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2008 XR650L Cutting Out When Given Throttle

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This is my first post and I hope I can learn something here as I'm kind of without a bike at the moment!

I have a 2008 Honda XR650L that is cutting out when I apply throttle at around 25 mph and up. The bike has an FMF Jet Kit, a Big Gun Exhaust, and a less restrictive air filter. I did not do any other modifications and I didn't grind off the little plate on the carb in order to have more adjustment on my mixture screw. I was running regular gas in it but at the advice of the guy that just worked on it I run premium gas in it now and I'm still on my first tank of that.

I hadn't ridden the bike in a while so I took it to a local shop and had them clean the carb, change the oil, and give it a state inspection. I went and picked it up and it started right up and sounded great. I went to take it home and everything seemed fine for the 1/2 mile trip. The next day (yesterday) I went to ride it to work, which is only two miles away, and when I was going about 35 mph I throttled it and the bike started cutting out like it was not getting fuel and wanting to die. It felt like I was tapping the front brakes a bit. Now I seem to remember having a similar problem once when I took the bike from very South Louisiana to very North Alabama. The bike ran fine at low speeds but when I started up into the thirties it wanted to cut out and sputter. I adjusted the mixture screw on the bottom of the carb and it went away. I tried doing that when I got to work and it didn't make the problem go away. It does seem to lessen the problem when I moved the screw all the way to the left side (driver's side if on a car) and up against the little plate that sticks off the bottom of the carburetor. Some other things I'm noticing is a lot of excessive popping on deceleration. Once it begins to cut out I just let off the gas and it stops.

I called Wild West Honda, in Katy Texas, and they wanted to charge me $170 to look at and "adjust" the carburetor. Not including parts of course. Since I just paid the registration, inspection, and mechanic fees to this other guy I'd like to avoid that. I'm hoping you guys can walk me through stuff to check to diagnos and fix this.

I should note that the bike did sit a while but was running fine before and nothing changed mechanically between the last time I rode it (about a year ago) and now other than now running premium in it. We did drain all the old fuel out of the tank before running it.

So that's where I'm at right now. I'm hoping this is easily fixable by myself. I'm very mechanically inclined but this is my first bike so I'm new to working on them.

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Just my 2 cents. First, new plug. Next remove pilot jet & main jet & make sure they are not restricted. Turning screw on bottom all the way in is the richest you can go but really only effecting idle.

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Thanks for the tip. I replaced the plug and it didn't change anything. The jets are clean as a whistle and have been checked twice.

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Ok, so tell me if I have this right. You put on a silencer and a foam air filter but did not rejet the carb? Is that right.

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Ok, so tell me if I have this right. You put on a silencer and a foam air filter but did not rejet the carb? Is that right.

Per my first post:

"I have a 2008 Honda XR650L that is cutting out when I apply throttle at around 25 mph and up. The bike has an FMF Jet Kit, a Big Gun Exhaust, and a less restrictive air filter. I did not do any other modifications and I didn't grind off the little plate on the carb in order to have more adjustment on my mixture screw. I was running regular gas in it but at the advice of the guy that just worked on it I run premium gas in it now and I'm still on my first tank of that."

So yes it has been jetted and unless I misunderstand your terminology when you say a "silencer" the big gun does the opposite. It is a very loud free flowing exhaust.

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It says FMF jet kit but not sure what the jets are?

I would have to figure that out. It's been about three years since I jetted it. The kit was a FMF 11704 but I can't find what size jet that included. I am on my iPhone though so it's hard to look up the product info.

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Although, at first you may think it's fuel/carb related because it cuts out when given throttle, I wouldn't rule out an electrical problem. It could be anything from a bad safety/ground to a loose stator wire or a faulty CDI that gets jostled around when given throttle.

If I were you, I'd start checking/testing the above components, starting with the easiest (bad safeties). :smirk:

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Started giving trouble with premium gas? drain the tank and carb and chuck a bit of regular in there and see how it goes.

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although, at first you may think it's fuel/carb related because it cuts out when given throttle, i wouldn't rule out an electrical problem. It could be anything from a bad safety/ground to a loose stator wire or a faulty cdi that gets jostled around when given throttle.

If i were you, i'd start checking/testing the above components, starting with the easiest (bad safeties). :smirk:

x2........

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Sorry, I didn't see jet kit at first.

Yes, turn off the gas and open the screw to drain the carb bowl. That'll clear out any water in there. If you drain it into a clean container, you can see what you have. If you find water, you should drain your tank and refill it with fresh gas. Water has a way of sitting at the bottom of the tank and unless you use "reserve", it'll continue to accumulate to a significant level.

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I doubt there is water in the gas although I did put fuel conditioner in there. It was refilled with premium just the other day.

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I should add that the tank was set to reserve when I picked it up and started riding it. I know on some tanks even when they get drained there can be some fuel left in the reserve reservoir but I flipped it to "on" and rode it and there was no change. Also it was cleaned afterwards and it's still having the problem. It seems cleaning the carb and running new premium through it would have helped te problem. I will do some research though about running premium as opposed to regular.

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You've got to fix this. I am having trouble sleeping:busted:

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You may have jetted it but you must cut the tab on the air/mix screw.

Then set it at 2 1/2 turns from in. This should cure it. If not the jet kit is off

I have used 52 pilot and 160 main and 2 1/2 turn from in.

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Or better, file down the tab on the bowl so you can use the tab on the screw to turn the screw.

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I should note that the bike did sit a while but was running fine before and nothing changed mechanically between the last time I rode it (about a year ago) and now other than now running premium in it. We did drain all the old fuel out of the tank before running it.

So that's where I'm at right now. I'm hoping this is easily fixable by myself. I'm very mechanically inclined but this is my first bike so I'm new to working on them.

So, from your above post I assume that the bike was running fine with the current jets in it, but after sitting for an extended period is now cutting out when given throttle? ... and after cleaning the carb it's still doing it? The exact same jets it had when it was running fine were put back in after it was cleaned and the old gas was changed out for new premium gas? :smirk:

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Diaphragm on the slide might not be seated correctly.

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