Topic: Is Oil Consumption Typical of K1 Head?

[PeWe]

Only 17 ft lbs and MLS. It must leak lil into the cylinders.
When I tightened the torque suddenly felt lighter just before 21ft lbs.

This when gasket crush and seal.
22 as Mike wrote.

[HondaMan]

Well, I'm not going to say its impossible something else is going on but I have seen oily residue in one of the old headers before I put my 4 into 1 on.

The ignition timing is advanced and there is ALWAYS white steam/smoke coming from the top cover breather.  Also the engine is consuming oil (about a quart in 800 miles).  Plugs are not oily so I assume this is happening at the exhaust based on the evidence I've seen.

Over-advanced ignition timing can cause the 750 to pull oil up the exhaust guides. If you're in the mood, try retarding the timing to be at the minimum full-advance site at 3000+ RPM. A spark advancer with weak springs, which returns the timing to normal too slowly, can also make them smoke when descending from freeway speeds.

[scottly]

Over-advanced ignition timing can cause the 750 to pull oil up the exhaust guides.

I've never heard of that before?? How can the timing cause oil to be "pulled up the exhaust guides"??

[HondaMan]

Over-advanced ignition timing can cause the 750 to pull oil up the exhaust guides.

I've never heard of that before?? How can the timing cause oil to be "pulled up the exhaust guides"??

It usually shows up after a long stint at high RPM, like freeway speeds (this showed up BEFORE the 55 MPH speed limits came about) when the owner was using poor (1970s era) gasolines. The oil rings (the 1-piece type, which the K1 had before about 3/71) would become hotter on their top edges than on their bottom edges while running at high RPM on the edge of ping, then when the engine slowed down and the oil was more available on the bores, it would pump up past the 2nd ring and smoke, and crankcase pressures would spike for a little while. This pushed oil up the guides, sometimes on both sides of the engine, but mostly on the exhaust side, often weeping out the header. When it pushed up the intake side the breather would blow smoke on the next takeoff, from below the bike. This is why so many of the early engines with the 1-piece oil rings often have split breather hoses to the oil tank and the back of the engine is solidly caked with burned-on oil and grease.

This whole cycle came back again when American Honda re-wrote the Owner's Manuals to recommend 10w40 oil for "all temperatures" with the F0 bikes: the 3-piece oil rings then could act the same way, mostly on bikes used in the American West where we largely ignored the 55 MPH thing.

[Tracksnblades1]

Over-advanced ignition timing can cause the 750 to pull oil up the exhaust guides.

I've never heard of that before?? How can the timing cause oil to be "pulled up the exhaust guides"??

It usually shows up after a long stint at high RPM, like freeway speeds (this showed up BEFORE the 55 MPH speed limits came about) when the owner was using poor (1970s era) gasolines. The oil rings (the 1-piece type, which the K1 had before about 3/71) would become hotter on their top edges than on their bottom edges while running at high RPM on the edge of ping, then when the engine slowed down and the oil was more available on the bores, it would pump up past the 2nd ring and smoke, and crankcase pressures would spike for a little while. This pushed oil up the guides, sometimes on both sides of the engine, but mostly on the exhaust side, often weeping out the header. When it pushed up the intake side the breather would blow smoke on the next takeoff, from below the bike. This is why so many of the early engines with the 1-piece oil rings often have split breather hoses to the oil tank and the back of the engine is solidly caked with burned-on oil and grease.

This whole cycle came back again when American Honda re-wrote the Owner's Manuals to recommend 10w40 oil for "all temperatures" with the F0 bikes: the 3-piece oil rings then could act the same way, mostly on bikes used in the American West where we largely ignored the 55 MPH thing.

Now you see it, then it’s gone…😏

[scottly]

Over-advanced ignition timing can cause the 750 to pull oil up the exhaust guides.

I've never heard of that before?? How can the timing cause oil to be "pulled up the exhaust guides"??

It usually shows up after a long stint at high RPM, like freeway speeds (this showed up BEFORE the 55 MPH speed limits came about) when the owner was using poor (1970s era) gasolines. The oil rings (the 1-piece type, which the K1 had before about 3/71) would become hotter on their top edges than on their bottom edges while running at high RPM on the edge of ping, then when the engine slowed down and the oil was more available on the bores, it would pump up past the 2nd ring and smoke, and crankcase pressures would spike for a little while. This pushed oil up the guides, sometimes on both sides of the engine, but mostly on the exhaust side, often weeping out the header. When it pushed up the intake side the breather would blow smoke on the next takeoff, from below the bike. This is why so many of the early engines with the 1-piece oil rings often have split breather hoses to the oil tank and the back of the engine is solidly caked with burned-on oil and grease.

This whole cycle came back again when American Honda re-wrote the Owner's Manuals to recommend 10w40 oil for "all temperatures" with the F0 bikes: the 3-piece oil rings then could act the same way, mostly on bikes used in the American West where we largely ignored the 55 MPH thing.

I'm sorry Mark, I don't buy that explanation. In any case, the OP's problem is much more than valve guides alone.

[johno]

Ditto everyone, That baby is breathing bad, I aint ever seen guides do that even with the seals popped off 
Nice bike though ! looks like cool classic with a tidy up. Sorry man, Id be checking the rings, not the guides. What rings did you use a lot of folks on this forum have been down this path with skinny arsed rings.
Chin up, get into it and have a play.👍
ciao Johno

[HondaMan]

Well, like a lot of things with the 750...it happened, and it got fixed. The letter circulated from American Honda to Honda Motor CO Japan complained about the 'smoking on freeway offramps' circa winter 1971, as Honda was extremely sensitive about the image of the Four when it showed up everywhere. The dozens of mods to the 750 in such a short time are witness to these sensitivities on Honda's part, and their concern to make it better in everyone's eyes. Ask racers: they don't like 1-piece oil rings, either, because they lose oil at 9k RPM-like speeds. I don't think any bike engines are made that way, now?

[Tracksnblades1]

Came across a K1 head from Kurt here in San Diego, the head was ported and something I couldn't pass up for my build.  I noted that the exhaust valves were the tapered non-seal version like the early sandcast heads.

With everything back together and 600 miles on the new motor I'm still noticing some white smoke in the exhaust.  Today I swapped exhaust systems and took a look at the exhaust ports and head had a little bit of oil coming from the exhaust valves, nothing crazy but I'm not used to seeing it.

Are these early valve guides known to let a little oil pass through?

Finn, when you wrote “ head had a little bit of oil coming from the exhaust valves,” was this the classic oil running down the exhaust valve stems tell tale sign?

What pistons and ring packs did you use in your build?

[Finnigan]

The piston rings were NOS Yoshi from the box, 1 piece oil ring.

The oil I could see coming from the exhaust values was starting at the top and had a wet oil stain down to the exhaust opening.

I took compression readings from my old cb450 which is 155 and this bike is 135 across all 4.

[Tracksnblades1]

The piston rings were NOS Yoshi from the box, 1 piece oil ring.

The oil I could see coming from the exhaust values was starting at the top and had a wet oil stain down to the exhaust opening.

I took compression readings from my old cb450 which is 155 and this bike is 135 across all 4.

I’ve never had an issue with the old one piece oil rings. I’ve torn down as late as 75ks with one piece oil rings and it wasn’t from burning oil..The 75f and 76f &k had three piece oil rings.. But if you seen what you saw where you saw it then that’s the direction I’d head. A bore scope would show if the top edges of the piston are oil washed clean. But you’ll see that when you address the guides..

Maybe PEWE will weigh in on cast iron guides and standard size valve stems. He’s had some two fold problems with bronze guides and high lift cams. He puts miles (km) on his 76 so he’s a good barometer for what actually works, instead of a garage ornament success.  I think he’s moved in the cycle X cast iron guides and standard stem size direction and is making good clean power out of smaller displacement build..

[PeWe]

My K6 ported head has Honda stock guides, shortened, reshaped and sunk deeper to avoid the keeper groove to dip into the guide seal. (Megacycle 125-75 cam)
33.5/28.5 Kibblewhite valves.

The head it had before, also ported but 34/28 mm valves had bronze guides for a while with 5mm stemmed valves. Guides worn very much at the top. Probably due to the too flexible thin 5mm stems.

That head restored with CycleX iron guides, also reshaped by my local mechanic.
CycleX 34/28mm SS valves they have sold for a low price.

[Finnigan]

Finally getting around to more investigation, I removed the headers and took pictures of the exhaust ports and where it connects to the header.

All ports are oily, seems that most of the exhaust valve is dry and the wet areas can be seen up high and flowing down.  I'm not ruling out anything just an observation.

Header tell an interesting story where 3 and 4 have some wet areas but are MUCH dryer than 1 and 2, in fact #2 has more shiny wet areas down into the first bend.

Next is tracking down a bore scope to see inside the cylinders and take a look at the pistons.

dumb questions below:

is it possible the pressure inside the head is higher than is registering at the gauge on the crankcase?

can the engine be cranked or even run for a short amount of time without the headers to possibly observe where the oil is coming from ?

[MRieck]

Because those exhaust guides without seals suck. That is the truth....sick of explaining it.

[PeWe]

.... and the head gasket only torqued 17 lbs you can use again.

[scottly]

Once again, my K1 head with bronze valve guides and no seals on the exhaust doesn't smoke that bad...

[Finnigan]

fellas, I'm posting my progress - sharing for the comradery and potential for someone to look up later in the future.  I like bikes and like talking about bikes, if you feel you're wasting your time reading this pay me no mind.

Lately it feels like I'm being talked down to because I'm running into problems.  You're on a forum talking about the same 3 bikes for the last decade so whatever I did that pissed you off simply unsubscribe and save the snarky #$%* for someone else.

I know the seals suck, I know everyone else has had success and it was likely this or that.  Thanks for the advice, I'm following it.  Please keep in mind we are all doing out best and chasing the fun that is vintage motorcycles and please keep in mind that what I eat doesn't make you #$%*.

[scottly]

What cylinder do you have this K1 head on? With heavy duty studs, sometimes oil can't drain from on top of the head fast enough, flooding the valve stems with oil. Per, haven't you experienced this before?

[Finnigan]

Small update,

exhaust, tank, carbs and motor mounts removed.  I attempted to remove the head cover by dropping the engine down into the frame slightly and even tilting one end with a car jack but space is just too tight.  next is a small shop crane and stand.

[PeWe]

Yes, more or less.
It was one guy that got a smoker due to this. He saw high oil level inside tappet caps. When standing on side stand more to #1.
I think he widened the oil return holes in gasket. He started a thread about this.

I had done the same when gasket holes were tight. MLS is very hard to grind.
That was a gasket with only 8.5mm holes for return if I remember correctly. Grind a little and let it cool to avoid the viton to burn.

I was very suspicous about thick HD studs and small holes feeding the head with oil.
One head had only around 8.5mm stud holes feeding the oil. Only 0.25mm around stud for oil.

So  I drilled the 2 oil feed holes from gasket side with a 9.5 mm drill. Protected head with thick tape, the drill chuck can suddenly hit when going thru.

(Blew the holes to avoid burrs into oil orifices I had removed.
Early ones trickier. A friend told me how to wich I did eith my early heads. Wrote about it with photos on this forum.)

All other holes 9mm. 8 of them oil return
The first head due to nuts had dug deep into head. I had to hammer on the ex spigots to get head off, alu had married the HD studs. (Thanks to Franks frame kit, engine in frame.)

Left head at my local shop that milled all 16 holes parallel to gasket surface. Drill all holes a must.

The other heads got same hole massage.

Maybe not my K1 head yet. It will get new guides, valves and seals when the nearby shop mechanic less than 2 km away has operated his left hand, done the right earlier this year. Carpal tunnel syndrome.

He is 72 yo, no reason to stop restoring, modifying engines he has worked with since the 70's.

[Finnigan]

What cylinder do you have this K1 head on? With heavy duty studs, sometimes oil can't drain from on top of the head fast enough, flooding the valve stems with oil. Per, haven't you experienced this before?

its a k6 cylinder

[scottly]

Yes, more or less.
It was one guy that got a smoker due to this. He saw high oil level inside tappet caps. When standing on side stand more to #1.
I think he widened the oil return holes in gasket. He started a thread about this.

I think this is the thread:
http://forums.sohc4.net/index.php/topic,180178.msg2089063.html#msg2089063

[PeWe]

Yes, more or less.
It was one guy that got a smoker due to this. He saw high oil level inside tappet caps. When standing on side stand more to #1.
I think he widened the oil return holes in gasket. He started a thread about this.

I think this is the thread:
http://forums.sohc4.net/index.php/topic,180178.msg2089063.html#msg2089063

Yes, that thread.

[scottly]

This problem seems to be related to early heads with HD studs and/or MLS gaskets?

[willbird]

Because those exhaust guides without seals suck. That is the truth....sick of explaining it.

I remember reading a Hot Rod magazine and seeing that some pushrod V8 designer had come up with the "novel" idea of not running valve seals on the exhaust valves. It was a few years after I had my K2 apart and looked over the valve seats and guides so I remembered that Honda did that in 1972. I also had a friend who ran his own Harley shop and he would put bronze guides in his Sioux valve and seat grinder and grind a chamfer on the top end so oil would not pool there and then he could kinda get away with no valve seals on exhaust.

My LOL was that the pushrod V8 guys thought that they had found some bright and shiny new thing LOL.

Bill