Post by captain chaos on Jul 14, 2013 7:26:26 GMT
Right then another little bad design with the old gsxr is a little good mod that can be carried out on the cvs.
This article is based what ive done on a set of 40mm cvs im presuming the 38 and 36 are the same but will need to check on this one.
The emusion tube and needle set up is not the best idea, where the needle enters the emulsion tube its only small lip that wears oval in no time which is pronounced by needle not held square.
When the tube starts to wear it causes a rich come bad fueling mixture in the mid range to low end which really messes things up if feels like a delayed throttle come bog, which when coming out of slow corners feels horrible and not confidence inspiring. I was replacing needles and tubes every other year to get fueling and performance back to what it was.
The 40mm cvs are especially sensitive to the slightest alterations.
pic of emulsion tube, not the best pics i know.
Right then first bad design is the plastic spacers that hold needle in slide, these either rotate and wear in time causing plastic to wear down or a grove is worn in the one side. as you can see by the next 2 pictures.
This would cause a lean mixture in mid range, as needle would be lower.
Plastic really worn
Right now slide. For some strange reason the area in slide needle sits on, is stepped which causes needle to constantley be pushed at a forward angle towards front of emulsion tube thus causing this area in emulsion tube to be constantly worn away.
This is real strange design floor was it designed that way to make fuel come round needle into a spray rather then globules who knows unless you are the designer who can say, or was it an oversight, either way it really messes things up with needle wearing down too.
The whole three items together causes complete havoc.
Solution.
Is to make these aluminium spacers that replace the plastic needle holders, they are stepped so fit into the slide square so when slide spring pushes down they are held pretty rigid and square and sides are milled to create clearance for the slide air holes.
Im not saying this is complete cure but ive done this mod 2 years ago and just checked carbs and there is next to no wear.
Carbs are set up so well on my 11 it feels like fuel injection ask uk lee as hes has ridden it and was surprised,
another view of mod
everything will now be square
Proper drawing, i hope this will help a few people out or ive just wasted my time.
Jonny.
This article is based what ive done on a set of 40mm cvs im presuming the 38 and 36 are the same but will need to check on this one.
The emusion tube and needle set up is not the best idea, where the needle enters the emulsion tube its only small lip that wears oval in no time which is pronounced by needle not held square.
When the tube starts to wear it causes a rich come bad fueling mixture in the mid range to low end which really messes things up if feels like a delayed throttle come bog, which when coming out of slow corners feels horrible and not confidence inspiring. I was replacing needles and tubes every other year to get fueling and performance back to what it was.
The 40mm cvs are especially sensitive to the slightest alterations.
pic of emulsion tube, not the best pics i know.
Right then first bad design is the plastic spacers that hold needle in slide, these either rotate and wear in time causing plastic to wear down or a grove is worn in the one side. as you can see by the next 2 pictures.
This would cause a lean mixture in mid range, as needle would be lower.
Plastic really worn
Right now slide. For some strange reason the area in slide needle sits on, is stepped which causes needle to constantley be pushed at a forward angle towards front of emulsion tube thus causing this area in emulsion tube to be constantly worn away.
This is real strange design floor was it designed that way to make fuel come round needle into a spray rather then globules who knows unless you are the designer who can say, or was it an oversight, either way it really messes things up with needle wearing down too.
The whole three items together causes complete havoc.
Solution.
Is to make these aluminium spacers that replace the plastic needle holders, they are stepped so fit into the slide square so when slide spring pushes down they are held pretty rigid and square and sides are milled to create clearance for the slide air holes.
Im not saying this is complete cure but ive done this mod 2 years ago and just checked carbs and there is next to no wear.
Carbs are set up so well on my 11 it feels like fuel injection ask uk lee as hes has ridden it and was surprised,
another view of mod
everything will now be square
Proper drawing, i hope this will help a few people out or ive just wasted my time.
Jonny.
