondawggie]

I really did not buy it to part it out.  However I also didn't want to tie up my time and money on a big project.

Please forgive me when I ask this...If you weren't willing to commit some time and money to a project...why buy an old bike?  Older bikes, even ones in perfect condition, require way more routine maintenance than modern bikes do, let alone all the stuff that it takes to get them in good running order.

I just revived an old 750 Kaw Vulcan.  When you see one of these V-twins out there, a 750 Vulcan, have a look at the carbs and ask yourself 'how do the carbs come out of there for cleaning?'  You haven't lived until you have removed and re-installed Vulcan carbs,  it is fun.  I do love to wrench.

But know at 51 I have a rule -- it is the 'demeanor' rule.  I deal with a lot of people in my line of work and get to know them -- I have a 'closed loop' of first meeting the person and getting that first impression of them then seeing how their actual behavior is.  A lot of people don't have this 'A-B' closed loop in dealing with a very large number of people like I do in my business.   Most people meet someone, get a first impression, then don't see how that person actually behaves over time -- most people don't have a chance to say "well he gave off a first impression 'A' and his true nature is 'B' " with a ton of people they meet in their lives like I do.

So my ability to size up a person's initial demeanor is highly calibrated -- I've had tons of closed loops in my work where I get a first impression then have to deal with the person over a long period.   My ability to form a first impression is highly informed because when someone gives me the impression of 'A' I know that probably means 'B'.   

So 'charmers' usually don't fool me.

This guy was not a 'charmer' -- his verbal and physical demeanor, his mental acuity and articulate communication ability said 'honest guy' to me and I believed him.  So I'm still hopeful he wasn't bs-ing me.  Considering the fact that I've only had the bike a few days I'm giving him the benefit of the doubt.    I do like to turn wrenches but crimey when you go from having the expectation of reviving a *recently*-neglected machine -- to a complete overhaul -- this is a huge change in the amount of wrenching.  I just wasn't expecting a big overhaul job on this one.

 

[d9canada]

Well, I am sorry to burst your bubble but you have gotten stuck with stuck motors 3 times??  Perhaps you should put aside your crystal ball and replace it with a little ol' down-home healthy scepticism - tinged with a little self-preservation.  How many guys sell something that doesn't run but "it just needs" this or that?  If it was so freakin' easy, they would do it themselves and sell it for more!!  You're just wrestling with a reality check and buyer's remorse.. 

Getcher head out of your butt and look forward.  It's freakin' beautiful, so quit whining and either get to work or donate that puppy to me. 

[754]

Condition of carb bowls may give indication of when last run.. Given the miles shown the bike has averaged about 125 miles a year.. or it did more per year, then sat for years.. iIlean to the latter..
 I think on tis one pulling the motor is not more work than some people do on their poor carb cleans that take 3 times.

 Think of this..if its just stuck, aint gonna cost a lot to fix it

[Stev-o]

Maybe you should sell it to one of us!

[d9canada]

There's an excellent thread with a downloadable plan for an adapter to hang from a portohoist.  Take your carbs off, slip the adapter into place and strap the motor to it, then disconnect the motor and slide it out.  It's the slickest thing I've seen for 4s.  Man you should see what it's like getting a 900C with shaft drive out of the boiler room.  I can't wait for the day I have it back in, because the day before that, it's gonna be a long hard day.

Make absolutely sure you disconnect everything because even a little crankcase breather hose can hold on like crazy.  Don't ask how I know 

[Spanner 1]

38 Replies and still no pic. of the bike .... just a rambling blog about very unrelated crap, and with a banner headline of 'Beautiful 1972 cb750' to catch your attention so he can go off on a rant. The OP likes the sound of his own voice ( in print ) .... no bike to see here, move along everyone 

[d9canada]

.. likes the sound of his own voice ( in print ) ....

Gee, look who's talking (in print).. and how are your comments helping anyone??

[Tews19]

38 Replies and still no pic. of the bike .... just a rambling blog about very unrelated crap, and with a banner headline of 'Beautiful 1972 cb750' to catch your attention so he can go off on a rant. The OP likes the sound of his own voice ( in print ) .... no bike to see here, move along everyone 

Plus one

Just want to see the bike

[Hondawggie]

FYI the 3 stuck motors is over a period of *several years*, not bad considering all the times people were honest with me.  Most people are honest and that's reflected in the number of bikes I've bought over the years that lived up to what the prior owner said.  Plus one of them, a 1973 cb750, I actually got freed up.  So the number of lying prior owners, good to find out, is very low, in my experience.   

I just did another check of the atf level in each cylinder -- I use a large horse-shot syringe that holds 4 ounces or so and what I'm using to check the level is a very very long flat-blade screwdriver, I'm using it like an oil tank dipstick to check the level.

On the kz650 I tried to un-stick (unsuccessfully), the level of atf didn't change much only by the amount (I suspect) of acetone that whicked away.   

However, in checking the Honda today -- I am seeing that the level of ATF has dropped off so I can't even see much moisture on the tip of the screwdriver.  Seems like the ATF is falling past the pistons.

I know the acetone evaporates but the ATF is disappearing real fast too.  It seems to me that the kz650 was rusted stuck so bad it had sealed up tight against the bore, that would explain why the atf did not fall down past the pistons on that bike.

Any advice why the ATF is apparently falling past the pistons overnight?

[754]

 Get a small light in there thru the plug hole. and have a look.. I mean if itgsot globs of rust its coming apart SOOONER...not later

[Hondawggie]

Thanks 754 -- I will do it tomorrow when I'm over there.  One thing I do when I get a new fixer is to pull the plugs.  One and only one of the plugs had anything approaching rust on it -- and the others looked normal.  So it may just be one cylinder holding up the whole works.

I know pulling the engine is a big deal.  How long will it take a gottdang ignoramus such as m'self to pull it out of there including removing all required bits?  I will be using the 'loosen/remove everything possible, put a big cushion down and tilt it over' technique I have read so much about.

[736cc]

I used ATF in the spark plug holes on a rusty stuck K1 that sat 30 years in a shed. Let the ATF sit in cylinders a week, remove alternator cover and put a loooong hollow pipe on the socket wrench and rock the nut. Worked for me. And motor didn't get rebuilt, ran it as-is and ran ok.

[Hondawggie]

I used ATF in the spark plug holes on a rusty stuck K1 that sat 30 years in a shed. Let the ATF sit in cylinders a week, remove alternator cover and put a loooong hollow pipe on the socket wrench and rock the nut. Worked for me. And motor didn't get rebuilt, ran it as-is and ran ok.

Yep I have read on a lot of different forums for both Suzuki and Kaw 4/4's that 'was stuck got it freed up and it ran okay'.    I'm going to take your advice, I have a few more days of refreshing the atf+acetone I've been doing these past 4 days -- then I will locate a long pipe if my long breaker bar is insufficient.  The spark plugs look too close to 'ran recently' to think my prior owner was fibbing.   The weather in the San Francisco area is very foggy and salty because of being right on the ocean and I can imagine, since he put the bike outside under a tarp last year after buying his new bike, that the air in that area could easily have oxidized one or more of the bores in one year to the point of sticking.

I've bought several bikes from up his way and several bikes down south my way -- I'm inland, away from the coast by about 1 hour, and we do not get any fog -- you would not believe the difference in oxidation from sitting outside for those folks living fogged-in half the day and next to the Pacific.  That air up in the  San Fran area just *attacks* a bike left outside.  There is so much salt and moisture in the air due to the fog, it's a bad deal for a bike's cosmetics if you leave it outside and don't clean it nor ride it.

I am just hoping he was as honest as he appeared -- I'll find out soon, I'm headed over to the shop now to see how the bike's doing and do an atf refill.

[yozuri54]

Here's what I did on the last couple of stuck SOHC engines:
1. Pull plugs and squirt in a bunch of Kroil brand penetrating oil (amazing product) - allow to sit for a couple of days.
2. You can try a breaker bar on the alternator bolt, but I have had quite a bit of luck putting the bike in neutral, plugs out using the kickstarter.
3. If after a couple of tries and nothing budges, you may have a broken cam chain jammed up (or worse!). Either way the motor is going to have to come out to check. I have also had to pound the pistons down through the cylinder with a hammer and chunk of wood.
4. I agree with the other posters that the engine should be rebuilt properly after inspection....good luck!

[phil71]

i like to use small explosives that'll fit in the spark plug hole(like firecrackers)

[Hondawggie]

I pulled the alternator cover off and took my 19mm socket and my 17" breaker bar to the alternator retaining bolt -- the works are still stuck tight. However, as I rocked the bolt back and forth I am pretty sure I saw the big toothed wheel that is inside the rotor (the big gear that is driven by the starter motor) I watched it carefully.

As I rocked the both back-n-forth I thought I saw that big toothed wheel move a few mm in the direction of normal engine rotation.   I stopped right then and re-filled all 4 cyclinders with aft+acetone, all the way to the dang top of the spark plug hole.  Just to be sure.

Then I went back to rocking and I swear I again saw that big toothed wheel inch forward as I pulled the bolt in the direction of normal engine rotation.  So I am hopeful.  But I'm gonna be patient.

The other time I freed up a stuck '73 cb750 -- I had atf in there for weeks.  I got distracted with some other stuff then I came back to it and I simply took it off the center stand -- the tranny was in gear -- and I heard a strange SCHLOOP-OHHH and there was atf all over the asphalt a few feet in front of the bike.

That '73 cb750 had sat outside the prior owner's shed  -- for a few years -- with all 4 carbs off -- and with the oil tank and all oil lines off -- and the motor still came free.   But it sat full of atf for a few weeks first.

So I'm gonna be patient here.   THANKS for the tip on the alternator bolt -- I'm hoping that will help. 

My technique thus far is:

- check the atf level with a long flatblade screwdriver and keep freshening it up if it evaporates

- put it up on the centerstand in 5th gear and stand up on the footpegs then force it off the centerstand so the back wheel hits the pavement in gear

- then rock it back-n-forth in 5th gear

- ADD: rock the crankshaft end back-n-forth with a 19mm socket and breaker bar on the alternator nut.


Patience.

[754]

 Patience my ass.....................................
........................UNSIEZE the moment...

[bjatwood]

Paitence is the key here, and it won't hurt ANYTHING on that engine to continue to soak it up and rock it with the alternator bolt. I bet in a week or so, it will be free enough to get it rotating.
Now, you posted up a pic of the tank, so we know you know how to post pics.
Lets see some pics of this bike!

[liPPy]

So you are uncomfortable posting shots of dirty motorcycle parts but have apparently no qualms, or shame, in showing us pictures of your vile, disgusting, mess of a kitchen that looks so filthy any salmonella, listeria & e.coli bugs in the area would most likely pack their bags and march off to find something less run down.

Bizarre.