Topic: 1978 CB750K — Post 836 OIL PRESSURE - not good

[jaguar]

i havenet but i was.

for whats ist worth im planing in running a cbr600 F2 front master and the stock 76 cb750F
they both have plastic res so the the brake fluid is not touching the powder coat.  maybe that makes a difference?

[KB02]

what tool grabs that circle bolt with the 4-notches? Any link to tool appreciated. I want to tourque it back on properly. I smacked it off with a hammer and screwdriver to get it started then used think nosed vise grips that I ground down to fit in the notches. Why would they use such a weird nut?

(Click on picture)

[SKTP]

Thanks KB02 I'm going to order one...

So the mystery of the messed up first gear continues...I'll totally disassemble the cases later this week. Hopefully the other chunk of the broken bit presents its self.

So since the engine cases are filthy I think this is all good that I have to teardown this far. Any suggestions for cleaning them? Would it be worth going to a professional-parts cleaner?

also what do I NEED/should I replace? I think so far (I'm talking in the engine since its apart):
-Piston rings
-Cam-chain
-Cam-chain tensioner (are there deal to be had on these? They seem pretty expensive)
-all rubber bits (I have the cycle x-complete gasket set)

the maybes?
-Transmission bearings? Should I bother? They seem to turn fine and have been sitting in oil for years.
-Primary tensioner?
-Primary chains? Do these wear out commonly? My biek has mystery miles on it...but I'm guessing over 30,000 easy

Here's what I did yesterday. If I had to do this all over again. I would have cleaned the outside of the engine MUCH, MUCH better before ripping it apart...also, so far nothing has seemed too crazy to take apart. I hope the opposite is true.

removed top bolts


Flipped it on a milk crate. Mashed my pinky pretty good in the process


Neutral switch. right?


Bottom bolts out, bagged and tagged


Wasn't too hard to split. tapped it with a rubber mallet at the frame mounts and then it lifted right off.



I really thought the broken bit would be the end of one of the bearing retainers. but this one and the other seem a-OK


Tranny pics. I guess the tranny problem must be hidden in the tranny somewhere...the search continues

[SKTP]

Engine teardown complete. I think I will leave the kicklever and gear in. That pin really dose  not want to come out. Yes, I saw the recent thread about the pin. Now it's cleaning time...so much cleaning.

[sangyo soichiro]

This photo puts a smile on my face.     They're heavy and awkward, aren't they?   

[SKTP]

More work completed:

- Cases are torn all the way down with the exception of the Kick-star shaft and gears. The pin is not moving...might just leave it alone and clean around it.
-freed up the stuck part of my CB450 K0 tach. Turned out the needle was soldered on and liek most things I probably could have left it on. I'm going to Epoxy it back on I think.
-Found some pretty substantial scoring on one shifter fork (see pic). Makes sense. Goes along with how the tranny was slipping and grinding.
-began the long process of cleaning and polishing. I'm going to go buy some Dremel polishing bits and see how those work. Right now I'm at the 320 - 400 wet/dry sandpaper stage. Its going to take forever, but I kind of like doing it. Its like some sort of arthritis inducing meditation!




slightly warped it getting it off...I think I can re-shape it









ever seen this happen?



Still have the question from before...

But mostly: Primary chains. I'm sure ideally I should get new ones, but budget wise...do they commonly stretch or wear out?

[RAFster122s]

Regarding the primary chain, on the CB550...yes they wear out...stretch and have no tensioner mechanism.
If your 750 has a tensioning mechanism for the primary chain then you shouldn't have to worry as long as you don't have too little travel left.  The CB550 primary chain would typically be ready for replacement at 30-35k miles. If it isn't replaced it can hit the cases and dig a hole in them over time...that can really ruin your day when you have the catastrophic oil loss and it's dumping the oil in front of your rear tire.


What does the gear look like that was rubbing against that shift fork?

David

[SKTP]

Polishing sure sucks but somehow I like it? That makes no sense...Here's about one-quarter progress. I am very pleased and think its going to turn out amazing

[the technological J]

Polishing sure sucks but somehow I like it? That makes no sense...Here's about one-quarter progress. I am very pleased and think its going to turn out amazing

what are u using? i sand from 300 to 800 to 1000 to 1500 to 2000 and then two different roushes..... just wondering if your going all out or not

[SKTP]

320, 400, 800, (maybe 1000 when I get there) "00" steel wool seems to be awesome for the uneven surfaces...might try "0" to get more bite

I forget the oxidizer compound I am using (its blue cream in a tub)...and cloth dremel wheels...I am only really at the 320 and 400 stage...I have 2 rouges, but I have not used them yet...as you can see from the before, there's a lot of oxidation to cut through...I was very surprised at how fast the Breather cover cleaned up...It looked horrible

[fastbroshi]

On the pieces I polished, it seemed 75% of the work was just getting the old clear off.  Has anyone tried using aircraft stripper first?  I don't think it would hurt the aluminum.

[the technological J]

thats what im trying also... i think tho that a bucket of strong dishsoap and a toothbrush will work just as good

[fastbroshi]

thats what im trying also... i think tho that a bucket of strong dishsoap and a toothbrush will work just as good

I disagree, that clear takes forever to come off with straight simple green and a green scotchbrite pad.  Stripper vs. soap...you tell me which you think is stronger.

[the technological J]

thats what im trying also... i think tho that a bucket of strong dishsoap and a toothbrush will work just as good

I disagree, that clear takes forever to come off with straight simple green and a green scotchbrite pad.  Stripper vs. soap...you tell me which you think is stronger.

i guess i wasnt thinking of a clear coat just some grime

[SKTP]

So far I'm surprised by how you can scratch it up so badly with 320 and how quickly it buffs out with the wheel...I tried a rubber pointed Dremel bit to clean around the raised "OHC HONDA" area, it was a bad choice...cut into the case too much...Happy I did only a small test area

[jaguar]

i just started to polish my controls and i found that the wheel with red seemed to cut through well.  i almost thought that i wasted my time with the sanding.

[SKTP]

my hands hurt...but I am happy

[wannabridin]

to knock down most of the grime, you should soda blast it.  it worked wonders on some of my carb parts.  i would blast, then ultrasonic clean and they'd come out pretty dang clean!  then some 000 and/or 0000 steel wool and they'd start to look slightly polished!  the valve cover looks good!

[SKTP]

Yes, after dealing with this cover (its not finished yet) I am going to pay a professional to clean the cases and crank shaft...they are totally black and I don't really have the equipment to clean them properly unless I wash grease and oil into the street (I'm thinking that wouldn't be very cool). How come it seems that nobody paints their carbs? Or do they and I am missing something....

I am hoping that the side covers will be far easier to polish (compared to the valve cover) due to their smoother shapes.

Any "Fin" cleaning tips appreciated (might bring them to the pros)...I plan on painting them black then sanding the sides of the fins black to metal

Who do you take parts to to be cleaned? A painter? Typically who has ultrasonic cleaners? Its Yellow Pages time...

[RAFster122s]

You can buy a decent sized ultrasonic cleaner (large one) from Harbor Freight for about $60. Then it is just a matter of disassembling and cycling the carbs through the cleaner. (You never want to mix the parts from your carbs...)
You have to put them on a riser off the bottom of the cleaner and not have the carb or part rubbing against the liner.
Some machine shops have the capability to do ultrasonic cleaning.

Want to be careful with what you use to do the cleaning with as some cleaners can attack aluminum.

Soda blasting works well for cleaning lots of things and it eco friendly but it is a slow process.

David

[wannabridin]

i use simple green HD, the purple stuff, at a 50/50 ration in my US cleaner.  the plastic tray on the bottom is fine for insulating the parts from the liner.  you can have various parts in there as long as theyre not touching.  for general, one piece parts, its ok if theyre close to each other...

[alaskahomes]

have you gone over every link on every chain.  could that be a piece of chain?

[SKTP]

have you gone over every link on every chain.  could that be a piece of chain?

Good call...I will do that tonight

[MasterChief750]

i have a 78 as well and i painted my carbs but there is a ton of taping you have to do. that is what probably took the longest.

[BlindJoe]

On the pieces I polished, it seemed 75% of the work was just getting the old clear off.  Has anyone tried using aircraft stripper first?  I don't think it would hurt the aluminum.

Mar Hyde Tal Strip II