Partzilla Live Q&A with John Talley – October 30, 2020

John Talley returns for another Friday edition of Live Q&A, taking on your motorcycle and ATV repair questions. 

Honda motorcycles and especially ATVs once again dominated this week’s conversation, but since we’ve highlighted those multiple times in these recap posts, we’ll instead feature some general repair and maintenance questions and answers here. Check out excerpts from Partzilla’s latest live Q&A session below, and tune into our YouTube and Facebook channels every Friday at 3pm Eastern for the next edition.

Partzilla Live Q&A 10-30-20

Partzilla Live Q&A Highlights – General Repairs

Charging System Problems

My bike won’t hold its charge after I ride. The battery is dead, but I know it’s not the battery since it’s brand new. Do you think it could be the rectifier?

John Talley: More than likely, it probably is. The three basic parts of your charging system are the battery, which you know is good now, although I’d still test it. Your regulator-rectifier, and then your stator and rotor assembly, which actually sends over the AC voltage, which the rectifier regulates and holds it around in between 12 ½ to 14 ½ volts, maybe 15 volts DC. So the best way to determine that is to get a voltmeter. And we’ve done several tests and we’ve got a bunch of different videos on testing regulator-rectifiers. … You will need to have a voltmeter, because you need to watch your voltage and see the changes from a static battery test as to when you’re revving the engine. It should be static at around 12.5 -12.7, somewhere in that neighborhood. And when it’s running, it should go as high as maybe 14 ½ to 15 volts. That’ll tell you right then and there if your system is being charged, and my bet is that it’s not …

ATV Resale Value

What is the value for a 2002 Honda 400 EX?

John Talley: The best baseline to find out what your machine is worth is usually to go to Kelley Blue Book. They’re going to give you a retail value, a trade-in value, and then a private party value. So go there and put in your information, and they also get more specific by your area code, or zip code, and that’ll determine what your machine’s value is. 

Oil/Spark Plug Issues

I have a bad valve cover seat on my Honda CRF450R, with oil getting all over the spark plug boot. Will the oil ground the plug?

John Talley: Actually it can. If it’s really that full, sure. I’ve seen it happen on a car before, so why not a motorcycle? … It’s time to replace that O-ring seal. Before you even get started, go ahead and tip the bike up so you can get all the oil out of it, or extract it with some type of vacuum system. … 

How do you tell if you’re engine is running rich or lean?

John Talley: Well the first indicator if you’re running rich is that usually you can smell raw fuel coming through the exhaust system. But the best way to tell for sure is to go ahead and take the bike out, get it on a straight-away, put it in 3rd gear, go ahead and nail the throttle, rev it and let it run all the way out, and then do what they call a hot cut, or cold cut. Cut your ignition, roll to a stop and then pull your plug. What you want to do is to take a plug read, to see what your wide-open throttle fuel burn is. And if you pull the plug and it’s black around the ceramic and around the base of the plug, you’re running way, way rich. If it’s completely white and looks like a new plug, then you’re very lean. Keep in mind that is at wide-open throttle, and if you want to see where you are at different points, you could just stop at whatever RPM you want to. Whether it be a quarter, half, three-quarter or wide-open throttle, and that’ll give you an idea after about 5-10 seconds worth of runtime at that RPM to give you a good read on the plug as to what’s going on inside that engine.

Want to see more live repair questions answered? See all of John’s Live Q&A sessions here.  


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