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Engine hesitation?

9329 Views 19 Replies 12 Participants Last post by  SoftailBilly
Hello Team and pardon my ignorance.

2008 Softail Rocker with 22,000. I got it used with 20,000 six months ago. Use it as my daily rider and commute bike around the City and Bar hopper.

Most of the time I ride 5MPH - 10MPH above the speed limit.

Last night was coming from a meeting with friends around 2:00AM and not a soul on the freeway. I decided to push the limits and see what the bike is capable. When I ride on the city I normally accelerate very hard and the bike feels very well planted and pulls hard. Last night everything was fine until I hit 90MPH and the bike starts to hesitate like if is running out of gas. It was very small hesitation but enough to make me get out of the freeway. The bike felt like 90MPH was the top speed and not able to go faster. Is this normal? I just switch the gas from premium to plus in my last two refills and have not see any difference. Bike has a Vance & Hines exhaust and the HDSE Heavy Breather.

No fuel management module. Was thinking that maybe is the sparkplugs and cables. Any ideas? Thank you very much.


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I`m thinking you have a lean condition. HD sets them lean from the factory.
Having added an after market breather and exhaust you have only added to the situation.
A good fuel management flash should take care of the lean condition, hesitation, and cool down the engine temp a degree or two.

I`ll assume plus is lower octane then premium. IMO, the switch was not a good idea. Especially since you are likely running lean\hot already.
Thank you.

Will go back to premium on my next re-fill. I also disconnect the O2 sensors to enrich the mix. Planning on the Powervision in the near future. Expensive but will like to be able to have a Tach. I know that I am revving the bike hard but no idea on what RPM's I am.
Don't disconnect sensors will make bike run poorly. 90 is about top speed. And always use premium, if trying to save money do it elsewhere besides your bike.
Agreed. Unless you've done some work to her, 90 is about all you'll get...
That hesitation that you are talking about could just be the rev limiter. The motor will stutter because it is only hitting on one cylinder, it is meant to do this so you do not over rev it.
Divine intervention?


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Did you tune the bike when the filter was added or was it already there? Also, premium will make a difference in the way she runs. Checking the plugs and wires would be a worthwhile exercise just to say you did. You never know what you may find.
I think you need more fuel too. My 2007 softail will top 100 with pipes and a big sucker and a power commander. I don't know how much over 100 it will go because the wind shield I put on started flexing pretty good so that was enough to satisfy my curiosity. The roads are getting pretty crowded where I live.
Why do you say 90 is top speed I've had mine at 120 and she still seemed to want more.. No engine work done


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Are the plugs new?, old plugs can be a problem. Pulled a 100 with my 96 engine 09 FXSTC. Look into some Exides fatten fuel mix a bit and cool down oil temp.
Why do you say 90 is top speed I've had mine at 120 and she still seemed to want more.. No engine work done


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About 90-95 is all I could get out of my 05 RK 88" and my 07 FB 96" while still stock...
If you were getting 120 - wow!! Out of what?
That hesitation that you are talking about could just be the rev limiter. The motor will stutter because it is only hitting on one cylinder, it is meant to do this so you do not over rev it.
That was my first thought. Rev limiter I think is set to 6200 rpm. I don't know what the speed is at 6200 rpms in high gear but I assume it's more than 90 mph.
That was my first thought. Rev limiter I think is set to 6200 rpm. I don't know what the speed is at 6200 rpms in high gear but I assume it's more than 90 mph.
The stock setting for rev limiter is 5800 rpm. Hit mine twice, engine went completely off no hesitation. Harleys re-flash raises revs to 6200.
About 90-95 is all I could get out of my 05 RK 88" and my 07 FB 96" while still stock...

If you were getting 120 - wow!! Out of what?

Just an 08 night train with pm air cleaner Bassani pipes and a cobra fuel system


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That was my first thought. Rev limiter I think is set to 6200 rpm. I don't know what the speed is at 6200 rpms in high gear but I assume it's more than 90 mph.
As softailbilly said the rev limiter is set at 5800 from the factory. After thinking about it the only way it would be the limiter is if he was in 4th gear instead of 5th. Unless he changed his pulleys to lower the ratio.
I got the bike used with the Vance & Hines pipes and the SE heavy breather. No idea if the ECU was re-programmed. I am having trouble to believe 90MPH is the top speed of the Twincam 96B engine. I dont think I had ever hit the rev limiter. Not having a tachometer sucks big time.

My previous HD was a 2011 Sportster Iron 883 and top speed was 90MPH with no hesitation.

I read that one of the best mods is to disconnect the O2 sensors to enrich the mix.
I got the bike used with the Vance & Hines pipes and the SE heavy breather. No idea if the ECU was re-programmed. I am having trouble to believe 90MPH is the top speed of the Twincam 96B engine. I dont think I had ever hit the rev limiter. Not having a tachometer sucks big time.

My previous HD was a 2011 Sportster Iron 883 and top speed was 90MPH with no hesitation.

I read that one of the best mods is to disconnect the O2 sensors to enrich the mix.
If the bike was running right I would think top speed would be about 105 to 108 since you do not have a windshield which will drop top speed by almost 5 mph. Also I have heard top speed is accomplished in fifth gear not sixth.
I read that one of the best mods is to disconnect the O2 sensors to enrich the mix.
That would throw a trouble code, and that may be somewhere to start.

See if you have any stored trouble codes and go from there.


And looking at the photo of your bike, those pipes are bad for performance.
If the bike has not had the stage 1 download, that could be part of the problem.
80mph would is approx. 3000 rpm in 6th. on my tach. What Kainam said, pipes and a/c running too lean. I would pull those plugs. You mentioned running hard around town, could be glazed over from the heat.
When you get things sorted out, check out the HD Combo Tach/Speedo, nice unit.
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