Total Motorcycle Community Forums

Alright, so ive got a 2013 yamaha vstar 650 custom that only has 20,500 miles on it. All put on by me, and the bike hasnt sat for any extended period of time since i bought it last year, brand new. Ive kept up with all my regular maintenance, and my plugs look fine. So when i take her up to higher speeds and higher rpm, i get an extreme hesitation sometimes, slight other times. But as soon as the hesitation starts, it wont stop, regardless of what speed or gear im in (including low gears/speeds) until i kill the engine and go again. I thought i may have gotten bad gas because i got some premium with ethanol in a hurry on the way to work yhe day it started, but i added seafoam, and almost 50 miles later, im still having the problem. Any suggestions? I would greatly appreciate any help i can get.

Hello Trip and welcome to the forum. How fast are you turning that over at? What's your redline? How about a picture of your bike?

I can't post a pic from my phone, but i don't have a tach built into my bike. It doesn't reach the rev limiter before it starts the problem though. I'm about to hook up a tach and check what it's idling at, then check and see if the carbs are synced. Idk where else to go from there if thats not it.

So i put a tach on and set idle at 1200rpm, then i made my own tool to check carb sync. They were way out of sync, so i synchronized them. That still didnt fix my problem though. My fuel filter doesnt seem to be clogged, and my pump clicks when i turn the key over. Any help would be greatly appreciated, I feel like pulling my hair out.

Hesitation at full throttle (not necessarily high RPM) can be due to excessive plug gap (worn plugs - plugs open gap as they age due to metal transfer) or a small gap inside the plug wire.

Closed throttle = vacuum in the cylinder = easy for spark to jump the gap.
Wide open throttle = cylinder full of air/fuel mixture = more difficult for spark to jump the gap (Air is considered insulator compared to vacuum)

Not saying this is it but it should be checked.
My Dad taught me long ago " check the ignition. If you didn't find the problem, check the ignition again because you probably missed something." (this in the days of points/rotors/condensers)

I checked the plugs first and they looked fine upon inspection, but ill grab new plugs after work amd see if i was wrong in my initial judgement. Ill post back after i change them and take a ride and let ya know how it works out. I appreciate the input, brother.

itstrip23 wrote:I checked the plugs first and they looked fine upon inspection, but ill grab new plugs after work amd see if i was wrong in my initial judgement. Ill post back after i change them and take a ride and let ya know how it works out. I appreciate the input, brother.

"looking" should include using a gapping tool to check the gap. Color is nice and all but if the gap has opened up you could get missing at open throttle settings.

Gap opens because each time the spark jumps the gap it carries a little bit of metal with it. Not much per spark but a few million sparks adds up over time. I think there can also be gas erosion as well though I'm not sure.

Again, I don't know if your high RPM situation is open throttle under load. If it's not then this doesn't apply. But new, properly gapped plugs at 20k is still a good idea.

I lost my gap tool, but these plugs havent been in there for more than 5-7k miles. Im still at work though, so i havent been able to go to the parts store. And the problem starts at wot, always after i reach higher rpms a few times. And it persists in lower gears and rpms after it starts. When i cut the bike off and cut it back on, its good until i get higher rpms again.

Fuel starvation? Clogged gas tank vent?

Well the fuel filter and pump seem fine, and the tank doesnt hiss when i take the cap off, so i dont think its either of those. But with the fuel pump, im basing its funcionality off of the fact that it clicks when i turn the key.

Update: i changed the plugs, it didnt fix it.