Partzilla Live Q&A with John Talley – January 29, 2021

Partzilla Live Q&A returns for another session with John Talley answering your motorcycle and ATV repair questions. 

Honda ATV repair questions usually dominate these live sessions, although Yamaha ATV questions sometimes take center stage, as was the case this week. However, in this session a good mix of OEM parts and aftermarket parts and tools topics were also touched on. 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 with John Talley 01-29-2021

Partzilla Live Q&A – OEM and Aftermarket Parts & Tools 

Aftermarket Parts: Wiseco Pistons

Are Wiseco pistons good?

John Talley: The simple answer to that is yes. I’m a big believer in OEM but I have no problems with the Wiseco brand, especially if you’re tending toward the higher performance aspect of it. If it says Wiseco on the top of it, that means it’s forged, and that makes a pretty big difference when you’re talking about a higher end engine build. I believe we have a video that explains the differences between the cast pistons and forged pistons, and the advantages and disadvantages of one or the other. 

Aftermarket Tools: Compression Testers

What is the best budget-friendly compression tester?

John Talley: There are several of them out there. And I know that we carry one from Motion Pro on the Partzilla site. I’ve had really good luck with it. If you’re looking for consistency, it doesn’t have to be dead accurate as far as the actual numbers, as far as calibration, because when you’re doing a multi-cylinder engine, you’re looking to see if the readings are within 2 to 3 to 5 percent of each other from cylinder to cylinder. Now if you have a single-cylinder engine, then it needs to be a little more accurate as far as its calibration because you’re basing that number on what it’s supposed to be from the factory, whether it be 120 or 140 or 160 psi. Depending on how the engine is actually built. The one from Motion Pro is a good unit … there’s also the compression tester from BikeMaster.

OEM/Aftermarket Parts: Air Filters

What would be a good air filter for a 1989 Honda TRX 350?

John Talley: You can’t go wrong with the OEM, but if you want one that you can actually reuse and has a little bit of better flow rate characteristics, I know K&N makes one for that particular unit

OEM Parts: Regulator-Rectifiers

What is the most common type of diode failure on a regulator-rectifier?

John Talley: They can fail in so many different configurations as far as which diodes go out and which ones are still operational.  Plus, the way the actual charging system or the way the regulator-rectifier may be designed. The simplest one of course is where you’ve got a series of diodes either on the forward or reverse bias configuration to change your waveform from, of course an AC waveform to a DC. I know that I did a pretty in-depth video explaining 3 different manufacturers’ regulator-rectifiers, one from Honda, one from Yamaha and one from Polaris, and I went through what the differences are on those and how to test all three. Some like the simpler one, like the Honda, yes you can actually get in there and use your multimeter to do a reverse and forward bias test of each individual diode. But as the regulator-rectifiers become more complicated, it’s harder and harder for you to look through that narrow window with your multimeter to test them effectively.  

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


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