OK, Enough of rules already!

A few things before we get started swapping. This will take you a while. A LONG while. This is entering into the "hours of labor" part of making a fast T-Jet.
Don't get discouraged. Just walk away and come at it again tomorrow. But The more time you spend swapping and polishing will pay off.

For the 14 tooth, find a good TIGHT gear. If you have a loose one, then peen the hole on both sides with the center punch and a SMALL hammer. GENTLY tap the punch as it sits in the hole until it creates a very small bevel. Then turn it over and repeat. This should tighten the hole to a point were it will stay on the motor shaft.
Then assemble the driven gear on the shaft, also peening if you must. Press this gear to a point were it has a small amount of play up and down. This should be at the stop, but not always.
Assemble the chassis with your setup shoes and everything else needed to run the gear train. I would not put on the rear tires yet. We will need to clean this thing and the tires will get ruined by the cleaner.
Place in the first idler, and attach the band.
Spool 'er up and listen to that box of rocks!
Now turn the idler over and see if it is any better. Repeat this with ALL of your idlers. You will find three or four that will sound better and rev higher than the rest. set these aside.
Now if you want to start pressing and swapping 14s and drivens you can do that or you can take what you have. The more work you put in, usually the better. You will find that the "Patent applied for" gears are usually better, especially the 24 tooth drivens.


Now for oils.
I try to use the lightest oil I can. The old AFX oil is great for running the gear train in, but is too thick for racing apps. Larry Thomas, John Habernal, Wizzard and trinity all make good oils.
Wizzard has a new product the I'm experimenting with right now. It is a product that is a coating for the metal pieces of the chassis. You simply apply the product and warm it up with a hairdryer. It adheres to the gears and will last MUCH longer than plain old oil. In any case, it is worth a try.

Oil all of the usual spots and note how much quieter the gears get. Also, and more importantly, note how much more RPM you get. A regular oiling schedule is paramount to smooth steady performance. I usually oil every 6 minutes of running.

Ok Now for the tricks:

#1 I'm assuming that you all know how to lap in your gears. But there are a few things to do while you do this. Use your AFX oil, or any thicker oil you have, Place it on the plastic idler gear shaft before lapping. it will keep the center hole from getting too big.

#2 Before lapping, take your 1000 grit sandpaper while the chassis is running, slip it under the 14 tooth gear as far as it will go without stalling the motor. Remove and listen to the difference. Repeat a couple more times.

#3 do the same thing to the 24 tooth driven gear. Get as deep as you can.

#4 Double over the sandpaper and start to hit the od of each gear.

#5 Stay on top of the center hole oiling. This is very important!!!

When you go to clean up, I've discovered that CRC makes a great product called "QD Electronic cleaner" This stuff is great and will not react with the plastic.
To put the finishing touch on your work. Try a final lap with "Novus #2" plastic polish. This stuff washes off with warm water, and is a very fine grit.

Sources for how to lap gears:

Front Range HO Racing - check out their Hop Up Hints
HO World - check out the Archives section

Tim

Next installment: Wheels & Tires
Previous installment: Stock Gears