Had some niggles with the engine- bottom end noise which I feel is the timing side bush, oil leak from head gasket area and one or two other niggles
I've rebuilt bantam and c15 engines before but not tackled a twin.
Any specific difficulties or problems I may encounter? Apart from a clutch puller and a few other pullers are any other special tools required?
The engine I believe is heavy so is it best to do most disassembly and reassembly in the frame or get the whole lump out?
Looking forward to my winter project!!
Hi Adrian,
There are few more parts than in a single but the principal is the same. Depending on what year you may need some AF spanners. The engine is a heavy lump and needs to be lifted slightly to get it out. I remove as much as possible and then take the cases out. If you are not touching the gearbox then leave it in but it does add to the weight.
Have you determined that the noise is bottom end/timing side bush? Perhaps as you strip the engine for removal you could check a few things and possibly avoid a total removal and strip down.
With the primary case off check for end float and movement in the main bearing. Check that the alternator rotor is very tight. Examine the chain for wear. Although it means removing the inner timing case you could also check the main crank bush, the cam and the idler bushes as you go. As you go you will get an idea of anything else that needs attention or not.
As the head will be coming off for a gasket replacement any problems with the rockers will be evident - unlikely as they are very reliable. With the barrels removed you can then check everything else. Condition of the cam and cam followers, big end and small end play, bore, pistons etc.
You may find the source of the noise as you go and avoid a total removal/strip down.
Dave.
Cheers Dave
Re the timing bush, it's quite easy to see how worn that it. When you remove the inner timing cover, the idler timing gear and the oil pump. Then try to move the crank up and down. You will soon see if there is any play. If none can be detected, it will be OK.
Re the removal from the frame, unless its a complete machine strip down for say powder coating the frame, when you can lay the engine and frame on the side and hover the frame around it, it's always easier to strip off all the bits first. It can then be lifted out but would still be a two man job.
I've got to take the head and barrel off so I assume I should also be able to feel any timing bush play.
My engine has a Boyer Branson ignition fitted so no points are present.. not sure how this is removed as it seems to be "sunk" into the inner timing cover but I am sure all will be clear when the inner timing case is removed.
Hi Adrian,
The rotor for the Boyer has a thread (cannot remember size off the top of my head) in the outer part. If you find a bolt that fits this and screw it in, it acts like a puller and releases the rotor from the taper. If you fitted the kit you should have one as they are supplied with it. You will need to do this to get the inner timing cover off. With the barrel off you may feel some up and down movement but this could be big ends so it would be best to do as suggested by Chris and get to the end of the crank to check the bush. Although you may be able to feel it by trying to lift the flywheel.
Dave.
Only thing I'd add is that being a twin makes it much harder to get the barrels back over the pistons than on a single. The barrels are not chamfered at the bottom (well mine aren't anyway) and the barrel assy is heavy. Had to get the proper ring clamps in the end.
:) :) :)
The bolt size to pull the ignition unit is 5/16th Mine is CEI but I believe that some of the later engines were BSF or UNF. Just get an ordinary bolt and screw it in.
Mike 8) 8) 8)
I didn't fit the ignition unit so haven't got a removal bolt.. I am sure I've got a suitable one in my box of bolts!