I have had my 2004 for 2 years now. It's a low mileage bike and has run flawlessly until now. I rode it yesterday for the first time in about two weeks and it backfired on deceleration and will not idle at all it just dies. I always run no ethanol premium and try not to let it sit for more than 2-3 weeks. I assume it's a fuel problem but don't know where to start as far as trying to fix it. Is there an easy way to drain the fuel tank and carbs?
First hiccup
- Thread starter blyoth
- Start date
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The tank has a plug, but you may find it's easier to reach by removing the tank. I've never accessed it on the bike.
The float bowls are similar, easy off the bike, very hard on the bike. Motion Pro does sell a Mikuni float bowl drain plug wrench for tight confines. I've never used it on a VMax.
See the pics, the hex brass plugs inboard of the carb bodies are the drains (carbs shown upside-down). The hex nut next-to the fuel level sending hole is the tank drain.
I just looked at their website, and don't see the smaller wrench I thought they had for the brass float bowl drain nut. Pretty-sure it's a 10 mm nut. Any low-profile box end wrench should fit it.
https://www.motionpro.com/c/fuel-system-tools
The float bowls are similar, easy off the bike, very hard on the bike. Motion Pro does sell a Mikuni float bowl drain plug wrench for tight confines. I've never used it on a VMax.
See the pics, the hex brass plugs inboard of the carb bodies are the drains (carbs shown upside-down). The hex nut next-to the fuel level sending hole is the tank drain.
I just looked at their website, and don't see the smaller wrench I thought they had for the brass float bowl drain nut. Pretty-sure it's a 10 mm nut. Any low-profile box end wrench should fit it.
https://www.motionpro.com/c/fuel-system-tools
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Carbs can be drained by loosening the phillips screws on the sides. You don't have to remove the plugs on the bowls. They are way up in the middle anyways since the carbs are sideways.
I'm not sure how accessible the drain plug is with the exhaust on the bike. Never tried with the exhaust on. I've done it with the exhaust off. No problem.
Before I bothered to pull the tank drain plug I siphoned the tank. I used a small diameter hose. I put a 5 gallon can beside the bike. Once the fuel starting coming out, I let it do its thing. Took a long time but got 99% of the fuel out so pulling the plug wasn't a nightmare spilling gas everywhere.
I'm not sure how accessible the drain plug is with the exhaust on the bike. Never tried with the exhaust on. I've done it with the exhaust off. No problem.
Before I bothered to pull the tank drain plug I siphoned the tank. I used a small diameter hose. I put a 5 gallon can beside the bike. Once the fuel starting coming out, I let it do its thing. Took a long time but got 99% of the fuel out so pulling the plug wasn't a nightmare spilling gas everywhere.
It can't have too much fuel left. I think I am about 25 miles away from reserve. I rode it about 15 miles yesterday trying to get it to clean up. It actually ran good on acceleration and cruise it just has a backfire when you let off the throttle and it will not idle unless I give it a little gas. It has Marks exhaust and has never backfired like that before. I'm kind of stumped.
Guessing it's a bit of debris in one or more of the jet block low speed jets, the one so-small you can barely see the hole. Unfortunately, that's a remove & disassemble the carbs job. Don't forget to change your fuel filter when you put it back together.
sdt354
Well-Known Member
Time for the shot gun? After fuel system inspection. Pilot circuits clog with no warning. http://vmax.lvlhead.com/tips/shotgun.htm
sdt354
Well-Known Member
It's not difficult, and if you get snagged we're all here to help out. It's something every Gen 1 owner will need done sooner or later. And not a bad maintenance procedure to do on a regular basis. A sync tool is also something you'll want to buy.
Steve-o
Well I may have dodged a bullet. I drained the tank put some fresh non ethanol premium and Sea Foam treatment in it. I had to run pretty much the entire tank through it before it just as suddenly as it started acting up it suddenly quit backfiring and idles perfectly. I'm so excited to have my clean running VMax back. I appreciate all the advice. I was really hoping to not have to tear into it. I will save the info for later reference if needed.
