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Discussion Starter #1
hi guys
i like these bikes
i saw non runner carb version up for grab in germany and got it for a very low price with only 23000 km
as you might imagine with that low mileage there is a catch
the exterior is very good but the carbs are well and truly bunged up

the guy selling it had a local old skool jap bike garage taken off the carbs and the butterfly's were solid with varnish
so i loaded the bike in my van and took it home ( 450 km ) and once home proceeded to strip the carbs ( did this on my nr 1 bb before )
indeed they are pretty c--p
using turpentine ( good for melting varnish ) i have cleaned most of the accessible parts and part cleaned the screw in jets( as best i can still leaving them to soak over night ) and the choke plungers and idle bypass screws
the butterfly's are now free and the body is clean and shiny
under the intake bell is a plastic plate with o ring type seal
under it is a series of brass stubs with holes
the outer ones there are 3 plus one blind hole that goes to a re-circulation valve two others i have opened up with a fine needle
on the inner two there are 4 in a staggered pattern
i am guessing that these are used to deliver a common vacuum to the other parts of the carb perhaps to actuate the slide?
i have managed to open up 3 of the 4 but there is one where the needle bottoms out ( maybe too fine a hole ?? )
so my question
what is the 4th one for? is it an issue if i cant un bung it ?

once the carbs have soaked overnight with the turps ill tbey clean them up and send them for a couple of hours of ultrasound cleaning
i did this on other less b---ered up carbs and they came out ok
with the ultrasound finish off what i started or is it a c--p shoot as to success , in which case i need to find a back up set ....
m
look forward to the oracles teaching me...
 

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The ultrasonic should clear them up fine.
 

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Discussion Starter #3
so last evening and part of the morning i took the carbs apart and they were ghastly to look at
all the jets were corroded and covered in varnish
the butterflies were frozen and corroded
the slides were frozen and covered in varnish
so off i started cleaning everything with solvents and got most of the things looking decent
the only thing i cant get right is the tiny meter hole in the low end jet its open but only partly
i put the whole thing and it started right off on full choke
warned it up and rode it
its missing on nr 1 or 2 and once you get into the secondary and main get its goes like a rocket
so ill take off the carbs again and take out the low end jets and probably order some replacements
ill need to change the infeed t piece o rings as its weeping fuel on one side
anyway i pretty happy that i could do a lazarus with those bunged up carbs..
cheers
paul
 

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:eyebrows: If you have access to an air compressor, blow the jets clean with a strong blast of air. I'm unfamiliar with BB carbs, but very familiar with FZR1000 carbs...... used to clean them every 10k kms and blow clean all jets/holes. Check the needle and seats (on the floats) - they should spring freely as the floats move up/down - may need new ones if they are solid as they can't be dismantled.

I had that varnish in a set of replacement carbs and it can take a couple of goes to get them fully clean.... but I wasn't aware of ultrasound way back in the noughtie's :thumb:.

Good news getting it running again..... more cleaning will help get it perfect...... a total strip is best but then you'll need to reset the mixtures, synchro the carbs for best tune.
 
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