Running an engine with a stuck choke

What would happen to an engine if No. 2 cylinder had been running on choke for a potentially long time?
I know that there will be a coke build up, but I'm interested in the valves and whether this would cause a loss of compression.....

I live in hope that changing the choke cable will sort this out, and that the head won't need removing and the valves re-lapping....

[Spanner Man]

Good afternoon.
Obviously the cylinder in question would have been getting a good wash! Any excess wear may not become apparent for some time. It would be a good idea to change your oil & filter, & carry out a second change sooner rather than later.....I would say that if after sorting the choke, & changing the oil the bike performs ok then that's all you will need to do, as any short term harm done will be obvious.
As to any long term damage, it's anybodies guess, but suffice to say, it wont have done it any good.

Cheers.

The plug wasn't too manky, and I believe that it has just had an oil change, but I'll let the owner know (have a feeling that they already do). I'm going to rebuild the carbs (with new needles as the originals were well scored), get them back on with a new choke cable. See if he runs, and then balance the carbs!

Cheers Spanner Man!

[Spanner Man]

Good afternoon.
Sounds like it wasn't too badly stuck if the plug wasn't too grotty.
hope it sorts out ok.

Cheers.

Yeah, it does look like the cable has seized half on. Just waiting for the new carb needles to arrive. The old ones were quite well scored and marked so I thought that as the carb is apart they might as well be replaced....

Cheers for your help mate!

Oh, you might be interested in this, whilst the parts are on their way I have turned my attention to a brace of Jampots; both 350's one a Matchless and one an AJS.....

Should be fine, it's not really a 'choke' on bikes like a car, there is no air flow reduction, just more fuel added.

I belive the proper term for it, as per old man suzuki, is "Starter-cable".

You're quite right, but that's a sh1te term and everyone knows what a choke cable is

It all depends on the design of the carb as to how much of a problem is was/is. I don't know much about carbs on bikes.

On cars, there were generally two types, Constant Depression/Variable Venturi (Stromberg and SU are two makes of this type) or Variable Depression/Constant Venturi (Webber is the most common make of these).

The chokes worked in different ways on each type. For Variable Depression type carbs the choke only worked at low rpm to stop the engine from stalling and assist in getting the vehicle moving. Once the rpm/air flow was high enough the Choke Flap opened and the engine ran under normal fuel/air mixture.

If the SV carb is of this type then only limited damage if any would have been done.

The choke on the Constant Depression Type of Carbs is usually just a fast idle with a richer mixture which is on all the time until you turn it off, so the mixture is richer through more of the rev range. This type of carb allways seems to have a moving piston. My guess is this is the type fitted to the SV.

With the choke jammed on, the engine will have suffered a too rich a mixture. This can result in poor lubrication of the valve guides and stems and the pistons/rings. Also the valves will get sooted up as well as the rings, leading to loss of compression. Also the oil would have got thinned.

Change the oil and filter and then give it a long hard ride to burn off the soot. Shell Optimax or whatever it is called these days will help with the clean up.

Tim.