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CVO Technical => Drive Train => Topic started by: fxdse on August 23, 2009, 10:32:30 PM
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I changed my transmission final drive pulley to a 30 tooth. Excellent results but in doing so, my speedometer is now out by approx. 8mph.. Digital Dakota makes a speedometer calibration unit that you splice in between the VSS and the ECM. It's simple and works great. We threw it on the DYNO to measure rear wheel speed and you just click a button to increment up the the proper speed.
So you are thinking, why is he telling us this ....... In doing so, I seam to have lost the 6th gear indicator light? Does anyone have an idea of what I might have done wrong or what has caused this. You splice into the green/white wires before the ECM and before the split to the cruise drive. I double checked everything.
Any second opinion or thoughts are more than welcome. It does NOT affect driveability. I just don't like the fact that a "light" is not working.
:confused5:
Cheers,
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Someone here some time ago while we were talking about changing out motor 30 tooth drive sprockets or clutch baskets with a 49 tooth count, they said that the ECM is programed to see a certain rpm for the speed being indicated on the VSS. They said that if you mess with the ratio the ECM will NOT see the preprogrammed parameters and 6th gear light will not work.
I thought that was way too complicated and that the MOCO had to have a switch someplace, but switches cost money and once a program is done just one time for engineering and they already have all the inputs to the ECM anyway, so I'm leaning towards the original suggestion that it IS an ECM ratio thing.
I'm still leaning towards trying the 49 tooth clutch basket as an option for me to get the lower end off the stoplight get up and go I need for two up. At least with this option you only have to pull the outer primary and not the inner. The clutch basket and new primary chain runs I believe around $350 for their kit. Don't know how much the output sprocket is that you changed nor really how much more labor was involved to get to it. I've done all that on my '76 shovelhead and the process is probably about the same.
On my new '09 SERG, the 6th gear green light is sooooo dim that in the daylight I can't see it anyway. In fact I had issues thinking it was not even working until I rode at night and it was working.
Just a thought, one way to test the theory of ECM program versus a switch for 6th gear would be to have the bike stopped and shift up through the gears to 6th and see if the light comes on with the clutch out. Now you'll have to use a test bike that has a known working 6th gear light see it it works. If it does not come on with the bike stopped, I would really be leaning towards the ECM as the provider of the 6th gear light. So unless you can hack into the ECM to adjust the ratio back to a ratio that now works with the regearing, you're going to be stuck without a green 6th gear light.
Did the output 30 give you more off the line to help get you moving? You said excellent results, but I'm not sure what your reason was to do this in the first place.
More info please....
:) :) :)
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Most appreciated for the response. It does make a fair bit of sense. Maybe I will just live without it until the winter when it's fun to dabble.
Yes ... I did change that gear to increase the bottom end torque. Off the light pull did improve noticeably and overall usuage of gears is much greater. I am now using 6th gear on the highway at a more reasonable speed and because of the 1:1 ratio up there my gas milage has improved.
Therefore ... all aspects of changing that gear worked great for me and the results I was hoping for on my bike. I bought the Baker Pulley which run me about $250.00 buy the time I got it up here in Canada. I had plenty of room to adjust the belt so could still use the stock belt therefore not needing to drop the wheel. Being a novice mechanic ... It did take me the weekend and the purchase of a clutch locking tool and a bigger socket .... but all went well. I also installed a chrome inner primary while I had it apart.
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Someone here some time ago while we were talking about changing out motor 30 tooth drive sprockets or clutch baskets with a 49 tooth count, they said that the ECM is programed to see a certain rpm for the speed being indicated on the VSS. ...........
:) :) :)
How do you slip a gold star through the ether?
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Just throwing out ideas here, but if you have a SERT or TTS tuner I believe you can change the speedo without resorting to an external device. Now, here's the part I'm not sure about; if you were to change the speedo calibration in the ECM with the tuner, would you then have a working 6th gear light? Might be worth investigating.
Jerry
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I do in fact run the latest SERT but they in formed me this was NOT possible. In fact. most third party products did not even work past 2006 because of the different VSS used in 2007 and up. Dakota Digital SIM-1 was the only one that in fact did work.
My tuner looked and tryed before we purchased it but said he could not modify that portion of the program? .... Hmmmmm
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I can't remember where I think I read that it could be done with a S/SERT, but there again my memory isn't anything to brag about. I did find where the TTS MasterTune indicates they can change the speedo - see attachment.
Jerry
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Hmmm ... I wonder if that would correct the light issue? Man, It's next to impossible to keep up with all this stuff. I really appreciate the tip and am passing this along to my tuner. he really has been excellent for me and if there is a way he will do it no question.
Thanks Again, I'll post back here when I find out something. In the mean time .... any other suggestions are welcome.
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Thanks for the information.
One thing with doing the clutch basket, it does NOT affect the speedo as it does the ratio change before the trans and the VSS pickup.
:2vrolijk_21:
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I hear what you are syaing about the clutch basket. I'm not regretting doing it my way but the light think is bugging me and maybe I jumped the gun getting a third party device to control the sppedo. I emailed Dakota Digital to see if they heard of this or know what the problem might be. But still ..... the device and everything is running excellent.
Maybe I am just to picky?
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It is true that the 6th gear LED is verified by RPM via the ECM. It's not a direct mechanical relationship like a neutral switch.
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Here is the response direct from Dakota Digital ....
The H-D computer is controlling that and is expecting a certain pulse rate. You changed that when you corrected your speed. If the speed is off by 6% you have a window of +/-3% for the 6th gear and cruise to work.
You can bring that back if you make your speedometer off a bit but not as much as it was before.
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With the TTS MasterTune when you do the speedo calibration, it changes it in the ECM and will correct your 6th gear light issue. Hopefully you already have the TTS tuner.
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:cherry:
OK, I'm jumping into this post as I have a serious desire to gear down my o9 Ultra too. My old 2001 RK Classic, had the final ratio of 3.37 as I recall, and wish I had that ratio in the new one.
I've investigated most of the alternatives here and elsewhere......I have one of those Evo Ind. 30T engine sprockets, but the damn thing lacks a compensator and many have suggested that's not a good way to go with a heavy tour model, etc. etc.
So, now I'm looking at these two alternative solutions (Both won't get it quite where I would like but indeed closer). Those would be the 30T trans sprocket which (often) calls for a shorter belt and the Dakota speedo modifier (OR) the 49T Clutch sprocket also mentioned here. This would not require the Dakota module as suggested. BOTH methods would result in a final ratio of 3.06 or about a 7% gain.
As someone stated above, the damn green lite for 6th gear is almost invisible during daylight.....so why care! However, I have a serious concern if these methods will disable my use of the cruise control????????????????
If cruise is not effected, It seems to me that the clutch basket change to 49 tooth presents the cheapest alternatives...........Any comments or experiences with this change :nervous:
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I just went through the 30t change and it is just a gear with new primary chain, no Comp Assembly. Off the line was improved BUT then had new vibrations that were making my feet and legs fall asleep at 55-60 with rpms at 3k at 60 a little more than was comfortable for me. Went back and put in the new comp assembly and much better but where the motor ran smooth at 58-60 now have to be at 63 to have the same smoothness. Am thinking about the 49t gear. As some have said no 6th gear light and 08 and up no cruise either. The 07 cruise will still work. This 49t should make it in between the 30t and 34t stock according to the people at Evo.
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Well, If the change (clutch sprocket) 49t disables my "cruise control", then I'm back to square one. I can deal without the damn lite which is almost invisible anyway. I seldom ever use cruise control available in my car and truck.........but I love it on the bike. NOt gonna go without it.
Not sure of my next move on this subject.
By the way, final gear ratio (overall), is (I'll use my 09 SE Ultra as an example.....(clutch46T divided by engine24T) X (Rearwheel 68T divided by Trans32T) = overall......so it's (46/34) X (68/32) = 2.87 overall.
This would translate to the (30T engine sprocket) giving an overall of 3.258
This would translate to the (30T Trans sprocket) giving an overall of 3.066
This would translate to the (49T Clutch basket sprocket) giving an overall of 3.062.........so both choices two and three are giving about a 7% gain.
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Moscooter, just try that primary kit and see how you like it. we have installed many with no issues. I will minstall it for you this spring for free. :2vrolijk_21:
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The people at EVO told me the 49t at the clutch would put you in the middle between the 30t and the 34t engine sprocket. That would be about right for me as the 30t engine sprocket was to low geared for me on the highway in town great and take off was great no stumble. The guys at EVO said it's ok to run without the comp but others have said no. Don't know who to believe.
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I had the same issue after installing the Baker F6F kit in my '07. The 6th gear light would only work when the VSS adapter was set within a very narrow range. For me it was trial and error changing the VSS setting while riding in 6th gear until the light worked. If the speedometer was not accurate at that point, THEN go and change the value in your tuning software (SERT, TTS, ThunderMax) and repeat the process.
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I had the same issue when I went to a 30 tooth pully. I have the thundermax ecm so I was able to adjust my 6 gear min tps setting and get the light to work and my speedo is dead on...After running that pully a year i think I am going to go back to stock. I prefer running the lower rpms at highway speeds which is how I ride 90% of the time ;D