Topic: NEW BIKE 1974 cb750

[black1.8t]

Hi guys Ive been lurking around for a few weeks trying to soak up some of the good knowledge on this site, And finally dove in and picked up a 1974 cb750, decent shape , but needs the normal stuff a 30+ year old bike needs, tune-up, carbs cleaned and tuned, timing etc......... I just have one major concern right now, shes marking her territory  ::)when its running, I have an oil leak thats running down the kickstand and seems to coming from inside where the chain goes in to the sprocket......Im just looking for some pointers to head me in the right direction of tracing it, or some starters on where to look first, I will have some pics for you guys on tues , and maybe throw a little video in there as well..............Thanks in advance for any help.............NOTCH

[Bob Wessner]

when its running, I have an oil leak thats running down the kickstand and seems to coming from inside where the chain goes in to the sprocket......

Sounds like it could be the automatic chain oiler needs flow adjusting or shutting down. It's in the sprocket shaft.

[jaknight]

HI NOTCH,

   Welcome aboard!! Hope you do enjoy the ride with everyone here!!

   I do have a '74 CB750 (aka K4).  Look at the words under my signature.

   Hey Bob- - - - -> Sorry, I hate to disagree with one of my idols, but I strongly believe that Honda had done away with the automatic oiler by the time the '74s had rolled around.

   I wouldn't presume to know where your oil leak is coming from, but........ try checking the oil pan itself or even the soundness of the fit between the oil filter at the front center below the 4 exhaust pipes.  Leaks from either of these places COULD get blown back along the bottom of the bike and end up on the kick stand, then appear to be dripping down the kickstand.  Also, make sure the drain bolt/plug for the crankcase itself, on the right hand side of the bike, make sure that bolt is tight enough.  I left mine a little too loose once and I had oil dripping down and spreading to the other side of the bike, leaving oil over both kickstands.  Just a thought, please don't take it as The Biblical Truth.........
   ~ ~ ~ jaknight ~ ~ ~

[TwoTired]

Here's a scary thought.
Take off the front chain sprocket cover, clean and check the engine cases in the area of the sprocket.  Maybe it's thrown a chain in its service history and cracked/holed the case?

Hope not...
 

[Bob Wessner]

  Hey Bob- - - - -> Sorry, I hate to disagree with one of my idols, but I strongly believe that Honda had done away with the automatic oiler by the time the '74s had rolled around.

I didn't realize it was that early, wouldn't doubt you, it was just a thought.

Perhaps not definitive, Haycock's book indicates the ser# when the chain oiler became 'adjustable' and later suggests it was not discontinued until the introduction of the F models. Is this correct according to anyone with later model K's or some F's?

[jsaab2748]

Bob, I believe you are right. I had a k4 in '74 that had an adjustable oiler. It made mom mad as hell at me for ruining so many t shirts. Every one i owned had an "oil stripe" up the back on the left side.
The stains never came out, even after washing, so I used them all for rags to wash the bike with
Notch....
There are a few different things that can cause oil to run down the stand, some already mentioned.
If you don't discover a holed engine case(Heaven forbid)
Get a can of brake parts cleaner (the non flammable kind) and spray the area of the leak down and let it dry. Do this with the sproket cover removed and a pan under the bike to catch the nasty oily mess you're making. And DON'T get any brake clean on anything else as it may harm painted surfaces. Once the area is clean and dry, start the engine and watch for the leak to appear. If you have an automatic oiler, there will be a slotted screw in the center of the sprocket shaft. turn the screw clockwise till it bottoms, not too tight. this will turn off the oiler and stop your leak IF the oiler is in fact the problem. Otherwise, look for a bad seal or o ring in the vicinity, I think the neutral switch is in this area, and it may have a seal or o ring. If you don't already have one, BUY or down load a service manual. Just my .02 worth to add with the others... Hope this helps...

[jaknight]

Hiya All, ...... Say there Mr.Bob--------> You gave me food for thought.......

   I was sure I had read somewhere that the automatic oiler was stopped in '73.  My Chilton's manual only breaks it down to the point of saying......"earlier models had automatic oilers, later models must be done in the usual manner."  It only specifies that '77 to '81 models were fitted with a chain which has rubber o-rings between the plates to aid lubricant retention.  For these, they recommend 80 or 90 weight gear oil only.  The manual claimed that commercial chain lubricants may have additives which will damage the rubber o-rings.  (This is a somewhat old book).

   I have another general motorcycle maintenance book that does mention that the '74 750 K4 does indeed have the auto chain oiler.  I have never referred to this book for work on the Honda, it seemed too general.  I think I will be looking at this book closer in the future

   So, indeed, once again I have learned from you Bob and this Superb Forum that we share here,
   ~ ~ ~ jaknight ~ ~ ~

[bistromath]

3 things it could be. First, like was mentioned, the auto chain oiler, if so equipped. Second is the countershaft sprocket oil seal, and third (and my personal guess) is the shifter oil seal. All three are in the general vicinity of the sprocket, and taking off the sprocket cover would be a good way to investigate further.

[techy5025]

Disabling the automatic chain oiler was one of the best inprovements I made to the bike.
It was especially bad because of the short chain guard...so instead of getting rid of the
oiler, they lengthened the guard.

I had to keep a pan under the side stand to catch the oil...yuck.

Jim

[750goes]

I have a 1976 750 K series engine in an F1 frame, it has the automatic chain oiler, which I have tightened up so it won't drip.. there was a big mess around the front sprocket also, which was mostly oil soaked dirt and whatever else.
Engine not back in the bike yet but I have a good feeling it won't leak - famous last words spoken.....for a while anyway.

[black1.8t]

Thanks for the info guys I just got the manual today, I will have a closer look at it tommorrow, I have a few pics of the bike as well as a couple where I think at some point it threw a chain, where the cover is cracked, oh ya pay no attention to The HD in the back ground LOL 
http://www.pbase.com/black98/image/55829826
http://www.pbase.com/black98/image/55829872
http://www.pbase.com/black98/image/55829882
http://www.pbase.com/black98/image/55829887   
 
 Not sure if these pics are going to post if not maybe someone can give me a couple of posting lessons LOL thanks .................NOTCH

[750goes]

Notch

from those photos it doesn't really show if the oil is from the chain oiler, but by the way it is shown in the last photo, check your shifter seal bearing...

to check the front sprocket and oiler is only two screws, and you will quickly tell if thats where its coming from.. simple solution to fix as well.

comment: your chain looks a bit rusty, not too much oil on that..so probably not the self oiler...

more photos if possible after you take the sprocket cover off..

nice bike as well