Topic: '77 750 maintenance

[Vintagelover]

Went to change the oil/filter today and couldn't get the filter off because of the exhaust. Any maintenance I should do when I take the exhaust off?

[DJ_AX]

You should probably change the exhaust copper crush gaskets.

[Stev-o]

I would install new exhaust gaskets to prevent a possible leak. About $2 ea.

[bollingball]

Are they blocking any thing on the bottom like the oil pan. May want to check the pan for sludge and clean the screen. Must be after market exh.even so bad design.

[Vintagelover]

YES! Def. aftermarket! I didn't see a screen though... hmmm. Where should that have been? (I feel the need to point out that the bike SEEMED to be running quite well)
Oh! I guess that would be inside the oil pan?
Took the plug off the bottom, but didn't take off the whole oil pan. Should I do that?

 The other interesting (curious?) thing is... that after I thought I had drained all the oil, I put the plug back (underneath) and the new filter in and cover thing back on (on front). Then I opened the oil cap (with the dipstick attached) on the oil reservoir, or tank, or whatever it's called (on the right side of the bike) and there was still a lot of oil in there. So i found the plug on the bottom of that thing, took it off, and drained what must have been close to a quart of oil. So I start putting oil back IN the bike, and that reservoir won't hold 3 quarts b/f it's full up. (calls for 3.7) Obviously none of that new oil has gone into the engine so I only risk turning it over a few times to see if the new oil starts to go into the engine: it doesn't. The oil tank on the right side of the bike is full and there's NO oil in the engine at all.

p.s. - there were no crush gaskets b/t the exhaust pipes and the engine. There were no gaskets at all. I guess I should get some of those Thx.

[bollingball]

Vintage How long have you had the bike? When I first get one I like to take the pan off just so I know if the screen is plugging up it is the best way to tell You do want to get a gasket first from Honda. It can wait till next oil change. These are dry sump engines very little oil stays in the pan like you are use to on a car. Most of the oil will stay in the tank. If you changed the filter leave the kill Sw. off so the motor will not start and turn the key Sw. on press the start button this will fill up the filter an the oil light should go off when it does then turn the kill Sw. so the bike will start. Fire it up run for about 2 min turn off and check the oil after about 30 seconds on the center stand. There is a check valve in the oil pump it is to keep the oil from draining down to the pan when the bike is off but they leak. Don't worry if the bike sits for a few days and the oil is low in the tank as long as you don't see a big puddle under the bike. Just start it up run for a few minutes and check again Oh by the way is this a F or K model

[Doggie]

Is there a difference if its a "K" or an "F"? How do I know what "K" I have? All it says on the paperwork is CB750K.

                                  Doggie

[bollingball]

If you are talking about a 750 the easy way to tell from 20 feet is the tail of the seat. Look at the service manual for all the other little things cam,carb jets,wheel just to name a few.

An take a look here
http://www.sohc4.net/?page_id=2011

[Doggie]

Thanks, Now I know I have a "K8"
                                                       Doggie

[Vintagelover]

Got everything back together, but the filter-cover is leaking. Anybody know what I should set the torque wrench to so I don't strip it out?

[wrenchmuch]

Don't over tighten the cover bolt . Lots of threads around here posted by people with messed up filter bolts . It shouldn't take much torque at all to get it to seal . If you buy a Fram filter you get the cover and bolt o rings with it ( I live in Canada . Canadian Tire sells them here .) . I think the model number is CH6009 .
Your present o rings are probably done . I find they last many changes before they need replacement .

[mick750F]

p.s. - there were no crush gaskets b/t the exhaust pipes and the engine. There were no gaskets at all. I guess I should get some of those Thx.

   The gaskets are there but they're flattened and blackened making them almost impossible to see. If they weren't there you'd know it. If you poke around with a pick you'll find them. Generally, because they are crush washers, they should be replaced whenever you remove the pipes.

Mike

[bollingball]

+1 mick If you take a dremmel with a wire brush you will see shinny copper. If you have that type there are some out now that look flat and green but I have not used them. I put a new set on top of a old set not seeing them and they leaked. You will need a good sturdy pick to get them out.
 If you use a little antisieze on the head flange of the bolt it won't stick so hard on next removal

[Vintagelover]

Thanks guys. Simple help is awesome help

After running the engine and seeing that it was leaking, I managed to take the middle 2 pipes off their bolts and squeeze them apart to get the filter cover off.
...But, since I already took the pipes off, and I hear what you're saying about the importance of new crush washers. I took the pipes off again.
I sanded on one of them (2nd pic)
Could the washer be on the inside of the female end? on the block?

And for extra credit: My oil filter cover bolt. A hollow bolt with holes drilled through like a big gun barrel. What is the hunk of metal inside of it?

I've seen schematics of the oil filter cover and they don't include the second aluminum piece with fins, between the filter cover and the block. Anybody know why?

Thanks again

[Vintagelover]

Also, should I clean the black off the rim? Or does the rubber seal do the trick?

[cookindaddy]

I have a 78 750 K8 which is for most purposes the same as a K7.

You probably have the copper crush washers in your head from the look of your pic. Take a small screwdriver and try to pry them out. The washer should come out easily. Then use the Dremel or some fine steel wool to clean the recess. You should see only aluminum.

The hunk of metal inside your oil filter bolt is a pressure relief valve, in case your oil filter plugs up so badly that oil cannot go through and pressure builds up. The valve inside the bolt will keep your engine from seizing due to lack of oil flow. It is for owners that do not change the oil filter regularly.

Bummer that you have to take the pipes off to change the oil filter. Could the manufacturer of your pipes have been so thoughtless??

I have no idea about the second aluminum piece with fins. Could it have been to space the primary oil filter cover forward out of the way of the pipes? Or someone's idea of additional oil cooling which probably isn't required. I don't think it is a Honda part. Perhaps leave it off?

I don't know what you mean about cleaning off the black off the rim. The part looks like the groove that the o-ring sits in needs some attention for a proper seal but it is hard for me to tell from your pic. Leave it off instead of worrying about cleaning?

Good luck! I love my 750 K8!

[mick750F]

I've seen schematics of the oil filter cover and they don't include the second aluminum piece with fins, between the filter cover and the block. Anybody know why?

   That is an oil "cooler" that came on the 77/78F bikes. Seeing as your engine looks black and you have the "cooler" I'm guessing that you either have an "F" bike or an "F" engine in a "K" bike. And yes, the crush washer will be lodged in the head.

Mike

[Vintagelover]

The engine says 750E ? The frame says F.

[Vintagelover]

YES! success! Got the 4 washers off, 2-4 were easier after I knew I wasn't just chiseling away at the head.

WOW. I know that some people love things to be ridiculously clean. I'm only interested in cleanliness insofar as it helps the engine run better, do I need to do some cleaning around the head exhaust 'ports' (still nailing down a lot of vocab here, fellas, bear with me?) Or maybe even inside (this is pic 2 I'm talking about)? Is it supposed to be that sooty?

The black stuff on the oil cooler is around the rim, on the metal next to the groove for the rubber washer (and seems a lot like the black paint that's on the exterior of the fins). Tried to include a better picture.  I'm just trying to do all I can to get the leak fixed this time so I don't end up taking the thing apart again. These oil cover and cooler rims: are they parts that need to be super smooth? would sand paper mess too much with the seal? Will solvents get into my oil and destroy the bike? Anything seems possible to a guy who doesn't understand the fundamentals of internal combustion 

[cookindaddy]

Good one on the exhaust washers.

My exhaust was pretty sooty when I looked in there. I think its probably normal depending on the mileage of course. Giving the things you are chasing, I would not worry about cleaning out the ports you can see because you might get sand from the sandpaper, whiskers from the wire wheel or shreds from the steel wool down into a cylinder through any of the valves that are open. Not worth risking.

The oil filter cover o-ring is pretty fat and would probably cover and seal minor pits and mesas in the surface it was touching and probably the very fine scratches that you might make with fine steel wool.

[KingCustomCycles.com]

I have to compliment vintagelover about his posts.  He appears intelligent, willing to listen, mechanically inclined, and appears to have an honest desire to do things right to an old Honda.  Congratulations, and welcome.

[Vintagelover]

  Thanks KCC!