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Discussion Starter #1
I have a 2006 stratoliner s with 33000 miles now new development intermittent idle surge not bad just a couple hundred rpm. Also feels like it's bogging down sometimes too but only if you hold constant steady throttle . Any thoughts would be appreciated thank you
 

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I'd start with the easy stuff like air filter, fuel filter, spark plugs. They probably need to be changed anyway. Maybe run some Seafoam through it.
 

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Seafoam!!!
 

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All the above, plus. Surging is hard to diagnose at times. I would start with the free stuff. A vacuum leak can cause an intake vacuum leak. The way I check, spray Carb cleaner around intake, does the RPM increase, if so you found your leak. Be careful if you use this testing method, if you were to spray on exhaust it could ignite and things will get ugly. A failing TPS sensor can also be a cause. TPS can be tested with ohm meter. Here is testing procedure.

Another simple issue could be clogged injectors, a good injector cleaner might fix that. Once you start testing things let us know the outcome. If you need the service manual here is a free link.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://mazko.net/docs/bikers/XV1900-RoadlinerStratoliner06-09REPAIR-MANUAL.pdf&ved=2ahUKEwiw-oKa2PLbAhVBXawKHenyAhQQFjAAegQIAxAB&usg=AOvVaw2tBh7CzBXoO3PnwkVxyArv
 

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Discussion Starter #5
Thanks for all the tips I will be working on it some tomorrow. I will let you know what I find. I did forget to mention that after about an hour of riding two days ago when I shut it down I noticed a gurgling sound coming from what sounded like the gas tank. It was really hot outside and bike was parked in the sun thought it could be venting but have never heard it from another FI bike. Any thoughts there?
 

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is it possible the fuel tank vent is plugged, and the fuel pump creates a vacuum in the tank when I is running?

I heard that can happen on some newer Ford cars. The 16 gallon tank is made of plastic, the vent closes off, and the fuel pump sucks the gas tank down to about 2 gallons of capacity (crushed). When the tank is empty you try to fill it, and it will only take 2 gallons.

If your fuel tank is not venting correctly the fuel pressure will be low on an injected engine, and it will not run right.
 

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if you pull the gas cap loose, and it makes a sucking noise, or that makes the bike start to run correctly... thats it.
 

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Discussion Starter #9
Thought I would give y'all an update. After air filter change spark plugs and oil change bike is running much smoother and stronger. I didn't find any horrible wear to any of the plugs and the air filter wasn't bad although I did not verify plug gap on the old plugs. I did however find a boot that appeared to be misaligned between the airbox and the throttle body.repaired that and it seems to have leveled the idle out. That's what I've found so far will keep y'all updated if problem returns
 

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Thought I would give y'all an update. After air filter change spark plugs and oil change bike is running much smoother and stronger. I didn't find any horrible wear to any of the plugs and the air filter wasn't bad although I did not verify plug gap on the old plugs. I did however find a boot that appeared to be misaligned between the airbox and the throttle body.repaired that and it seems to have leveled the idle out. That's what I've found so far will keep y'all updated if problem returns
Glad you figured it out. It's always nice when the easy things fix it.
 

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That would do it. Last time I checked the valve clearance on my 650, when I was putting the carbs back on it took me 3 tries and about a half hour to get the air box to attach correctly to the top of one carb. I think the plastic has deformed over the last 13 years from all the heat coming off the engine when you park the bike.
 

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Discussion Starter #12
Thanks guys I hope that's all it was. The problem was intermittent before so time will tell I suppose. I put some miles on her today with no issues but not enough for me to say it's fixed yet. I will let y'all know in a couple of days if the problem returned or not
 

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one way to debug a problem is to look at it backwards - what could I intentionally do to my bike to make it run poorly, in a specific way... ?

The air box and intake filter are an important part of the air/fuel mixture flow and control. I see bikes for sale online, vintage bikes that have been modified - it makes me cringe when i see a 4 cylinder Honda with the filter and air box replaced with those cute little air filters bolted right to the carbs.

Looks nice, runs like crap.
 

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The gurgling sound when you park is probably your gas "boiling" in the tank from the heat of the engine. Mine does this as well. It sounds terrifying but it is mostly harmless unless you park it in a small space and light a cigarette. I park mine in the driveway until the engine cools. I also try to fill the tank near to home on the return leg of a journey, more fuel is harder to heat up. You can aim a fan at the engine, to blow the heat sideways as well. All of this advice came from several long time aircooled V twin riders, as this is my first.
 
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