Newbie problem - can't close choke...

Hi All

A bit of a newbie here, I might be asking things that have been covered on the forum before (esp. http://www.st70.net/forum/viewtopic.php ... rich#p1462 and http://www.st70.net/forum/viewtopic.php ... rich#p3584) but I thought i'd ask anyway just for clarification/moral support.

I have a Lady Dax ST 70 that was my mums 30 years ago and has been sat in the Garage the whole time. Its taken me three years on and off but i've eventually got it running and on its way towards an MOT (engine rebore as it had siezed, everything else original).

Having google around i've now wrapped my head around the choke and getting it going. But no matter what the engine dies when I fully close the choke. It seems to move through the throttle smoothly so no other problems there.

I also think the engine is running rich. After taking it up and down the road yesterday this is what the spark plug looks like.

https://dl.dropbox.com/u/58668/IMG_3155.jpg

I assume the issue of richness and the need for the choke are connected? I'm guessing its an airflow issue? Does this sound logical? My next step will be to check for airleaks and try and replace the rubber around the air filter as it begun to disintegrate.

https://dl.dropbox.com/u/58668/IMG_3162.JPG https://dl.dropbox.com/u/58668/IMG_3163.JPG

Is there anyway to confirm that the fuel injection is not the issue?

Two final questions (sorry - now im typing i realise there is loads to ask! )

On the exhaust there is an output that is dumping dirt onto the chassis - is this normally covered or piped elsewhere and i've lost a piece?

https://dl.dropbox.com/u/58668/IMG_3159.jpg

Taking off the bolt that connects the parcel shelf ruined the thread - any ideas as to how i could fix this? My only thoughts are to take it to a metal worker and see if they can rethread it there and then?

https://dl.dropbox.com/u/58668/IMG_3160.JPG

Many many thanks in advance.
Best
Eliot

On the exhaust there is an output that is dumping dirt onto the chassis - is this normally covered or piped elsewhere and i've lost a piece?

https://dl.dropbox.com/u/58668/IMG_3159.jpg

There is supposed to be a breather pipe from the top of the engine aswell, just inside frame area, and another breather pipe that connects to this part of the exhaust. Just 2 open ended pipes (there are only breather pipes)

defadog wrote:,
There is supposed to be a pipe from the top of the engine, inside frame area, that connects to this part of the exhaust.

Brilliant thanks defadog. I presume it runs over the airfilter metal clip as thats empty at the minute? I'll hunt around. Do you know why it is piped? It is pulling air in?

My pipe was damaged at the butt of the exhaust and found the tube inside the frame, just behind the air filter. I cut the end off and reconnected it to the exhaust. Yours may still be attached behind the engine like mine was !!

Ok let's deal with the pipes the one that goes to the exhaust is a drain for the exhaust and just hangs down, the one from the top of the crankcase is another breather and goes through a hole in the frame do not connect them they are just breathers.If you are getting oil from the crankcase you could have knackered piston rings
Regards Clive AKA Tufty

Thanks Tutfy. All makes sense. Just found the one of the top of the crankhouse but that seems fine. Have just lost the breather pipe for the exhaust so will buy a replacement.

Just a quick, incredibly simple question. Now i've taken off the air filter im beginning to think that my fuel mixture issue is much simpler than i thought. On the ST 70 the choke should be pulled *open* during driving? Namely, pulling the lever *towards* the frame. Pulling it away from the frame and toward the front wheel closes the trapdoor into the carb and therefore increases the richness of the fuel mixture - right?

Hi
yes that sounds right,Im glad you sorted out your breather issue and dont forget to post a picture of your bike
Regards Clive AKA Tufty

Almost no oily damp should escape from the engine breather, and definately not trough the exhaust.

If there is, there is definately something wrong.
The spark plug looks like it has met some oil as well.

How many miles have you run with the rebored cylinder?
I guess you're still running it in? If not, are you sure they have fit the correct rings for the oversized barrel?
Piston has been replaced?

Waynus wrote:How many miles have you run with the rebored cylinder?
I guess you're still running it in? If not, are you sure they have fit the correct rings for the oversized barrel?
Piston has been replaced?

Run hardly any miles at all. Its yet to be MOT'd or Taxed etc so its not been on the road. I'm still running it in. Given i've figured the choke i think i'll just get it onto the road. Give it a few miles driving before i return to the richness of the mixture issue later. How can i check if the spark is meeting oil? Just oily deposits on the spark?

I'm just about to add a question about the Certificate of Conformity as im trying to fill in the V55/5...

Give it at least another 100 miles or so and check again.
It's completely normal during running in. (which takes +-350miles)

Yeah, black choal on the spark plug means you're burning oil.