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Discussion Starter #1
'Beast' is an 07 Nomad bought new that now has 51K miles on it. When nearing the point at which you would normally upshift, the engine seems as though it is skipping/hesitating/running rough and will not turn faster until you upshift. 75 mph in 5th is the top end before this problem starts. Seems like it is not getting enough air or gas. I have replaced airfilter, spark plugs, always use premium gas, and have never abused the bike, although I am an aggressive rider. The bike runs smoothly until you roll the throttle on and it nears the shifting point. I live in B'ham, Alabama and the problem appeared recently with the cooler temps of 30-50 degrees. I ride every day, and the problem seems to be worse the colder it gets. I am by no means an expert mechanic, but I do some of the maintenance myself. I really do not want to give to the dealer if this is an easy fix because if it is not raining hard, I'm riding! Bike is still under factory warranty. Could this be an fuel injector/pump problem? Any ideas or suggestions?
 

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Navy Vet Search & Rescue
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When was the last time it had a complete tuneup? Have you ever run any injector cleaner in it? I'm thinking you probably don't have a tach but if you do, how close to redline is it when it has the problem.
 

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Discussion Starter #3
Had the recommended services done by dealer. I do the oil changes every 3k myself. Independent shop does tires and brakes. No tach, but nowhere near redline. Have not used injector cleaner. Speedometer is off by about 10% accd to GPS and radar; ie, reads 60 but is really 54mph. Issue starts when in 5th gear bike is actually doing 73 (shows 82); 4th gear bike is actually doing 54mph (shows 60); 3rd gear- 48mph (shows 54); does this also in 2nd and 1st I'm just not sure the speed. Bike in past 50k miles has not had this problem at all.
 

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itching to ride
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Have you checked valve clearances? Tight valves will float at higher rpms and can cause loss of power. Also your ignition can cause this. Check to see that your advance is working properly.
 

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Discussion Starter #5
Thought this had self adjusting valves- was hoping for easy fix from someone that had this problem before. I did not want to leave with dealer for 1-2 weeks. Was thinking that injectors, fuel filter, or fuel pump might be problem. I am not much of a tech. Will try injector cleaner next....any suggestions on brand? I have heard references to 'sea foam' on vulcan owners site.
 

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Navy Vet Search & Rescue
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It could be several different things causing it but I would start with the simple and inexpensive things first before going to the more involved and expensive things to try. As already mentioned, Seafoam would be a good starting point.
 

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Discussion Starter #8
Thanks for the advice. Never had any problems with my bike before. Had thought of looking into computer. Will post outcome of seafoam.
 

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Discussion Starter #9
Have run 1 tank through with BG 44k injector cleaner.....no difference yet. I have noticed that when the air temp is above 50 the problem almost goes away. Yesterday the temp was 30-35 and the problem worsened. Anyone know what could cause this? Local dealer suggested a hotter firing spark plug, but this does not seem like a logical cause or solution
 

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I have a few questions:
1. How do the plugs look...any signs of something out of the ordinary?
2. Does it do it equally in all gears or seem to be worse in the higher gears?
3. Does it do it worse when pulling a steep hill? Try finding the steepest hill around, put the bike in the highest gear it will handle without lugging and go up at wide open throttle. Did it do it at a lower RPM than normal when doing this?
Say "no" to the hotter plug.

Post back.
 

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A few more questions that I forgot to include in above post:
1. Any aftermarket add-ons... fuel processor, pipes, etc?
2. Start ok, hot/cold?
3. Any other driveability issues, no matter how small?
4. Any recent work done?
5. Has it seemed to vibrate more recently?
 

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Discussion Starter #12
1. Plugs look ok
2. It does do worse in higher gears, especially when going uphill
3. Starts ok...hot or cold
4. No work done recently
5. No engine or performance mods- stock exhaust, fuel processor; I do run auto tire- have been for 15k+ miles
6. There does seem to be a little more vibration at times- not sure of this, may just be me paying closer attention
7. No other draceability issues
 

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Discussion Starter #13
1. Plugs look ok
2. It does do worse in higher gears, especially when going uphill
3. Starts ok...hot or cold
4. No work done recently
5. No engine or performance mods- stock exhaust, fuel processor; I do run auto tire- have been for 15k+ miles
6. There does seem to be a little more vibration at times- not sure of this, may just be me paying closer attention
7. No other driveability issues
 

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The problem, as you describe it, seems to be fuel related. On FI bikes, this does get a little more complicated. The problem becoming worse in higher gears and going up hills sounds like a fuel starvation issue. What you might want to do (or have done) is a fuel pressure test. What this will check for is:
1. Partially plugged in tank filter screen.
2. Weak fuel pump delivery.
3. Faulty pressure regulator.
4. Kinked or blocked fuel lines.
5. Any internal fuel leaks.

The exact specs for your bike would be found in a shop manual, but should be in the area of:
1. 45psi pump on.
2. 41psi pump off.
3. 38psi bike at idle.
4. 40psi bike throttle opened.

Also, a check for full battery voltage at the pump connector when the pump is running would be a good item to look at, also.

Post back.
 

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Discussion Starter #15
The mystery is solved. After 12 days in the shop blowing out fuel lines and rails, replacing injector after trouble code came up, checking fuel pressure, it turns out that the fuel pump wasn't putting out enough volume. After replacing that, today's first day riding shows the bike to really kick butt. It seems like the bike is substantially faster than before and it makes me wonder if many more pumps might be like this with a gradual decline in performance. Today I blew away my buddie's Road King where before I just a little faster. You should see the :) on my faceI had all day.
 

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I am a little suprised that the fuel pump did not show a slightly lower than specification idle pressure. It would have been nice as it might have saved a little unnecessary work.
It is critical in an FI system that the correct fuel pressure be maintained thoughout the RPM and load range of the engine.
Anyways, glad its fixed. It is always nice to have you machine back running better than ever!
 
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