Topic: F2 head with K Cylinders, leaking oil all around the head.

[Mandic]

Just took out my 77 F2 for the first test ride.  Put 7 miles on it and it is leaking oil pretty badly.  When I first really railed on it I felt it hit and burn my leg a little.  Thought it was the cheap Ebay gauge I have on there, but that seems fine.  Looks like oil is leaking ALL the way around the cylinder head.  I mean it could be leaking at a few spots and just running along, but the entire head all the way around seems at least damp with oil.  That is the highest spot I can find it that doesn't seem have blown up a little.

Oil pressure seems a slight bit on the high side, I know I saw 70-80 psi when I was at around 4-5000 rpm and wasn't looking(dark and fast) at higher RPMs.  The thing is a mess with oil now. 

Everything I read and what Ken at Cycle-X said it shouldn't be an issue, but I am running a F2 head on top of K cylinders with an F2 836 kit.  I put all 8 knock pins back in and rubber seals, even though the F2 only needs the inner 4, I figured why not put them all in, I had them laying around anyway.  I did put "High Tack" on both sides of the gasket surface.  I'm guessing this may be where I went wrong.  Though I don't see how since I know I saw notes a few places about using similar sealants on gasket surfaces. 

Any input on this?  Seems like maybe a combo of the sealer I used and a bit too high of oil pressure is just pushing it out wherever it can.  But does that mean I am not draining oil from the head properly?  I popped off a tappet cover as soon as I got home expecting the head to be filled, and it simply wasn't. 

[Mandic]

Peaking through the tappet covers again it looks like I put the Capped nuts and copper washers on the wrong studs.  I put them on the inner two and not the outer two as I should have.  Would this really cause a big oil leak?  I don't see how that could be, but then I just don't know enough about this design I think.

[Mandic]

Another semi-important piece of information. The head was decked by a machine shop when the valves/springs/guides were replaced. Also I installed HD cylinder studs that were then burnished and step torqued to 22 ft-lbs.(11 all around then 22 all around).

[scondon]

Peaking through the tappet covers again it looks like I put the Capped nuts and copper washers on the wrong studs.  I put them on the inner two and not the outer two as I should have.  Would this really cause a big oil leak?  I don't see how that could be, but then I just don't know enough about this design I think.

I believe that the K cylinder block negates any worry about which studs get the copper washers. Both inner and outer lead to internal oil drainage in The K block.

"oil everywhere" is a hard thing to diagnose. As your posts show there are just too many possibilities, some minor, others major.

 Best to clean everything off real good, and get it running on the center stand to see where it's coming from exactly. It doesn't sound to me that anything you describe in your posts would cause such a leak.

[Mandic]

Agreed. Brake clean and some cleanup is in order. Need to calm down from being angry before I post.

[scondon]

Agreed. Brake clean and some cleanup is in order. Need to calm down from being angry before I post.

Ya done good, Mandic. Always err on the side of LOTS of info

There are many points on these engines that could leak. Fingers crossed that yours is of the forgotten tappet cover o-ring variety. But we would just be guessing right along with you until the exit point is determined.

In the worst case that the motor has to come back out, just remember that it usually goes together twice as fast the second time around. Sounds like you got a nice engine there, so "deep breaths" and take your time. It'll be worth it.

[Mandic]

I think at this point I will cut the frame and repair it afterward if the head has to come off, haha.  That was the biggest bear of this whole thing was fitting the engine back in the frame. 

Most likely leak spots as I can think of them are either hte rubber pucks under the cam holders, or the headgasket itself.  Either way I'm not looking forward to it.

[Mandic]

Well with the bike somewhat cool I just cleaned it down, propped the kickstand up(no center stand) and fired it up.  No visible oil leaks.  But at around 1,500 RPMs the oil pressure gauge is reading 65 psi.  I cranked it up to 3,000 rpms and it hit 80 psi.  I am thinking that the oil pressure bypass is stuck and letting this thing just push tons of oil pressure.  Anyone concur with that thought?  I mean it is fairly cool at the moment with SAE-30 oil in it.  So I don't expect super low numbers. 

I will let it warm up and really rev it up tomorrow.  10pm I don't want the new neighbors hating me already, ha.  One came over today to introduce himself cause he is into vintage bikes and offered the use of his shop complete with plasma cutter, tig/mig welders, and drill press.  So pissing people off is not in my best interest, ha.

[Terry in Australia]

Er, just so you know, you can't actually use a K cylinder block with an F2 head. Or it'll leak oil and burn your leg. Cheers, Terry.

[Silverback]

I put all 8 knock pins back in and rubber seals, even though the F2 only needs the inner 4, I figured why not put them all in, I had them laying around anyway. 

Not all K cylinders are not made to accommodate these knock pins and seals. Did you machine the cylinders to use these? If not, your head might not have sealed against the cylinders because of interference with these. Surprised Ken did not tell you to just leave these out.
Terry, why cant you use the K cylinders? I think you might have it reversed. No F0/F1 or K heads on the F2/3 cylinders without machining the oil passage openings on the bottom.

Edit: Modified post to F0/F1 not F1/F2

[Mandic]

All 8 knock pins and seals dropped right in like nothing. I didn't even have to tap them with a hammer they just slid right into place.

The information regarding what combinations work with the F2/3 parts and K parts is very confusing. Don't know if I am alone in that but it sure seems to be the case. If you read the stuff in the FAQ section it sounds like a politicians double speak.

[Silverback]

I don't think width is the issue. As long as they seated in deep enough, I think your OK.

[MCRider]

Well with the bike somewhat cool I just cleaned it down, propped the kickstand up(no center stand) and fired it up.  No visible oil leaks.  But at around 1,500 RPMs the oil pressure gauge is reading 65 psi.  I cranked it up to 3,000 rpms and it hit 80 psi.  I am thinking that the oil pressure bypass is stuck and letting this thing just push tons of oil pressure.  Anyone concur with that thought?  I mean it is fairly cool at the moment with SAE-30 oil in it.  So I don't expect super low numbers. 

I will let it warm up and really rev it up tomorrow.  10pm I don't want the new neighbors hating me already, ha.  One came over today to introduce himself cause he is into vintage bikes and offered the use of his shop complete with plasma cutter, tig/mig welders, and drill press.  So pissing people off is not in my best interest, ha.

The worst oil leaks I ever had came because I had stripped the 4 front mounting posts for the cam towers. My repairs, helicoils, 1/4-28 screws were never up to it and those holes are open to the atmosphere at about mid-fin on the head, drips down all over everything. Not pressure related at that point.

As to the pressure, I think its more likely your gauge is bad than the oil pump. Based on experience. The head gasket/head area leaks are mostly from wicking in unsealed return areas and not from pressure. Its a "vein" leak, not an "artery".

OCICBW but i don't think so.

[Mandic]

I don't think width is the issue. As long as they seated in deep enough, I think your OK.

They seemed to seat pretty well flush with the block surface as well. 

Talking to my Dad he just made a mildly valid point.  This motor is brand new.  New bore, new pistons, and new rings.  There is a chance that with the rings not being fully seated they pushed compression into the crankcase and spiked crankcase pressures.  I'm going to try cleaning off the bike, warming it up, rev it a bit in the garage and if I can't find an obvious leak, just take it out for a leisurely ride and try to get some miles on it. 

I couldn't find a torque spec I was happy with for the cam tower bolts.  I torqued them to about 8 or 9 ft-lbs since the book called for 6.8-9.4 ft-lbs.  I really dislike the lack of a good torque chart for these motors.  But that is just how things were back in the days of inaccurate torque wrenchs(beams style and such).

[TwoTired]

There is a chance that with the rings not being fully seated they pushed compression into the crankcase and spiked crankcase pressures. 

The crankcase is vented to atmosphere (or more properly the air induction) up near the valve cover.  Did you seal that?  I think that's the only way to "spike the crankcase pressure.

Cheers,

[Mandic]

It has an aftermarket filter on it.  Just some cheapy "APC" or whatever brand filter.  I mean, if a full cylinder worth of compression is pushing into the crankcase, or multiple cylinders partial compression the crankcase vent likely will not be able to deal with that.  Though I'd expect to see more pushed out through there too.  It is slightly odd color from the K&N filter red it was.  So something has pushed up there a bit. 

[Mandic]

I'm still slightly tempted to construct a PCV system for this thing.  It would certainly help sealing everything up.  Surprised no one markets one.  Especially with a 4-1 exhaust like mine has.

[scondon]

Er, just so you know, you can't actually use a K cylinder block with an F2 head. Or it'll leak oil and burn your leg. Cheers, Terry.

Bugger all to hell, the Aussie is right  

In the K models, and F0/F1 bikes, all 8 (inner and outer) oil returns are utilized. On the F2 model the inner four returns are not used(the ones capped with copper washers). These are plugged at top with the copper washers, and at the bottom of cylinder block(different casting of F2 cylinder block, and rubber seal).

If you look with a flashlight through the fins of your F2 head(just outside the 2-3 exhaust ports) you will see your heavy duty cylinder studs peeking out. These returns are venting to atmosphere, and oil is backing up the bottom of your K block and pouring out of them. Crap!

"Everything I read and what Ken at Cycle-X said it shouldn't be an issue, but I am running a F2 head on top of K cylinders with an F2 836 kit."   If Ken Sold the pistons and block as a kit for you then hopefully he can help with the fix.

[Mandic]

Idling and revving right now I've got no oil leaking.  I see the tops of the short studs in between the 2/3 ports but nothing else.  And they look fine.  I am going to take it for a leisurely ride in a minute and see if it pukes again. 

[MCRider]

I don't think width is the issue. As long as they seated in deep enough, I think your OK.

They seemed to seat pretty well flush with the block surface as well. 

Talking to my Dad he just made a mildly valid point.  This motor is brand new.  New bore, new pistons, and new rings.  There is a chance that with the rings not being fully seated they pushed compression into the crankcase and spiked crankcase pressures.  I'm going to try cleaning off the bike, warming it up, rev it a bit in the garage and if I can't find an obvious leak, just take it out for a leisurely ride and try to get some miles on it. 

I couldn't find a torque spec I was happy with for the cam tower bolts.  I torqued them to about 8 or 9 ft-lbs since the book called for 6.8-9.4 ft-lbs.  I really dislike the lack of a good torque chart for these motors.  But that is just how things were back in the days of inaccurate torque wrenchs(beams style and such).

wITH a 360degree crank you have the same pressure whether the rings are seated or not, seems to me. Same amount of volume is opening up with 2 pistons rising as is being compressed with 2 pistons falling. Seems to me. Basically.

[MCRider]

Idling and revving right now I've got no oil leaking.  I see the tops of the short studs in between the 2/3 ports but nothing else.  And they look fine.  I am going to take it for a leisurely ride in a minute and see if it pukes again. 

Lets hope not.  Oil leaks are frustrating and rarely fix themselves. But stranger things have happened.   

[Silverback]

If you look with a flashlight through the fins of your F2 head(just outside the 2-3 exhaust ports) you will see your heavy duty cylinder studs peeking out. These returns are venting to atmosphere, and oil is backing up the bottom of your K block and pouring out of them. Crap!

Interesting! I have never read this info before and should be added to the FAQ. This is a major issue in compatibility. I have a set of F2 jugs ready for boring if you need to go that way. Maybe we can do an exchange, although I don't have the pistons for that bore.

[TwoTired]

wITH a 360degree crank you have the same pressure whether the rings are seated or not, seems to me. Same amount of volume is opening up with 2 pistons rising as is being compressed with 2 pistons falling. Seems to me. Basically.

Agree, IF there is no combustion blow by the piston rings.  (You probably mean rod journals at 180 degree crank positions, too.)

Cheers,

[Terry in Australia]

Er, just so you know, you can't actually use a K cylinder block with an F2 head. Or it'll leak oil and burn your leg. Cheers, Terry.

Bugger all to hell, the Aussie is right  

In the K models, and F0/F1 bikes, all 8 (inner and outer) oil returns are utilized. On the F2 model the inner four returns are not used(the ones capped with copper washers). These are plugged at top with the copper washers, and at the bottom of cylinder block(different casting of F2 cylinder block, and rubber seal).

If you look with a flashlight through the fins of your F2 head(just outside the 2-3 exhaust ports) you will see your heavy duty cylinder studs peeking out. These returns are venting to atmosphere, and oil is backing up the bottom of your K block and pouring out of them. Crap!

"Everything I read and what Ken at Cycle-X said it shouldn't be an issue, but I am running a F2 head on top of K cylinders with an F2 836 kit."   If Ken Sold the pistons and block as a kit for you then hopefully he can help with the fix.

Thanks Sean, as you'll recall, it was our crazy English mate Karl (KaceyF2) who told me back in 2005 that the F2 head is not compatable with a K cylinder block, but of course as you'd expect I "poo-poo'd" him, and used a K6 block on my F2 engine with an F2 head. I fired it up, went for a 50 mile ride, and my legs started stinging. looking down, I could see a fine spray of nice hot oil misting over my jean legs and burning my shins. By the time I got home I had a light mist of oil fogging over the rear of the engine, the sidecovers, swingarm, and rear wheel.

The bike had only lost a tiny amount of oil, but that experience was enough to make me pull the engine and install a K6 head that Hondaman sent me, and of course, as soon as I installed it, there were no more oil leaks. I'm seriously thinking about using an F2 head on my 1060cc engine with an RC cylinder block I've got here, I'm just hoping the two are compatable. Cheers, Terry.

[Mandic]

Can you tell me WHERE the leak was?  I know it was mentioned that the studs would be visible through the cylinder head vents between 2/3 but I am not seeing that.  Also it seems bone dry through there.  The main leak seems to be most of the way around the head.

Just got off the phone with Ken at Cycle-X and he still insists there is no issue using an F2 head on K cylinders.  I don't see why to disagree.  The only thing folks are noting is that the studs in between 2/3 are exposed to the atmosphere, but I am not see that nor am I seeing oil leaking from there.  In fact I capped those studs (incorrectly) with the cap nuts and copper washers.  So in reality shouldn't they be as seal as they will get then? 

I think I have to pull the head to investigate this.  However greatly I do not wish to do that.  Ken mentioned those dowels holding up the head same as one or two of you did.  He said that is rare, but the dowels are brand new from Honda, so if they were ever going to be too long or stick up too much, now would be when. 

So heavily against this but not really having much of a choice.