Intuition or Workshop manual - which proceedure works best ?

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Hi Chaps and Chapette,
All the bits I 'need' have arrived from Staffordshire, the bits I 'want' will have to wait for another overtime shift. Looking at the manual it seems that replacing the head can be a bit of a 'fag' in respect of lining up the pushrods - I've had plenty of pactice on triples though. Seems to me that while I've got the rockers out it might be easier to fit the head first and then slot the rockers in place and then pop the spindles back in.
Any thoughts or experiences ?
TIA
Roy, Kent - UK
 
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Chapette here! :)

Seems like the main problem with doing it your way would be the possibility of having the spring washer and/or thrust washer slip out and drop down inside the engine. Might be a good idea to stuff some rags in there first as a precaution :!:

I've always done it the traditional manner, working the pushrods up inside the head and then holding them in place with my third hand. :roll:

Debby
 
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Listen to the lady.....remember the rods have to be one short, one long for each pair, and the longer goes to the intake, I think. Don't forget the head gasket!
Push the pairs into the head and loop a length of good string around each of the two pairs, and knot the string on the top of the head, so the pushrods stay in place even when the head is turned over and the rods point to the ground, then tilt the head towards the back of the bike and fit the rods into the holes in the barrels, and lower the head down, leaving space enough to cut the string, and pull it out from under the head. Rods will be almost in the right place, and just watch when lowering the rest of the way, that the tips of the rods are seated in the right place on both the cam followers, and the rockers....rocker ends can be tricky. Make SURE all is in the right place before installing the head bolts and starting to tighten. The bolts will bring the head down even if you were not very careful, and didn't see one of the rods had missed it's socket in the rocker, but then the rod will be shoved where it won't do so happy and you will be pulling the bolts out again....careful and methodical is the trick. All this is much easier the second time around, naturally, but, as Debbie has said...getting the rockers, washers and shafts into the head, when it is already mounted, is a passtime for the foolish and those with lots of time...one washer down the tube, and it's a mistake you will never repeat.... :wink:
 
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I think I used to use some rubber bands to hold the pushrods in the head while positioning the head onto the barrels. (been a long time!) Ran them out to the exhaust studs. You can push the 'rods around without them slipping out. Then you cut them while holding on so they don't go where they shouldn't.
BTW, I always used a copper filled gasket spray (Permatex brand) to coat the head gasket, preferably the solid copper one. You can reuse the solid ones by annealing them. Never had one leak, even with high compression motors. Put a couple of the nuts between the fins to hold the head off while you position the pushrods, rotating the rockers into the cups, then pull them out and drop the head down. Make sure you replace the hidden fasteners in the middle of the head!
 
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Thanks for the tips, I guess I'll stick to the 'approved' method (I'll also wait untill its done properly before opening up the industrial grade lager). I gave up on copper head gaskets ages ago after a few failures on Trumpet twins and Triples. I do put a thin smear of 'copperslip' grease on the fibre head gaskets and it's always worked well. I also 'found' the hidden head bolts during dissassembly - Ok I read the manual afterwards!
With good fortune and a following wind all should be up and running for Monday and a quick trip under 'La Manche' to Frogland before the Easter chaos.
Chiz
Roy
 
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Will be replacing my head soon if it ever comes back from the CHS. It's a good idea to put a smear of silicone around the pushrod openings on the head and barrel. Mine have never leaked here despite earlier fun with pulled studs etc. You'd have to be careful with the grease though.
use the centre bolt to pull the head down against the valves but be sure to have the pistons at TDC so there's not so much load on the fastener.
Once you have the pushrods located (before tightening that centre bolt) lift the valve ends of the rockers so they are loaded against the rods and won't pop out while the bolts get torqued up.
You might find that when you push the rods up into the head they jam against each other and self hold but be careful not to overdo it in case you shave off any metal against the head. Push the inlet rods up first and then the exhausts....that works for me. You might have to manipulate the exhaust rockers and rods while doing this. Good luck.
 
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Perhaps the reason I never had headgasket leaks was lapping the head before reinstalling it. If I had the cylinders off I would lap that also.
The purpose of lapping is to assure you have a flat, smooth sealing surface.
The simple way to lap parts: obtain a piece of plate glass about 10mm thick - the thicker the better- you don't want the surface to bend while in use-(kind of defeats the purpose) by about 300mm(12 inches) square. Place the glass on as flat and stiff a surface you can find. You may want to protect the bottom side with a sheet of paper or thin cloth.
If you can find a source of sandpaper sheets, you want to start with 400 to 600 grit. Self-sticking would be easiest, otherwise tape the edges down on the glass. Autobody shops would use the right sandpaper. (Sorry, can't recall the British term, panel beaters perhaps?)
Other method would be to use valve grinding compound directly on the glass.
Lapping technique: It may help to see the surface if you first coat the gasket area with machinist blue, or use a magic marker.
Slide the head (or other part) around in a figure 8 pattern, occasionally rotating the part for a different orientation. With a large part like a head, you will not need to apply any downforce.
The reason for the specified movements is to avoid developing a non-flat surface, ie: barrel, cylinder, wedge, bowl, or some combination shape.
Lap for 30 seconds or so, then wipe the surface and observe the results. This is to get an idea of how good (or bad!) the surface is. Repeat as needed, extending the time between examinations if it's not close. If it is not flat and smooth, decide if you need to switch to a courser grit for faster material removal, but you want to finish with a fine grit to give best sealing ability.
When you finish, make sure you thoroughly clean the surface, especially inside any holes that will collect the grit.
 
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