Topic: Anyone ever try tying the cyl down to hold base gasket in place?

[alacrity]

Re-doing my top end with a fresh head gasket and o-rings because I have had an annoying leak from the right side o-ring on my cb550k.  There are only a few thousand miles on it, so I am thinking that maybe if I run some twine through the airvents in the cylinder and down around the engine and pull tight, maybe it would make it less likely that it (which has been perfectly oil tight) would be disturbed when I release the nuts and pull the head.

Anyone ever try this? This will save time and cut risk... The bike has made good power with really even compression on all four from the full top end I did and I am loathe to disturb anything with the piston/ring/cyl interface. Plus I don't have compressors - and it's a pain to do it by squeezing the rings with my fingers (which is how i did it before).

Most likely, since it's a fresh engine, and there is no goop on the head gasket to lock it down, the block wont be disturbed anyway, but I thought tying it in place couldn't hurt.?  maybe?

[seanbarney41]

can't really see how that would really help...is the base gasket leaking now?  If not, don't worry about it or disturb it.

[alacrity]

No it's not leaking at all -- that was my point. I don't wanna disturb it at all, and so I was staring at the engine trying to imagine how gentle I could be removing the head and replacing the gasket and o-rings ... and this (perhaps idiotic) idea occurred to me.  maybe just some safety wire past the side fins and wrapped straight down and around under...

[Dino]

I see no reason why that wouldn't work. You're right. It would leave the base gasket undisturbed.

[mystic_1]

I'm not sure about the 550, but on the 750 there are some bosses on the cooling fins that can be used as pry points to (gently) crack the seal between the head and cylinders, that make it pretty easy to get the head off without disturbing the base gasket.  So, tying the cylinders down certainly wouldnt' hurt, but may also be unnecessary.

mystic_1

[alacrity]

those pry points (also present on 500/550) are very helpful when disassembling very old, stuck engines.  As I said this is all a very fresh "sandwich."

I am gonna give it a try.... a few minutes of wiring to save time and perhaps a bigger f'up is worth it.

[mystic_1]

Yup, I hear you.  I had to pop the lid on my 750 after only 100 miles or so and I had the same concern about disturbing the base gasket.  I decided to just have a go at it to see how hard it would be so I gave it a gentle lift using wood levers on the bosses, and it popped right up easy as pie.  No problems and no leak in the base gasket after reassembly.

That said, I'm all about preparing for contingencies and 28.3 grams of prevention are worth 453.6 grams of cure, as they say. 

You might consider using, say, insulated solid copper house-grade wiring to secure the cylinders, rather than a twine.  Twine or cord may stretch and allow the cylinders to move enough to disturb the gasket. 

Good luck!

mystic_1

[PeWe]

I have lifted my CB750 head without disturbing the base gasket at least twice. The head had not be sitting very long either.  2 years vs 8 months.
I remember an old std head gasket with a kind of glue on each side. PITA to remove from cyl and head. This must have disturbed cyl with base gasket a lot.  I teared evrything apart that time

EDIT: If dusturbing without cracking the base gasket. It must work if tighten the cyl studs a little bit harder 2:nd time, right? like + 0.5 ft lbs

[alacrity]

thanks guys.. .yeah some nice 18ga wire ought to be a good idea - better than using SS safety wire as it wont scratch anything.

thanks