drill bits - jet sizes

[petejw]

i remember seeing a thread regarding
drill bit sizes compared to the equivilent
jet sizes. i cant seem to find it
can anyone help me out with the thread
cheers

[petejw]

its ok
i finally found what i was looking 4.

[pggg]

Pete, mikuni jets aren't rated by diameter eg.. 1.5mm drill doesn't equal a 150 jet.

[petejw]

hey pggg,
yeah i know,
but there was a thread in tec tips that
showed an equivilent drill no for the jet size,
dnt know how to put a copy of thread on here but this was what i was after.

For those of you who don't know it, you can drill your jets out for larger sizes instead of spending big bucks to acquire a vast selection. You can also solder the ends closed and redrill them smaller if you are so inclined. Of course, the millionaires among you will scoff at this, so please ignore. Those of you however like me who have more time than money can read on.

After some surfing I've calculated that you can use the following drill bits to come close to the sizes needed, or actually be bang on with many of them. So here goes. Remember that a jet marked 120 is 1.20mm in size, 135 is 1.35mm etc. Perhaps those who know more accurately can correct me if I'm way out on this, but I think I'm close.


50____#76
55____#74 approx.
60____#73
65____#71 approx.
70____#70
75____#69 approx.
80____#68
85____#66 approx.
90____#65
95____#63
100____#61
105____#59
110____#57
120____3/64th's
130____#55
140____#54 150____#53
160____1/16th's
165____#52 approx.
170____#51
180____#50
185____#49
195____#48
200____#47
205____#46
210____#45
220____#44
225____#43
230____#43 approx (close to 225)
245____#41
250____#40

[petejw]

yamaha wanted $25au each for a main jet
and $26 for pilot jets, i couldnt aford that
when the drill bit kit costs $28.
probably wouldnt b any bettr priced in the NZ hey?

[pggg]

Hey pete, $11.00 each for mikuni jets down here. Get them from any motorbike shop. Yeah, us billionares resize them by twisting the jet onto the drill bit with fingers. Here's a bit of sizing info http://vmaxoutlaw.com/tech/dyno-mikuni.htm

[petejw]

hey pggg,
thanx 4 the link,
u wouldnt know the equivelent 4 the pilot
jet, was wanting to go to 45.
tiny hole! mite need to buy those.
4 sum reason with this bike i think i have
2 buy genuine all the time
, usually when i need something 4 it
no one else has it, so i try yamaha first,
instead of last.

[petejw]

im slow pggg

so all that info was wrong,
having to many late nites lol
so any one know how 2 work out
the drill bit sizes for the corresponding jets.

[pggg]

Probably about 3 hair widths! Genuine Yamaha parts pricing calculation sheet - add 100% then multiply by about 10

[petejw]

so they would still be close enough?
havent got the bits yet have jst
ordered them ill find the closest 1 that fits then
just go up 1 size at a time or mayb 2,
once i get the jets sorted out
the bike has been running the best since
ive had it.

[edgo]

For my jetting needs I ordered my mains and pilots from Mikes XS650 page. He sells them for $6.00 a pair and if your order is over $35.00 shipping is free and it is next day shipping. Pretty good deal.

Ed

[mro]

hey petejw

"so any one know how 2 work out
the drill bit sizes for the corresponding jets."


good luck, fluid dynamics/chaos theory are beyond me

the difference between the numbered 140 jet and the dyno equivalent size is about 6.428% and the % seems to change with other sized jets.

mro

[pggg]

Well, a 1.5mm drill wont slide thru a 142.5, does slide thru a 147.5 with a tiny tiny sideways slop, my 145's are in my bike so can't accurately say - but a 1.5mm hole in a mikuni would be damn close to the standard 145 mikuni jet.