Then there is plan D,Will and I drive down,pull the engine and fix it.Did the same without the drive,out and back in a day,I think that was engine out Number 4 or 5,lost count.maybe we should stop using engine mount bolts and go to cable ties,speed it up a bit.Our leak was down the cam chain tunnel and out at the bottom of the barrel,its character building I kept saying at the time.Thank the bike gods all sorted now.
Cylinder head oil leak
- Thread starter Dellortoman
- Start date
Tetley Laverda
Senior member
In my first few days of ownership I had to replace several studs and in all ignorance I did it with the engine in the frame . For what it takes and the hassle it saves you I would definately remove the engine to remove the head every time !
Good Luck
Kind Regards
Tetley
Good Luck
Kind Regards
Tetley
Dellortoman
Hero member
- Location
- Tasmania, Australia
Well, it's been officially confirmed (again) that I'm an idiot.
I had my torque wrench on the wrong setting. I had set it on 25Nm rather than 35. Once I'd set it to 35, all the head stud nuts went down another 1/4 to 1/2 turn. The little nuts on the outer ends of the head and front/rear of the cam chain tunnel were barely finger tight. Took a good half turn on them. Hopefully that means the head gasket had settled and the slack has now been taken up. We'll see on tomorrow's ride if it still leaks.
I don't remember the pitch on those threads. If it's the usual 1mm then the gasket has squished somewhere between 0.25 to 0.5 mm. Although I have a feeling it might be a finer thread pitch.
Cheers,
Cam
I had my torque wrench on the wrong setting. I had set it on 25Nm rather than 35. Once I'd set it to 35, all the head stud nuts went down another 1/4 to 1/2 turn. The little nuts on the outer ends of the head and front/rear of the cam chain tunnel were barely finger tight. Took a good half turn on them. Hopefully that means the head gasket had settled and the slack has now been taken up. We'll see on tomorrow's ride if it still leaks.
I don't remember the pitch on those threads. If it's the usual 1mm then the gasket has squished somewhere between 0.25 to 0.5 mm. Although I have a feeling it might be a finer thread pitch.
Cheers,
Cam
breganzane
Hero member
- Location
- NSW Australia
Cam,
Glad you found such a simple possible solution.
The pitch is 1.25. A significant proportion of the 'turns' after everything is otherwise seated down is stud stretch, that's why in theory the longer M9's should be done to a slightly higher torque than the short M9's, because you want the same % elongation in each stud so they exert an even seating pressure. So anyhow, much of your extra half a turn would have been the studs stretching rather than the gasket compressing, but a higher pressure on the gasket will certainly result, one way or tother.
Cheers
Steve B
Glad you found such a simple possible solution.
The pitch is 1.25. A significant proportion of the 'turns' after everything is otherwise seated down is stud stretch, that's why in theory the longer M9's should be done to a slightly higher torque than the short M9's, because you want the same % elongation in each stud so they exert an even seating pressure. So anyhow, much of your extra half a turn would have been the studs stretching rather than the gasket compressing, but a higher pressure on the gasket will certainly result, one way or tother.
Cheers
Steve B
Dellortoman
Hero member
- Location
- Tasmania, Australia
G'day Steve
Yep, I'm aware that the stress/strain in the studs. My (possibly incorrect) logic is that I did the studs up to 35Nm when I installed the gasket. It slacked off and has now been re-tightened back to 35Nm, so the elongation of the studs should be exactly the same as it was before. That means all the extra tightening is doing is taking up the distance the gasket has compressed.
It would have been interesting to measure the gap between the head and barrels before and after, but I didn't think of it.
According to Isaac Newton, the bike will actually weigh more now because the head is a few thou' closer to the centre of the earth. I wonder if Tim will notice it in the handling
Cheers,
Cam
Yep, I'm aware that the stress/strain in the studs. My (possibly incorrect) logic is that I did the studs up to 35Nm when I installed the gasket. It slacked off and has now been re-tightened back to 35Nm, so the elongation of the studs should be exactly the same as it was before. That means all the extra tightening is doing is taking up the distance the gasket has compressed.
It would have been interesting to measure the gap between the head and barrels before and after, but I didn't think of it.
According to Isaac Newton, the bike will actually weigh more now because the head is a few thou' closer to the centre of the earth. I wonder if Tim will notice it in the handling
Cheers,
Cam
If you saw that program on Newton on Discovery last night,I know he was a product of his time but wow,what a nut job.I wounder what he might have done if he hadn't spent so much time trying to decipher the hidden codes in the Bible and experamenting to find the Philosophers Stone,base metal into gold and all that nice in modern terms conspiracy gear.
Dellortoman said:According to Isaac Newton, the bike will actually weigh more now because the head is a few thou' closer to the centre of the earth. I wonder if Tim will notice it in the handling
Cheers,
Cam
lol, build it tall enough and it'll weigh less than zero.
Yr new lowered special there will also age a bit slower. win.
andrew112_uk
Senior member
Noooo don't make it tall, you will suffer from tidal effect. The gravitational pull will be less at the top than the bottom and will tend to stretch it. And as the head will be higher than the barrels, you may get an oil leak.... Be back where you started ???
Dellortoman
Hero member
- Location
- Tasmania, Australia
You guys have trumped my Newton with an Einstein.
I'll see your Einstein and raise you a Hawking. But I'm not showing my hand yet - I could be bluffing...
Cheers,
Cam
laverdakeith
Hero member
Carefull chaps, he may well be packing a Freeman Dyson..
Keith
Keith
oh good choice Keith, as much for his views on error in design, as for the planetary-scale engineering ideas.
for this hand though, the card I lay is Robert Forward
Aside: did you hear see the sub-metre measurement this year? abstract here. Not happy with namby pamby demonstations of special relativity's Buck Rodgers style relativistic time dilation, they also demonstrate proper gravitational well time dilation on a scale measurable between yr head and yr feet. Belief not reqd.
for this hand though, the card I lay is Robert Forward
Aside: did you hear see the sub-metre measurement this year? abstract here. Not happy with namby pamby demonstations of special relativity's Buck Rodgers style relativistic time dilation, they also demonstrate proper gravitational well time dilation on a scale measurable between yr head and yr feet. Belief not reqd.