Can somebody help please

[2008 venture]

I have a 2008 Royal star venture. I was working on it again today and it seems like it doesn’t matter what Gear it is in when I get a past half throttle it starts to bog out. I have rebuilt carburetor put new spark plugs and a new fuel filter and fuel pump I have drained all the old gas out and put new gas in. If anybody has any ideas of what is causing the problem please let me know thanks

Edited April 7, 2020 by 2008 venture

[Condor]

I have a 2008 Royal star venture. It runs decent in first and second gear but when I go to third fourth and fifth it starts Bogging out and won’t let me go over 50 miles an hour. I have rebuilt carburetor put new spark plugs and a new fuel filter and fuel pump I have drained all the old gas out and put new gas in. If anybody has any ideas of what is causing the problem please let me know thanks

 

Fuel starvation... Pull the petcock and check the standup filters over the standups....

[Marcarl]

Check the fuel shut-off valve to make sure it's all the way open, fresh gas?, kinks in the fuel line? battery voltage and voltage on the supply lines?

[cecdoo]

Vent in gas tank clogged, with a low tank of gas try riding with gas cap cracked open. Just an idea?

 

Craig

[Karaboo]

At 50 you should just be shifting to 3rd.

 

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[2008 venture]

Check the fuel shut-off valve to make sure it's all the way open, fresh gas?, kinks in the fuel line? battery voltage and voltage on the supply lines?

Thank you for the post I’ve checked all that and they seem to be fine.

[cowpuc]

All sound advice IMHO. This may sound wayy out there but if it was mine I would be double checking the carb slide diaphrams.. Maybe pay close attention to the areas that contact the carb body as well as the areas down at the slide as well as the usual pin hole/tear inspection. Also maybe double check and make sure you dont have a brake hanging up.

[Rafterd]

Carbs are about half stopped up. Gonna have to clean them. Might try this, put about 2 gallons of fresh gas and add one hole can of Sea Foam. Ride it about 50 miles. Let it sit over night. Fill it with gas and add another can of Sea Foam. Ride it. It should be better, if not, you’re gonna have to clean the carbs.

[Patch]

Wondering if you can give us more of an explanation as to what exactly the symptoms are like. Do you smell fuel, does it kick or pop, backfire, regain if you let up on the throttle.

I agree with Puc that if your slides are rubbing then that can cause this.

So too fuel starvation.

Timing as well.

Also if the pickup coil is faulty when hot: that means read resistance cold and then hot.

[CaseyJ955]

Just spitballing here, bear with me.

 

Try the guidance offered above first...

 

Patch is right, more specific description of symptoms will help us get closer to the issue. When it starts to fall on it's face, is it bogging like out of gas or is it breaking up/missfiring/sputtering during the power loss? At about what RPM does it start to get fussy?

 

The carbs being rebuilt doesn't necessarily mean they were done properly or with quality parts. When the carbs were rebuilt were the parts/kits used OEM Yamaha or a Japanese quality aftermarket like K&L? Chinese kits are all to often a source of headaches.

 

A couple simple free checks to RO other possible issues.

 

When you installed the new plug wires did you check where they slide into the nose of the coil for that green gunky buildup?

 

You installed new plugs, how do they look now after having run it. Each plug should tell us something.

 

The network of vent tubes that are fixed to the top of each carb, make sure those are free and clear, if they get plugged up or kinked they can cause problems.

 

Were the carbs synchronized after re-installation? Out of synch doesn't really hit me for what your describing, but again it's a quick free check if you have access to a meter.

 

Wet float level check can be done without tearing into the bike, adjustments will require removal of the rack though. Float levels are critical for CV carbs. Wet float level checks are the same process as for a Vmax and I think there is a youtube video on that.

 

I had something similar with my Vmax falling flat after about 4k, I found the issue after looking down the carbs while it was idling, as I blipped the throttle I noticed one slide was sticky and not responding like the other three, I sorted that out and problems solved. Keep in mind it will run like **** without the air airbox, filter and lid snugly fastened in place, CV carbs rely on that intake restriction to function correctly.

Edited April 11, 2020 by CaseyJ955

[Patch]

Just spitballing here, bear with me.

 

Try the guidance offered above first...

 

more specific description of symptoms will help us get closer to the issue. When it starts to fall on it's face, is it bogging like out of gas or is it breaking up/missfiring/sputtering during the power loss? At about what RPM does it start to get fussy?

 

The carbs being rebuilt doesn't necessarily mean they were done properly or with quality parts. When the carbs were rebuilt were the parts/kits used OEM Yamaha or a Japanese quality aftermarket like K&L? Chinese kits are all to often a source of headaches. And if the emulsion tubes are clean

 

A couple simple free checks to RO other possible issues.

 

When you installed the new plug wires did you check where they slide into the nose of the coil for that green gunky buildup?

 

You installed new plugs, how do they look now after having run it. Each plug should tell us something.

The network of vent tubes that are fixed to the top of each carb, make sure those are free and clear, if they get plugged up or kinked they can cause problems.

 

Were the carbs synchronized after re-installation? Out of synch doesn't really hit me for what your describing, but again it's a quick free check if you have access to a meter.

 

Wet float level check can be done without tearing into the bike, adjustments will require removal of the rack though. Float levels are critical for CV carbs. Wet float level checks are the same process as for a Vmax and I think there is a youtube video on that.

 

I had something similar with my Vmax falling flat after about 4k, I found the issue after looking down the carbs while it was idling, as I blipped the throttle I noticed one slide was sticky and not responding like the other three, I sorted that out and problems solved. Keep in mind it will run like **** without the air airbox, filter and lid snugly fastened in place, CV carbs rely on that intake restriction to function correctly.

All good points Casey:thumbsup2:

[sldunker]

If you are sure your carbs are clean, make sure you have the lower fairing pieces on or bike will exhibit the same symptoms.

[wrscomncents]

I have a 2008 Royal star venture. I was working on it again today and it seems like it doesn’t matter what Gear it is in when I get a past half throttle it starts to bog out. I have rebuilt carburetor put new spark plugs and a new fuel filter and fuel pump I have drained all the old gas out and put new gas in. If anybody has any ideas of what is causing the problem please let me know thanks

 

Here is something that happened to me. I did some work on my bike including rebuilding the carbs and took it out on a test ride before replacing the lower leg cowlings. The ram air into the carbs would cause the engine to do exactly what you are describing. Not sure if you are riding without those but if you are put them on and ride it again.

[Freebird]

Make sure that the rubber boots on top of the carbs are have not slipped up on one or more of the carbs. That will cause exactly what you describe. I found that over tightening them would cause them to slide up and then it would suck air there.

[Marcarl]

Make sure that the rubber boots on top of the carbs are have not slipped up on one or more of the carbs. That will cause exactly what you describe. I found that over tightening them would cause them to slide up and then it would suck air there.

I remember that!!! down right confusing it was,, after all, I had just put them babies back on and checked and rechecked them, so no need to check them again,, Right??? WRONG!!!