Here's a picture of my LS gallery plug The crank turns freely without sound of scraping. The gallery plug seems to be set against main bearing. Q. Does it appear to be backing out? Q. Is it good to go? Thanks for advice, John
Mmmm.....yes, I would definately say it was backing out. It should be set further in the thread You can see it through the filter strainer hole at the bottom with use of a small mirror too for a different angle
Its the 900ss transplant I've recently aquired. OK I'll split the cases. Thanks enormously to both of you for your speedy good advice.
It is definitely backing out. Lucky catch. Sorry DesmoQ, it isn’t possible to see the crank from the filter area.
Yeah, just checked not sure where I was thinking of then, it was definately somewhere other than the cylinder...it was so long ago when I did mine
I wanted everything to be alright, having examined the barrels and heads, plus big end and mains by feel; then after painting the cases I was going to sling it in give it a go. Luckily, I can now go ahead and separate the cases without feeling like I'm wasting time! First time splitting a desmo. This was an engine I acquired off Andrew who used to race with it at Donnington. He was lucky too!
It's actually not a daunting as you might imagine. I've done a few and they are relatively straightforward to work on.
Cheers. Last engine I dismantled and rebuilt fully was was my son's cg125, last month. Before that, Norton Commandos and Rover-mini engines, a few. I'm ordering a clutch hub holding tool, doubt if the Haynes home-made suggestion will serve me working alone, given the torque. I'll check end float beforehand.
Thanks, most kind Desmo. I have one important question to kick of with, concerning mains bearings inner race clearance. I lack the knowledge for these cranks. When turning the crank (crankcase not split), I observe the mains' inner races on both sides move out of sync with the crank... ie slower. This is an indication of clearance. Would this be expected, cold? (Perhaps Ducati E.G. fitted 'C3' spec bearings, with the greater clearance/ looser fit) OR, Should they be firm-push to fit, when cold? Cheers, John
Closer Observation, gallery plug: Although the slot on the plug is clearly visible, indicating only little degree of wear, the plug is at one point touching the bearing, its top plane surface being at a definite angle to the mains bearing, and I see a little swarf being raised at point of contact. Definitely time to address the issue. Grateful I was warned to check it in other posts, and sound advice here to see to it, and that it is in fact backing out.
The inner races are (should be) an interference fit on the crank and definitely should not spin on it.
Thanks. As I suspected. Must check crank closely on disassembly. Can these cranks be built up or not? And has this happened to others , under certain conditions?
I might have to disagree with @Jon Wright here, the crank should be a good sliding fit on the bearing, which is an interference fit in the cases. I haven't worked on these engines, but if the bearings are radial thrust then there will be no crank endfloat as the bearings are pre loaded. If the crank and bearings have 'slippage' then there is no pre load. If the crank end shafts are damaged they can be repaired but with these engines a new crank may be cheaper. Lots of articles on pre loading on the web
Hi, just done the some work on my 900ss engine, and your plug is definitely backing out. If you can get a small screwdriver or similar onto the edge of the plug it’ll probably be free to rotate, mine was finger tight. The cases came apart with no real drama other than removing the primary gear, for that I recommend the proper tool Case gaskets are available from wemoto and are the same 0:3 thickness, so retaining your endfloat on gearbox and crank On the crank bearing you might be confusing the inner race with the ball race holder, which does rotate at half crank speed. All will be revealed with primary gear off !!! Keep us posted, and get the spanner’s out
When you put the new crank plugs in, deform the main one with a centre punch on the edge. Also loctite.
you're a gem too you are Bumpstart, Dissassembly ........................ I understood from preliminary reading of Haynes, that the cases were split on the 900ss (unlike 750ss) w/o removal of primary gear; ar eyou talking specifically about a 900 or 750? Mains Bearings FIt ............................. Now, you give me considerable hope, concerning the ball race holder - I shall take another look whilst I await arrival of my clutch holder. If both inner bearings slide on crank when cold (and if they should not be), then that itself begs the question why both - what has happened here?
