Engine lag from launch
Thread Starter
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Tourer
Joined: Mar 2011
Posts: 262
Likes: 22
From: South of Indy
Engine lag from launch
Hard to describe this but... When Starting from a stop, especially when riding two up, the engine seems to lag to the point that it nearly dies. I try to give it more throttle, but it still lags. I couldn't start quick off the line if I wanted too, which is concerning because sometimes I need to be able to accelerate quickly from a stop (i.e. merging into traffic). I've only had this bike for a few months so I don't know what changes or upgrades have been made to the engine. I do know that the P.O. had the engine upgraded to a 103 and I have some cables in a box that he gave me that say reads somthing about a race tuner. He said I would need this cable if I ever had engine work done. Any suggestions on what may cause this condition? Bike runs great otherwise.
Road Captain
Joined: Oct 2007
Posts: 634
Likes: 8
From: Plum & Nearly
You need to first verify what you have in the engine and then verify the correct ECM calibration is loaded for your engine.
I would note that free flowing exhaust like your "true duals" will affect bottom end torque grunt. A little back pressure is probably needed to give you that take off torque.
I would note that free flowing exhaust like your "true duals" will affect bottom end torque grunt. A little back pressure is probably needed to give you that take off torque.
Tourer
Joined: Nov 2006
Posts: 448
Likes: 20
From: In a van, down by the river
Had similar issues with my bike, it was the Power Commander map. This past Sunday I uploaded a newer map and its like a completely new bike.. its an animal! The zero power at the bottom is gone now.
Road Captain
Joined: Feb 2008
Posts: 559
Likes: 0
From: La Vergne, TN
Hard to describe this but... When Starting from a stop, especially when riding two up, the engine seems to lag to the point that it nearly dies. I try to give it more throttle, but it still lags. I couldn't start quick off the line if I wanted too, which is concerning because sometimes I need to be able to accelerate quickly from a stop (i.e. merging into traffic). I've only had this bike for a few months so I don't know what changes or upgrades have been made to the engine. I do know that the P.O. had the engine upgraded to a 103 and I have some cables in a box that he gave me that say reads somthing about a race tuner. He said I would need this cable if I ever had engine work done. Any suggestions on what may cause this condition? Bike runs great otherwise.
Thread Starter
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Tourer
Joined: Mar 2011
Posts: 262
Likes: 22
From: South of Indy
You've lost me...I don't know what a map is. Is this something I can do, or is it a dealer only thing? I've read other posts about tuning the bike but I don't know where to go to learn about it.
Thread Starter
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Tourer
Joined: Mar 2011
Posts: 262
Likes: 22
From: South of Indy
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Tourer
Joined: Nov 2006
Posts: 448
Likes: 20
From: In a van, down by the river
A "map" is a custom set of instructions/rules that tells your EFI "tuner" how to alter the gas and ignition ratios for maximum performance based on your mods. You need to verify what model tuning device you have before you can diagnose any further. From what you said so far, I am guessing you have the Harley race tuner.
I had same starting from 2nd gear feel whenever I had my wife on the back. Uploading the right map fixed it all up. Best part was, after uploading, I told my wife I am taking a quick test ride to see how it feels. I ended up having so much fun on my "new" old bike that I was gone for over an hour.
I had same starting from 2nd gear feel whenever I had my wife on the back. Uploading the right map fixed it all up. Best part was, after uploading, I told my wife I am taking a quick test ride to see how it feels. I ended up having so much fun on my "new" old bike that I was gone for over an hour.
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Road Warrior
Joined: Jun 2009
Posts: 1,943
Likes: 3
From: NYC
when a twin cam gets an upgrade, adjustments to the system that manages fuel ratio are required to be reviewed. Simple things like air intake modifications, exhaust modifications, and certainly a 103 upgrade. Most of the adjustments are compromises.
it sounds like your bike has been upgraded to a state which needs further adjustments of the system that manages fuel/air ratios. the cables are part of a third party system. the assumption is that you will be able to review the fuel management system documentation, and apply the principles discussed in the documentation. you indicate that you have cables, but does the cables go to a laptop to do the anlaisys (do you have a laptop) or do they go to a controller (do you have the controller). ask the person you purchased the bike from for more information.
it sounds like your bike has been upgraded to a state which needs further adjustments of the system that manages fuel/air ratios. the cables are part of a third party system. the assumption is that you will be able to review the fuel management system documentation, and apply the principles discussed in the documentation. you indicate that you have cables, but does the cables go to a laptop to do the anlaisys (do you have a laptop) or do they go to a controller (do you have the controller). ask the person you purchased the bike from for more information.
Advanced
Joined: Dec 2010
Posts: 53
Likes: 1
From: South Central, WI
Something easy that you might want to check out would be the spark plugs and their gaps. Additionally, you might want to check out your plug wires.
I know myself that I am a plug wire murderer. Seems that I always forget how fragile those wires are. I bought the Screamin Eagle Fat Plug wires recently and they are much stronger. I only bought them because they were less money than the stockers and stock wasn't in stock.
And for plugs, they are really cheap. Make sure to gap them before you install them. I run mine on the smaller gap side.
I was having trouble with a motor that was built not wanting to run below 2200 RPMs with a load (picture taking off from the neighborhood at 5 AM for work....) The dealer couldn't get it figured out and were thinking that it was my tuner, but they didn't really spend anytime with it, so I don't really know. I called a great indy dyno guy and had him work on it, and the first thing he notices was the wires were junk, and the plugs were gapped way to wide. When I did my Limited, I had the same issues, so plugs and wires........all good now.
I know myself that I am a plug wire murderer. Seems that I always forget how fragile those wires are. I bought the Screamin Eagle Fat Plug wires recently and they are much stronger. I only bought them because they were less money than the stockers and stock wasn't in stock.
And for plugs, they are really cheap. Make sure to gap them before you install them. I run mine on the smaller gap side.
I was having trouble with a motor that was built not wanting to run below 2200 RPMs with a load (picture taking off from the neighborhood at 5 AM for work....) The dealer couldn't get it figured out and were thinking that it was my tuner, but they didn't really spend anytime with it, so I don't really know. I called a great indy dyno guy and had him work on it, and the first thing he notices was the wires were junk, and the plugs were gapped way to wide. When I did my Limited, I had the same issues, so plugs and wires........all good now.