Alternator Rotor Nut

[starfield181]

I am part way through stripping the drive side of the G5 to fit the 20t gearbox sprocket. The nut on the crankshaft is extremely tight and before I go any further can I check that its a normal rh thread. The spares book makes no mention of it (Part #000230) being lh nor does my copy of the F Neill book but I just want make sure before resorting to more extreme measures to get it off.

Thanks

PeterF

[Rob Harknett]

That's an old prewar part STD 230 timing side axel nut. 5/8"x 20TPI. The old parts books state if its LH thread, its not stated as LH so I guess its RH.

[Ozmadman]

Definitely standard RH thread, there should be a large wavy washer under that nut as well. Normally they are not that tight but make sure you tighten it up well and with loctite if possible when you put it back

[starfield181]

Nut had no wavy or indeed any washer and was extremely tight but application of some heat has got it off thanks. The rest of the nuts were tight - I think someone had used loctite eveywhere - but its now apart and I have replaced the sprocket. So far so good but of course its never that simple.

DSC_0114s.jpg

The picture shows a pool of oil in a place I suspect it is not meant to be. Not clear to me if the oil has come out of the main bearing or if it came from the breather and dropped through the slot just below it. There was rather more oil than this, the bulk of it drained out when I pulled the inner cover. I have not yet cleaned up hoping for clues as to the source of the oil.

If it came from the breather it is odd that the pool does not extend to the section immediately under the slot. On the other hand,If it came through the main bearing I would have expected it to finish up in the primary chaincase as the inner cover is sealed to the crankcase. It could of course be historical dating back to the time when I first ran it after delivery. It had wet sumped and smoked heavily for ages at the time. Something it never seems to have done since.

I am tempted to drill a hole where the oil gathers and put in a drain tube with catch tank. Would save the drips on the garage floor and a chance to see if the loss from the oil tank is matched by the gain in the catch tank.

PeterF

[Ozmadman]

As long as the gasket around that main bearing housing is ok then any oil coming through that main bearing would go into the primary casing, it would not drip down to there, even if it was overfilled and left on the side stand. Looks like you have the latest type of engine breather (as you have that small bolt which secures the breather stator in the casing) could the oil be coming from that bolt. I see no other option as everything else is sealed?? BTW I had a serious leak from the gearbox main bearing on mine yet when I stripped the engine that part was bone dry so I doubt that it is coming from the breather. Also see pic of washer behind rotor nut

[starfield181]

Well the G5 is now back together and after a brief 4 mile or so road test all seems well. The higher gearing certainly improves things. Most noticeably making 1st gear much more usable and it still pulls smoothly from below 30 in top. I reckon it could easily pull an even higher gear but as far as I know 20t is the largest available.

I did learn a few things along the way and it was probably as well I did the job despite the hiccups. Some of this may be of use to others, in no particular order:
I nearly finished up with the same indentations on the magnetic rotor that Paul (I think) displayed a while back. In my case ( and I suspect in his) it was caused by the primary chain which has a split link and the pins on this are just a tad wider than the riveted pins. I tried putting some shims between rotor and sprocket but this was not really enough. Final solution was to install the split link from the outside as there is plenty of clearance on the inside. Remembering of course to check the direction of the open end of the split link!

Whilst doing the above, I realised my duplex chain link had been assembled without the middle plate; fortunately, I found a spare plate. The mystery is why the chain did not mark the rotor before I dismantled the engine. I can only conclude that the crankshaft nut was not fully tightened.

The clutch had behind it a couple of shims which I suspect are the type intended to space out the engine sprocket. A trial assembly did not seem to require them so they got used in an attempt to space out the rotor – see above. Hope no one is going to tell me they were behind the clutch for a purpose.

No outer chaincase gasket was fitted and I can see why. It's a bit fiddly to hold it properly located in spite of the locating pins as it was a bit frisky. I remembered too late an old trick of steaming gaskets to make them a bit more malleable. Finally the Wellseal went tacky enough to hold it. The fit was also not too good at the back but it does not seem to be leaking.

I had to cut of the crimped bullet connectors from the stator wires. All three in a bunch would not pull through the L shaped brass tube which guides the cable into the chaincase. I have replaced the crimps with soldered bullets which are a less bulky and spaced them out to avoid the bunching. The several yards of insulation tape which had been used to protect breaks in the outer sheath were replaced with shrink wrap also helping to slim things down. Hopefully I will not need to remove the outer case again but if I do it should be a lot easier next time.

Still don't know where the pool of oil in the inner case originates from but looking at the picture again I can see a tide mark maybe 2-3cms up the wall so there must have been quite a lot swilling around. I have fitted a drain tube to which I will fit a catch tank to see how quickly it builds up. – Just seen Paul's suggestion that it might have come from the bolt which secures the breather stator. Hope not as it's now way too late to check without a total dismantle.
My rear chain needed adjusting but was plenty long enough to cope with the larger sprocket.

A couple of side panel transfers came with the other parts so now the bike looks a bit less bland as well. Hopefully I can now enjoy the bike and keep a low profile on the forum for a while.

PeterF

[Ozmadman]

I nearly finished up with the same indentations on the magnetic rotor that Paul (I think) displayed a while back. In my case ( and I suspect in his) it was caused by the primary chain which has a split link and the pins on this are just a tad wider than the riveted pins. I tried putting some shims between rotor and sprocket but this was not really enough. Final solution was to install the split link from the outside as there is plenty of clearance on the inside. Remembering of course to check the direction of the open end of the split link!

Whilst doing the above, I realised my duplex chain link had been assembled without the middle plate; fortunately, I found a spare plate. The mystery is why the chain did not mark the rotor before I dismantled the engine. I can only conclude that the crankshaft nut was not fully tightened.
PeterF

The reason my rotor had those indentations and needed shims between the rotor and sprocket is that the sprocket was put on the wrong way round by the P.O and it seems this is a common error by most who have to remove the sprocket and put it back. It has nothing the do with the split link. The shims are for use between the back of the sprocket (when it is the correct way round) and the outer crank bearing and there are no shims between the sprocket and rotor. For reference, the sprocket should fit with the extension part facing the rota and not the crank, it does fit ok and at first looks like it will rub the casing but it doesn't. Maybe this is why why you don't have room for that wavy washer? You are correct though, there are no shims behind the clutch

[starfield181]

oh b******r, then it looks like I have fitted mine the wrong way round as well. Just when I thought it was all sorted! Cancel the ride out tomorrow, book some workshop time.

Anyway I am glad I mentioned it and thanks for the correction. Two out of three's not bad.

[clanger9]

Yep, it's easy done! You definitely need the sprocket "extension" towards the rotor and away from the crank. It looks wrong at first, but it's definitely right the way 't other Paul describes it. You'll know it's right because the crank end float will disappear when it's all tightened up properly...

[starfield181]

The sprocket was removed and refitted the correct way round this morning. Took it for a 20 mile test ride this afternoon, mainly country lane pottering with no issues. Even did a mild green lane. Top gear is still very usable so it was worth the effort. Not sure if there is a connection, but I fitted the new oil filter while the bike was on the bench and today the engine oil level does not seem to have dropped at all. And there is only the odd spot of oil underneath after standing for an hour or so.

Could I have cracked it - answers on a postcard!