Float height on RH Carbies

[petejw1966]

Well here's another question, i've now got BS36 carbs off i think xjr1200, these would be similar to late xs11 carbs??? if so what float hight? i've set mine at 25.5, if they should be 23 then that would be the reason why my plugs are very grey in color after a half hour run at around 120k's seems to be too lean to me, opinions anyone?

u need to set the float heights for that particular carb model,
unfortunately I don't know what that is,
go thru the post scarfey put up and see what that is
I haven't had a chance to read tthru it.

btw, when reading sparkplugs don't go by the colour of the white
porceline, that use to be fine for leaded fuel, but doesn't work for unleaded fuel,
do a google search for reading plugs, will be easier than me rtying to explain it on here.

[SCARFEY]

Found this...........


Mikuni BS (CV) Carburetor Rebuild Tutorial
Float height for BS32 & BS34 carbs is 22.4 mm. The
BS36’s shown in this tutorial are to be set to 21.4 mm.

http://www.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

or page 11 of this
http://www.xj4ever.com/setting%20fuel%20levels.pdf

or this....... from the http://www.yamahaxjrownersclub.com/phpBB3/portal.php

OK then mate, here's the XJR1200 carb spec. The 13's are slightly different and became BSR37 X 4 for 2002 models on, plus the obvious jet size differences etc.

Type Mikuni BS36 X 4
Engine idle speed 1000 to 1100
Carb synchronisation - intake vacuum at idle 235 mmHg
Carb synchronisation - max, difference between carbs 10mmHg
Fuel level 4.5 to 5.5mm below float chamber line
Float height 21.3 to 23.3mm
Pilot screw settings 3 turns out
Main jet 95
Main air jet 45
Jet needle and clip position 5D66 - 3/5
Needle jet Y - 2
Pilot air jet 135
Pilot jet 40
Starter jet 32.5

[makzy]

Well here's another question, i've now got BS36 carbs off i think xjr1200, these would be similar to late xs11 carbs??? if so what float hight? i've set mine at 25.5, if they should be 23 then that would be the reason why my plugs are very grey in color after a half hour run at around 120k's seems to be too lean to me, opinions anyone?

[petejw1966]

Thanks Pete Ive got the later model carbie now the job of assembly you mentioned leaning out the mixture needle what problem did you have with yours  Coops

hey coops, the slide needle if set on the middle notch will run
the mid circuit to rich, so use the 2nd notch from the top down,
what did u have yours set at?


and set your floats to stock setting 23 mm.

[Cooper]

Thanks Pete Ive got the later model carbie now the job of assembly you mentioned leaning out the mixture needle what problem did you have with yours  Coops

[petejw1966]

hy makzy,
there's a Cpl of ways, the later carbs had the mixture screws
hidden in a 'tunnel', early carbs the screws are exposed,
later carbs have 4 holes at the back of the carb bell compared
to 3 for the early ones,
the size of the main jets later carbs are 110, early carbs 142.5 I think from memory,
float heights for later carbs 23mm
early carbs 25.7mm
slides are different sizes between models.

jat, be very careful setting the float heights more than half a mm on the lean side,
it will cause the engine to run hot and u run the risk of damaging pistons and valves
there's a few other things it can do to the running of the engine and nothing beneficial.



not sure here but in the states they had a 'bastardized' set of carbs (around 1980) that had a cross
pipe from the main jet tower to the pilot jet tower that took the large size main jet
and had the pilot jet blocked off.

post pics if youre not sure makzy.

[makzy]

how do you identify late model carbs? the two sets that i had no luck with had no identifying numbers,
they had 4 holes in the throught and brass floats, but both had different emulsion tubes.
I was always setting the floats at 25 to 26, but always had overfueling problems down low and underfueling up high thats why i went to the bs 36's.

[petejw1966]

coops,
also if they are definitely the later model carbs
set the slide needle on the 2nd clip down from the top, the middle
position is to rich.   jat

not aware of any downloads, anything else u need to know
about the carbs let me know.

[Cooper]

Many thanks Peter your right 25.7 early models I'll give 23 a shot when new needles etc arrive is there a download for an RH somewhere Coops

[petejw1966]

no the later model carbs are set at 23mm.
the older carbs are set at 25.7mm from memory.

[Cooper]

Is the float height for RH carbies the same as for earlier models PO has messed with the tabs fuel  bowls etc look the same Coops