Is there a way to drill jets?

[outlawfox13]

Hi, I was wondering if anyone has drilled their jets with good results, and can give me an explaination on how to do it, and what bit size to use. I am asking this cause I would like to save some money and to have the experience and knowledge to do it.

BTW I am trying to drill the jets on my carbs, since I have pods and an exhaust from my 1000L with baffles removed(not by me by PO)

Thanks Mike

 

[tejasmud]

I would start with 1/4 inch

then 3/8 inch

then 1/2 inch drills should work.

:smart azz: giff...




No really.

Please, do not drill any jets.

One thing to do though if you ever buy a bike that has been modified by an unkown PO. Includes any 4 into 1 or pods on any bike,

buy new jets!!!!!

$12 or so a set of 4 all day long. Just buy new ones.

All jets are marked, but if someone drilled them???

A good "tell all" is stock jets in a bike that has been tweaked. Pipe, or pods and Black plugs.

The time it would take to drill them, if you could ever get them right, and then what if you went over.

 

[tkent02]

$12 or so a set of 4 all day long. Just buy new ones.

$5 or $6 for a set of four ain't bad either.
http://www.z1enterprises.com/catalog.aspx?pid=KPCF2

 

[tejasmud]

$5 or $6 for a set of four ain't bad either.
http://www.z1enterprises.com/catalog.aspx?pid=KPCF2

Something like that..... lol

Z1!

In opinion, aint no substitute in the customer service world, top of the line!!!!

If I didn't see it on the site I called them. They usually have it or can get it.

 

[outlawfox13]

Yea I just found out how cheap they are on Z1
I am gonna order a set, but not sure on the size.

120? 122.5? or 125?

I have an 81 GS750L with and exhaust from a 1000L w\o baffles(removed by PO) and individual pods.

 

[Steve]

120? 122.5? or 125?

I have an 81 GS750L with and exhaust from a 1000L w\o baffles(removed by PO) and individual pods.

What's in it now? Are they stock?

Rule of thumb is to go about six sizes with pods and a pipe, then be prepared to tune from there.

.

 

[67fire]

Just get some 115's and check the plugs after you run them.
Edit: I was living in VA at the time, so it should be close.

Eric

 

[outlawfox13]

What's in it now? Are they stock?

Rule of thumb is to go about six sizes with pods and a pipe, then be prepared to tune from there.

.

Stock Jets.

 

[streetfighters]

Spend the money, buy the jets! You will end up doing this anyway so save yourself the headaches. I used a " pin drill" set and my dremel when "custom jetting" my 85 V-Max. A small scratch will alter flow and quantity of fuel metered. I overhaul aircraft fuel systems for a living and spend every day calibrating carburetors and fuel injection servos.
streetfighters

 

[Dunger King]

I use a test jet set that I made to do jetting (Mikuni CV's only, have not tried other types) and have drills from 0.1mm to 2.5mm

1. solder up the jet opening
2. drill to size closest (up or down from stock depending on requirements) using bench drill and jig setup for accuracy, not forgetting to make sure lead in angle on jet is cleaned up
3. put carbs in and test run
4. repeat process until desired result is achieved
5. buy and fit correct jets.

have used this process on several street ridden bikes and results were great, If I was setting up a race engine I would not bother, just get a good shop/tuner to set it up on a dyno.

 

[midnightcafe]

don't do it. jet size increments are smaller than drill size increments. Drilling jets not only bores the holes but removes part of the tapered 'nozzle' essential to the jet performance.

 

[Guest]

I tried drilling the pilot air jets on my 1150 carbs and it failed miserably.

 

[Dunger King]

don't do it. jet size increments are smaller than drill size increments. Drilling jets not only bores the holes but removes part of the tapered 'nozzle' essential to the jet performance.

the drills I use are not from Wal-mart, they are a part of a precision tooling kit for milspec applications, mikuni CV mains are incremented in 0.05 mm steps

The tapered nozzle lead in on my jets are 118 degrees off a 2.5mm bore........ I've always been able to get my machines to run as desired on these jets before putting up cash to buy the right size

 

[midnightcafe]

mikuni CV mains are incremented in 0.05 mm steps

You mean 0.005mm steps? they're incremented in 0.0002 inches which is 0.005mm. pulled it from this article:

http://www.mediafire.com/download.php?5bmfmxmngyf

 

[tkent02]

I thought Mikuni jets were graduated in flow rates, not diameters?

 

[DMorris]

I thought Mikuni jets were graduated in flow rates, not diameters?

That's what I was thinking too.

Everything I've read on the subject says not to drill jets.

Drilling does not produce a hole smooth and consistant enough to produce reliable results. Very minor inconsistancies at this size can make a large difference in flow. Your jets will, very likely, all flow at different rates.

In fact, I read that even trying to clean a jet with a piece of steel wire is likely to distort the jet by raising a burr.

 

[tejasmud]

Pretty sure they are too. Everything I have read points to grams of fuel to grams of air, I think on Mikuni mains. Keihins run by drill size, I have measured them on an optical comparitor many times.

Not that drilling jets can not be done by someone who knows what they are doing, but if one has to ask, just buy them.