Mikuni VM 33 Carbs

These carbs use a lot of fuel when you get on it. Clogged filters can mimic too small of jets at WOT. It became obvious when going on reserve. I'll run it and see how it does. I know now I need to adjust my float levels.
Steve

This is why you need a reserve.
Steve

How do you know you can get 17-20 miles on reserve? :whistle:

What setting do you torque your spark plugs?

I learned the hard way and I tighten my plugs by feel.
Steve

I agree on tightening them by hand.... I recently tightened my plugs (for the first time) to the min using 2 diff wrenches and they felt too tight for me (damn near a full 1/3rd).... same with the filter bolt, drain plug and valve cover bolts. Pan, oil pump, cam gears, cam cap bolts, starter clutch bolts etc I carefully went with the min on the wrench (sneaking up on them with a 3 inch wrench then the torgue wrench) but will go back to a good feel on most. Do you use a small amount of anti seize on the plugs.... some don't but I pull mine quite a bit too and I think its really protecting the threads from wear.

I don't use anti seize on anything except my old Ford truck heads or things like that. I use a stubby ratchet or box end wrench. I've broken and stripped plenty of bolts in my time and have developed a feel for them. Others may prefer to use a torque wrench and I do use one for head bolts and such.
Steve

Well, that explains why my spark-plug crush washers are flattened out after one or two removals. I thought the FSM torque spec of 20 ft. lbs. was to be taken as gospel, but such is the result of my experience. :pinch:

Back to my jet question... :S

My RS36 carburetors are setup with 17.5 pilot fuel jets and 0.7 air jets.
Does that have exactly the same effect as using 20 pilot fuel jets and 0.8 air jets?

I would suspect the air jets are for the mains not the pilots. Pic?
Steve

swest wrote: I would suspect the air jets are for the mains not the pilots. Pic?
Steve

Steve, hope this helps.
Pic: Note Pilot Air Jet is the small one on the right.

Main air jet plugged? Is that a accelerator pump nozzle? Have you tried looking on the jetsrus charts like they have for the Micunis? Maybe try Sudco for the jetting for your machine. Also the float level looks a little high. That would make it rich on the bottom.
Steve

swest wrote: Main air jet plugged? Is that a accelerator pump nozzle? Have you tried looking on the jetsrus charts like they have for the Micunis? Maybe try Sudco for the jetting for your machine. Also the float level looks a little high. That would make it rich on the bottom.
Steve

Main air jets plugged, yes as exploded part list states and what looks like a jet is actually a plug.
Yes, the accelerator (pump) nozzle is shown vertical in the bore in front of the throttle slide, directly below the blue P.
All good on the instructions for jetting, except for the Mikuni application chart indicates Pilot screw setting range from 1/4 - 1/2 turn (off lightly seated I believe), not 2 1/2 - 3 turns. Runs well at 1/4 turn out currently.
Float levels measured and set correctly at 17 mm per Mikuni instruction manual. There is no measurement information on which to base using the clear-tube float setting method that works on the BS34's so well.

I agree with Swest , that fuel level looks high, even if the floats are correct lowering the fuel level a mm or less at a time is worth a try if your having problems.
Float level is a viable and accepted way to fine tune a carb , within reason of course.