Head Removal

marshg246 said:
Caveat! I just finished an 850 where the fins behind the nut interfered. I had to grind a little off and then it was fine. This is the first engine of many it didn't just slip right on. Also, not as important, but the body would not fit between the fins so it took more turning than usual.
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I purchased and used the AN wrench for the nut under and behind the head. It worked perfectly.
 
When I removed the head several of the washers that were on the various nuts and/or bolts that were holding the head on were split lock washers. The parts list shows the washers as being plain washers. Are there any issues, pro or con, with using split lock washers instead of plain washers when reinstalling the head? I’m specifically wondering how it might possibly effect torque values.
 
WEM said:
When I removed the head several of the washers that were on the various nuts and/or bolts that were holding the head on were split lock washers. The parts list shows the washers as being plain washers. Are there any issues, pro or con, with using split lock washers instead of plain washers when reinstalling the head? I’m specifically wondering how it might possibly effect torque values.
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They should be plain washers imo
And if you replace them it's best to use the original heavy duty type
 
WEM said:
When I removed the head several of the washers that were on the various nuts and/or bolts that were holding the head on were split lock washers. The parts list shows the washers as being plain washers. Are there any issues, pro or con, with using split lock washers instead of plain washers when reinstalling the head? I’m specifically wondering how it might possibly effect torque values.
Click to expand...
I agree with baz. Also, lock washers won't accomplish anything but gall the aluminum and nuts when undoing. To you torque question, the torque on the 3/8" bolts is plenty to overcome the lock washers so no issue with torque there. On the 5/16", possibly - not sure.
 
Something that I have found helpful, but is not in any of the manuals I've read.
When removing the head (in-frame) prise the gasket off the barrel and hold it up against the head. The 3 studs will help retain it "up".
This will make getting the lower end of the pushrods up and over the lip at the front of the barrel easier.
It's even more important to have the "gasket up" on reassembly, for ease of fitting but also to ensure the gasket doesn't get damaged.
Once again, the 3 studs will hold it up nicely.
Cheers
 
Spent some time today cleaning up the head bolts and studs. I may have an issue with Bolt #1, which is the bolt located at the front center of the head between the fins that threads into a blind threaded hole in the barrel. All the rest of the bolts, studs and nuts run cleanly all the way down. The blind hole into which Bolt #1 threads is approximately 25 mm deep and the threads on Bolt #1 are approximately 22 mm long but it will not go all the way in. It threads in about 15 mm then stops with about 7 mm of thread left above the surface of the barrel. I can’t get a good look into the threaded hole so I don’t know if it is threaded all the way down or not. The threads on the bolt appear to be fine. I’m not sure if this is an issue or not. I don’t know how much of the bolt needs to go into the threaded hole before the head is tight against the top of the barrels. Just wondering if this issue needs addressing or if it’s okay as is.
 
WEM said:
Spent some time today cleaning up the head bolts and studs. I may have an issue with Bolt #1, which is the bolt located at the front center of the head between the fins that threads into a blind threaded hole in the barrel. All the rest of the bolts, studs and nuts run cleanly all the way down. The blind hole into which Bolt #1 threads is approximately 25 mm deep and the threads on Bolt #1 are approximately 22 mm long but it will not go all the way in. It threads in about 15 mm then stops with about 7 mm of thread left above the surface of the barrel. I can’t get a good look into the threaded hole so I don’t know if it is threaded all the way down or not. The threads on the bolt appear to be fine. I’m not sure if this is an issue or not. I don’t know how much of the bolt needs to go into the threaded hole before the head is tight against the top of the barrels. Just wondering if this issue needs addressing or if it’s okay as is.
Click to expand...
Drop it in the head, with the washer, and measure how much sticks out.
 
WEM said:
Spent some time today cleaning up the head bolts and studs. I may have an issue with Bolt #1, which is the bolt located at the front center of the head between the fins that threads into a blind threaded hole in the barrel. All the rest of the bolts, studs and nuts run cleanly all the way down. The blind hole into which Bolt #1 threads is approximately 25 mm deep and the threads on Bolt #1 are approximately 22 mm long but it will not go all the way in. It threads in about 15 mm then stops with about 7 mm of thread left above the surface of the barrel. I can’t get a good look into the threaded hole so I don’t know if it is threaded all the way down or not. The threads on the bolt appear to be fine. I’m not sure if this is an issue or not. I don’t know how much of the bolt needs to go into the threaded hole before the head is tight against the top of the barrels. Just wondering if this issue needs addressing or if it’s okay as is.
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You haven't said but I presume the threads on the stud are in good condition. Maybe check with a nut?
You also haven't stated if the barrel is mounted on the lower engine assembly.
If not, I would lay the barrel on it's side and spray some brake cleaner (or similar) using a nozzle, into the hole to flush it out. Next test if the stud will go in.
Of not, I would say it's time to use a bottoming tap in that hole. Then flush it out and all should be good.

If the barrel is fitted to the engine the the abouve procedure could work but you'd have to be very careful not to get debris into the engine (pushrod holes, piston/bore gap, etc). Maybe lay the bike on its side too?
 
Just put a dab on grease on the end of the tap will collect most of the swaft from thread and a blow out with air.
 
marshg246 said:
Drop it in the head, with the washer, and measure how much sticks out.
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Unfortunately, the head is out for rebuilding but your idea is excellent and I’ll be sure to check when the head returns. But in the meantime, if someone has a head and bolt available, is curious and has some spare time to measure how much of the bolt sticks out of their head, it would be great to know if I‘m okay or have to pursue another option like tapping the threaded hole. My tap and die set is pretty standard. It has UNF and UNC taps only. What size tap would be required for the thread for Bolt #1? The bolt head takes a 1/4” Whitworth wrench.
 
WEM said:
Unfortunately, the head is out for rebuilding but your idea is excellent and I’ll be sure to check when the head returns. But in the meantime, if someone has a head and bolt available, is curious and has some spare time to measure how much of the bolt sticks out of their head, it would be great to know if I‘m okay or have to pursue another option like tapping the threaded hole. My tap and die set is pretty standard. It has UNF and UNC taps only. What size tap would be required for the thread for Bolt #1? The bolt head takes a 1/4” Whitworth wrench.
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You probably know this, but you have five similar bolts. The four outside head bolts and this one. The four are longer but the same threads. So, you can test the bolt in four other holes and you can test that hole with four other bolts. If you have a nylon or brass round brush a little bigger than the hole, you can put a little grease on it, shove it all the way into the hole and then "unscrew" it out of the hole. Usually, if there's grit in a hole, that will get it out.
 
Now for the next step...I usually fit the head with just the four outside bolts just snug, remove the primary cover to access the crankshaft nut, and CAREFULLY turn the motor over listening and feeling how the motor is turning. If there is the slightest stop to forward rotation STOP and find out why. It is not unheard of to have the pushrods not engaging correctly and the result is a broken valve guide and a bent valve...or two, if you decide to power it through. It requires very little pressure to bend a valve so err on the side of caution. If all goes well then install the rest of the head bolts and torque down.
 
ashman said:
Very easy to see if the push rods are sitting in position as well you can put it in 4th gear and slowly rotate the wheel to move the pistons slowly to make sure everything is in place before tensioning the head down.
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That works too but it's a clumsier method. Turning the crank nut allows for a better feel. It is really easy to make a mistake and bend a valve. I even turn the radio off when I do this.
 
If you're new to this, you look in exhaust ports and a flashlight helps - you can see both the intake and exhaust pushrod and rocker ends from there. Also, before starting, I fill each pushrod cup with grease. Then when the head is sitting about 1/4" from down, you can lift each rocker into its cup and the grease will hold it there. If one pushrod isn't aligned, it's easy to manipulate it with a thin screwdriver. Once you can see that all are in place you can tighten the head.

The workshop manual says to first bring the head down with the exhaust-side center bolt. I do that but I put the four outer head boles in finger tight to act as guides and to make sure the head gasket stays where it belongs while tightening the center bolt and don't go straight to the final torque on any of the bolts.

There is much more info on this here: https://www.gregmarsh.com/MC/Norton/NortonTorque.aspx
 
One thing that I do so that I can see if the if the pushrods are successfully registered into the tappet "buckets"...

On each pushrod I have rolled, with a blunt knife, 2 light grooves that align with the top of the barrel.
First groove is for compression stroke at TDC (both valves closed)
Second groove is for top of exhaust stroke at TDC (both valves open to some extent)
So one pot I should see both "first grooves" level with top-of-barrel, the other pot both the "second grooves"
Saves fiddling and jiggling pushrods that are already "in" but more importantly gives clear visual indication of any that are not "in" (i.e: could cause a bent valve).

NB: I "roll" rather than "scratch" the line to minimise creation of a stress raiser (although rods are only in compression)

Cheers

EDIT: the thread seems to have drifted from head removal to head refit. No harm done @WEM ?
 
Last edited:
robs ss said:
One thing that I do so that I can see if the if the pushrods are successfully registered into the tappet "buckets"...

On each pushrod I have rolled, with a blunt knife, 2 light grooves that align with the top of the barrel.
First groove is for compression stroke at TDC (both valves closed)
Second groove is for top of exhaust stroke at TDC (both valves open to some extent)
So one pot I should see both "first grooves" level with top-of-barrel, the other pot both the "second grooves"
Saves fiddling and jiggling pushrods that are already "in" but more importantly gives clear visual indication of any that are not "in" (i.e: could cause a bent valve).

NB: I "roll" rather than "scratch" the line to minimise creation of a stress raiser (although rods are only in compression)

Cheers

EDIT: the thread seems to have drifted from head removal to head refit. No harm done @WEM ?
Click to expand...
No harm at all. The information that has been provided on both removal and refit is excellent. Every head that is removed hopefully eventually gets refitted.
 
I always go the manual way with the first front bolt to pull the head down to position then as said by Marshg said use a fash light to see if the push rods are sitting in position usually one well be off and a small screw driver well easily put it in position, I have never done it with a bit of grease to hold in position as I have never had any problems with them getting out of position but a good idea anyway, once in position tighten the first bolt down as well putting the 4 big bolt screw down and checking the push rods as you go, do it by the book always work for me.
 
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