Going to need help with the French car

[RedMF40]

Just a heads up, I’ll elaborate in a bit. I’ve rebuilt the top end, put new piston rings in and the motor sounds strong. Getting a “miss” or kind of spitting through the carb. I’ll post a video of what’s going on. The heads were professionally redone by a very good local guy.

1966 Citroën 2CV
Twin opposed 435cc engine
4 speed with centrifugal clutch for 1st gear
(Leave it in first at a stop and just accelerate)

Condition in the photo is as good as it’s going to look.

Overall assessment: a junker that lives to see another day. I bought it in non-running condition so there is some progress.

I’ll be in touch and thanks in advance.

Gerrit

 

[JD Dave]

Always wanted one of these to replace my Gator. As I remember, 2-cycle. There's probably a service and parts manual out there somewhere. Think chainsaw engine, - only bigger. Might be something simple like a reed valve or the like. There is a following out there for these french fries. Someone will know.

 

[RedMF40]

Always wanted one of these to replace my Gator. As I remember, 2-cycle. There's probably a service and parts manual out there somewhere. Think chainsaw engine, - only bigger. Might be something simple like a reed valve or the like. There is a following out there for these french fries. Someone will know.

Thanks, I have the repair manual and full restoration guide as well. FYI-regular 4 stroke engine, nothing fancy. Single barrel carb.

Actually thought I was posting in tractor talk.

 

[docmirror]

1st guess; valve adjustment.
2nd guess; Ignition timing.

Get a compression gauge on it. If the comp is ok, try messing with the timing.

 

[RedMF40]

1st guess; valve adjustment.
2nd guess; Ignition timing.

Get a compression gauge on it. If the comp is ok, try messing with the timing.

Thanks for the reminder, compression test was next on my to-do list.

 

[Loosehandle]

Cool, Bond movie For your eyes only had one of those in it.

 

[old]

Thanks for the reminder, compression test was next on my to-do list.

Remember now days with all the bad parts it could be as simple as a bad spark plug or plug wire or distributor cap.

 

[RedMF40]

I have new plug wires ordered—all two of them. The current ones look like they’ve been on the car since 1966. When I was doing the engine work I replaced the spark plugs (some strange French brand) but forgot the plug wires. Odometer reads around 34k miles which is probably accurate. These cars were meant to hold up for around 7 years.

 

[Duner Wi]

7 years averaging 20 miles an hour is over 1,200,000 miles. Don't sell the little guy short.

 

[drsportster]

It is like someone said can you make my Volkswagon uglier ?

 

[lodoc]

Since you're a Citroen fan David LaChance has an article about his 1977 Dyane in the Sept, 2026 Hemmings Motor News.

 

[Texasmark]

If it's coming out of the carb. something isn't closing off the air/fuel intake when the explosion occurs. Intake valve not sealed would be the first guess and the question would be why? Bad machine job, foreign object preventing the valve from closing all the way, bad adjustment, something wrong with the head gasket installation. I would expect this kind of problem to be continuous.

An intermittent problem I would direct to ignition related. Could be numerous things that control the ignition just have to go after them one by one.

 

[RedMF40]

It is like someone said can you make my Volkswagon uglier ?

 

[RedMF40]

Since you're a Citroen fan David LaChance has an article about his 1977 Dyane in the Sept, 2026 Hemmings Motor News.

I’ll see if I can find it online. Used to subscribe, occasionally sign on for a year when they offer a deep discount. I enjoy looking at the auction results.

 

[Charles in Aus.]

If it's coming out of the carb. something isn't closing off the air/fuel intake when the explosion occurs. Intake valve not sealed would be the first guess and the question would be why? Bad machine job, foreign object preventing the valve from closing all the way, bad adjustment, something wrong with the head gasket installation. I would expect this kind of problem to be continuous.

An intermittent problem I would direct to ignition related. Could be numerous things that control the ignition just have to go after them one by one.

Corrosion on a valve stem from a long inactive period will do this .

 

[V509]

I have wanted one of those since my first time in Italy in 1994. The windows do not open they fold down three lug nuts per wheel, but loaded with character.

 

[T.R.K.]

Is the timing adjustable? If so, you might try retarding the timing a few degrees and see if the backfiring improves. If it was a Briggs and Stratton, I would say check your flywheel key.
I am also thinking a leaner fuel mix might contribute to backfiring.

 

[RedMF40]

Thanks for the replies. I’ll post a short clip of what it’s doing. My valve adjustment may be suspect, will look at timing as well. No distributor but I believe it is adjustable at the points.

 

[sotxbill]

defective valves... either leaking, sticking intake, or non opening exhaust both will cause this. bad cam timing. Some engines just do it due to aggressive overlap, most visible at an idle. Just a wonder, does it have the "wasted firing ignition" on the exhaust stroke? in lui of a distributor? Lots of two cyl engines do this.

 

[RedMF40]

Here's a short clip only because I said I'd post one. But I just checked compression and it's 125 psi on one side, ZERO on the other. Obviously that explains what's going on. I'll go back and recheck my work and valve adjustments and re-torque the cylinder heads. Feel free to offer anything else you can come up with. I'm sure I'll get things right after a few more tries.

2CV engine running

For sotxbill, yes it has the wasted firing ignition. Just read that in one of my repair manuals.