Narrowcase crankcase screws

Ducati single cylinder motorcycle questions and discussions, all models. Ducati single cylinder motorcycle-related content only! Email subscription available.
Moderator: Morpheus

Moderator: ajleone

Eldert
Posts: 548
Joined: Sun Nov 01, 2009 3:23 pm
Location: Hazerswoude Rijndijk Netherlands

Re: Narrowcase crankcase screws

Postby Eldert » Wed May 23, 2018 5:59 am

another thing is when shimming the gearbox pull the shafts all the way in the bearings , so put on the front sprocket and for the clutch side i use the centre piece and a piece of tubing to pull the shaft in the bearing .

Eldert

ranton_rambler
Posts: 122
Joined: Sun Jun 04, 2017 11:33 am
Location: Stafford UK

Re: Narrowcase crankcase screws

Postby ranton_rambler » Wed May 23, 2018 8:51 pm

PhilR wrote:Nigel Lacey gave me this wise advice..

As the gearbox is an input/output type design, end float is not so critical and in fact only governs the amount of end float on the end gears of the shaft. On the input shaft there is no shim on the end of the shaft as standard and putting shims of less than 0.5mm is not likely to be a good idea as they will probably just get spat out.  Certainly 0.3mm float is perfectly acceptable for the input shaft and this will allow 4th gear to also move and allow lubrication of the inner spinning surface. I would say anything between 0.3mm and 0.5mm would not cause a problem. On the output shaft you may find even more than this and there is no real way of shimming the end clearance because of the roller design. There again needs to be a reasonable clearance either side of this gear to allow oil to lubricate the bronze bush and generally speaking I would leave as is.  My experience with the gear selector drum is that generally a 0.5mm shim either side of the drum usually gives reasonable clearance and any attempts to shim the drum tight will usually show up tolerancing/design problems with the gearbox and lead to burnt out selector forks. If the dogs are in good condition once they have been introduced to each other, under load that should hold the gears engaged. The selectors are not actually designed to hold the gears in mesh.
Cheers
Phil

Thanks Phil. I spoke to Nigel today and am going to build the gearbox back up with its existing shims. Perhaps has a bit more endfloat than 0.3mm on the input but Nigel thinks it will be fine. His other advice was to build the cases without the crankshaft and then check the gear meshes and selector operation through the barrel aperture.
Was it you that wanted details of the guy that painted my tank? I dropped some other bits off and totally forgot to ask him if I could pass on details, but will try and remember when I go back to collect.

ranton_rambler
Posts: 122
Joined: Sun Jun 04, 2017 11:33 am
Location: Stafford UK

Re: Narrowcase crankcase screws

Postby ranton_rambler » Tue Jun 19, 2018 9:02 pm

I had a bit of a diversion onto wheels, tyres and brakes but got the bench clear and got back to the motor.
All the shafts are loaded into the right-hand case now and I'm ready to bolt it together. A couple of questions:
Any preference for best gearbox position before assembly? I have put it in neutral for now.

Sealant on the gasket? No mention in the workshop manual and Mick Walker advises against using any.

Ian

Bevel bob
Posts: 748
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Narrowcase crankcase screws

Postby Bevel bob » Wed Jun 20, 2018 8:04 am

I read somewhere that the old race mech(Franco Farne?) used to coat the gasket with ( olive?) oil and tighten up till it sqeezed beads out.As they knew they would need to get back inside sometime soon they probably did not mind a bit of oil seepage in use.

PhilR
Posts: 26
Joined: Sun Nov 17, 2013 4:57 pm
Location: High Peak, Derbyshire, UK

Re: Narrowcase crankcase screws

Postby PhilR » Thu Jun 21, 2018 9:12 pm

Ian, yes it was me after the painter.

Phil

ranton_rambler
Posts: 122
Joined: Sun Jun 04, 2017 11:33 am
Location: Stafford UK

Re: Narrowcase crankcase screws

Postby ranton_rambler » Mon Jun 25, 2018 9:36 pm

PhilR wrote:Ian, yes it was me after the painter.

Phil

I'm hoping to get my remaining bits back soon so I'll try and remember to mention you to him this time....


Return to “Ducati Singles Main Discussions (& How to Join)”

Who is online

Users browsing this forum: No registered users and 9 guests