The gearbox project begins

Maestro, SEI-V

The gearbox project begins

Postby penman » 17 Oct 2017 08:45

Yesterday I had a bit of time and started stripping the engine. It's always a slow start I find with these jobs as there are a lot of bits and pieces to strip off the bike before you really begin. Anyway, the first proper job was to take the heads off and bear in mind that this is the first time I've worked on a Morini engine. I was aware of the "hidden" cap head bolts recessed in the cylinder head, but I wasn't prepared for how tight they were. These take a 5mm hex driver and I really thought I was going to break it. They did come out in the end. Big surprise was this:

Image

Image

There were corresponding burn marks on the head gasket. That looks pretty bad to me, but I was unaware of a problem, though I did think the front exhaust was blowing a bit from the header. So, already it was worth doing this job!

Maybe someone can help me here. The gasket looks like aluminium (a new one on me!) and the Blue Book tells me I should use silicone sealant on it - does everyone agree with that? The last person to have had this apart went mad with sealant, it is everywhere and it is rock hard, it looks like JB Weld to me. As well as on the gaskets, it was on the head studs:

Image

and it was also on the washers, which I had to almost chisel off:

Image

Surely this isn't necessary?? Again, can someone confirm or otherwise the need to seal these bolts. Thanks!

I haven't taken the barrels off yet, they are really glued down and are going to put up a bit of a fight. I'll probably get the engine out of the frame now and do that on the bench.

Next instalment in a day or two!

Regards to all,
Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
penman
 
Posts: 286
Joined: 08 Mar 2016 09:20
Location: Milton Keynes

Re: The gearbox project begins

Postby 72degrees » 17 Oct 2017 09:49

The head and base gaskets NLM supply are now alloy. When I rebuilt the project 350 I used a tiny smear of V-tech 'vital copper' RTV on them. Certainly not enough for it to migrate up the studs to the washers and in to the cap head bolt! The last person inside had used lashings of some horrible red stuff everywhere.

It might be worth checking for stretch on the studs - but I have no idea how long a 'good' 500 one should be. I've never seen a gasket blowing as badly as that (on a 350 at least). One advantage of the Heron head design is that it's pretty easy to check for head warp and correct if there is just slight unevenness.

Makes you wonder what else you will find as you delve deeper in to the innards.
User avatar
72degrees
 
Posts: 1031
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: The gearbox project begins

Postby penman » 18 Oct 2017 08:40

Well the engine is out and almost fully stripped now. I am a bit disappointed to see that the pistons are already at +0.4mm, so in less than 30,000 km it had been re-bored at least once and maybe twice. The good news is that it doesn't need doing again yet. I haven't taken the valves out of the heads yet, so those are still waiting to be checked.

The dratted gearbox! At the moment, I can't see anything really wrong with any of the parts. I still need to take all the gears, bushes, etc off the shafts and clean and examine them with a magnifying glass. I may have missed something. There is visible wear to the gear teeth, but it's very minor and normally I wouldn't hesitate to put them back. I can rock the gears a little on their bushes but again, it's not excessive and I'd say it is in line with normal running clearances. The only thing which makes me hesitate is that there is some wear to the cylindrical "teeth" on the selector wheel. It certainly doesn't seem excessive, but I'm looking for a fault and so far that's the best I can come up with. Maybe a clean up will reveal something else. There is no visible wear to the tips of the pawl or the index arm and the indexing detents are fine. All the springs seem really good to me.

All the bearings seem perfect so far, so the plan is to replace the cheap/easy ones and leave the difficult ones alone. Again, I can review that if the clean-up reveals anything else. The plain main bearing seems to be in great condition as do the big ends. Small end bushes are perfect.

I shall now fire up the parts washer and do a bit of cleaning - this is a one-off opportunity for clean crankcases! OK I know it won't last!

One interesting snippet. When I got this bike, it had been unused for a long time (20+ years) and there was predictably a thick layer of sludge in the sump. I poked an air and paraffin gun in through the oil strainer hole and gave it all a good blasting, followed by 24 hours to drip and then fresh oil. Well that clearly worked well, the inside of the crankcase is very clean, no sludge anywhere. I will clean out the sludge traps though!

Someone offered me the use of a cutaway crankcase half. I'll find that posting and take him up on that, I do need to check the adjustments.

Wait for the next thrilling instalment!

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
penman
 
Posts: 286
Joined: 08 Mar 2016 09:20
Location: Milton Keynes

Re: The gearbox project begins

Postby penman » 22 Oct 2017 11:16

Time for another update!
I'm conscious that this mght be a bit boring for the experienced Morini engineers, but I also hope some of this will be helpful to other newcomers like myself - it's certainly a voyage of discovery for me!

Back in the 1970s oil filters were uncommon on motorcycle engines and crankshaft sludge traps were common. The idea is that metallic particles etc would be centrifuged out of the oil stream and collected in the trap. I don't know why, but the plugs are always difficult to remove and the Morini was no exception. There are 3 plugs on the 500 crankshaft and the large one eventually came out with an allen key. The two smaller ones had to be drilled out, thus ensuring that the crankshaft was covered in metallic swarf!

Image

Initially I thought the sludge traps were clean, but they are in fact quite a bit deeper than I thought. I used a drill to remove the sludge deposit, which was about 20mm deep:

Image

Image

To get all the crankshaft oilways really clean is a bit of a poke and hope job because you can't see if they are clean or not. I used several generous shots of carb cleaner and compressed air. When nothing visible was coming out, I pumped in a lot of oil and started to reassemble.

I was very lucky to be able to borrow a cutaway R/H crankcase half, so the next job was to reassemble the gearbox and adjust it. I had carefully cleaned all the gears, etc, so I double-checked the assembly order against the parts book. There are so many plain washers, splined washers, circlips and so on, there are numerous opportunities to make a mistake! The selector stop plate needs to be adjusted on its slotted holes so that the selector pawl travel is equal in both directions. The travel needs to be enough for the detent arm to drop into its grooves without starting to climb up the other side. This adjustment is easy - if you have a cutaway crankcase. You can now check that all gears can be selected cleanly and neutral has a positive stop.

The crankshaft is now re-fitted to the L/H crankcase with the nut on the oil pump drive gear done up as tight as you can with the crankcase open. The important thing is to close the two halves of the L/H main bearing so that the crank is properly located. I found it easiest to fit the camshaft into the R/H crankcase first, but I think it can be done either way. You really need an oil seal protector for the R/H end of the camshaft, doing it without needs a lot of care and patience. A final check and the R/H crankcase should slip on quite easily.

And that's as far as I've got. So far so good. All gears still engage correctly and easily and the crankshaft turns smoothly without play in any direction. I'm hoping to get a couple of hours on this tomorrow. In the meantime, does anyone know if the barrels and heads can be re-fitted with the engine back in the frame? If so, that will allow me to do a lot of reassembly while I'm waiting for the heads and barrels to come back from being skimmed and having new valve guides fitted.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
penman
 
Posts: 286
Joined: 08 Mar 2016 09:20
Location: Milton Keynes

Re: The gearbox project begins

Postby 72degrees » 22 Oct 2017 11:26

penman wrote: In the meantime, does anyone know if the barrels and heads can be re-fitted with the engine back in the frame? If so, that will allow me to do a lot of reassembly while I'm waiting for the heads and barrels to come back from being skimmed and having new valve guides fitted.


I'd have thought so. You can even get the barrels and heads back on a 350 in a 250 frame by getting inventive with which engine mounting bolts are in place.
I've never worked on a 500 though so someone who really knows will be along in a while.
User avatar
72degrees
 
Posts: 1031
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: The gearbox project begins

Postby George 350 » 22 Oct 2017 12:40

Hi Joe.
The Loctite for crankcase sealing I mentioned when I called round is 5699. Similar or same as Yamabond, Hondabond etc. Good for all the metal to metal joints on the engine including heads and barrels.
What was your final choice on the 3rd gear bush?
George
George
350 sport 1978, 350 Strada 1978
George 350
 
Posts: 252
Joined: 16 Jun 2007 09:43
Location: Northampton

Re: The gearbox project begins

Postby penman » 22 Oct 2017 13:50

Hi George,
Thanks for the Loctite info.

I eventually went for the "new" gearbox complete. After cleaning up, there was slightly more play in the bushes on my old one - I think the oil was misleading us the other day. Having said that, it isn't awful and I would have thought both sets of bushes were perfectly useable. There is a bit more wear to the gear teeth on my old gears and also to the edges of the dogs. Again though, I would normally say they were just nicely run in! Anyway, in the absence of anything else to guide me, that's what I went for. I did move the stop plate just a touch, but realistically I don't think it was far enough out to make any difference. I can't think of anything else I can do, so it's a case of giving it a try.

The valve guides were pretty sloppy, I wouldn't re-use those, so it is worth doing the job for that. My local engineering shop are making new ones for me. I'm also having the heads and barrels lightly skimmed - it would be good to stop it blowing!

It's interesting that it wasn't using any oil despite very worn valve guides - as I well know, if that was a 1970s Triumph, it would be using buckets of oil with guides in that state!

Regards,

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
penman
 
Posts: 286
Joined: 08 Mar 2016 09:20
Location: Milton Keynes

Re: The gearbox project begins

Postby Steve Brown » 22 Oct 2017 14:44

You wondered if this thread was boring? Well I've been inside a few Morini engines over the last 35 years, along with lots of other types as well. A lot of what you are covering is familiar ground to me and many other here, but no, it definitely isn't boring. Every bike you work on, especially those which have been 'fixed' :roll: by well meaning previous owners, will throw up some new challenge or puzzle. So please keep the updates coming.

The cutaway case is very useful for sorting bad gear selection jobs. I see you used the replacement cluster, was that with the selectors, drum and everything else? I only ask as it would have been interesting to check how well aligned the original plate was, along with the other selector bits. So far I've been lucky there!

I've just picked up another 500W project bike that has had the well meaning attentions of various have a go heroes in a previous life :wink: Still, what is one more project on top of the other four, eh? I'll be advertising for bits wanted soon, just you wait. :)
All donations to the rest home for old Camels, Leicestershire.
Steve Brown
 
Posts: 472
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: The gearbox project begins

Postby penman » 22 Oct 2017 18:58

Steve,

Thank you for your comments and encouragement!

After cleaning and examining all the gears, etc without finding any very clear problem, I just fitted the new cluster with its selector mechanism. I didn't check the stop plate setting with the original gears. I only moved the plate a whisker and I'm far from convinced that it made any real difference.

I've just been looking for the torque wrench setting for the oil pump drive gear nut - the one on the end of the crankshaft. I'm sure it'll be in the blue book somewhere, but I'm blowed if I can find it! Anybody help me here? Thanks!

Joe
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
penman
 
Posts: 286
Joined: 08 Mar 2016 09:20
Location: Milton Keynes

Re: The gearbox project begins

Postby Steve Brown » 22 Oct 2017 20:25

deleted
Last edited by Steve Brown on 22 Oct 2017 20:30, edited 1 time in total.
All donations to the rest home for old Camels, Leicestershire.
Steve Brown
 
Posts: 472
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: The gearbox project begins

Postby Steve Brown » 22 Oct 2017 20:28

penman wrote:I've just been looking for the torque wrench setting for the oil pump drive gear nut - the one on the end of the crankshaft. I'm sure it'll be in the blue book somewhere, but I'm blowed if I can find it! Anybody help me here? Thanks!

Joe


Hi Joe, I was about to say it's all together on one page-but I looked and it ain't! Found it on page 59 though. It says 4.5 to 5 m/kg which a google search says is 33 to 36 ft/lbs.
It does need to be tight for obvious reasons, but it's worth checking the locknut is still locking. The basic idea is that when the nylon or whatever it is insert starts to engage it does prevent the nut from running freely on the crank thread. I think NLM has new ones too.
All donations to the rest home for old Camels, Leicestershire.
Steve Brown
 
Posts: 472
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: The gearbox project begins

Postby norbert » 22 Oct 2017 21:59

In the manual of 5 languages they say 13 Kgm for that nut, the tightest of all!

norbert
norbert
 
Posts: 321
Joined: 15 May 2007 15:15
Location: Lübeck/Germany

Re: The gearbox project begins

Postby penman » 24 Oct 2017 09:57

Thanks for the info guys! Curiously that torque figure has now appeared on Page 59of my copy of the Blue Book, it definitely wasn’t there last time I looked!

For most purposes, mkg x 10 is near enough equal to Nm as marked on modern torque wrenches. My old Norbar torque wrench has mkg marked on it. I think 13 mkg can’t be right for that very slim nut. Can it? Anyway, I’ve gone with 36 Nm and that was difficult enough!
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
penman
 
Posts: 286
Joined: 08 Mar 2016 09:20
Location: Milton Keynes

Re: The gearbox project begins

Postby morini_tom » 24 Oct 2017 11:33

The last of the manuals (the 'cagiva era' one for the kokusan engines) has a handy torque chart in the back.

Whilst I wouldn't guarantee the torque figures didn't change over the years, it's a handy cross reference, incase any of the figures in the blue book were misprinted, or they changed the setting due to some kind of issue identified in production.

The Cagiva manual agrees with 13kgm for the oil pump nut, so it's probably right. As you say, that's f-tight, but bear in mind that is what retains the crank axially and provides drive to the oil pump. I don't specifically remember what I did when I rebuilt mine, but do know I followed the manual, and I have a feeling I borrowed a torque wrench from work as mine only goes up to 100Nm, and possibly waited until the engine was in the frame to torque that one up...

A copy of the torque chart is below. I would advise the specified 13mkg, unless anyone on the forum suggests to the contrary.

The full Cagiva era engine manual is in the club's members area for download, and is a good book even if you don't have a kokusan engine.
Attachments
torque chart.JPG
torque chart.JPG (96.84 KiB) Viewed 3273 times
morini_tom
 
Posts: 494
Joined: 05 May 2006 13:47
Location: Northampton

Re: The gearbox project begins

Postby penman » 24 Oct 2017 13:35

Hi Tom,
and thanks for the torque settings list. 13 mkg (~130 Nm) is not the answer I wanted, particularly as I have now reassembled the primary, clutch, etc. Neither of my torque wrenches go up that high and the tool I got from NLM for the oil pump nut is not suitable for such a high torque, so I’ll need to think about this. Obviously I don’t want to under-tighten it.

Just thinking aloud for a moment, I wonder why it would need to be so tight? The blue book figure of 4.5 to 5 mkg is already tight by motorcycle standards - and it’s a nylok nut. The blue book is quite specific about the torque figure, I doubt if it’s wrong, though I guess it could easily have been changed for later engines for some reason - and that’s a very thin nut to hold such a tight torque.

Any more ideas or suggestions? Thanks!

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
penman
 
Posts: 286
Joined: 08 Mar 2016 09:20
Location: Milton Keynes

Next

Return to The 500

Who is online

Users browsing this forum: No registered users and 3 guests

cron