Topic: Cb 750 owners how much oil do you add to the tank after an oil change?

[MCRider]

I know I have this doc'd somewhere but can't find it. Trust me.    I may be 20-30 high or low, but the point is the same.  Head temps on our bikes run 230 to 270F. Cooling fins a little less, rocker box a little less, cylinders a little less. ALL are hot enough to fry spit, eggs, skin, whatever you want to put on them.

Oil temp is around 190 (I think). The oil tank/dry sump is a way to keep it cooler, You want to keep it cooler than the engine and it is. Still 125 or so is near immediate scalding 3rd degree burns. So any way you cut it everything about a normal operating CB750 is way hot. Sure it can get too hot, but that would be even higher. Like 300+ at the cyl head.

You'd need a gauge to tell you where you're at. Or a lot of operating experience.

With this in mind treat your air cooled engine with care. If you are coming in from a hot ride, park it outside for a while to let it cool off in a beeze. If you can't do that I keep a floor fan handy in the summer and put that on the engine within a few feet.

Do not let it idle in a garage for more than a few minutes without the fan, and even then keep it short.

Speaking of manuals, my Clymer has a section on preparing your bike for storage. it says to start it and let it run for 20 to 30 MINUTES to unify the oil, whatever that means. Do that and you'll have a pool of molten aluminum o your arage floor. I guess that'd be storage all right. What engineer was playing tricks on the poor manual writer that day?

[jcarthel]

Hi all!  I had been absent from the forum for a bit so I didn't know this was a repeated thread and a sort of dynabeads muffler bearing thread at that.  Now that I have been enlighted, Gordon, will you accept my apology for nitpicking your post?  I lost sight of the fact that there always multiple roads that lead to the same destination.  The road I take is really no better than John Doe's because we both arrive at the same destination.  With that mind, sorry, Gordon.  Personally, I have always enjoyed your posts because you come across with wisdom and as a person who knows sohc fours so well that you must have owned one brand new in 1969, even though you, as well as me, were only a glint in our parent's eyes when the first CB 750's left the starting gate.

Justin

[lostmykeys]

 touching 

[NewOldSchool]

I know I have this doc'd somewhere but can't find it. Trust me.    I may be 20-30 high or low, but the point is the same.  Head temps on our bikes run 230 to 270F. Cooling fins a little less, rocker box a little less, cylinders a little less. ALL are hot enough to fry spit, eggs, skin, whatever you want to put on them.

Oil temp is around 190 (I think). The oil tank/dry sump is a way to keep it cooler, You want to keep it cooler than the engine and it is. Still 125 or so is near immediate scalding 3rd degree burns. So any way you cut it everything about a normal operating CB750 is way hot. Sure it can get too hot, but that would be even higher. Like 300+ at the cyl head.

You'd need a gauge to tell you where you're at. Or a lot of operating experience.

With this in mind treat your air cooled engine with care. If you are coming in from a hot ride, park it outside for a while to let it cool off in a beeze. If you can't do that I keep a floor fan handy in the summer and put that on the engine within a few feet.

Do not let it idle in a garage for more than a few minutes without the fan, and even then keep it short.

Speaking of manuals, my Clymer has a section on preparing your bike for storage. it says to start it and let it run for 20 to 30 MINUTES to unify the oil, whatever that means. Do that and you'll have a pool of molten aluminum o your arage floor. I guess that'd be storage all right. What engineer was playing tricks on the poor manual writer that day?

My point exactly, although much more eloquently put

[lostmykeys]

 This is good to know I seem to remember worying about the temps of a 79 cb750f dohc air cooled that I had in the early 80's.
 But the GPZs I had from the mid 80's never got that hot nor did the Z1 I just traded.
 Must be a honda thing and I have owned alot of hondas over the years too.

[MCRider]

This is good to know I seem to remember worying about the temps of a 79 cb750f dohc air cooled that I had in the early 80's.
 But the GPZs I had from the mid 80's never got that hot nor did the Z1 I just traded.
 Must be a honda thing and I have owned alot of hondas over the years too.

No one's got a magic bullet on engine temps. If its air cooled it runs in the range described. (Air cooled aircraft engines run even hotter) If your experience seems to have been less its just the config of how the heat gets to the rider.

In fact they can't run too much cooler or performance will suffer.

Liquid cooled engines don't run that much less, maybe 30 degrees or so. But the temp is much more consistent, and the higher ranges are harder to get to, increasing longevity. Also they are quieter which is an EPA issue.

The only way to know for sure is to put a gauge under the spark plug. All else is just conjecture. Since I haven't actally done this, my comments (and other's) can be relegated to the peanut gallery if they don't make sense.   

[lostmykeys]

 Thanks M.C.
 If its running hot I"ll find out soon enough.
 I like peanuts but Im not so sure I would go to a gallery to to see portraits of peanuts.
 All kidding aside I thank you for your response.

[MCRider]

Thanks M.C.
 If its running hot I"ll find out soon enough.
 I like peanuts but Im not so sure I would go to a gallery to to see portraits of peanuts.
 All kidding aside I thank you for your response.

No prob. This has actually got me interested in getting a temp gauge just for fun.

[lostmykeys]

 M.C if that is the case then i would be interested in what you find