Partzilla Live Q&A with John Talley – April 08, 2022
John Talley is back with another edition of Partzilla Live Q&A, answering your motorcycle and ATV repair questions.
Honda ATV fuel and starting problems were brought up several times during this edition. Check out some 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 Highlights – Honda ATV Fuel and Starting Problems
I have a 2003 Honda Rancher TRX350 that only starts with starting fluid. Do you have any ideas on how to fix it?
John Talley: Well I think you answered your own question. This is a fuel delivery problem and being an 03, one of the first places you need to look is at the fuel petcock itself. Because if you let fuel sit in there for a long period of time inside of the fuel tank on the pickup tube of that petcock, there’s a small plastic covering, if you will, that has an even finer filter on it. And that will be subject to clogging up, especially with older fuel. If you’ve ever seen older fuel or smelled it, it has the same consistency of really cold maple syrup. So I would say to start there, make sure that it’s actually making it down to the carburetor. Because it sounds like it’s not. To verify that you do have fuel in the carburetor bowl, there’s going to be a drain screw all the way at the bottom of the drain bolt and you can access it I believe, on the right side of the machine, looking back down at the bottom of the carburetor. Open that up a little bit with your fuel turned on and see if any fuel flows through, and that’ll tell you whether or not your petcock valve is working.
I have a Honda TRX450 ER that runs great, but after a while it starts acting up. It’ll cut off and struggle starting, and I need to give it a lot of fuel to take off. What could be the problem?
John Talley: Well, you didn’t tell me the year, but that’s still probably a carbureted unit, even though the E is for the electric start. That sounds like you’re building up a vacuum in the tank. So I would make sure that the little one-way valve in the gas cap or the breather tube isn’t stopped up, because it sounds like it’s starving itself for fuel because of the vacuum. So take a peek at that.
I have a 2005 Honda TRX 400 that for some reason the motor lost power. What can I do?
John Talley: Well, when you say it lost power, is it still running? Is it smoking? Start with the basics. Do a compression test on it and see if it bent a valve or something else has gone wrong. If the compression test shows that she’s down something under 75 or 80 pounds, then maybe you’ll want to do a leakdown test. That will tell you if your rings are shot out, which I doubt because that usually happens over a long period of time. What you’re describing is possibly a bent valve, because one split second and that piston touches that valve and it’s not going to seal. And it might still start, but it’s going to be down on power after that. If you’re thinking it’s not anything in the engine, I guess your main circuit could be getting stopped up on the carb. But do the compression test first and if that isn’t it, then take a look at your carb. One other thing I have seen in the past, where everything’s running fine and then the bike will start losing power is actually a misfire, and that’s usually caused by either a crack in your CDI or coming off of your coil going to your spark plug, or the coil actually breaking down itself. The hotter it gets, the worse it performs until it doesn’t let the bike run at all, so just a couple of things you can look at. Compression test first, then take a look at the carburetor if it’s fuel-related, and if it’s not, head over to that coil wire or coil pack that goes to that spark plug cap.
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