Anybody know what the conversion is between the main jet sizes, i.e. if I had a Keihin 150 in a carb, what would be the equivalent Mikuni size?? (And yes, there's a long ugly story, and no, I'm not the bonehead in question.)
I'm not sure,but I think they are the same. Jets are numbered by the I.D. You can check with Sudco International Corp.,They handle both carbs. Good luck!
On the Mikuni take the number of the jet and divide by two, that is the size in mm. i.e. a 320 main has a bore of 1.60mm . On Keihin the size is the bore in mm i.e. a 150 main jet has a bore of 1.50mm. Hope this helps Dave.
The jet number represents the cubic centimeters of fuel a minute that will pass through the jet at a low pressure-a head of 1ft.(30cm).A 150 jet will pass 150cc/min. at wide open throttle. So the higher the number the more fuel it will pass at wide open throttle.
If that is correct how come the Mikuni #300 Large style is the same size as the Keihin #150 on the bore or do they use a differant standard. I have looked in the manual and it appears the number for the mikuni carbs depends on the main jet syle. I run tm32 with the large hex body and the jets are #300 at 1.5mm. On my other machine I use Keihin CR26's with a #130 which measures 1.3mm. Perhaps there is no straight cross referance and it is just a coincidence that the jets I use match these sizes.
Well mybe there isn't a standard between manufactures. The formula that I posted is true for Amal carburetors. Mybe someone else can set us straight.
