[black&chrome]

hi all;

well, I am about to pull the head and thought i should ask a few questions first.

I have a 76 bonnie, with the four ball plunger pump which i had hoped would sort out wet sumping issues.

it's been resleeved and had the top end done within the last 7000 miles i would guess, but can't find out where i wrote down the milage at the time.

i pulled the sump drain after it sat for the last 5 months of our long Canadian winter, and about 3/4 of a cup of oil came out - which seemed reasonable to me after such a lengthy hold up. it always seems to wet sump a small amount when parked for more than a few days, smokes on the left side when starting, then clears, and starts smoking again once it has really heated up.

i have new bronze guides ready, if needed, but wanted to consider also putting seals on them - despite seeming like i will have to lathe them slightly thinner on top and put in retaining grooves.

also threw a compression guage on one side today and only got 50psi! i had already drained the sump and any oil would have leaked past the rings while it was sitting - but this seems extrordinarily low right?

i pulled the oil pressure release valve domed nut for cleaning, and it seems to work smoothly... at least unless the plunger is supposed to stop on it's way out. seems to have a very slight lip preventing from coming out all the way without pulling the body and letting it out in the direction it usually would go into the engine. this is okay right? it has also never seemed to more than mist oil out of the breather or fill the primary at a noticably fast rate

thanks for any advice and all replies

 

[black&chrome]

update!

well, after stripping the top end i found the valve guides are leaking around where they push into the head, a gouge up the side of the barrel, so both are likely contributing to the problem!

also the valves have been kissing the edge of the piston cutaway pockets - this has me a bit freaked - did i float the valve by accident? could the new mushroom ended valve adjusters cause this?

why, lord why?

a previous owner may have put in a high lift cam, so i will be investigating this too

let me know any thoughts

 

[Rathlindri]

I have a '78 TR7RV with similar symptoms....smokes especially on left hand side if left on sidestand....I haven't had the head off yet but suspect a worn valve guide on that side. I'll be watching this thread carefully to see what's recommended for you. Good luck!

 

[Caulky]

Now you`ve got me thinking...I put the mushroom headed adjusters in mine, an improvement I thought. But now I have exhaust valve problems...I wonder???
The trouble is, its impossible now to completely unscrew the adjusters...because of the mushroom heads. And the threads are very tight.

If you run the bike on the side stand, the left carb will tend to flood and be rich, the right carb lean.
Maybe a block of wood under it would help.

 

[pookybear]

BandC,

well it seems that you have the perfect storm going on over there.
Most of the time, smoking on the sidestand is just worn guides
or valve stems. Adding seals is a great idea as well. As for a
gouged bore just depends on how deep it is. Maybe a light hone
will clean it up. As for the valves kissing the pistons, you guys
got some secert club going on or what?

Oh and since you know how to fix the first two, leave them for
last, and start with the valve kissing the pistons.

Pookybear

 

[Caulky]

"As for the valves kissing the pistons, you guys
got some secert club going on or what?"
Yeah, wanna join?

Just phoned the man who did the work on my cylinder head. He`s not too keen on me fitting a thicker .080" head gasket, to cure the problem.
"This will affect the valve spring pressure and other things", he says.
"But take the head off and see what`s happenening".
If you can get the head to me, I can skim the seats in half an hour for nothing...(round of applause). Then you can fit the normal gasket.
Mmm, next?

 

[pookybear]

"As for the valves kissing the pistons, you guys
got some secert club going on or what?"
Yeah, wanna join?

Just phoned the man who did the work on my cylinder head. He`s not too keen on me fitting a thicker .080" head gasket, to cure the problem.
"This will affect the valve spring pressure and other things", he says.
"But take the head off and see what`s happenening".
If you can get the head to me, I can skim the seats in half an hour for nothing...(round of applause). Then you can fit the normal gasket.
Mmm, next?

No me no want to join!

As for skimming the seat, what? I have no idea of what he is
talking about. And if it is what I think, you do not want to go
there anyway.

Pookybear