Drilling new jet sizes?

Does your Spree/Elite already run great, and you're trying to make it quicker/faster? Need a monster motor swap? Discuss your ideas here.

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Fishman43
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Drilling new jet sizes?

Post by Fishman43 »

Is it at all reasonably possible to manually drill new jet sizes? If so does anyone know the drill bit size #'s and corresponding jet sizes? I have a drill press and can get the jet lined up accurately, if this is something that has/can be done.

Thanks!
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ZMUD
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Re: Drilling new jet sizes?

Post by ZMUD »

JUST MY OPINION!....I have drilled alot of jets with no issue's. Others will say differently. But here is the link I use for chart reference.

http://www.affordablegokarts.com/Drilli ... 20Jets.php
94 elite 50s
----
66cc bbk
118jet/Pre-Mix32:1
1"uni-filter,Keli 9g
1k center,8.44 gears,ZX Trans
V8 Pipe,IRC MB38 80/90 tires
H4 H.I.D

94 elite 50sr
-----
50mm BBK,105jet
1" Uni-Filter,8:44gears
Fishman43
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Re: Drilling new jet sizes?

Post by Fishman43 »

Thanks Z! Lucky enough I have some spare stock jets laying around so if I really screw up I am out not much more than time. Do you oil the bit for drilling brass or is it soft enough to not worry about?
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evilone
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Re: Drilling new jet sizes?

Post by evilone »

No oil needed. You can actually hold a drill bit with pliers then spin the jet with other hand and it goes right through. P.S. I'm not recommending drilling 8)
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Bear45-70
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Re: Drilling new jet sizes?

Post by Bear45-70 »

Jets are flow rated and not just a certain sized hole. So the correct answer is NO!
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'83 Aero 80 X 3
'84 Aero 80 X 3

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'84 Aero 125 X 2
'84 Aero 125
'84 Aero 125 X 2
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ZMUD
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Re: Drilling new jet sizes?

Post by ZMUD »

Yup just hand roll with a pair of plyers. the drill bit will cut like a hot knife on butter with the brass jet! :thumbwink:
94 elite 50s
----
66cc bbk
118jet/Pre-Mix32:1
1"uni-filter,Keli 9g
1k center,8.44 gears,ZX Trans
V8 Pipe,IRC MB38 80/90 tires
H4 H.I.D

94 elite 50sr
-----
50mm BBK,105jet
1" Uni-Filter,8:44gears
Fishman43
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Re: Drilling new jet sizes?

Post by Fishman43 »

Thanks Bear & Evil for your input. I figured drilling jets isn't the correct way to go, but if the CDI and coil I just recieved from Marty doesn't fix the Aero then I really am going to have to try dive into the jetting as the likely problem. My problem with that is getting the larger jets for the Aero carb in small enough increments (they tend to increase in 5's). I know the next jet size up (+5) from what I currently have in the carb is WAY too much (barely ran, smoked like a Bob Marley concert). So I may be seeking smaller jetting increases.
fatcharlie
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Re: Drilling new jet sizes?

Post by fatcharlie »

I've drilled jets... here is the way I see it.

Lean motor = Bad
Drilled Jet = Not so good
Reamed Jet = better than drilled.
The correct unmolested Jet = Best

It works in a pinch, and you may never notice an issue with it... but jets are cheap for the bikes we are working with, buy a set and tune with proper jets.
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Fishman43
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Re: Drilling new jet sizes?

Post by Fishman43 »

I have a set that came with 85, 90, 95, 100, 105, 110. I am currently running a 100 and there is a possibilty I am just a touch on the lean side, but the 105 is way overkill.

How is a jet reamed?
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