Carbie air cut-off valves

[Peter Hunt]

Hi guys – having my carbies checked over and need to ask a dumb question….do the rc’s have 1 or 4 air cut-off valves? I know the cbx and 900f have just the one with a connecting tube, but can’t see that tube on the rc….if there are 4 do you have to take the carbies off the rack to access the valves?
Cheers
Peter.

[JohnS]

Hi Peter, yes each carb has its own air cut off valve. I live by the rule if the first one is good
then the others are good and dont separate. If the first one is bad then you have to separate the carbs
to replace all 4.
JohnS

[Peter Hunt]

Thank you John! Yes, the outside one (ie the easiest) has a split, so looks like I’ll be ordering 4 and splitting the carbs (well, my mechanic will be haha).
Thanks again mate.

[Peter Hunt]

So the carbs are back together….all 4 valves were knackered, and also found that the needles had been machined (maybe in an effort to compensate for the quite free flowing 4into1?), so have replaced those. Bike runs beautifully when cold/warm, but breaks down badly when hot. Sparks look weakish and erratic. Multimeter reveals coils to be an issue, so trying a borrowed set before buying to see if it fixes that issue….we’ll get the old girl to run right if it’s the last thing we do!
Interesting that the spark issue revealed itself after the carbs have been done…the breaking down is quite different to the fuelling up and black smoke issue of before (now gone since carbs done)…coincidence or connected? Don’t know.
Mechanic has some experience with the R’s and can’t believe how hard this one pulls (when it’s working)….he suspects it might have a big bore kit or cams….unfortunately I don’t have that much history on it.

So we push on and hope that we’ll have it good to go in the next few days.

[Peter Hunt]

Boom! A test ride (in very hot conditions) with the replacement coils fitted had the bike running like a well sorted 1100r should run.😎
In the next week or so I’ll take it on a day trip somewhere giving it a good run. Still a couple of jobs to do (isn’t there always?) but at least it starts, runs and goes like the clappers:o

[Anonymous]

Good work Peter. Always good to see effort rewarded. Did you fit original type coils for the trial or aftermarket ones?
I understand that there are many cases of guys in the DOHC Honda world who run CBR600 coils very successfully on the early fours.

[Peter Hunt]

Original ones Andy….actually a cbx one and a 900f one, they’re the same anyway and they were lying around spare.
Anyone have experiences with the aftermarket ones? I was going to order some from Silvers.

[Trevor Hughes]

I know many of the guys use CBR600 coils on the R/F’s. Apparently a direct replacement and an improvement over standard.

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