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splitting crankcases
« on: November 06, 2019, 09:01:05 pm »
Hello all.  New to the forum.  Am splitting the crankcases for a friends 1974 Nuovo Francone, an ex military bike.  Cylinder and top end no problems but am having trouble removing the pinion (the one driven by the main pinion) from the crankshaft.  Clutch assembly. oil pump, camshaft all removed OK.  I have a good 2 legged puller on the pinion with plenty of pressure applied, have tapped the puller head and also applied a smallish amount of heat but no result.  Any suggestions?  I have a 3 legged puller on order to see if  that helps.
Are there any hidden fasteners etc that I need to know about to let me split the cases?   Drawings on the engine seems very sparse.
All suggestions gratefully received.

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Re: splitting crankcases
« Reply #1 on: November 08, 2019, 08:53:42 pm »
Hello again.  Pleased to report the heavier 3 legged puller worked.  Removing the pinion from the crankshaft showed that the main bearing ball cage is breaking up, so that needs changing.  More advice please on the following and I say again that I have never worked on this type of engine before, hence the asking for advice;  1) Does the crankshaft have a sludge trap fitted?  2) The exhaust valve guide is well worn, as is its valve only less so.  Both need to be changed. The inlet valve and guide are good.  3) All piston rings are well down on gap sizes, especially the oil ring.  They will be changed.  4) The bush in the primary case where the mains oil feed into the crankshaft-and the crankshaft end that mates with the bush are badly scored.  I will need to re-face the crankshaft end and make a bush to suit.  Can anyone advise what clearance the bush needs?  5)  Where should I go to for the required spares?  6) Is there a site where I can find engine details/drawings etc as there seems to be no manuals in English, apart from Martin Noke's which is not detailed enough.
Thanks in anticipation.   

banquo

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Re: splitting crankcases
« Reply #2 on: November 10, 2019, 11:42:40 pm »
Sorry for the delay in repying; as you have discovered, we don't get much traffic on here.
I've only ever had the top end off, so can't really help with the bottom end.
The bush in the clutch casing is a known weak point, and wear results in loss of oil pressure. Some have replaced it with an oil seal, but it needs to withstand full oil pressure, as the oil gallery is behind it. It's never going to work well with a bush, as it can't be guaranteed it's in line with the crank, and of course there will be run-out on the crank too. I don't THINK there's a sludge trap, as the strainer should be designed to eliminate the need, but I'm not sure. The manuals and parts books are available via links in the Links section. Only the rider handbook is available in English. Workshop Manual is in Italian, but has many diagrams and dimensions.
Glad you got the pinion off OK.
Also on the links section there should be a link to the advrider thread by Leafman, which gets a lot more traffic than here, and some serial engine workers who should be able to help out. I'd try there, in case nobody chips in here

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Re: splitting crankcases
« Reply #3 on: November 11, 2019, 01:27:00 pm »
Sorry for the delay in repying; as you have discovered, we don't get much traffic on here.
I've only ever had the top end off, so can't really help with the bottom end.
The bush in the clutch casing is a known weak point, and wear results in loss of oil pressure. Some have replaced it with an oil seal, but it needs to withstand full oil pressure, as the oil gallery is behind it. It's never going to work well with a bush, as it can't be guaranteed it's in line with the crank, and of course there will be run-out on the crank too. I don't THINK there's a sludge trap, as the strainer should be designed to eliminate the need, but I'm not sure. The manuals and parts books are available via links in the Links section. Only the rider handbook is available in English. Workshop Manual is in Italian, but has many diagrams and dimensions.
Glad you got the pinion off OK.
Also on the links section there should be a link to the advrider thread by Leafman, which gets a lot more traffic than here, and some serial engine workers who should be able to help out. I'd try there, in case nobody chips in here

Many thanks Banquo.  Your input is much appreciated.  The crankcases are still refusing to come apart completely, just a 1 mm gap, and that's after spending 6 hrs on it yesterday.   I believe the problem is that the lower locating dowel on the mating faces of the crankcases is sticking (corrosion?) so I have left it overnight soaking with WD40.  I will have a look at Leafman's advrider as you suggest, thanks again.

banquo

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Re: splitting crankcases
« Reply #4 on: November 11, 2019, 01:30:11 pm »
No bother at all; sorry I couldn't be more help.
1mm sounds good - at least they're not stuck at the faces  :o

olebmw

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Re: splitting crankcases
« Reply #5 on: December 20, 2019, 05:17:16 pm »
Mine has a sludge trap on the crank.You'll see it when you get it apart.
Make sure that something other than the dowel pin is keeping it from parting.

banquo

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Re: splitting crankcases
« Reply #6 on: December 20, 2019, 06:01:06 pm »
Thanks olebmw; I stand corrected (a not unusual occurrence!)