Partzilla Live Q&A with John Talley – November 05, 2021

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

Yamaha ATV repair questions dominated this session. Read 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 11-05-21

Partzilla Live Q&A Highlights – Yamaha ATV Repair

My YFZ450R won’t turn on. It smokes from the intake when I try to crank it. Any ideas? 

John Talley: It almost sounds like it jumped timing to me. I think I’d start with that first. Take off your inspection caps at the crankshaft, bring it around to top dead center, maybe pull your valve cover and let’s make sure she didn’t jump time. That’s what it sounds like to me. If it’s spitting back through and she doesn’t want to start, she may have jumped a tooth. 

How often should the drive belt be replaced on my Yamaha Grizzly 700? 

John Talley: Alright, well that’s a little bit of a loaded question. Honestly, it depends on how you’ve got your machine set up, and how hard you’re actually running it. That’s going to determine how quickly it’s going to wear. I mean, you throw some 130 pound man or woman on it and they’re just cruising around the woods, not working it at all, it’ll probably dry rot before it actually wears out. You put somebody my size pulling a trailer with it and yeah, it’s going to wear it out a whole lot quicker. My rule of thumb is to check it at least annually when you wake your machine up if it took a nap during the winter months, and just visually inspect it. See if there are any cracks in it, see if there are any teeth missing on the inside of the belt. Now it’s not like those teeth are engaging anything, because the belt is actually getting squeezed on the sheaves on the sides. But those teeth in the middle are going to give you a good indicator if there’s a problem there or not. Or if the belt’s getting old and brittle, and that means it’s going to cut loose with you. The best time to look at that is at the beginning of the season, because that’s when it’s been sitting the longest and that can save you from being towed on your first ride out.

What’s up with the thrust washer in Yamaha ATV diffs? I’ve taken three apart and all three have failed thrust washers bearings. What is the stop bolt on the diff for that seems to contact the bevel gear?

John Talley: I haven’t run into that yet. … Do you have yours modified at all? Is it having to work harder than a normal differential? I’d also be curious to know what kind of fluid you use and your fluid change frequency if you’re running it that much harder. You may need to change up the concoction in there to maybe something not Yamaha related, or do something that could put up with that additional stress that I think your machine may be going through. 

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

 
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