Separating Head from Barrels

sfcpiet said:
No need to remove the studs, a few (careful) deft whacks squarely from front and behind with a hide mallet will break the base seal and allow you to lift the barrel.  The base gasket will partially loosen from the case, partially from the barrel.  Once you can get at it, loosen it from the barrel so it won't catch on the top threads when lifting.

Won't find a position with 120 cams where there is no pressure on the camshaft.  Explains why the locating slots in the head and the spigots at the bearing base are so often buggered beyond recognition, Mr. Hamfist just pulls 'em down, regardless!  When loosening, do it bit by bit, relieving the cam evenly along its length.  Same on re-assembly.

piet
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I've got the barrels separate from the block, but as I pull them off, the studs seem to be binding and they won't let me pull the barrels the rest of the way off.  I'll keep at it.
 
Is the base gasket still stuck to the bottom of the barrels?
The threads on the studs can grip the holes in the gasket.
Usually a fight to get the new base gasket over these threads.
 
if some of the pistons skirts are showing out of the bottom of the barrels then they may be cocked over, straighten them and barrels will come off easy

 
Also please do check via this thread what torque settings you are going to use when refitting the cam blocks.

My blue cover RGS manual shows very incorrect settings making me strip a stud. Don't want this to happen to you.

I understand that bent cams are common. Why not get them checked by an expert who can also straighten them. Laverdakeith
did mine.

Andrew
 
OneThinBloke said:
I do hope that I am not the only one questioning why you are doing all this?

Was something not working before you took it apart?

James
Click to expand...

same here! 120 degree engine with the later type head needing a strip down?
High mileage engine?
 
Gerald said:
same here! 120 degree engine with the later type head needing a strip down?
High mileage engine?
Click to expand...

Well, they do wear out eventually... and there's no end of possible damage inflicted by the owner! :D

Cam straightening is no big deal, is part of my re-build routine.

piet
 
Mate while you have got it down this far open the cases and check the surface of the main gearbox shaft that runs on the needle races in the output shaft (5th gear) I have seen some where the hard surface has been damaged where the needle races run)
 
Gerald said:
same here! 120 degree engine with the later type head needing a strip down?
High mileage engine?
Click to expand...

No. the engine had only 5.000 Km or so, but it was standing for 15 years (at least) with no airbox and filter and as you might know, a 120? engine always has at least one valve open. this gives corrosion a lot of possibilities to "work" on the internals. also a sticky piston ring is not uncommon, even on low-millage engines. as you might know, if you fire up an engine with a sticky piston-ring, this can cause the ring to turn into several pieces that then cause huge damages on the liners which at the end causes a big, big repair with new pistons etc.

A gasket-set is 100? or so and the whole thing - going that far already to take the engine out - takes you maybe 10 hours for a complete strip down and check of the engine. If nothings wrong - good. If it is, you found it before more damages occur.

And as you might have guessed it: I have recommended that strip-down to Scott, as I sold him the bike and was very unsure about - as Piet said correctly - how the previous owners have treated the bike. I have re-worked the 2nd bike I bought in the package with this bike and after finding so many faults on this daily rider (stupid modifications, worn connections, non-working parts, miss-adjusted settings, wrong use of nuts and screws at the right places etc. etc. etc.), I felt forced to highly recommend this strip-down to Scott for safety reasons. At the end, it is wedging two possible routes against each other: no investment into the engine at the risk of causing a 4.000USD bill or going the safe route and spending 100USD for a set of gaskets and peace of mind. Happy Scott agreed to my suggestions and went the safe route.  ;)
 
Rubber hammer always worked for me. Pushrod twins just kick it. Turning it over can't be bad if you slacken off the adjustment a tad, as the gasket will leak as soon as it lifts?
On a parallel note unseizing an E27N Fordson with sledge and 4X2, didn't work until we towed it with another tractor, it had spadelugs so no lack of grip! my brother was leaning over no 4 cylinder (full of penetrating oil and deisel) when it let go!! Faceful, I had to laugh.

Neil Mc
 
OneThinBloke said:
I do hope that I am not the only one questioning why you are doing all this?

Was something not working before you took it apart?

James
Click to expand...

Never been in there and had to see how it worked!  :D
Actually, the bike had been sitting for some years and I was concerned the rings may have been attached to the barrel walls.  So, now I get freshened up valves and seats and know for certain nothing inside is doing anythin untoward.  Peaceful, easy feeling....
 
Scott, while you are at it...:

the valve-guides from the OUTLET have a kind of funnel on top. This is to lead oil to the valve stem to a) lube and b) cool it a bit. Don't use any valve guide seals on these, please.
 
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