1-I bought another complete yellow hy-71 police car,opened it up and it has a red/red arm, is that original on that car or if not what arm is?2 -doe's anyone have hop up tips for those heavy cars(the 70's 80's caprice police)?You guy's always come correct on info.

The red/red arm is the correct arm for that chassis. It was wound to power the car given the loss of some of the power sucked up by the flashing lights. Some of my fastest cars have that arm in it. All the normal mods help these cars including shiming the magnets and reducing gear drag...

yup what he said.if you own a dremel,lap the gears (if they are brass)with a wire wheel (VERY CAREFULLY!)you do not want to risk cutting one of the wires on the arm!all this does is get rid of any burrs on the brass gears that occurred during the stamping process.removing these burrs is important as it will assist the gears in meshing properly,reducing drag in the geartrain.when doing this a couple tiny drops of oil should be used to assist the gears,and keep the motor cool.this is the biggest enemy to pancake motor'd cars.friction.you can also gently ream the axle bearing points,if need be,to reduce some friction there.make sure there is not too much pressure on the comm plate from the brushes,aswell.a little extra,and you have more power,too much,and you can fry the motor!the red red arms are great.i have a few,and the scream when ya get everything else going well to help these shine.polish the comm plate.a clean comm is a happy comm!clean the brushes,and polish all electrical contact points.any way you can improve conductivity is good.:thumbsup:

And those are the responces that i was looking for thank's guy's.I put green /gold in it's place and the car was just as fast but the light's where slightly dimmer.

if you can find the green/green arm,thats the fastest i have seen that came stock in afx cars

When I get one of those cars, I add what I like to call my little "9-C1 Police Package" to it. I start with the usual mods (shimming the magnets), then I add: silver pick-up shoes (nos afx that came on the non-magnatraction), performance axle ratio (at least a 19 tooth crown gear), performance arm (mean green or blue drag arm, but the red-red works too), new JL magnets and silicone tires. With this package, it is at least as fast as a good magnatraction, which is good considering that it has to deal with the mechanical drag of the overhead light mechanism and the electrical drain of the lights. You could swap in mini led lights in place of the stock bulbs for less drain.

I've been 'sperimenting with a paste made of Commet cleanser and water to the consistancy of tooth paste for lapping in gears. It's grittier than tooth paste and easier to clean out of the gears than Valve Lapping compound. So far it works great on brass and a little less good on AW plastic gears. I have a MM chassis that will coast a mile...

Thank's,I'm trying it this evening!Cause it's snowing!

Yes all the above work's and thanks to all! BUT -Define shimming the magnets? and polish the com with? i'm very new!

Shimming - placing a small piece of paper (or other non-conductive material) about the same size as the magnet directly behind the magnet. This keep the magnet closer to the arm and keeps it from moving, which gives better performance.

And you can keep the comm plate clean by wiping it with a paper towel or toilet paper. Electrical contact cleaner may be used, but don't leave any on the comm.