Author Topic: 1978 Le Mans restoration  (Read 314 times)

Offline 2WheelsUp

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1978 Le Mans restoration
« on: November 29, 2021, 07:38:18 PM »
Iíve been lurking on this site for the last few months picking up useful tips and facts about how best to restore my 1978 Le Mans I bought a few months ago. Before jumping into my project, a bit of background since I haven't posted on this site before.  I grew up on the Western Suburbs of Chicago but now live in North Georgia. I've been riding motorcycles since my teens, started with Nortons and became a fan of Guzzis when I bought a new 78 Le Mans from Ellis at Geneva Cycle shop, a unique experience for anyone who knows him. Over 20 years I toured most of the continental US and Northern Rockies on the Le Mans.



Outside of minor issues, it never left me stranded or broke down during all the trips and miles I put on that bike. I sold it to buy a new '97 Ducati 748, which I still have, a wonderful bike but I never, ever, should have sold the Le Mans. I also have a 2001 HD RK which I love and a Ducati 939 SS which is my daily rider and awesome around the roads in N GA. I sold my Norge over the summer, had it for over 10 years, just fell out of love with it and it wasn't getting ridden, so off it went.

Back to my project... I bought the Le Mans from the second owner since 1984 with 8900 miles on it.


Based on a close inspection I believe those miles to be reasonable given it's condition. It was obvious the bike hadn't been ridden for some time but after a tune by @GuzziSteve, who is helping me with this project, it ran surprisingly good. I was able to do a couple shake down rides of about 70 miles with a few runs to around 80 mph. The problems we found are a couple oil leaks; final drive fill plug is stripped, and its leaking oil from the gearbox/engine bell housing and clutch slipping presumably from the oil. The pumpers were not working well but after some riding they seem to get better. There was a bit of smoke coming out of one exhaust but that also seem to correct itself after riding it... sticky rings? The previous owner had just changed the all the fluids to synthetic so perhaps that was causing some leaks. I changed back to standard oil before my shake down rides. The frame is fair, usual scratches, marks, but the swing-arm was rattle can painted gloss on one side with a lot overspray. Looks like a battery leak pealed the paint from the rear of the main frame and it now has surface rust on it, hence the gloss paint job on the swingarm. It had fallen at least once, top two head fins on the left side has been repaired; more like filing them down to blend in, reasonable job, not sure what else could be done short of a new head. The wheels had been painted gold... sigh. The body was fair but tired from age. Given condition of the frame, the fact the gear box had to come out, and being a 43 old bike that had been sitting for who knows how long I decided to do an extensive restoration made possible with a lot of help from @GuzziSteve. Strip and repaint the frame, re-paint the wheels, new clutch, cables, replace seals, bearings, and gaskets on the frame, forks and drive train.  Overhaul the brake system; rotors resurfaced by TruDisk, new pads, and new lines, maybe rebuild the calipers. Maybe a new wire harness... I'm talking with Gregory Bender about it now... but the old harness is pretty good so not sure yet it makes sense.  Is it worth it, is it straight forward?

Originally I was going to leave the body paint alone but that changed once I committed to all of the above so it's going to be repainted. I know there's a lot of debate about whether and how to restore vintage bikes but all my other bikes are pristine, they all are ridden regularly (no garage queens here), I'm not much of a patina guy, and I don't plan on selling this one, ever, so why not, it's for me?

We started a few weeks ago and now have the frame completely stripped and Steve is going though the drive train. 







I'm thinking we might want to pop off the heads to see the condition of the valves and cylinder walls given it was smoking a bit before the tear down.  We did a compression test (180/175) and leak down test that didn't show anything significant so perhaps I'll get lucky. I may want to look at the timing chain and tensioner... that's a bit more work.

I just had the valve covers Vapor Honed

...wow what an amazing finish. I'd love to do the engine block, cylinders, and heads but that means a lot more work, tearing down what looks to be a good motor, multiple people are telling me it's not worth it... but does that ever look good... decisions. There are two thoughts that I keep encountering... do I pre-emptively tear down things that appear to work to prevent a possibly failure later... or do I leave things along until I have a clear signal there's a problem.  Add to that .. I hopefully will never having things torn down again with this bike. I've never done this before so it's something I'm struggling with. What do you think?

Kent at GMD Computrac told me to not put the frame in an oven so it's being painted by a local guy who is doing my body work. It's also been suggested that I paint my wheels rather than powder coating due to the heat. What have you all done? Can I powder coat the wheels?

I have the PPG code for Mahindra Red Passion ... just picked up a sample, any other suggestions are welcome (e.g. MGB Flame Red?). I need to find the color codes for the florescent orange and the silver wheel color.  My painter requires PPG codes and so I need to come up with those.

One other thing... the front suspension. I have Koni's on the rear and I've reviewed my options for the front and it appears a great option would be a SD20 fork cartridge from Maxton Suspension in the UK https://www.maxtonsuspension.co.uk/files/sd20.html. Anyone know about these or try them? They look like a drop in from the measuring document they sent me, possibly some work to the fork legs but hoping it'll fit, or they make it fit, into the spring guides at the bottom of the legs. I ride all the bikes I own and am in an area with good/challenging roads so installed under $1k may be worth it.

I'll keep posting my progress, hoping to have it back on the road by early Spring.  Thanks for reading my thread, and please pass on any advice you may have. 

Cheers!
Bruce


Offline Groover

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Re: 1978 Le Mans restoration
« Reply #1 on: December 01, 2021, 12:07:07 PM »
Thank you for sharing this!

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Offline Canuck750

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Re: 1978 Le Mans restoration
« Reply #2 on: December 01, 2021, 06:01:24 PM »
Nice project!

With respect to tearing down the motor, I would vote yes, regardless of what condition the engine apears to be in its over 40 years old, and every Guzzi 750 / 850 I have been through needed new valve guides at a minimum and just about every one of them (six engines in total) needed a pair of main bearings, big end shells and a crank shaft grind. Rear main crank seal, rear main bearing gasket, clutch kit etc, is most always needed. Steering head bearings, swing arm bearings and all the wheel bearings and seals are typically replaced.
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli Barracuda, 66 Aermacchi Sprint, 68 Gilera 106SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline 2WheelsUp

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Re: 1978 Le Mans restoration
« Reply #3 on: December 02, 2021, 08:52:38 AM »
With respect to tearing down the motor, I would vote yes, regardless of what condition the engine apears to be in its over 40 years old, and every Guzzi 750 / 850 I have been through needed new valve guides at a minimum and just about every one of them (six engines in total) needed a pair of main bearings, big end shells and a crank shaft grind. Rear main crank seal, rear main bearing gasket, clutch kit etc, is most always needed. Steering head bearings, swing arm bearings and all the wheel bearings and seals are typically replaced.
A lot of what's on your list is being done... only thing we're debating is the going through the lower end given the low miles. That said, once we have the head off and dissembled, how do I know if the valve guides need replacing?

Another topic... I noticed you powder coated your wheels. I've been warned against that for older wheels due to the heat required to coat them. Should I have concerns powder coating my Le Mans wheels?

Wildgoose Chase Moto Guzzi

Re: 1978 Le Mans restoration
« Reply #3 on: December 02, 2021, 08:52:38 AM »

Offline Canuck750

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Re: 1978 Le Mans restoration
« Reply #4 on: December 02, 2021, 09:01:02 AM »
I would take the heads to a machine shop and ask them to inspect the guides and at a minimum cut the valves and seats.
Powder is cured between 350 and 400 F, no problem for aluminum or steel.
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli Barracuda, 66 Aermacchi Sprint, 68 Gilera 106SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline berniebee

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Re: 1978 Le Mans restoration
« Reply #5 on: December 03, 2021, 09:36:28 AM »
Looking forward to seeing progress on the bike!

Regarding the wire harness, the first thing to keep in mind is that they were never designed to last that long. Have a look at the spade connectors in the fuse box area and the other connectors under the backbone and at the headlight. Especially if the bike has spent any time in a damp location, you'll see the green corrosion. That corrosion usually makes it's way up along the wires, under the insulation.  Flex some wires and see if the insulation is brittle or cracking. If there are any questionable bits, just replace the entire harness while you have the bike apart. For lighting, the minimum you should do is remove and reinstall each bulb in order to scrape off some of the 40 plus years of corrosion on the connectors.

My '83SP electricals didn't look too bad at first glance, but the deeper I dug...well, I rewired the whole dang thing.

Offline Scout63

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Re: 1978 Le Mans restoration
« Reply #6 on: December 03, 2021, 12:43:42 PM »
Once the engine is out, gearbox and clutch removal are pretty straightforward.  I would go all the way and pull the crank, vapor hone the crankcase and gearbox, and renew all oil seals and gaskets.  They are 40+ years old.  I did this for my G5 and it was a very rewarding experience.  Itís sitting next to my non vapor honed SP and the difference in the look is significant. Iíd also install new harnesses as they would be your problem area in the future. Great project and great story. Ben
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Offline Antietam Classic Cycle

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Offline 2WheelsUp

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Re: 1978 Le Mans restoration
« Reply #8 on: December 04, 2021, 09:56:44 AM »
Thanks for the feed back.  Wire harness is a good idea even though mine appears to be in great shape, don't want to chase electrical problems.  I'm pulling the front cover and installing a new timing chain, auto tensioner, and new rotor/brushes.

On another topic... I don't want to powder coat the frame as per Kent @ GMD Computrac's recommendation. My painter suggested PPG Ditzler Hot Rod Black https://us.ppgrefinish.com/PPG-Refinish/Product-Annoucements/Ditzler-Hot-Rod-Black-Kit . It's a multi-part single stage Acrylic Urethane topcoat applied over a primer. I was planning on using it for all the black bits... the frame, swing-arm, foot controls, triple trees, headlight bucket/lens and the clip-ons. It claims to be a satin finish but I haven't been able to find any samples since it's a kit and the PPG stores can't mix it so I'm a bit concerned that I won't see it before it's being laid down but I'm thinking we'll do a sample and see if it's ok before proceeding, worse case we toss it if we have to and move on to plan b. There are other kit's like this from SEM and Eastwood that might have a bit more gloss to them.

Related note... I removed my VIN plate in preparation for frame painting by using a curved head bolt along with a coupler nut that you stick into the neck and expand by unscrewing the nut. Worked perfectly... the drive screws look like new but MG Cycle has replacements I'll use.

Question for those who have had their wheels recoated.  My rear wheel is disassembled except for the sleeve that is pressed into the wheel. Do I need to remove this before powder coating and/or before chemically stripping the paint on the wheel?  If so, does this need to be pressed out by a machine shop or is it something I can do?

Offline Canuck750

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Re: 1978 Le Mans restoration
« Reply #9 on: December 04, 2021, 04:53:29 PM »
I believe the Le Mans frame paint was a low gloss, almost flat black, not the same as the typical Guzzi Tonto frame semi gloss black. I think the chassis paint you are referring to may have a higher sheen than the original LeMans finish.

I have always gone for powder coating of the frame and related chassis parts but on my 1948 Airone I had all the chassis parts painted with single stage enamel and will finish the tin parts with base coat and clear over the pins stripes and decals. What I have found working with the enamel paint (it has been curing for a couple months) is that it chips much easier than powder coat. Assembling wheel bubs, break drums, etc on the Airone I am having to be very careful to not knock a part or it chips. Now I can touch up the enamel but I could just a easily touch up the powder cured finish with a matching enamel paint. I have found the powder coated frames to be much more durable, my 72 Eldorado had been on the road for eight years now and hardly a mark on it, same for my 75 Ducati after a coup0le summers riding. It is vital to use a powder coater who is experienced with coating motorcycle frames, that will bake out an oils, prewash the frame and be light around stampings etc.

just my two cents.
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli Barracuda, 66 Aermacchi Sprint, 68 Gilera 106SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline 2WheelsUp

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Re: 1978 Le Mans restoration
« Reply #10 on: December 06, 2021, 12:11:58 PM »
Ok so I've decided to powder coat the frame after all... now just need to choose the powder.  The frame is stripped and hole for the pins are blocked but do I need to block off all frame holes, just threaded holes, or don't worry about it? 

I'm planning on powder coating the headlight bucket, lens, and the ears.  Should these more delicate parts be chemically stripped rather than sand blasted before coating?
« Last Edit: December 06, 2021, 01:55:44 PM by 2WheelsUp »

Offline Canuck750

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Re: 1978 Le Mans restoration
« Reply #11 on: December 06, 2021, 05:58:38 PM »
Ok so I've decided to powder coat the frame after all... now just need to choose the powder.  The frame is stripped and hole for the pins are blocked but do I need to block off all frame holes, just threaded holes, or don't worry about it? 

I'm planning on powder coating the headlight bucket, lens, and the ears.  Should these more delicate parts be chemically stripped rather than sand blasted before coating?

The powder coater I use specializes in automotive and motorcycle work, he also does commercial work but understands the expectaions of customers completing a restoration. The shop I use does all their own blasting, preheating, cleaning etc, and they take care of blanking off all holes, bearing surface etc. Doing your own prep requires a lot of work to get the base material properly cleaned and prepped, I use my vapour blaster and acetone wash for the small parts I powder coat in my shop with an old wall oven, I also use metal prep wash to treat the fresh blasted surface before any surface rust starts. I would make sure the coater shop you plan on using is familiar with motorcycle restorations, that they do their own blasting, metal prep and they bake out any residue grease and oil in the oven before coating.
Sand blast is too aggressive for this kind of work, at most I would use a fine glass bead or a soda blast.

this is a picture of the matte black powder i used on my 77 Le Mans restoration

« Last Edit: December 06, 2021, 06:09:52 PM by Canuck750 »
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli Barracuda, 66 Aermacchi Sprint, 68 Gilera 106SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline 2WheelsUp

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Re: 1978 Le Mans restoration
« Reply #12 on: December 06, 2021, 07:34:58 PM »
Thanks for the info. I'm heading over the powder coater tomorrow to see his shop. He does a lot of motorcycles but not sure how he preps them.  We'll see...

 


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