Dear Boss,

We own an old 1999 Honda TRX300. The battery had been weak for years, and we just kick-started it to get it running. Well, my son purchased a new battery and installed it, but the cables were frayed, and when he first started it, the positive cable touched the battery-hold-down plate on the frame, and it got red hot, sparks flew and the cable melted. Luckily, the machine didn’t catch fire. But, now everything is dead. What are my options now to get it back in operation, or do I just part it out?

Christine Weller
Empire Point, FL

Well, Christine, there is a bunch of testing that needs to be done before we “part it out.” You need to start with a shop manual, either in print or online. In print, there is a Haynes manual, #2125 and a Clymer manual, M346. An online manual is available for download here: 990666/Honda-Fourtrax-Trx300.html. The battery cables will definitely have to be replaced, either with OEM parts or small engine battery cables from an auto parts store. The Honda part numbers are 32601-HM5-730 for the ground and 32402-HM5-730 for the positive cable. With these in place, you should look at the twin fuses. One or both may be blown. They are 15 amps. Purchase the correct length. (Take one with you.) Reinstall the battery and see if the neutral light comes on. Hopefully it does and this indicates your battery wasn’t damaged with the direct short. Next, using your shop manual, find and remove the regulator/rectifier and test it using a VOM meter. (You can pick up a cheap one at most any auto parts store.) If it tests okay, then reinstall and fire your machine up. Set the VOM to voltage and put the test leads on the battery (red to positive and black to negative) and have your son slowly increase the revs. If the stator is out- putting a charge into the battery, you should see the voltage rise above 12 to about 14 volts. This indicates your battery is charging. If you see the volt- age climb above 14.5 volts, then shut it down and replace the regulator/ rectifier, because the regulator side of the unit is fried. Previously, you only tested the regulator side to make sure the alternator’s AC (Alternating Current) was “rectified” to DC (Direct Current) the battery can handle. The part number is 31600-HC5-970. If the battery voltage doesn’t rise at all, then your stator most likely is fried (part number 31120-HC4- 750). If the quad doesn’t start at all, the black box electronic ignition module may be fried (part number 30400-HM5- 506) or the pulse generator (part # 30300-HA0-033). Before electronics, it was the points that did the same thing. I never have had much confidence testing ignition modules, because they can pass all the factory tests and still be bad. Replacement with a “known good unit” is the best bet. Beyond these tests you may have to enlist an ATV mechanic. Also, be aware of the cost of new OEM parts. Look to the aftermarket for new OEM equivalent or used parts at a salvage yard. My final advice is to get your son some vocational training in ATV/small engine so he can actually be a help in the future.


Boss McKannick knows how to fix it.

All you have to do is E-mail your questions to him at [email protected]

Include your name, city and state address.

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