Restoration of the LM3

[caspar]

Ok, the story behind my possession of the LM3 is long and tragic (literally) so I will keep it out of this thread. How the bike got into its current state is equally length, but less tragic, the basic jist is that I was riding to Wagga from Canberra after riding the bike around Canberra as my commuter for a few months. About 14km (8.6mi) out of Wagga I had to stop at some road works. After taking off there was a huge knocking sound from the motor and the oil light came on. Naturally I stopped it and got it towed into town.
After getting it home Dad and I did something (I can't remember what, which frustrates the HELL out of me) and decided it could be ridden again. We rode into the city (20 min odd) with no worries. On the way home the knock returned, and I discovered that if I kept the revs high the knock would go away. Dad, being the self taught bush mechanic that he is said the 'she'll be right' till be get home, me being young and dumb followed his fatherly advise and kept it above 'the threshold' and rode on home. We were probably about 3 mins from home and the revs required to stop the noise was equivalent to 120km/h through suburbia. I stopped and told Dad to organise a trailer while I waited with the bike.

That was probably about a year before I posted this on the 28/12/2007, so it is all quite some time ago...

Well today I finally got around to doing something.

With the help of my dad I managed to get the engine out of the frame, which was a whole lot easier than I expected.

Now I just need to split the engine and gearbox, so I can have a look at the damage on the crank (if any).

Heres some photos of the newly departed:

The frame has been relegated to under the house...hopefully I can pull it out soon.

This was followed by this on 2/6/2008

Alrighty, I got bored this arvo and was looking through some of my pics...and I realised I hadn't updated this in a while. So hear goes.

My sticking point from last time was getting the crank out, and that was my aim for this visit to the garage (which is in Canberra, when I live in Melb...long story) anyway....I recently discovered that the mashed looking thing in the centre was in fact a nut that needed to come off...so 13mm in hand I had at it.
The nut was fucked...and needed serious attention with a screwdriver and hammer:

The scary thing is, not even half of that is my doing :unsure:

Once that was off the cam chain and gears came out a piece of piss.

You can see I had a play with the bearing carrier to get it out.

The crank was obviously not going to come out with conrods in so the sump was removed to get to the bottom of them

Ahh I can use the 13mm again....well I think it was.

Once they were out of the way, all it took was a puller and a plastic mallet for persuasion to get things out.

I was surprised at the condition of the bearing surfaces...I was expecting something ugly

They may not be completely circular though...have to get that checked out.

I also took the oil pump off which I suspected to be damaged in some way...but the pump itself looks ok, where it sits, doesn't look great...but I am not sure what to do about that...the lay of the scores is with the rotation...so I dunno, advise on this would be nice

I also discovered I had acquired some critters while the engine had been sitting there for 3-4months not being touched

Ok...ill have to update when I get all the new bearings and surfaces machined.

Hahahhahahhahahahha, that last comment makes me laugh. 2 years later and I'm only just getting to the crank.

I have brought some of the parts down from Canberra and here they are:

Ok, well having a look at the crank again, the bearing surfaces are ok, but there are ridges between the contact surfaces...so will probably need machining and an under size bearing put in.
Speaking of, where can I get a list of set under sizes? and do I need to buy the bearing with the carrier, or can the bearing be pressed out and replaced?

Any help and constructive comments would be great. I really can't wait to get this moving...it has been way too long since I've felt the Guzzi goodness, way too long.

 

[Penis Rotor]

While I no longer work on the older models I'm more than happy to advise. I fly out to the USA again next monday but if you can bring anything you want inspected up before then I'd be more than happy to inspect and help. I'm only 40km from Canberra.

pete

 

[caspar]

Thanks for the offer Pete, unfortunately I have all the engine parts with me in Melbourne, and getting them to you just wont happen with what I have going on.
I have a contact with the engine builders who did the Hunwick-Hallam bike so I might be using them for some of the heavier things I can't do in my garage.

 

[Penis Rotor]

My engine rebuild piece is still up on Greg Benders site archived in the Guzzitech dk section. You might find that helpful.

pete

 

[caspar]

Well things went from costly to bloody expensive on this project.

I checked the bearing surface diameters on the crankshaft, so I would know what under-size I would need. Turns out the last time this was rebuilt it used the 3rd under size.
It is now measuring well under the limits for that, so there is no hope of me just cleaning up the surfaces and getting a new set of bearings. Which was the original plan.

There are a few different options here as I see it.
- Buy a new crank
- Buy a second hand/refurbished crank
- Make this one work

I'm in the process of enquiring about the first two options. From all the conversations with people about this project I have a healthy list of names to contact so I will work through those to get pricing.
I have also used the local site 'findapart.com.au' which has always been helpful in finding parts (whodatunkit) when I need them.

So that's the first two options.
The last option, which often gets over looked these days with our 'throw away' society. I've noticed not too many people fix things, they just buy new ones.
Anyway, my first thought was to build up the bearing areas and machine them down to standard size. This has a myriad of problems all to do with heat treatment, hardness and mismatched materials. I was hoping to find someone who had done it before, as a guinea pig, but that is unlikely.
The other option that I came up with this morning in one of those 'wake up in a cold sweat at 2am' ideas. I could machine down the bearing surfaces to a mm or two under size, then get a sleeve made up of the appropriate material/hardness which will fit over the top. This should get rid of the problems of building up, and with a sufficiently skilled fitter and turner it should be a trivial task. Of cause getting the correct material/hardness and tolerances for fit are critical, but not impossible. The only issue then would be the oil gallery holes and the possibility of oil getting in between the crank and sleeve. This should be able to be mitigated by an appropriate interference fit, I'm thinking having a requirement to freeze the crank to get the sleeve on.

Now I'm sure most of you are much more experienced than myself, so I would like to know your thoughts on what I have described.

Cheers.

 

[Penis Rotor]

2nd hand cranks come up frequently in the USA on fleabay etc. many are out of what over here would be considered very low mileage bikes and are sold often with mains as well. It would be a lot cheaper to buy one and get it shipped back here than buying new and the other options sound like a lot of effort for a still inferior end result.

Makes me wonder what happened to the engine for it to be down to 3rd under! Guzzi cranks usually last for ever unless something catastrophic happens to 'em.

Pete

 

[Chris R]

I agree with Pete - finding a used crank is probably the best and cheapest option. However if you do have have trouble finding a crank you can find a crankshaft grinder that does flame spraying. This is a specialist operation - the 'man' will know all their is to know about materials and heat treatment- and the shop will be dedicated to just crankshaft grinding, largely of big diesel engines, and that is it. My local one is 'Canadian Crankshaft and Chrome' for anyone in toronto. I think they typically charge $50 to 75 per journal. If you can't find anyone go ask a trucking company - this is standard maintenance in their world.

 

[caspar]

After much research and calling around (managed to avoid the sleeping around...this time...). I have the crank in at the rebuilders to be refurbished back to standard size.
Finding the rebuilders was a troubling and difficult task, their puzzling and misleading name of 'Crankshaft Rebuilders' really had me scratching my head. A quick chat cleared up that they were who I was after.
They come highly regarded both from the crazy guy at Stein Dinse.
They had a look at the shaft, they were quite impressed, then I pulled my pants up and got the crankshaft out of my bag. They were again impressed and shocked. The bearing surfaces had been ground down severely, one look at the bearings themselves and two of the guys jumped to the conclusion that the head had been bead blasted previously. Unfortunately I have no idea if it has or hasn't, so it will remain a mystery.
The bearings had the appearance of having sand embedded in it at some point. Hence the conclusion that it was bead blasted. How they got to the bearings? Well the beads might not have been cleaned out of the head properly and the motor was put back together with beads in it in places. The beads have then made a home in the oil and main bearings.

This would explain the original problem and the severely undersized mains.

It is a mystery how my uncle had the bike running for quite a while before it found it's way to me. Hopefully the old man can shed some light for me.

Anyway, after much discussion the rebuilders came to the conclusion that it would be best to grind down the surfaces, nickel plate them then grind them to match some bearings. They will also grind the big end to one undersized.
So I have to acquire some standard sized mains and some one undersized big ends.

This also means I have to go through the rest of the engine with a fine toothed comb to make sure any other damage is rectified before she will burst into life.
Hopefully I will have the money to release the crankshaft from the rebuilders in a monthish.