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motor meltdown

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mikeyboy1

motor meltdown

on her maiden voyage after only 35 mi. here's what my 78 750 did.cruising along at 60,sudennly-nothing!! had to get towed home.the camshaft just snapped.clearly it got real hot in the journals.for some reason it stopped getting oil to one side.the tappets looked like they roasted.this happened on my 82 nitehawk 650 but I caught it in time. so.... anyone got a camshaft for a 78 750K ? also need the journals/tappet holders-whatever they're called

9see pics

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shinyribs

Re: motor meltdown

Administrator

Plugged oil passages in the head/cam towers? Pretty common on these bikes sometimes. especially if there is any silicone present anywhere.

I may have a set of cam holders. I'll have to check.

mikeyboy1

Re: motor meltdown

they were clean when I put it together.thanx shiny

mikeyboy1

Re: motor meltdown

In reply to this post by shinyribs

I used Permatex on the gaskets & maybe I should'nt have.I found a lot of dried chunks of it in the oil pan.I assume this is what caused a blockage in the oil passages in the tower ,although I didnt find anything in there.something had to have plugged those tiny oil ports,which I am going to drill out to 1/16th.what gasket cement to use ? I've had valve covers leak if I dont use glue.any ideas ?

rich

Re: motor meltdown

Would drilling out passages have a negative effect on your overall oil pressure?

89 VN 750A - Given to son-in-law
79 CB 750K-sold 3 May 21
78 CB 750K
77 CB 750K
77 GL 1000 x 2
77 CB 550F
Holton, KS, US

TOOLS1

Re: motor meltdown

Administrator

In reply to this post by mikeyboy1

DO NOT DRILL OUT THOSE OIL PASSAGES!!!!!!! They are sized to meter the oil to the top end!!!! As for a gasket sealer, I hardly ever use it. Sometimes I will use weatherstrip adhesive on one side of a gasket, but that is it. However where the case halves meet, I use Hondabond.
TOOLS

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I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)

shinyribs

Re: motor meltdown

Administrator

Hondabond works safely. So does Indianhead gasket shellac. Neither will find it's way in to the oiling system.

Silicone is FAMOUS for plugging up those tiny oiling ports and killing the top ends.

No silicone guys and girls. Ever.

shinyribs

Re: motor meltdown

Administrator

In reply to this post by TOOLS1

TOOLS1 wrote

DO NOT DRILL OUT THOSE OIL PASSAGES!!!!!!!

This cannot be stressed enough. Not even an option.

These engines are very well machined at the gasket surfaces. I always install my gaskets dry and I've never had even a hint of a leak.

They're not like my old Chevrolet's I love. They seal just fine with dry gaskets.