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General Category => General Discussion => Topic started by: neetones on June 11, 2025, 07:20:36 PM

Title: Looking at a '69 Amb - Red Flags?
Post by: neetones on June 11, 2025, 07:20:36 PM
Hi all.

I've owned many bikes and even a modern Guzzi (V7 850) but I'm looking at a '69 Ambassador that has 36k miles. I doubt the engine has been rebuilt. Apparently it runs fine and starts up well.

What should I look out for? I am looking for a bit of a project, but I don't really want to be rebuilding the short block in the next couple of months.

Any suggestions would be appreciated. Hoping to get this project going.

Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Antietam Classic Cycle on June 11, 2025, 07:49:34 PM
The most important issue will be the chrome-plated bores. You'd need to have the cylinders replated or sleeved. To do the job right, the engine should be disassembled completely so that the sludge trap can be cleaned out and everything else inspected.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Moparnut72 on June 11, 2025, 08:34:46 PM
There are a lot of threads on this site covering the chrome bore issues.
kk
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Turin on June 11, 2025, 10:23:42 PM
I did the cylinders on my Ambo and it's as reliable as an anvil. I can't think of any red flags other than what's been mentioned and neglect.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: John A on June 12, 2025, 12:28:28 AM
Yep, chrome cylinders is the only red flag. Chrome over aluminum eventually flakes off. It is hard and the bits embed into the bearings and grind away. Fix that and they will run forever. I got a hundred and sixty eight thousand miles on my first one when I was a riding fool. I bought that one used in Minnesota and rode it out to California where I was stationed. I found a place that fixed Eldorados for the police who sleeved the cylinders and recut the ring grooves to fit automotive rings . Riding the mountains, it reminded me of an old gravel truck. On the plains it would run a hundred miles an hour for days. It had a decent seat. If I wasn’t so old, I’d get another one!
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Antietam Classic Cycle on June 12, 2025, 08:36:54 AM
I bought my early '69 Ambo in '97 with 36k miles on it. Should have replaced the cylinders as soon as I got it, but I didn't know about the issue then. At 54k it was getting pretty tired - on one trip to NC on the BRP, it would get hot enough to smell on long climbs. When I removed the cylinders, the top ring on both sides fell into 3 pieces. Not a lot of chrome missing though. I pulled a rod cap to check condition, finding none buttoned it back up, replaced the cylinders, had the heads rebuilt and ran it. Now at 111k miles it needs the heads rebuilt again.

Issues I had in all of those miles: Original ignition coil cracked and was leaking oil, replaced it with a new Echlin that failed within a week. Replaced that with the Bosch Blue Coil that's still on it. Fuseblock melted where the power wire to the headlight switch connects. Wired in a separate fuse and later added relays for the headlight. Starter button fell apart at ~ 96k miles. Replaced. On the way back from a rally, the generator light started glowing brightly at speed, but was dim at stops. Found that one terminal on the generator was only connected by one thin strand of wire. Crimped on a new terminal and it was good to go.

Still has it's original clutch and u-joint, bottom end of the engine (other than the rod journal inspection) and transmission have never been apart, rear drive was resealed at 98k miles - gears and bearings all looked perfect. Original wiring is looking a bit tattered, but still does the job. Original switches all still work fine.

Best bike I ever owned. Will never sell it.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Moparnut72 on June 12, 2025, 09:03:16 AM
I had a hard time deciding on one of these and the newly released R75/5. I went with the BMW as it was a bit more sporting, more suitable for a young guy. I put just under 100,000 miles on it with not too many issues. With the amount of mileage I put on it in a short period of time I probably would have had chrome bore issues in no time. I had 32,000 miles on it in the first year and a half that I owned it. It was one of the first ones built, BMW through the dealership was following my progress as kind of a beta tester. I was in the Army with a 7 to 5 job with lots of free time and leave. I lived on that thing. Good days.
kk
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Antietam Classic Cycle on June 12, 2025, 09:57:37 AM
I had a hard time deciding on one of these and the newly released R75/5. I went with the BMW as it was a bit more sporting, more suitable for a young guy. I put just under 100,000 miles on it with not too many issues. With the amount of mileage I put on it in a short period of time I probably would have had chrome bore issues in no time. I had 32,000 miles on it in the first year and a half that I owned it. It was one of the first ones built, BMW through the dealership was following my progress as kind of a beta tester. I was in the Army with a 7 to 5 job with lots of free time and leave. I lived on that thing. Good days.
kk

The chrome bore issues arise from not being used, you would have been fine. I know of an 850-T3 that went 250k miles on it's original chrome bores, never sat for very long obviously.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Moparnut72 on June 12, 2025, 10:28:05 AM
Nope. It was my only transportation so I rode it daily. I even had a heater for the oil so it would start on really cold mornings.
kk
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: neetones on June 15, 2025, 09:08:05 AM
Thanks for all the input. I picked the bike up yesterday.

It hasn't been ridden in some time so it's not running all that well. Time to dig into it and get it road worthy.

https://ibb.co/8L3wvZP3
https://ibb.co/Mk9yK4dB
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Turin on June 15, 2025, 10:31:21 AM
Someone has done some minor customizing. Do you have the airbox and sidecovers?
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: JBU on June 15, 2025, 12:17:38 PM
What is this thing?

(https://i.ibb.co/RTxBy6DZ/Screenshot-2025-06-15-at-1-14-30-PM.png) (https://ibb.co/tp7xX2Jk)
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: neetones on June 15, 2025, 01:50:29 PM
The previous owner was a fairly masterful fabricator. Many custom parts, including a custom leather battery box and seat with suspension.

That item is a battery status indicator. Press the button to see how much voltage you've got.

It's running pretty terribly right now. Going to pull the heads off to look at the cylinders.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: cliffrod on June 15, 2025, 03:11:02 PM
The previous owner was a fairly masterful fabricator. Many custom parts, including a custom leather battery box and seat with suspension.

That item is a battery status indicator. Press the button to see how much voltage you've got.

It's running pretty terribly right now. Going to pull the heads off to look at the cylinders.

Unless there’s some obvious issue indicative of a piston or valve issue, There’s a lot that I would do before pulling the heads off simply because it runs terrible. randomly taking things apart and making unnecessary adjustments is more likely to simply causenew issues.

Carbs in need of a proper cleaning is the first thing to inspect & resolve on a bike that’s been sitting for a long time. 
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Turin on June 15, 2025, 03:37:58 PM
 +1
drop the float bow and look for smutz.

Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Antietam Classic Cycle on June 15, 2025, 03:49:52 PM
With a new to me (or new to a customer) I assume everything is wrong tuning wise. I start with retorquing the heads and adjusting the valves. Correct heat range plugs and proper gap, cleaning the points, setting the gap and checking static timing. Check condition of the plug wires, particularly the ends where they go into the cap and coil. Then checking the carbs over - crud, correct jets, float level, etc. Check carb balance and sync mechanically (with various sizes of drill bits). More adjustments with it running...
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: neetones on June 18, 2025, 01:46:25 PM
VERY excited to check the cylinders and see "GILARDONI" cast into them.

Things are looking up already - no chrome!
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: jumpmaster on June 19, 2025, 07:27:58 AM
VERY excited to check the cylinders and see "GILARDONI" cast into them.

Things are looking up already - no chrome!

I remember happily discovering that a previous owner had at some point gotten Nikasil plating on the cylinder walls of my new-to-me 73 Eldorado.  I had already budgeted (in my head) for new cylinders when I made my offer on the bike.  Of course, when I took the bike to Charlie Mullendore for some electrical work, he found a fair number of other issues needing attention & they quickly absorbed the money I had "saved" for Nikasil, and then some!  :grin:
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: neetones on June 19, 2025, 10:35:19 AM
I remember happily discovering that a previous owner had at some point gotten Nikasil plating on the cylinder walls of my new-to-me 73 Eldorado.  I had already budgeted (in my head) for new cylinders when I made my offer on the bike.  Of course, when I took the bike to Charlie Mullendore for some electrical work, he found a fair number of other issues needing attention & they quickly absorbed the money I had "saved" for Nikasil, and then some!  :grin:

Hey! I see you're in Gaithersburg. I grew up right off of Shady Grove.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: jumpmaster on June 19, 2025, 02:41:36 PM
Hey! I see you're in Gaithersburg. I grew up right off of Shady Grove.

I currently live off of Mid-County Highway, just up the hill from Shady Grove Rd.  Do you still live in this area?  If so, I may be able to give you some tips on local resources, etc., or vice versa... :grin:
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: Tom on June 19, 2025, 03:04:10 PM
Just because.....check your generator to see if it moves.  If it does check the mounting bolts. Before tightening.  Remove the mounting strap.  Take a look at the bolt holes.  Do not over tighten.  🤦‍♂️  There's a fix w/o removing the engine.  Anyone can jump in.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: neetones on June 19, 2025, 07:09:28 PM
I currently live off of Mid-County Highway, just up the hill from Shady Grove Rd.  Do you still live in this area?  If so, I may be able to give you some tips on local resources, etc., or vice versa... :grin:

Unfortunately, nope. I'm in California. Hope the humidity and mosquitoes aren't too bad.
Title: Re: Looking at a '69 Amb - Red Flags?
Post by: jumpmaster on June 19, 2025, 10:32:28 PM
Unfortunately, nope. I'm in California. Hope the humidity and mosquitoes aren't too bad.


We've had a few vicious thunderstorms and some flooding in various DC-adjacent areas, but generally this spring was relatively comfortable in weather and humidity.  Starting yesterday, that has changed to typical hot & humid DMV weather, so the mosquitos will soon come out in force, too.