Partzilla Live Q&A with John Talley – September 03, 2021
Partzilla Live Q&A returns with John Talley answering your motorcycle and ATV repair questions.
Motorcycle fuel system problems and solutions came up several times during this latest live 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 – Motorcycle Fuel System Issues
My fuel pump isn’t getting power and the relay is good. I can’t figure out the issue. What should I look at first?
John Talley: Alright, it isn’t getting power? I would say let’s head to the fuse first. And how are you sure if your relay is good or not? Did you replace it? We’ve got a couple of different no-start condition videos that you can reference. Go to our YouTube channel and find a machine that’s close to what you’re working on, and I walk through the steps of what it takes to run down a no-start condition. But I would say start with the fuse first, keep it simple.
My motorcycle is hard to start cold. The valves are in spec. I had it at the shop and they didn't find anything wrong with it. What could it be?
John Talley: Are you telling me that you looked at your valve clearance cold? That would be where I usually run first when a machine is hard to start when it’s cold. Make sure your intakes aren’t too tight, because as you know, when the valves start to wear on the face, that shortens the distance and hence makes the clearance less. And that can make machines very difficult to start the first time up. Anything beyond that, I’ve run into this before, where it just takes a little while for the fuel to get up to it, so you may want to … check your fuel pressure. Because I think she may be starving on startup. You may be having a pump that’s either getting tired or maybe that filter is getting stopped up and it’s having that initial startup of building up pressure to what it should be maybe a little bit low, so take a look at that first.
Do you think a fuel pump from a 150 Suzuki bike can fit a 250 Suzuki bike? It’s the same model, just a different displacement.
John Talley: You’re taking a bit of a gamble, because the amount of fuel that a 250 is going to go through is significantly higher than a 150. What its requirements would be, it’s like asking if you can put a carburetor from a 150 on a 250. No, it can’t send in that high of a charge of air/fuel mixture, so I’d be a bit leery of trying to graft in a fuel pump from a smaller machine. It would be very difficult to determine, because I doubt the manufacturer gives the specification as the to the fuel flow that the 150 is capable of versus the 250. My question would be why would you want to put on a 150 fuel pump? I can’t imagine the price difference would be that much, so why not go with what the manufacturer designed the bike to deal with?
Want to see more live repair questions answered? See all of Partzilla’s Live Q&A sessions here.