 4000-5000
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Joined: Jul 2005
Posts: 213
Adjunct
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OP
Adjunct
Joined: Jul 2005
Posts: 213 |
I haven't posted in a real long time but finaly have time for the bike. I deleted the airbox, re-jetted the carb, already had straight pipes and it runs great around town but when I get on the highway it hesitates around 4000-5000 rpms. In 4th gear it will power through and do fine but in 5th it pretty much stops accelerating at around 4800 (70-80mph). It is not the end of the world because I really dont need to go any faster but would like to know it is running its best. This is a '05 speedmaster.
Thanks
Cbass
-Sebastian
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Re: 4000-5000
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Joined: Sep 2005
Posts: 3,816
Freelance Jedi Knight
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Freelance Jedi Knight
Joined: Sep 2005
Posts: 3,816 |
seems like jetting is not right
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Re: 4000-5000
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Joined: Jul 2005
Posts: 213
Adjunct
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OP
Adjunct
Joined: Jul 2005
Posts: 213 |
Yeah at that rpm with a hesitation would that be too lean or too rich? Also could this be a needle shim problem?
Thanks for all and any help
-Sebastian
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Re: 4000-5000
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Joined: Feb 2008
Posts: 2,671 Likes: 15
Loquacious
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Loquacious
Joined: Feb 2008
Posts: 2,671 Likes: 15 |
It would be helpful to know exactly how it is currently tuned...which jets/needles/filter/pipes, yadda yadda...
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Re: 4000-5000
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Joined: Jun 2009
Posts: 84
Member
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Member
Joined: Jun 2009
Posts: 84 |
To determine if it's too rich or too lean at that RPM find a straight road with little traffic. Take the bike up to speed and hold it there for a minute or so. Then, without decreasing pull in the clutch and shut off the engine. Pull over and pull out your plugs and read them. This should give you a good idea of what you need to do.
08 America, A/I &, Calif emissions "stuff" gone, air box removed & battery relocated, billet intakes, UNI Pods, 145 mains, 42 pilots, Stage 2 igniter, intminators, 813 cams, Progressive 412's, modified seat.
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Re: 4000-5000
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Joined: May 2010
Posts: 5,720
Check Pants
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Check Pants
Joined: May 2010
Posts: 5,720 |
Quote:
To determine if it's too rich or too lean at that RPM find a straight road with little traffic. Take the bike up to speed and hold it there for a minute or so. Then, without decreasing pull in the clutch and shut off the engine. Pull over and pull out your plugs and read them. This should give you a good idea of what you need to do.
Should you not take note of the throttle position as well at that RPM, so your plug readings will correspond to the correct part of the fuel circuit to adjust? Seems to me, Dinqua and knowledgeable others have said again and again, it's not RPM, but T. position to know what needs to change. 
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Re: 4000-5000
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Joined: Jan 2005
Posts: 11,126 Likes: 13
Should be Riding
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Should be Riding
Joined: Jan 2005
Posts: 11,126 Likes: 13 |
Blowing gravel off rural roads
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Re: 4000-5000
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Joined: Jul 2011
Posts: 2,212
Oil Expert
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Oil Expert
Joined: Jul 2011
Posts: 2,212 |
Quote:
To determine if it's too rich or too lean at that RPM find a straight road with little traffic. Take the bike up to speed and hold it there for a minute or so. Then, without decreasing pull in the clutch and shut off the engine. Pull over and pull out your plugs and read them. This should give you a good idea of what you need to do.
With the fuels we use today this might give you an idea but very likley will not, my first guess is you are running out of fuel up there and need larger mains, if it does this in all gears that is likely gonna be your problem. Oops just read that in 4th gear it does not do this at those rpms? So in first sencond third and 4th is will run to the rev limiter?
2007 Speedmaster and miss it!
2013 T-Bird Storm and Luvin it!
Catching a yellow jacket in your shirt at 70 mph can double your vocabulary
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Re: 4000-5000
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Joined: Feb 2007
Posts: 23,217 Likes: 61
Fe Butt
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Fe Butt
Joined: Feb 2007
Posts: 23,217 Likes: 61 |
Quote:
With the fuels we use today this might give you an idea but very likley will not,
+1 todays fuels do not color the plugs like the old leaded gas did.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: 4000-5000
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Joined: Sep 2010
Posts: 457
Adjunct
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Adjunct
Joined: Sep 2010
Posts: 457 |
also, don't the older ones have a lower tooth-count front sprocket? mine came with 18, went to 17, decided the low end improvement wasn't enough to trade for the lower top speed, and went back. iirc, yours should have a 17 tooth stock.
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Re: 4000-5000
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Joined: Feb 2007
Posts: 23,217 Likes: 61
Fe Butt
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Fe Butt
Joined: Feb 2007
Posts: 23,217 Likes: 61 |
mine came with a 16 tooth front and I can still put my speedo needle at 120mph.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: 4000-5000
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Joined: Mar 2009
Posts: 12,964
Stickman Yogi
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Stickman Yogi
Joined: Mar 2009
Posts: 12,964 |
Let me just step in as the voice of our one and only Gregger. Once when I was having trouble determining the cause of performance issues with my bike, Greg chimed in and said...
Here is a seat of the pants test to check for proper main jet size. On a long straight (free from the local police), wind the bike out in 4th or 5th. Get it above 5000rpms accelerating hard and then slightly back off the throttle. If the bike seems to pick up speed, your mains are too small. The opposite, too big. Nothing and you are just right.
It really does work as a quick and easy means to determine if your jet size is working for your bike's setup.
Live to love, love to live.
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Re: 4000-5000
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Joined: Jul 2005
Posts: 213
Adjunct
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OP
Adjunct
Joined: Jul 2005
Posts: 213 |
thanks guys, it does seem that my main jet is too small, so I will start there and see how it goes. I will let you all know how it goes.
-Sebastian
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