What do I have here?
- Thread starter Nigeldtr
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pete.v said:
I will assemble the engine on the bench and check with Plasticine for the valve clearances to the pistons, I will also check the push rods etc for the rocker angles. I hope it all fits with the combat head but I'll check. I assume I use the standard timing marks?
What do I need to mod on the springs?
Will the head, piston and cam work well together?
Nigel
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The only "pointed lobe" Norton cam I've ever seen is the Dunstall PD05 profile. I have one of those and it looks a lot like the one you have.
DogT
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Other thing you may want to deal with is the breather. The timed breather was not very effective, plus the oil tank breather dumps out in the air filter and if you let the bike wet sump, some oil ends up in the oil tank breather which drips down on the gearbox and on to the bottom of the bike from there. There are several fixes, but I opted to use a catch bottle off the oil tank breather and leave the timed breather. This has been discussed a lot here. Also you cannot use the comstock sump breather because the frame brace under the sump will not let you install it.
I have links to parts books, workshop manuals and riders handbooks if you need them.
Dave
69S
I have links to parts books, workshop manuals and riders handbooks if you need them.
Dave
69S
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Those pistons look good to go. Install the better breather too.
Torontonian said:
The barrels have been honed and new rings came with it. I have checked the clearances and the pistons have 4 thou and the new rings 12 thou gap so all in good order. Barrels have been painted black but I suppose they should be silver?
DogT said:
I am used to bikes wet sumping and try to fire mine up regularly or at least draining the oil out of the engine and putting it back in the tank. A pain but much better than a "death valve" - different issue. Links or other info would be great - thanks for the offer!
I have fitted a breather bottle on my A10 and works very well. The bottle on the tank breather seems to make a lot of sense. If I don't need to modify the engine breather then I will leave it as standard. I'll take a look on the bottom end next week and see whats in there!
DogT
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Parts book, notice the S, R and later Roadster is a supplement in the back of the book. http://www.eurooldtimers.com/eng/manual ... 1970-.html
Riders handbook, S and Roadster model. http://s251.photobucket.com/user/DogTi/ ... t=6&page=1
If you want an early (68) Workshop Manual, I have one in PDF I can email you.
Good link, http://www.members.shaw.ca/randell/
Riders handbook, S and Roadster model. http://s251.photobucket.com/user/DogTi/ ... t=6&page=1
If you want an early (68) Workshop Manual, I have one in PDF I can email you.
Good link, http://www.members.shaw.ca/randell/
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the ' S S ' Cam would be G O O D , then . 
usually you set the valve springs at 40 thou of coil bound at full lift with shims under the seats .
the W&S springs came with all the bits bar valves , if you can find any .
Checking the cam followers have adequate range ( still clearance at full lift ) & pushrod length .
Throwing the breather up where the Mag. would go , and drilling a few vent holes in the cases
in line with the lower timing chain run , used to be the go , once .
usually you set the valve springs at 40 thou of coil bound at full lift with shims under the seats .
the W&S springs came with all the bits bar valves , if you can find any .
Checking the cam followers have adequate range ( still clearance at full lift ) & pushrod length .
Throwing the breather up where the Mag. would go , and drilling a few vent holes in the cases
in line with the lower timing chain run , used to be the go , once .
Well I had a bit of time this afternoon and as the bottom half was only in with a couple of bolts I decided to pull it out! Well the cases weren't even bolted together so getting a the crank out took 5 mins! It seems to have big roller bearings both sides and the journals seem to be good although they look stained? I have measured them up and they seem to be about 001 undersize 1.749. The journals are not scored and not oval just the discoluration - could this be from moisture during long storage? The shells look a little messy perhaps perhaps from the old cam failing but nothing serious. I'll add some more pictures.
Ron L
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If you are using the Combat head and are going with a 560 Megacycle, be sure to measure your intake manifolds. The Combat head will have 32mm intake ports, but if the PO simply bolted on the original '68-'71 intake manifolds, their port side is only 28.5mm. The manifolds that came on the Combats were 32mm at both ends and used 32mm Amal Concentrics. The originals for a '70 Commando would be 30mm at the carb and 28.5mm at the port. If you want to use the 30mm carbs you should blend the manifold to the 32mm port size.
It will run and idle OK with the port mismatch, but I expect it will take away a lot of the performance gains from the high compression head and the cam. We put a Combat head on a buddy's 'S' because his was warped and the Combat was all I had in the shop. He used his stock carbs and manifolds and he ran that setup for several years.
It will run and idle OK with the port mismatch, but I expect it will take away a lot of the performance gains from the high compression head and the cam. We put a Combat head on a buddy's 'S' because his was warped and the Combat was all I had in the shop. He used his stock carbs and manifolds and he ran that setup for several years.
Ron L said:
Thanks for the info. Fortunately, it has 32 mm carbs and manifolds, I had a look earlier today the cards don't seem too bad and I can give these a good overhaul - plenty of practice
The head looks good and seems to have new valves etc. I will take it apart to check it out. The 560 seems to hit in the middle of the camshaft tunnel so it seems it will need to be bored out or at least cut back. Don't really what to bore out the circular brace on the timing cover side as it seem rather thin as it is. The camshaft bushes seem a little sloppy but don't know how difficult they are to replace?
Here's a picture of the old shells. If I don't have to have a regrind, then I will pop in new shells. I can't feel any surface damage on the journals not even when I run my finger nail across the dis-coloured area. Just seems a little odd- never come across this before.
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" I will pop in new shells "
YES , look a bit sad . Looks corroded , maybe acids in ancient used oil .
Your going to have to look up ' crank polishing ' , bootlace or finest paper around - maybe .
Might need to check sludge accumulation , in crank :x too . :cry: .
were the any gloops of the silvery grey crud in the bottom of any crevises , or timing chest .
the burnt on coke or however youd describe it shows a bit of use , if not wear .
The shells ' Std. ' or undersize ?
YES , look a bit sad . Looks corroded , maybe acids in ancient used oil .
Your going to have to look up ' crank polishing ' , bootlace or finest paper around - maybe .
Might need to check sludge accumulation , in crank :x too . :cry: .
were the any gloops of the silvery grey crud in the bottom of any crevises , or timing chest .
the burnt on coke or however youd describe it shows a bit of use , if not wear .
The shells ' Std. ' or undersize ?
Matt Spencer said:
I have a feeling its been sitting round for a good few years! Its actually all reasonably clean but someone has already had it apart and taken out the old cam. I'll take the crank apart next week (away for a few days on business) and see what is in there. Journals seem to be standard as I measured 1.749". I assume the main bearings are the newer ones - seem to be in good condition - chunky
Thanks for the tip, I'll check out crank polishing.- Joined
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Flick out a shell , should be stamped on the back , std .
you realise , if you split the crank , it will be clean inside .
but if you dont , of course it will be fill of crud . :x
See a post recently where someone used a durometer , and found the new crank studs softer , so used the originals , with the new nuts .
you realise , if you split the crank , it will be clean inside .
but if you dont , of course it will be fill of crud . :x
See a post recently where someone used a durometer , and found the new crank studs softer , so used the originals , with the new nuts .
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