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Rostra CC problems

1047 Views 3 Replies 2 Participants Last post by  ianbh
Did a quick ride after Rostra install before completely buttoning it up-good thing!
Cruise sets but drops about 15 mph before going back to set speed.
When riding downhill with cruise on, speed ratchets back and forth about 3 mph. For example, when speed set at 54 mph will drop to 51 and abruptly accelerate back to 54, this cycle is repeated as long as running downgrade.
(See note at end)
Resume works but with considerable delay (like initial setting of speed)
Accelerate and decelerate seem to work normally.

Here’s what I have done:
CC cable attached to front throttle body, two balls slack on cable attached to rear throttle body. Measurement according to manual would have been three balls slack.
Dip switch settings (1-12)
off off - extra low gain (sensitivity)
off on off on – 9650 pulses per mile
on off off – 4 cylinder low
on –square wave input
off – manual transmission
off – open circuit control switch

When first starting, the red error light stayed on and there was an FI error code. It went out after turning off ignition and restarting in 10 miles. Error code returned when restarted at home.
When idling, engine “hiccups” every few seconds. There is also abrupt throttle response when running with CC off.

Hope I haven’t screwed up the throttle bodies. I’m sure I got them back in their boots OK. I also think I got the bottom of the air box installed correctly on the throttle bodies but almost impossible to see front boot even with mirrors. Seems stable when rocked and I don’t hear any whistling from this area when idling.

I’m planning on taking the #$%^ airbox off again, shortening the chain one ball, and checking all hoses and wire connections.

Any thoughts/suggestions? TIA Ian, Iowa

Edit: While idling on the centerstand, there is an audible metallic click coming from under the front of the tank when the hiccups occurs.
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· Registered
212 Posts
I think you have too much slack in the cable. If there is too much slack, your speed will drop while the servo is gathering in the slack. Rostra says they design for 1/8". I have found that 1/16" works best for me.

It's important to get the cable travel and cable slack squared away before getting too serious with switch settings.

I have found that 8000 ppm works best for me. Other than that, my settings are the same as yours with the exception of manual transmission. Mine is set for manual.

I have a similar situation with the down hill surging in certain circumstances. I haven't been able to adjust it out completely on this bike (2011 DL650). I haven't had the issue on two previous bikes.

Sorry, but I don't have any relevant comments on the red light and the clicking noise.

Ron :mrgreen:

· Registered
270 Posts
Discussion Starter · #3 · (Edited)
Removed the airbox, didn’t see anything amiss so shortened up the CC cable by two beads and reinstalled everything. I used Dielectric grease on all electrical plugs this time. Started it up, no error codes. Took it out for a test drive and all is well. YIPPEE!! Thanks for all the help.

BTW, I used a trailer plug (4-pin plug) to connect the control pad to the servo. I used a male/female crimp plug (that I soldered) for the ground. This way, the pad is easily removed.

It’s a little notchy maintaining speed so I’ll mess with the dipswitches. If no better, I can live with it easily. Thanks again. Ian, Iowa

· Registered
270 Posts
Discussion Starter · #4 ·
I do have a question about the electrical draw of the Rostra.
When monitoring the voltage using my Escort, the volts don't drop from the indicated 14.1 when I engage the CC or when I push the accelerate button which I assume would be using full power through the servo.

An example of other current draw:
the air horn draws down to 13.8, the aux lights draw down to 13.2.

I want to switch the CC and the switches I use from RadioShack are only 5-amp. Sound too weak even with this small draw.
Ian, Iowa
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