Author Topic: TTS: TTS timing f & r cylinders  (Read 567 times)

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Offline 60wt

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TTS timing f & r cylinders
« on: December 01, 2017, 05:48:04 PM »
07 RK stage 2..using CAA176-04 timing map... noticed on the map a few areas where the front and rear cylinders have a degree or two difference in the same RPM/MAP...after doing a half dozen data runs removing a degree or two at a time here and there to get rid of pinging in the hot summer months, Ive noticed I have about 7 or so areas that have different timing on front and rear cylinders. any where from 1/4 degree to  2 degrees...               Just wondering if that's the norm.. ???        ( PS:   Bike runs just fine)
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Offline Coyote

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Re: TTS timing f & r cylinders
« Reply #1 on: December 01, 2017, 05:49:33 PM »
Front and rear timing will be different, that's normal.
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Offline Ohio HD

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Re: TTS timing f & r cylinders
« Reply #2 on: December 01, 2017, 05:50:51 PM »
It's fine, it's called giving the motor what it needs / wants. I don't think I have a MAP for any of my current or previous builds where they are exactly the same front to back.
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Offline harleytuner

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Re: TTS timing f & r cylinders
« Reply #3 on: December 01, 2017, 06:55:56 PM »
 If they were supposed to be the same there wouldn't be separate tables.   
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Offline Coyote

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Re: TTS timing f & r cylinders
« Reply #4 on: December 01, 2017, 09:48:21 PM »
This is the timing difference from front to rear on the the last bike I tuned.  Just what it needed.

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Offline 60wt

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Re: TTS timing f & r cylinders
« Reply #5 on: December 03, 2017, 09:39:13 AM »
thanks for the reply's ...the example posted helps to see and compare to what I did... :smile:
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Offline K4FXD

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Re: TTS timing f & r cylinders
« Reply #6 on: March 04, 2018, 05:56:16 PM »
Does the rear cylinder usually need more or less timing, or is it random?

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Offline kd

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Re: TTS timing f & r cylinders
« Reply #7 on: March 04, 2018, 06:48:42 PM »
The way I understand it, slight differences in compression, exhaust, etc. can remove any similarities between cylinders same build engines for that matter.
KD

Offline Paul in Alaska

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Re: TTS timing f & r cylinders
« Reply #8 on: March 05, 2018, 12:52:09 PM »
Do you use the software recommendations or set it manually?
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Offline BVHOG

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Re: TTS timing f & r cylinders
« Reply #9 on: March 08, 2018, 06:58:37 PM »
Back when I first started tuning the original SERT pretty much every timing table had more aggressive timing in the rear cylinder, this always surprised me as the rear runs on average 40 degrees hotter than the front.  With all the tools available now it gets set to what it needs, not always front and not always rear higher or lower.  S&S ran the timing the same front to back on the VFI system and most carb type ignitions will do that as well.
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