Partzilla Live Q&A with John Talley – December 11, 2020

Welcome back to another Friday edition of Live Q&A with John Talley answering your motorcycle and ATV repair questions. 

Honda ATV questions always seem to dominate almost every one of these live sessions, and this one was no exception, with the Honda TRX 400 EX taking the spotlight. 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 John Talley 12-11-20

Partzilla Live Q&A – Honda TRX 400 EX Highlights 

Honda TRX 400 Starting/Charging Problems

I have a 2008 TRX 400, but I have to jumpstart it every time I ride it. I left it charging but it won’t charge. Any advice?

John Talley: Well, are you sure the battery is in good shape? There are several videos we have out there where I go through the testing procedure to see if it’s your battery, or if it’s your charging system. … I’d look at the battery first. What I would need to know is how old it is. Typically if a battery is set up correctly and you have a trickle charger, and you’ve really maintained the health of it, you’re maybe going to get four years tops out of it. And if you didn’t maintain it well, or it wasn’t set up properly initially, I’ve seen them not even last a year, so look at the age of it and go through some of the testing procedures from our videos. 

If a Honda 400EX turns over but doesn't crank, would that be the piston losing compression?

John Talley: It could be a combination of several different things. The first thing that you would want to look for is if it’s getting compression, if it’s getting fire, if it’s getting fuel. … Put a compression tester on there, and see what it does, see if it’s in range. You should easily be in the 120-140 range on the 400EX, if memory serves. … Do a compression test first, and then work your way from there. I know we did a “Help! My ATV Won’t Start” video … so check that one out and it’ll walk you through some of the electrical things you can look for that would keep it from starting. 

Honda TRX 400 Carburetor Problem

How do I fix it when the 400 EX cuts off whenever I come to a stop and takes a while to crank back up, even when it’s in neutral?

John Talley: If it’s cutting off when you’re coming to a stop, that tells me that it’s probably starving for fuel on what I call the idle/air or the pilot jet, the small jet. It shouldn’t do that when you’re coming to a stop … I would say you need to take a peek and make sure it’s getting the fuel that it needs to run, and just idle. And I’m betting we did a video on the carb cleaning on that one, didn’t we? 

Honda TRX 400 Oil Change

What’s the best oil you would recommend for an older TRX 400EX?

John Talley: The same oil I would recommend for a new 400 EX. That would be the semi-synthetic Honda oil that comes in the gold bottle. You want to make sure it’s the gold, not the gray. The gray has the molybdenum in there and you don’t want that because the clutch would not care for that at all. 

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


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