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POINTS TIMING CB500/4

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Bryanj:
What model 550 is it as i have all the genuine books

Oldbuthopeful:

It's a 550 K3 which, incidentally, I haven't yet managed to idle at anything below about 2500 without running rough
and then cutting out   -   and the slow-running jets are clear !   Any other suggestions please ?

z1100r:
 Its running lean..your pipes are very blue. The carbs are a bit fiddly on a K3 to get the slow running right. You need to take the carbs off and start again. I'll assume you can do needles (needles may be too low) and main jet, so for slow running:-

 1) Remove float bowls
 2) Pull out slow running  jets with a firm twist and pull with a good set of pliers. Use small new pliers with good teeth, its better to mark the outside than to crush the jet with too much squeeze with a big blunt pair..
 3) blow through with airline both empty hole and jet.
 4) Hold jet up to light and you must be able to see through it. Its a very small hole, you must be able to see light through them and they must all appear the same.
 5) Remove air screws carefully. There is a washer spring and oring in that hole that must be replaced in the correct order.
 6) Blow down hole with air line.
 7) shine torch at pinhole in venturi and look down screw hole to see light. You must be able to see light.
 
 Finally, and I know they say dont do this, but if you spot a blockage in a jet you need some of these
http://www.ebay.co.uk/itm/20-Pc-Micro-HSS-Drill-Bit-Set-0-3mm-to1-6mm-Mini-V0930-/360354126518?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item53e6c79ab6

Find the right drill by trying them in a good jet then gently twist it through the blocked one - by hand. Usually its just dry hardened varnish you are removing and it comes out as powder, you wont remove any brass.

K2-K6:
The comment about a waste buying the Boyer:- I don't think that's the case if it's what you really want as those systems have clearly been contructed by people that know what they are doing.

It's more that the standard kit is a really good design in the first place and it comes pretty close to the performance of electronic for a standard road engine.

Ths assumption if something is not running correctly just because it has an old type setup is very often incorrect and the NEW system is fitted in the hope of curing something that may have been caused elsewhere.

Oddly though, a lean running engine at lower speeds (550K3 tickover)  is one area that in theory the electronic system probably will hold more of it's expected design advantages if the coils are feeling able. So you may get to feel you've got good value if you get the carbs all clear/well adjusted.

Oldbuthopeful:
Thanks z1100r for replying at such length.  I'm afraid the blued pipes are a red herring, because they came as part of the deal
when I bought the boxes of bits from the PO  -  and they've now been replaced by a 4-into-2 system which gives the bike a
much better balanced look.   So...........given that I carefully removed the slow running jets and drilled them out before I sent
the carbs away for refurb, would altering the needle height as you suggest still improve the slow running ?  And something that
bugs me every time I replace the carbs after a fiddle   --     can you please advise whether I really need to go to all the trouble
of replacing the rubbers just for a test start-up or will leaving them off in the short term not make any difference ?  It would be
music to my ears to hear you say it didn't matter either way !!!
Whilst you're on my wavelength z1100r, could I ask what your take is on float height ?   BryanJ will hopefully be able to
throw some light on the subject, but it's always useful to get another opinion.
Thanks also to K2-K6 for your comments.  If carrying out these carb adjustments results in a smoother-running motor, then the
Boyer can stay.  But if there's no improvement, I'll be strongly tempted to put the original kit back on, using new points and condensers
and see where we go from there.   Thanks again for the input.

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