Topic: GOD#*&N OIL LEAK... does anyone have 650 cylinders on the shelf? Soos?

[paulages]

Thanks, bryan. The impregnation sealing will cost me $15-20 if I can get it into another batch, so this is clearly the way to go. It'll cost me more to ship it than to have the sealing done.   

[paulages]

well, i found my smoking gun. with the sleeves removed, oil stains are clearly visible in the sleeve bores exactly where the leak seems to be coming from. i ran the block through the dishwasher a few times, and the porosity became very visible when cleaned up. hopefully the impregnation sealing will be the cure.

[bwaller]

Yikes I hope so too for your sake.

Would it not be worth it while the sleeves are removed to also machine a new groove in the bottom of the bores for o-rings?

[paulages]

Yikes I hope so too for your sake.

Would it not be worth it while the sleeves are removed to also machine a new groove in the bottom of the bores for o-rings?

i think there's enough room for an o-ring of the right cross section. the sleeves have a taper already. maybe someone can tell me, as I can't remember and don't have an engine open: is there actually a lip machined for the o-ring, or does the o-ring just fit between the taper and the bore? i believe it's the latter, right?

[bwaller]

I don't have any 650's but the 500's & 750's have a notch machined in the block for the ring.

I should stay quiet now because I can't remember...you used 750 sleeves with a tapered bottom, maybe the 650 cylinder is taller? In a stock 750 the sleeve taper begins 10mm or so below the block surface.

[paulages]

I don't have any 650's but the 500's & 750's have a notch machined in the block for the ring.

I should stay quiet now because I can't remember...you used 750 sleeves with a tapered bottom, maybe the 650 cylinder is taller? In a stock 750 the sleeve taper begins 10mm or so below the block surface.

i had the sleeves machined down to the same exterior dimensions.

[bryanj]

The geriatric grey cells tell me they all have a counterbore in the alloy block that the "O" ring is a @stard to get into

[paulages]

i have some pictures of the smoking gun before i send it off to be sealed..





lots of holes! 

[bikebitzofvt]

Are those pics with the liners removed?  I read back a little farther and confirmed the answer myself
Seems to me some where around the late 70's Honda's aluminum casting quality went dramatically down hill...
While the sleeves are out would it make sense to add some o-rings to the base?

BTW  - that pic of the 400F is kinda cool in an artsy way...

Glad you found your culprit!

[Terry in Australia]

Geezus, if anyone ever says anything bad about my RC big block's crap casting, they should refer back to your pics Paul! Can the impregnation sealer handle the heat? Cheers, Terry.

[cb650]

Hel l  just have one made out of billet.   

[paulages]

Geezus, if anyone ever says anything bad about my RC big block's crap casting, they should refer back to your pics Paul! Can the impregnation sealer handle the heat? Cheers, Terry.

as far as i know, terry. they seemed quite familiar with this dilemma. it will be o-ringed as well, so hopefully it won't be an issue either way.

[paulages]

Ok, got the cylinder block back and painted and the liners installed. i shipped the part out last friday, and had it back at my shop wednesday. now that's quick turn around!

it had a powdery film on it, so i ran it through the parts washer. when it came out, the entire surface was darker than bare aluminum. you could tell that the sealer had really soaked into the aluminum, which porous to begin with even with a well cast surface. just waiting for cometic to get my gasket to me and it's back together!

[Frankenkit]

Good luck, Paul! Hope this solves all your problems!

[bwaller]

How is it applied Paul? Pretty cool, I hope it works for you too.

[paulages]

How is it applied Paul? Pretty cool, I hope it works for you too.

they put the part in a chamber, which is depressurized to a -26 PSI vacuum. the chamber is flooded with the sealant, which is sucked into every pore in the part, then the chamber is flushed with water and the part cured with 180F water. it is obvious from the surface how well the sealant is drawn into the metal. it adds zero thickness to the surface, but fills any open pores.

machining for an o-ring would cost me $100... i hope i'm not making a mistake by relying on this process and a sealer at the base, but i'm going to try. at least this way if it still leaks i know that the process didn't work.