DIY....re-jetting a 6.5

cjtmini

cjtmini

#1
#1
The HF 6.5's come from the factory lean and easy jetting changes can make them run much better.....even when stock. You must change the main jet when replacing the stock air filter housing with an open air filter like a K&N or UNI filter.

You can replace the jets with larger ones or purchase small # drills. A complete set of #61-#80 drill cost about $12, or individual drill can be purchased for about $1 each. These drills are tiny and must be treated gently. The jets are brass and drill easy but take it easy!

Opening up the idle jet can make a stock engine start easier and reduce popping while decelerating. In this DIY I will show the steps required to re-jet your carburetor.

Before starting make sure there is no dirt at all around or near the carburetor before working on it.

Most all new HF 6.5 engines have a cap over the idle speed screw. Use a pick to pop it off, it comes off easy. Thread the idle screw out and then with the pick remove the idle jet.
 
cjtmini

cjtmini

#2
#2
You will nee a #77 drill to open up the idle jet. I grip the drill in a pair of small vise grips and gently rotate the jet between my fingers over the drill. Go slow, take your time the tiny drill is very fragile. You are only opening up the jet .001” or .002” Your only drilling thru the brass stop once you see the drill like in the photo. Use some carburetor cleaner and compressed air to make sure the jet is 100% clean before re-installing it
 
cjtmini

cjtmini

#3
#3
If installing an aftermarket air filter you’ll have to open up the main jet. Turn the fuel valve off and remove the carburetor bowl with a 10 mm wrench. Gas will begin to leak when you loosen the bolt so have some paper towels ready. Remove the bowl it seals on an o-ring. Get the proper sized flat blade screwdriver to go up inside the carburetor body and remove the main jet the emulsion tube will come out with it.
 
cjtmini

cjtmini

#4
#4
You will need a #65 drill to open up the main jet. I grip the drill in a pair of small vise grips and gently rotate the jet between my fingers over the drill. Go slow, take your time the tiny drill is very fragile. You are only opening up the jet .006” or .007” After drilling the jet is equal to a #89-90 jet this is perfect when using an aftermarket filter. Use some carburetor cleaner and compressed air to make sure the jet is 100% clean before re-installing it.
 
Oldschool

Oldschool

New Member
#9
#9
A couple of different ways to do this:

If you have a good drill press put the jet in there and spin it.
Hold the drill in a vice.

Set up is very important for a centered hole.....
 
J

johnhonda

New Member
#12
#12
where is a cheap place to get the small# drill sets.I have been using a torch tip cleaner and would file the main jet then road test then file some more.takes some time and a good ol redneck way of doing it
 
D

DARK AGE 53

New Member
#13
#13
Clyde

Clyde

New Member
#17
#17
Excellent tutorial.:thumbsup:
Thanks for posting this.

The perfect "tool" to drive the small drill bits is called a "Pin Vise".
[ same type as Dark Age 53's example, and Strigoi's prior post]

Hobby stores, on-line tool supply, etc have them. Under $10 USD is normal price (I see them for $4-$6 a lot). They can be used as mini screwdrivers (with proper tip) OR to clamp in a small needle and micro pick apart gaskets or dirt when cleaning. Also good for reaming clogged carb jets/passages with micro needle, drill bit, or Q-tip.
The ones with metal collets, (versus plastic) are more versatile, and some even interchange with Dremel Tools}

PS--- good practice is to not hold a brass/bronze jet (or piece) in a steel vise without cushioning the jaws with a rag/tape/rubber etc. Use something like this for a third cushioned hand http://tinyurl.com/48kjrld

 
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