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model identification please

U

Unimog63

Just got it firing!
Joined
May 11, 2024
Messages
14
Location
Bar Harbor, Maine,United States
I was given a 1975, non running, "Moto Gus" according to the title. I now think it's a 750 S. Dusty but not bad, engine turns, tank is clean, rear brake works. Front master cylinder looks bad, missing banjo bolt. All three rotors are rusty, not sure if I can resurface them. Tack housing is bent, a project it is but I have two Ducati's and an opposable thumb.
Parts and advise desired!!

Steering head stamped:
DGM OM (no numbers between letters)

engine # VD 100084 (yes, stars before and after numbers)
 
Unimog63 said:
I was given a 1975, non running, "Moto Gus" according to the title. I now think it's a 750 S. Dusty but not bad, engine turns, tank is clean, rear brake works. Front master cylinder looks bad, missing banjo bolt. All three rotors are rusty, not sure if I can resurface them. Tack housing is bent, a project it is but I have two Ducati's and an opposable thumb.
Parts and advise desired!!

Steering head stamped:
DGM OM (no numbers between letters)

engine # VD 100084 (yes, stars before and after numbers)
Click to expand...
VD prefix means it is an 850-T3. The 750S had a drum rear brake, 750S3 had triple disks. Both have a "VK" prefix. Neither was officially imported into the US though.
 
very nice!!

Here are pics via bore scope of the cylinder bores. Chrome?? The magnet test you mention in other posts suggest as much magnetic pull as steel has. Should they be chrome what are my options??

This is the best forum ever!!

M-

IMG 0023 IMG 0024 IMG 0025 IMG 0026
 
Doesn't appear to be chrome. The top two pictures make me thing steel liners were installed. As far as I know, the 850T was the last chrome bore. The T3 I had did not have chrome bores.
 
Are you saying that a magnet is sticks to the bores strongly? If yes, then iron liners. If no magnetic attraction, then chrome. I can't see anything in the photos that is definitive, but the speckled areas sure look like worn thin chrome to me. And yes, T3s did have chrome bores, I've replaced several sets of them in customer bikes. The only 850s that came from the factory with iron liners were the 850 Le Mans and 850 Le Mans II.
 
Amboman said:
And yes, T3s did have chrome bores, I've replaced several sets of them in customer bikes. The only 850s that came from the factory with iron liners were the 850 Le Mans and 850 Le Mans II.
Click to expand...
Apparently not all T-3s as mine did not have chrome. I can confirm that as the bike was hit and I used the cylinders on a different bike.
 
Sorry for the delayed response. My impression was chrome, I've seen a lot of liners (with the heads off) and none looked like this. I'll post a line picture from this bore scope tomorrow of a known iron liner as a comparison. The magnet sticks, and seems to have the same attraction as on steel so I'm hopeful.
For the price of a head gasket I think I'll remove a head.
 
Unimog63 said:
Sorry for the delayed response. My impression was chrome, I've seen a lot of liners (with the heads off) and none looked like this. I'll post a line picture from this bore scope tomorrow of a known iron liner as a comparison. The magnet sticks, and seems to have the same attraction as on steel so I'm hopeful.
For the price of a head gasket I think I'll remove a head.
Click to expand...
Won't be a wasted effort for if they are chrome they need to be replaced.
 
For comparison: #0024 850 T-3 Guzzi, #0028 Evolution Harley Davidson. I'll report back once the head is off, hope to find time tomorrow. . .
 

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Cylinder head off today, chrome is the answer. The magnet was sticking to the head gasket near as I can tell. I'll cut open the oil filter and inspect but I see no sign of flaking, nothing in the pan.
MG Cycles cylinder / piston kits are out of stock, I can wait for them, with the rest of the drive line old and stock what are your recommendations, big bore or stock? Not much price difference.
 
Unimog63 said:
Cylinder head off today, chrome is the answer. The magnet was sticking to the head gasket near as I can tell. I'll cut open the oil filter and inspect but I see no sign of flaking, nothing in the pan.
MG Cycles cylinder / piston kits are out of stock, I can wait for them, with the rest of the drive line old and stock what are your recommendations, big bore or stock? Not much price difference.
Click to expand...
Keep it stock. You wouldn't gain much going to big bore and you will eliminate any balance issues. While it is down, check to see if the clutch has been updated to the 4mm splines. Also good time to replace the cam tensioner. The original tensioner is basically worthless. Go for a Bow type tensioner. If you find anything in the oil filter, inspect the rod journal and rod big ends and main bearings. If you have to go that far, remove the plug from the crankshaft and flush the crankshaft. Then you can look at updating all the seals in the engine, gearbox and rear drive. You have time to go through everything waiting for the cylinder and piston kits.
 
MG Cycle isn't the only parts supplier in the US.
crustycycle.com/products/moto-guzzi-cylinder-complete-83mm-850t-t3-eldorado-850gt

harpermoto.com/products/gilardoni-cylinder-kit-850-eldorado-gt-t-t-3-1044400

In order to complete customer projects in a timely manner, I sometimes buy direct from Stein-Dinse in Germany. Orders are always packaged very well and delivery time is usually only 4 days.
 
I too have ordered a ton of parts from Stein Dinse. In almost every single case, I have received my parts from them in Germany, within 3-4 days. Always packed perfectly and never an issue. They are a first class outfit.

Never knew about Crusty Cycle. Thanks Charlie for the tip! 👍
 
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Amboman said:
In order to complete customer projects in a timely manner, I sometimes buy direct from Stein-Dinse in Germany. Orders are always packaged very well and delivery time is usually only 4 days.
Click to expand...
With the low production rate on these kits I would call the company to make sure the items are in stock. The nice thing about the MG Cycle web site it is tells you if in stock or not.
 
john zibell said:
With the low production rate on these kits I would call the company to make sure the items are in stock. The nice thing about the MG Cycle web site it is tells you if in stock or not.
Click to expand...
Both Crusty Cycle and Stein-Dinse show if a part is in stock or not. Harper's often shows items in stock that aren't really.

10+ in stock at S-D: stein-dinse.com/en/moto-guzzi-cylinder-complete-83-mm-850-t-t3-t4-v7-850/item-1-1078339-3459.html
 
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