My float levels are correct at 7.5mm and the plugs are very sooty throughout rev range. Mixture screw has no effect on reducing the sooty plugs and jets are standard with standard air filter and exhaust. My next step would be to adjust float levels. From experience what would members recommend? Going up by 1.5mm from 7.5 mm to 9 mm or more than this?
What main jet are you using and do your carbs vent to atmosphere or into the airbox
Hi Bif,
Carbs vent to rear swingarm (see pic) Mains are 145.
One cylinder only fires from 1500 rpm with clean idle jet so need to get in and clean all passages.
Amazingly it idles very smoothly on 3 cylinders!
I have two sets of R carbs,both are VD83A
the set that vent to the airbox run 145 mains.
The set that vent to atmosphere run 125 mains.
There was a revision kit available,if yours has solid grommets fitted in the alloy plate in the picture where the two holes are,then the jets should have been swapped for 125’s at the same time as the kit was fitted
Hi Bif,
The air chamber has no holes (solid casting) for venting so this is an 85 or later part designed to vent to atmosphere. Mine is an RE so over the years someone must have changed it.
I stand corrected on the jets - they are 120/38.
Bike starts first time pulls well, idles well but plugs are very sooty and so is the exhaust.
Float height varies from 9mm on the US 85/6 model with 125 main jet to 7.5mm for the RE.
Germany,Switzerland and France have differing venturi diameters and main jets as low as 95 but use the same float height as my RF at 8.5mm.
I would be looking at a good clean and making sure all the choke plungers are operating full stroke and in sync.It could well be the choke circuit is the problem,especially if it needs little or no choke to start from cold.
Out of interest,what is the serial number on your carbs?
Hi Bif,
Thanks for the info. I will set the float height at 8.5mm and check the choke action and see how we go. The carb ID is per the photo. The bike is originally RE from France. Is the whole carb setup a later French version or taken from, say, an Australian bike?
The French didn’t get the 85 model,and the 86 uses VD85 carbs.That would suggest they have been altered at some point.
The float height however is correct at 7.5 for the carbs you have
Hi Bif,
So the correct float height for my carbs is 7.5mm even running revised airbox and 125 mains?
That is correct
Taken carbs apart and replacing float needles. I noticed that 3 valve seats are 2.4 and one is 1.6 Will this affect float height/ restrict fuel flow?
It won’t affect float height but it will alter the fuel flow,all should be 2.4
Gooday Downunder, wondering how you got on with your carbs and jetting. I have only seen Aus VFs with 145s or larger. Interested to know if you got it set up right as I’m starting the same process on an RE now with airbox etc?
Hi Speedy,
I have my carbs off at the moment as one cylinder will not run at idle so giving it a good clean. Bike runs great with the jets as mentioned above but mixture still seems a bit rich as plugs are sooty.
As Bif mentioned above it, jet size varies depending on the venting system.
Thanks for the quick reply,
its interesting that people seem to stick with the standard jetting - maybe cause it’s such a bastard of a job pulling carbs and changing!
I have my carbs off now, cause I had to fix the o rings on the cooling pipes below them. This bike hasn’t run for maybe 20 years. I`d like to plug the airbox, and run breather down below. I’ll look through my large stash of carbs and parts, but can’t remember any 120-125s there, only 165, and 145s.
My FF, and nearly all VFs that I’ve seen locally run rich.
Hi Speedy,
Put carbs back on and running nicely now. As for running rich I tried setting floats at 9mm instead of 7.5mm but not much difference at all.
If your bike hasn’t run for 20 years it will definitely need a good carb clean.
I picked this bike up in bits from Melbourne months ago. All cabs cleaned float heights set and refitted. Was just about to start it for the first time and noticed the coolant leak below carbs. Leak fixed, but just before I refitted carbs I saw your post.
So to confirm - you have 120 main jets, and airbox breather venting below?
I found a set of carbs, (77AAYB series), with nice clean 120 mains I’ll fit if yours is running OK. Currently have 145s in, which is the same as my FF, which runs rich.
I`m in Canberra, which is about 500) plus metres above sea level, whats your altitude?
thanks for your help!
Hi Speedygp.
Which cooling pipes did you have to replace orings to have to remove carbs?
I replaced these ones one the cross pipe that go into the block.
Replaced the o rings on the ends of the two pipes under the carbs which go into each cylinder water jacket. This pic shows the wire I put holding them back in while the semi hardening sealant setsimage|666x500
Hi Speedy,
Yes, I’m using 120 mains and 38 idle jets with carb venting to atmosphere. I have not tried other jet sizes as the bike has never had a running problem apart from richness.