Bultaco Electronic Ignition And Carb.

[bondy]

Yes i use mikuni never had any trouble with them easy to set up. However i do have a bing on my 199A it dose work well on it so i leave it on but i had a 198A same as your's it had a Amal had nothing but trouble with it but now you have the new jets may as well try it but i did the same thing and i just had no joy hope it works for you but failing that mmikuni are good and a popular choice for many.

Edited November 3, 2015 by bondy

[woody]

As someone else mentioned, it sounds very much like a blocked pilot jet or maybe the pilot circuit itself seeing as the bike has been standing for a few years. The pilot circuit can stop a bike running altogether if it is blocked. Crank seals wouldn't give the problem you have.

 

Carb cleaner may not always penetrate a blockage, a sonic cleaner as you've mentioned should have more success. Also, a friend of mine has had success by gently warming a carb with a blow torch (obviously you need to be careful with how much heat) which has melted some sort of gooey deposit in the pilot circuit which his sonic cleaner didn't remove

 

The Amal carb itself is fine unless it is worn (same as any carb)  If it isn't blocked and it's not worn, with new jets and slide etc the bike will run fine. I'm using a MK2 Amal on a 1972 325 at the moment with no problems.

[trialsrfun]

An airline from an air compressor is the only satisfactory method of cleaning a carb, there simply is no other way.

[sparks2]

Yes, blow the pilot jet air passages out with an air line, they get blocked with water that does not evaporate.

Edited November 4, 2015 by sparks2

[chappo]

'STOP PRESS'

No Sonic cleaning required.

The jets came before the cleaning was sheduled to be done , so I popped in all the new jets ( full set ), that Amal UK sent me.

By the way fabulous service, spoke to a very helpful guy in the Technical Section, agreed the jet sizes from what I had to what they say should be in which were identical, ordered them and there the next day.

Couldn't wait so cleaned the carb again, put the jets in and she fired up straight away.

Running like a dream.

I can honestly say that every jet and orifice was cleaned with carb cleaner to within an inch of its life so it wasn't an obstruction. Each jet examined under a magnifying glass and clear, slightly oval not round but clean.

The only thing I can see that may have been worn was the needle and main jet through wear.

The only other possibility was that the original carb, which I didn't notice initially until the spares arrived was that the overflow pipe was a continuos loop with no outlet.

The spares kit came with two small pipes for each overflow but not connected.

Could it have been it caused a vacuum and lack of fuel ???????

Someone with more knowledge and ability could probably answer that.

Just thought I'd post my findings, as many people ask advice, get it and don't bother to to give everyone the answer when they solve the problem.

Thanks guys, terrific site.

[trialsrfun]

Pleased you have got it sorted, enjoy the bike.

[sherpa325]

The needle and needle jet when worn create all sorts of drama when trying to get the bike to run nicely, the worn slide 'which looks terrible' doesn't have any effect on the running of the engine. As regards the overflow tubes, I can remember one of my bikes, either a sherpa t or a 348/349 cota having the one continuous piece of plastic hose running from one side to the other from new, however it had a  section removed from the hose under the carburetor - about half the diameter was removed for about 20mm .

Cheers Greg