Topic: '73 CB750... How much oil and what plug???

[jpmire11]

My manual calls for 3 quarts or 2.7L and a d8es plug. I have a friend who has a 72 CB750 and his manual is telling him 3.7quarts and a d8es plug! I think this is why my bike is smoking blue because I might be running the wrong plug and under filling it! Please help so I can get this bike on the road. I live in Louisiana and would like to run a hotter plug. So what do I run and how much oil???

[david 750f]

Download the Honda Service manual that is on this site, it gives you all the oil capacities as well at the oil change procedure.

http://forums.sohc4.net/index.php?topic=17788.0

The stock plug is D8ES, one hotter would be D7ES.

[jpmire11]

Just realized this... My buddy's manual is calling for a D8EA.

[jpmire11]

So I downloaded the manual and shows it does call for a D8ES. I am currently running a D8EA plug. Combined with overfilling the oil, could this make my bike smoke? Please tell me yes.

[rklystron]

Overfilling the oil yes that could cause the smoke. The plug I bet not. The D8EA is the one you want if the bike is stock.

[GreenHornet74]

When doing an oil change i would recommend to add about half a quart less than the manual specs. Run your bike for a couple minutes, let it cool, check the oil, add as needed, run the bike and add more if needed. Its easier to add oil than remove it.

[OldSchool_IsCool]

D8EA is the same plug as the D8ES.  NGK changed their numbering system in the years between now and when the manual was written.

[jpmire11]

D8EA is the same plug as the D8ES.  NGK changed their numbering system in the years between now and when the manual was written.

That makes me feel alot better.

[Johnie]

Keep in mind these 750's will leak oil from the oil tank back into the crankcase when they sit a while. So if you check the oil when the bike has sat for a while there is a good chance it will say you are low when you are indeed at the proper level. That is how many guys end up overfilling and blowing oil out the breather. During the riding season check the warm oil after a ride for a more accurate level reading.

[jpmire11]

I plan on draining a little out today and then letting it run for a few minutes. Then set it upright and checking it again. According to the shop manual on here it says it should be between the upper and lower level notches on the dipstick.

[chickenman_26]

D8EA is the same plug as the D8ES.  NGK changed their numbering system in the years between now and when the manual was written.

Not quite. The EA is a half heat range hotter than the original ES. This mod was at Honda's request. The ES is still available as a resistor plug - DR8ES. There's also a DR8ES-L which is a half heat range cooler than the D8ES was.

According to the shop manual on here it says it should be between the upper and lower level notches on the dipstick.

With the dipstick being inserted till the threads touch the case - don't screw it in.

Stu

[MCRider]

So I downloaded the manual and shows it does call for a D8ES. I am currently running a D8EA plug. Combined with overfilling the oil, could this make my bike smoke? Please tell me yes.

In my opinion, neither the oil level nor the plug choice will cause a 750 to smoke. The engine does not "know" how much oil is in the tank. One quart or 3, all it cares about is that there is enough oil in the tank to feed the draw from the oil pump. One quart in the tank is enough. No contribution to smoking.

The plug is definitely a non-starter.

A smoking engine comes from a few things. Condensation will come from a cold engine start, producesa white smoke water vapor and goes away after warmup.

A blue smoke from the tail pipes is oil from either piston rings or valve stem seals. Put some SeaFoam in it and run it till you're ready for engine work.

Blue smoke in general (seen in the headlight at night for example) is oil from the breathers. Base cause is once again rings or stem seals.

OCICBW but i don't think so.

[chickenman_26]

In my opinion, neither the oil level nor the plug choice will cause a 750 to smoke.
The plug is definitely a non-starter.

[jpmire11]

So I downloaded the manual and shows it does call for a D8ES. I am currently running a D8EA plug. Combined with overfilling the oil, could this make my bike smoke? Please tell me yes.

In my opinion, neither the oil level nor the plug choice will cause a 750 to smoke. The engine does not "know" how much oil is in the tank. One quart or 3, all it cares about is that there is enough oil in the tank to feed the draw from the oil pump. One quart in the tank is enough. No contribution to smoking.

The plug is definitely a non-starter.

A smoking engine comes from a few things. Condensation will come from a cold engine start, producesa white smoke water vapor and goes away after warmup.

A blue smoke from the tail pipes is oil from either piston rings or valve stem seals. Put some SeaFoam in it and run it till you're ready for engine work.

Blue smoke in general (seen in the headlight at night for example) is oil from the breathers. Base cause is once again rings or stem seals.

OCICBW but i don't think so.

I figured that but was just praying that I didn't have to lug that heavy motor in and out again. I guess its time to pull it apart again.

[MCRider]

Hope springs eternal.

Why did you pull it before?