Bis erratic running

[mintex]

Is this accelerator pump easy to fix and where do I get one from?

I've taken some pictures and done a small video for you to see what yours should do.
If you work the throttle with the engine off and look in the carb you should see it squirting a small jet of fuel in.

As dadandlad said if yours isn't working it might be blocked or need a new diaphram in the pump located on the carb. 

Hope it helps a little 





[youtube]https://www.youtube.com/watch?v=GEs1MS--GJw[/youtube]

[Pete126]

Thanks Dave for the photos I'm sure they will help other members

[Bambino126]

Thanks both of you I will check that out, the pictures explain it all 

[dadandlad]

Well the plot thickens
Checked the valve clearances as per Petes idea to no avail all found to be correct

Accelerator pump working fine

Ordered a Ultrasonic cleaner from ebay and going to fully strip carb once again

[mintex]

Bit of a strange one? Will it go on full throttle or are you still running it in?

[dadandlad]

Still running it in but I have opened it up on to the second choke but not to the stop, so long as you give it chance to catch up it revs fine

I will keep plugging away at it

[dadandlad]

I have asked on Retro Rides for help and in doing so could have stumbled on the answer

When I originally stripped the carb it had sat for years full of gunk

The accelerator pump jet was blocked solid and nothing I did would clear it, so I got online and found a shop selling said jet.
The original jet didn't  have  a size marked on it so I wrongly or rightly assumed one size fits all

Opinion seems to think it is running rich, made even worse by giving it a little choke

I have found a company selling the correct jet so hopefully this will cure it fingers crossed

If it cures it I will be kicking my own backside for a month

[dadandlad]

Well the carb is off again and in lots of bits

I managed to find some info on the Weber 30 DGF online but fitted to a Panda 30 and it appears I have the correct size accelerator pump jet fitted

What I did notice though was the very low fuel level in the float bowl approx 6mm deep barely covering the two jets in the bottom

I have also purchased a Ultrasonic cleaning tank and had the carb in and cooking

I will post some pictures of the carb before and after so you can see the results

Should have the carb back on tomorrow night

 

[dadandlad]

I didn't get chance to refit the Carb this evening but have rebuilt it once more
I did find a issue with it and if it works all will be revealed tomorrow

[dadandlad]

Well where to start

Today refitted rebuilt carb and if anything its worse 

Well I decided to start right from the very basics

Removed rear panel and bumper and stripped off timing cover to check timing of crank to camshaft all found to be correct so everything refitted

Checked valve clearances all found to be correct

Removed and examined spark plugs found to be very sooty

Started her up and checked timing again

For some very annoying reason it now runs and revs fine with only a very very slight hesitation when opening the throttle

It is so annoying that I dont know what the problem was

One thing I think is worth mentioning which I could see someone else falling into the trap of doing is

The big jet just to the right of the accelerator pump has a tapered seat which I can only assume seats internally, now if you do as I did and replace the O-ring with a copper washer the jet will not seat internally as in effect the washers jack it out slightly
What if any effect this would have I dont know

[mintex]

So its running ok now.

A bit strange it's fixed itself but maybe are lucky and have one of them rare self maintaining cars..... you and me wish this were true eh lol 

[dadandlad]

Hi Dave

Yes it appears to be running fine and I really do wish I could put my finger on what it was

I think I will replace the spark plug leads with some high quality ones just as a matter of course, they are new ones that are fitted but of unknown make

At least I can move on now

[Bambino126]

You said that the copper washer is stopping the jet from seating, well if it works the same way as an idle jet then that will allow too much fuel to flow through at a certain part of the rev range, running too rich. You also said the spark plugs are very sooty, which could be a sign of running rich.
If you're after quality HT leads, I fitted Magnecor ones to mine, I fit them to every car I own because they seem to last forever.

[dadandlad]

I assumed that is what was happening with the copper washer and expected it to be a instant fix but it was actually worse

I tried her again yesterday just to be sure and seems to be running really nice

Magnecor are the leads I have been looking at , did you have to fill out the application form or did they already have the spec for them

[Bambino126]

I bought my Magnecor leads from Ricambio actually. They are listed as being for the air cooled car, but I asked him specifically if they would fit the Bis so he opened a box and compared the lengths of the leads with a set of Bis leads and they were almost exactly the same.

Of course 1 lead (the king lead) is wasted because the aircooled uses 3 leads and the Bis only 2.