Getting a 1940s Moto Guzzi GTV back on the Road

[chuckthebeatertruck]

Exactly one year ago I had the opportunity to acquire a late 1940s Moto Guzzi GTV in northern Wisconsin. The GTV was essentially a pre-war bike, based around the Guzzi 500 cc horizontal single, that was continued after the war and "updated" with hydraulic dampners at both ends. The GTV means it was OHV -- with exposed valves. The Astore (and later Falcone) used much the same layout, but with friction dampners on the rear and enclosed valve gear. The model I picked up is titled as a 1949, but is likely from 1947/48. We've sent a letter off to Guzzi to find out what the frame number has to say!

Long story made short; I shared the process of checking the bike out and getting it back on the road in the Badger Heritage Chapter's newsletter over the past year. This forum series will follow the same format as what I shared in the Chapter Newsletter over the past year.

The GTV came to life on 21 January 2023 -- pretty much one year to the day after I won the auction to bring it home. It was the first time in at least 10 years, and more likely 30, that it was run.

Here we go!

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The 25 year itch

In 1997, I wandered into an overstock bookshop and went straight to my favorite section: transportation. Amidst books on canals, railways, and airplanes was a single motorcycling volume: The Vintage Motorcyclists Workshop by Radco. I bought a copy and devoured the content.

Until that time, my experience only covered bikes from the 1960s forward. Radco’s book ignited a desire to learn about pre-1950 machinery. Over the next few years I got my hands on everything from Rudge to AJS to the very odd Scott Flying Squirrel. However, there was one bike featured in Radco’s tome I never got a chance to experience: the Moto Guzzi Falcone. It would take the next 25 years and a trip across Wisconsin to scratch that itch.

The Moto Guzzi Falcone was introduced in 1950 as the successor to the GTV – itself a direct descendent of the 500cc swing arm frame singles introduced by Guzzi in the early 1930s. There was nothing earth-shattering about the big, slow revving Guzzi, which first debuted in 1921*. They were known for being robust, easy to ride, a treat on dirt roads, and rewarding to own.

Though their performance was greatly eclipsed by more modern machinery, Guzzi continued to sell these big singles through 1969 and the introduction of the “Nuovo Falcone.” This gave the motor family a life span of 48 years of continuous production. By comparison, Harley Davidson’s legendary 45-inch (750cc) flathead was introduced a few years after the Guzzi single and produced for 42 years. Few other motorbikes can claim to have been in production as long and with so few major changes. Like the Harley 45; the Guzzi Single also saw widespread police and military use.

Because these Moto Guzzi models were never particularly popular in the US, they were imported in small quantities. The loosening of grey market imports in the 1990s and 2000s saw more of them imported from Europe, but they still do not appear on the open market very often. It’s a treat to encounter them at AMCA meets and seeing a 250cc Guzzi Airone on our (Badger Heritage Chapter) October 2021 Pokey Run made me double down on finding a 500. While I had hopes, the past 25 years taught me to be very patient when looking for one of these bikes.

Much to my surprise, a terrific 1949 500 GTV came up for sale in Cameron, Wisconsin. After a short bidding war; we won the auction and made arrangements for the 6.5 hour trek from our home south of Chicago to northern Wisconsin. We made a weekend of it traveling to Eau Claire for an overnight stop and enjoying a Valentine’s dinner at Johnny’s Italian Steak House. The next morning we awoke to -11 temperatures and headed out to find a hearty breakfast. After a stop at Heckel’s Family Restaurant in Chippewa Falls, we made the final 45 minute drive to Cameron up Hwy. 53. It was a stunningly beautiful drive through fresh, white snow.

The excitement at finally finding “my” Guzzi meant we did not notice it was still -2 when we loaded up the bike. Much to my surprise, on physical inspection the bike was nearly complete and appeared to still be wearing its original paint. To protect it from any damage, we encapsulated the bike tightly in pallet wrap. When done correctly, the plastic wrap doesn’t move or rub against the paint – but it does keep rocks, salt spray, and junk off your bike.

A more detailed inspection of the Guzzi after we got it home revealed it has terrific compression, and strong spark. It mostly needs service items like control cables and tires. Over the coming year, I will give the bike a thorough inspection and 10,000 mile chassis service. We will document the process and share some tips/tricks for getting a barn find back on the road in future newsletters. The goal is to have this bike running smoothly and reliably for our 2024 National Road Run in Eagle River.

Until then – speedy safely and keep looking for your dream bikes. They are out there . . even if it takes a couple of decades to track them down.



*In 2021, Moto Guzzi became one of only a handful of manufacturers to enjoy continuous production of motorbikes for 100 years or more. Others include: Peugeot (1898), Royal Enfield (1901), Harley Davidson (1903), and Benelli (1911). BMW will join this tiny group in 2023.

[chuckthebeatertruck]

Getting Gramps Back on the Road

In our last installment, I shared the story of bringing home a 1949 Moto Guzzi nicknamed Gramps. Many of us dream of finding a bike like Gramps which is complete and while not 100 percent original, it is not too far off, either. Usually, we want to jump right into making the bike run and tend to forget about the chassis, electrics, and braking until our first run down the road. However, these systems often suffer from old lubricants, corrosion, and neglect. Electrics, in particular, can cause massive problems if not checked carefully – and even cost you the bike if they catch fire.

To ensure we don’t overlook anything in our excitement, I usually begin the process of getting a bike like this back on the road by giving it a full “10,000 mile service.” Most manufacturers recommended a complete overhaul of the chassis and attendant systems at intervals of between 5,000 and 10,000 miles. This consists of a stripping of the front and rear suspension, tire/brake checks, clean/check of the electrics, and full power train service.

We started by looking over the bike and recording what was obviously in need of attention.
Our inspection showed the need for all of the control cables to be replaced along with rebuilding the petcocks for the fuel and oil tanks. While some of the cables are available, it was easier to order cable making supplies from Flanders Handlebars and make our own cables. We will share that process in a future Club newsletter. We also found that the foot controls will need bushes to deal with excessive wear. The lathe will be getting quite the work out this spring and summer!

The original wiring was long gone, as were the battery hold downs. Thankfully, the bike is very easy to wire and to convert to modern, 6V LED. We also will replace the original mechanical cut out on the dynamo with a modern solid state unit out of the UK which fits under the original cover. I also decided to replace the rear marker lamp with a proper stop/tail lamp. A trip to Menards revealed an $8.99 trailer lamp that is awfully close to the CEV units installed by many Italian makers in the 1960s. Two holes drilled in the non-original license holder had it mounted with no damage to original parts. We also discovered that while the tanks were stored dry – they were not treated and had rusted badly. The oil tank had rust on the outside and the inside! We soaked the tanks in vinegar for 10 days to get rid of the rust and followed up with ospho to neutralize any remaining rust. Despite nearly an ounce of rust debris falling out of the fuel tank after cleaning – it held liquid!

We then moved to stripping the front suspension. Surprisingly, the tires are only a handful of years old with matching tubes. However, the front axle was bent and the bearings damaged as a result. The axle had been on and off the bike so many times over the years the threads on the right side were almost worn away! Rather than deal with trying to restore the part, we made a new axle. Cross referencing the bearing size revealed they are a common item and were used on the Renault Dauphne suspension. Rather than replace the original felt seals and cages; we changed the front to modern oil seals. I have done this modification on several bikes; but this was the first time that I was able to order seals in metric sizes and have them fit right in without modifying parts!

The rest of the front suspension revealed no surprises beyond grease older than the Nixon administration. The brakes, however, were a mess. The original linings were very worn out and caked in grease from missing grease felts/shields in the front bearings. To deal with this, we ordered several feet of high-friction, woven brake lining from McMaster Carr industrial supply. The old linings were woven material, making this an easy swap. I have been using these linings for almost a decade on my personal bikes. They work very well and it costs about $10 to reline a pair of shoes. If you are uncomfortable lining your own shoes; most truck stops or small airports will have a mechanic that is comfortable bonding or riveting shoes for you.

Over the next couple of months, we will move onto the rear suspension and then see how the bike performs on the road. However, we couldn’t resist checking the motor out. We have healthy spark from the magneto and just under 60 psi of compression. While this figure sounds low, it is correct for this 5:1 bike and indicates we should experience little fuss getting the bike up and running in the near future.

Speed Safely!

[chuckthebeatertruck]

Here's some photos from the front end work . . part 1

[chuckthebeatertruck]

Making Control Cables for Your Vintage Motorbike


Sooner or later, it happens to us all – a broken control cable. For many popular makes and models of motorcycle, replacement cables are widely available. However, if you have an unusual bike or non-stock controls, custom cables may be your only choice. While you can order custom from companies such as Motion Pro and Barnett, it is easy to make your own cables. In this article, we will talk a little bit about cables and walk you through doing one up.

The first thing to understand is where to get supplies and the terminology to get the parts you need. There are several companies selling Bowden Cable supplies (Bowden is the name for type of control cables found on our motorbikes.) I mostly use Flanders, the same company which also makes handlebars. You can reach them at www.flandersco.com; Phone: 1-626-303-0700 or Fax: 1-626-377-9752. They have a detailed website which lists all the various cable making parts they sell, with an even bigger inventory offline. I usually e-fax them my order and in an hour or so get a phone call to confirm the order and take a credit card number.

When ordering supplies, the four terms you need to know are:

1. Control wire – this is the “inner” wire or cable that connects a lever to the item being controlled. There are multiple types of cable in multiple sizes. Flanders can advise.
2. Control conduit – this is the “outer” spiral wound casing that contains the control wire
3. Ferrule – the cap which goes over the end of the control conduit and often fits into a receiving cup in a lever end or other control surface. Usually alloy or nickel plated steel
4. Wire ends (aka nipples) – these are the specific fittings found on each end of the cable which transfer the lever motion to the item we are trying to control. Usually brass or mild steel.

Armed with this basic vocabulary, you can begin researching what is needed for your bike. In essence, we want to aim for the most tightly wound conduit we can use and the heaviest gauge of control wire we can use and still have clean routing/actuation. The stiffer these components; the more smoothly and easily we can actuate something. This is particularly noticeable on brake and clutch cables. For most motorbikes, 5mm conduit and .046-.084 wire will cover most of your needs. In most cases, the supplies will cost you around $15 per cable.

The next question is whether you wish to include inline adjusters. Many vintage bikes only had one point of adjustment where as more modern bikes often have two points of adjustment. Therefore, for non-points bikes; I often do include inline adjusters to make side of the road adjustments just a bit easier. Remember to site adjusters on straight runs of conduit, not on curves. The straighter the run, the less motion is lost to the adjuster as the conduit pushes against it. Similarly, it is personal preference whether to use Teflon lined conduit. I do like Teflon conduit for brake and clutch levers; but rarely use it on choke, timing advance, or throttle cables.

From that point, it is a matter of measuring the lengths of wire/conduit that you need. It is easiest if you have a cable to copy. If you do not have that luxury, a four foot long piece of 10-14 gauge household wire is very handy. Simply use the wire to simulate the routing of the cable and carefully measure the end to end length. Add 10 percent for waste/mistakes. This is your conduit length. You will then order the same amount of wire, plus six to eight inches to give you the necessary overall length.

I use a notebook to draw each end of the system when making custom cables. I then order the necessary parts based on the drawings and rough notes. For example, many bikes use 10mm or 3/8 diameter barrel ends for the hand levers – but the length of the barrels can vary from 10mm to 20mm. Keeping track of which end you need helps speed production of your cables and avoid frustration.

The last items you will need are solder and flux. Make sure the flux you choose is compatible with stainless steel and brass or steel end fittings. In terms of solder, make sure you use either plain or acid core solder, in either 50/50 tin-lead or 60/40 tin-lead formulas. Do not use resin core solders. Avoid “hard” solders such as high antimony compositions or 95/5 plumbing solder. Either has a tendency to crack and fail in use on control cables.

A large roofing soldering iron or solder pot are recommended over a soldering gun or torch. It is very easy to overheat wires with even a small propane torch. Overheating the wire is what contributes to premature fatigue failure. You can often find large roofing irons at antique shops for $10-20. Solder pots are about $30 on Amazon. Pots also contribute to a professional appearance for your cables.

It just so happened every single cable on the 1949 Guzzi I am waking up from hibernation needed replacement. However, only two of the six cables were available commercially. I also wanted to route the cables more cleanly than OEM. Off-the-shelf cables were not an option.

The only two cables to “survive” intact on the ’49 were the clutch and front brake. Both had broken in the past and were rescued with clamp on wire ends. [note to editor – photo 1]



Here’s what a box of parts from Flanders looks like when you are making cables for an entire bike. There is something like 55 individual parts in this photo – all just for the ’49 Guzzi. I often buy duplicates of items just in case I lose a part or make a mistake.


I bought a new solder pot for this project. It was $28 on Amazon and came with a spare pot.


Here are the soldering supplies used for this job. The big roll is 50/50 stearic core solder. I put a few ounces of solder in the pot and let the stearic bubble to the top before skimming it off.




I started by laying out the conduit. Make sure your routing is clean and that you can waggle the bars without pulling the conduit. I like to mark with masking tape and then cut dead in the middle of the tape. You can use a hot needle to reopen the Teflon liner if it nipped up from the heat of cutting.



The ’49 Guzzi did not come with adjusters at both ends. I added inline adjusters to give more options for adjustment. For the clutch cable, I chose to place the adjuster about 4 inches from the steering stem where it will be mostly hidden but readily accessible.



Fit ferrules on the two ends that will insert into the inline adjuster and a ferrule onto the end that will fit into the control lever. Insert your control wire and run it through both lengths of conduit and the adjuster.




Let a couple of inches of wire hang out the lever end – and mark the control surface end where you want it to be. Remember to be generous so you can adjust the length in the final steps.

Take a moment to tin the wire before you cut it. This helps keep it from unravelling. I dripped some flux over the area I marked and then dipped the wire in the solder pot for a count of 5. This tinned the wire about ½ inch on each side of my mark.

Insert the barrel end through the wire. Using a center punch; splay the wire in the barrel end so it is distorted and fills the cavity. This step is what gives us strength and prevents the cable from pulling through the end fitting. You will have to smack the punch smartly. I usually clamp the wire in a vice and set the end fitting on the jaws of the vice. That allows me to hit the wire end pretty hard without fear.




Dip the barrel end in flux to about 1/2 inch past the barrel and flick off the excess.

Dip the fluxed parts in your solder pot to about a ¼ inch past the barrel end. Count to 5 and pull the items out.

You should have a very nicely soldered on end fitting.

Hook the cable up to the control lever and run all the adjusters to their minimum point. Carefully line up the wire end with the control surface and carefully mark your final length.




Cut the wire to final length, add a ferrule to the cable, and add any accessories such as an adjuster. Like with the barrel end; add your fitting and carefully splay the wire.

Flux and solder the end fitting as before.

Clean up excess solder with a medium file and lube the cable

Install the cable, check the function, and admire your handiwork.








After you do a few cables it will take you minutes to make up new cables. The biggest mistake is either not splaying the wire well before soldering or not allowing enough time for the solder to fully penetrate the fittings and wire. Take your time here and the resulting solder join will be very strong and last decades.

Speed Safely!

[chuckthebeatertruck]

With all that done; we were on to rewiring the bike and repairing the generator/dynamo.

The wiring had been all pulled out - and everything needed replacing. We did choose to use an original style high/lo beam and horn switch; but everything else was altered in some way. The dynamo was in particularly bad shape. It uses a tufnol gear which had slowly sheared all of its teeth -- making a mess in the primary. Adding to the mess was the fact the seals were left out and oil mist had been allowed to accumulate in the dynamo. It needed a good soaking and cleaning before it went back in with a modern solid-state 6v regulator. The battery itself are two 4ah wired up to give 6v and 8.2ah of capacity. Along with the LED lamps -- it equates to some 14 hours of riding regardless of whether the dynamo is working well.

Similarly, checking the timing showed it to be exactly on 100mm of flywheel movement before TDC or just about 40 degrees. Original specs range from 95 to 110mm. Most importantly, the magneto retard function took a full 30 degrees of advance out -- making it relatively easy to start the bike with the valve lifter.

Therefore, we turned our attention to dealing with the oblong wear in the rear brake and shift mechanisms. The shift mechanism was due to bolts, instead of pins, being substituted in the linkage arms -- as well as extreme wear at the pivot. The end result is that the lever moved 1/2 inch in or out and as much as 3/4 inch before it acted on the shift mechanism! To correct this, I turned the pivot bolt in the lathe whilst boring out shift lever to 26mm. I then cut a bar of 660SAE bearing bronze to act as a custom bushing for the "repaired" surfaces, fitting them .001/.002 loose. I then bored the holes in the linkage to 8mm to take care of the oblong mess and made new pins out of 4140 steel. Once drilled and fitted; the pins eliminated the remainder of the play. After about an hour, the mechanism was operating smoothly for the first time in decades.

I then moved onto the rear brake. A quick look at the photos will show this is an unusual heel operated brake which also uses an "over camming" effect on the rear brake via a pivot. Every single bit was worn oblong -- from the pedal pivot to the control rods. The rear rod was worn a full 1/8" and pretty much dead. I carefully welded up the worn end and then refiled it round to fit. I also had to surface the rear pivot, bore the holes oversize, and make custom "top hats" to mate the worn parts. I chose to make the top hats out of ptfe (teflon) rod. This allowed a certain amount of give in the system and ensured I don't have to lube them all the time (thus attracting grit and wearing the top hats faster than if left unlubricated). I also replaced the rear brake springs with new ones -- which made a major difference! Once again -- after about two hours of work the rear brake finally stopped correctly!

At this stage, all seemed well except the front end had a consistent drag -- but it appeared at random places in the wheel rotation. After a lot of detective work -- I discovered the right side race, which I didn't replace, had been installed nearly .035 cocked compared to the other side of the race. This explained a lot -- and the only solution was to disassemble the wheel and sleeve the bore.

I started by fully despoking the wheel and making sure the drum surface ran true to hub centerline. That done; I carefully fixtured the hub in the lathe and adjusted it to zero run out. At this stage, I began boring the hub oversize to release the cocked up race. After some heat and use of a 20T press -- it popped out leaving me with a visibly worn and eccentric bore/seat. To correct, I bored the hub just a touch over .125 oversize and carefully squared the race seat. I then cut bar of 6061 aluminum to be a .003 press fit in the hub. Once the hub was warmed to 200 degrees; I coated the sleeve blank with loctite 630 sleeve retaining compound and pressed it home. I let that sit 48 hours and began the process of boring the sleeve to match the race. I fit the race with a .0025 press fit -- again heating the hub (and sleeve) to 200 degrees before pressing the race home in a 20T press. With that done -- the hub FINALLY rolled straight and true.






I then relaced and trued the rim; installed the tube/tire; and installed all the fuel lines.





I rolled the bike out and first put it on the roller starters to circulate oil. After 2 minutes on the rollers total -- I had oil going in -- but nothing returning. I pulled the oil pump to find a small, but real amount of sludge clogging up the return line. That cleared, the bike started returning oil immediately.

At this point -- I was out of excuses. In went a gallon of fuel. The left petcock had a little drip and the carb needs some tuning . . . but we were ready.

Tickle the carb for a count of 4.

Bring the bike up on compression.

Set the Air Lever to 1/2 open (it was 30 Degrees F outside!)

Set the timing to full retard

Pull the valve lifter lever in and ease the bike over TDC

Release the valve lifter lever

Kick!

First kick -- nothing

Second kick -- it sputtered

Third kick -- the bike fired right up and settled into a 1500-1800 rpm idle. Advancing the timing smoothed it all out and pulling the air lever fully open made it howl! Oil was returning and the bike took throttle well despite being dead cold.

I pulled the valve lifter lever after about 45 seconds to stop the motor. I let it sit 10 minutes and in one kick it started right back up. Did that a few times and called it a day.

I still need to address the fuel drips from the left petcock; but we're ready for some road testing as soon as the weather warms a bit.

And, just like that, another old derilict is back on the road.

I hope this series helps folks to understand there are many ways to approach a bike sitting for a long time.

In this case, had I just added oil and fired it up -- I would have likely wound up doing more harm than good. By going through the whole chassis then the motor, I addressed most of the problems straight off.

The cost of reconditioning the bike was really cheap compared to many others. My total parts investment was less than $250 and all the bits I made for the bike came from scraps in the shop.

[exeric]

I love your Moto-Guzi and think it's a beautiful motorcycle. Great build document that promotes a motorcycle that deserves love, recognition, and attention. Thanks for the details, and photos of a motorcycle I always liked, but didn't know much about.

[PaulCDF]

Beautiful Bike and Nice Work (as always) Chuck!
I bet it's a blast to ride!!!!

[gitguy]

Great synopsis. Another project well done! Thanks for sharing.

[ChiefTwoKicks]

am I the only guy who hasn't been able to access the pictures ?

[HDSmitty]

Thanks so much for an excellent write up on the Guzzi. A thoroughly enjoyable piece that I'm sure will benefit anyone who takes the time to read it. I know a person that has one of these bikes (or very similar) and I will certainly point him in this direction because after all, ya gotta admit they're not seen too frequently. Your mechanical expertise and the ability/willingness to document/relay it all are very appreciated. .....Smitty

[chuckthebeatertruck]

Thanks for the kind words, all.

With these Guzzi’s there is a tiny bit of info out there and a couple of restoration threads on the 250cc models. There are pdfs of the workshop manual as well. BUT all of them are classic shop dopes with vague descriptions and assume both a newish machine and a ready supply of new spares. Dealing with extreme wear from 70 years of use somehow gets left out of shop dopes ;-)

Parts availability for most of the cycle consumables are available from specialists in italy. i was bummed at the prospect of having to make my own dynamo drive gear. gear hobbing on manual machinery is a slow process. I was shocked to find new tufnol gears from a supplier for 30 euro. Similarly, the square section o rings in the rear shocks are still available from mcmaster carr and other major industrial suppliers. Like many bikes from the 30s and 40s, with some detective work you can often track things down in unexpected places.

the most unusual one for this bike was the chain guard. i got connected with an italian-argentinian living near burgos aires. He reproduced the guard for me and reproduced the exhaust header flange, all for $100, shipped.

Now, i just need to finish convincing Mrs Chuck we really do need a 500 Rudge to keep the 500 goose company.

[chuckthebeatertruck]

For the curious, here’s the link for requesting info from guzzi about your bike.

https://service.piaggiogroup.com/Vin...p?L=EN&B=Guzzi

It really is as simple as filling in details and paying the fee.

[RichO]

Chuck. I stumbled on some paperwork on your model Guzzi in my files. You may or may not already have them but if you send me a pm with a mailing address I'll send them to you on my dime. Rich

[JoJo357]

Great story Chuck. It especially hit a nerve when You mentioned the drive to go get the Guzzi. I vividly remember picking up a 1938 ULH, that i just bought, back in the mid 1990's. Driving through secluded virgin snow in the middle of winter in upper Michigan can be hard to beat. Brought back some fond memories~Thanks. Good luck with the Guzzi Chuck.

*M.A.D.*
*Almost the same color too~haha. A perfect day, until my wife found out~haha.

https://www.ebay.com/itm/16589276579...sAAOSwaEpjx9Qu

Photo on 6-4-17 at 9.36 PM.jpg

[RichO]

JOJO, Loved the flipped negative. you had me going there for a second. Rich