Cheapest DIY Servo Bypass

This is by far the cheapest servo bypass so far, so for anyone who want to save a few bucks and DIY, this is the way to go.

All you need is a 7.5k resistor (I have two 3.75's because I couldn't find the smaller 1/4w ones, so I went with the 1/2w). Unbolt your servo motor from under the battery, flip it around and unplug the motor. Drop the motor into your box of parts, cause you aren't gonna need it anymore. Then take your little 7.5k resistor, and stick one end of it into the red/white socket of the now exposed plug. Take the other end of the resistor and stick it into the black/red socket of the plug. Voila! You have now bypassed the servo and your ECU won't throw a CEL! You can solder small pins to the ends of the resistors and then plug them into the exposed servo plug, then tape it up nice and tight, and tuck it in beside the right side of the battery box where there is a little spot just made for it to go.

Wow... your bike is getting lighter everyday!

Time for a lighter battery mentioned in another thread

Yeah...we can't get them here yet otherwise I would....

You can't get them there?

Why not?

I heard that JOE at TurnTech is a nice guy to communicate with...

It looked like it was out of country when I looked at the link. NVM..I just saw the NA link... D'OH!! *smacks* Here we go again thread derailing. Gary, you're terrible.

mtb wrote:

You can't get them there?
Why not?
...

In Canada a battery is considered a hazardous good an must be transported and imported differently. It is possible to get such goods shipped over the boarder, but much more difficult and folks that sell things like that on-line typically are no set up to handle the extra hassle, paperwork, and shipping methods.


Meanwhile, Looks good SheWolf! I like simple.

Me too, simple AND cheap.

Ooh... Lesson learnt! Thanks!

Wolfie... have you taken it out for a spin with your homemade sub?

(Actually I think we should call the sub the CEL eliminator instead... According to Yamaha Motorcycle Technical Guide ... The valve drive is operated on the basis of information about RPM,
machine speed, throttle opening/closing speed, the gear the
transmission is in etc. This combines with the ignition timing control
to achieve outstanding response. And I am not 100% that the sub we have can actually behave as it should... I am even thinking of putting back the servo motor and modify my pipe like this guy did in SMJ)

If you do add the EXUP back into your system with the slip-on, please post some dyno results of the slip-on vs. the slip-on with EXUP.

To my knowledge that would be a first to have such a comparison with numbers and would truly answer weather or not Yami's EXUP is actually doing what it claims.

If I add it back, I will surely go for a dyno.... and surely I will show off HERE

Just kidding.. good night all

I did take it for a rip with the servo bypass and that light never even flickered. I didn't notice any abnormal engine noises or stuttering or hesitations upon accel or decel; now whether or not that has anything to do with removal of the servo or the addition of the Q4, I'm liking how the bike feels performance wise. I'd love to get it dyno'd but there isn't anyone around here with that kind of setup.

**EDIT** Replaced the 2 3.75 1/2 resistors with a proper 1/4w 7.5k one, re-solderded it in and siliconed the piss out of the plug end so no moisture will get in there. No CEL thrown by the ECU, so I'm not gonna go WTF when I end up SOL on the side of the road and go AWOL.

mtb wrote:

Ooh... Lesson learnt! Thanks!

Wolfie... have you taken it out for a spin with your homemade sub?

(Actually I think we should call the sub the CEL eliminator instead... According to Yamaha Motorcycle Technical Guide ... The valve drive is operated on the basis of information about RPM,
machine speed, throttle opening/closing speed, the gear the
transmission is in etc. This combines with the ignition timing control
to achieve outstanding response. And I am not 100% that the sub we have can actually behave as it should... I am even thinking of putting back the servo motor and modify my pipe like this guy did in SMJ)

I think the question is, does the servo provide information the ECU and does this feedback affect fuel and ignition
In my experience, they dont really use feedback the ECU simply assumes the servo is doing what it's supposed to and the valve is where it's supposed to be
They need the processing power for other thing's so the test circuit really look's to see that the servo is there and within resistance spec
I spent the time making the servo sub but after I got finished I convinced myself that we are overanalyzing it and all we need to do is make the light go away

The light want away with ONE little resistor, not a bunch and diodes.

Not sure if anyone out there has encountered this problem but I created two servo bypass circuits and when I fitted them to the bike in place of the Exup it worked for 10 seconds and then I got an Error1 (the usual ECU screwed, short circuit etc.). I unplugged it and refitted the servo and it went back to the usual errors (EXUP stuck open - because I'd removed the cables, of course). It did this with both circuits I'd made.

Shewolf - how are your resistors holding out? Any probs. Might try your single resistor-job later..

Anyone know how to bypass the speedo sensor. My speedo produces strange numbers and I'm out of warranty. I'd like to get rid of the error light and just use my GPS instead. (I'll get it fixed one day)

So far my one little resistor is holding strong and hasn't thrown any code...and I've done a lot of rough stuff with him.

Thanks. I've just spent some time with my exup in pieces trying to figure out how a single resistor does so much . Like why doesn't the exup motor whirl every time you turn the key? The potentiometer accounts for 3 of the 5 wires coming out of the exup - if I isolate the gears that turn the potentiometer and plug the exup into the loom it still gives an error even though the motor is in place!

http://www.flickr.com/photos/26567922@N00/3990502907/?rotated=1&cb=1254948987855

I'll try your 7.5kOhm trick tomorrow..

I made my servo up today and it still displayed the 17 code.
This was because I had dry soldered the reistors so it looked like they were good but if you jiggle the ends of the wire left sticking out they move slightly.
All I needed to do was re-solder so they don't move and it worked.
Anyone who has had sub trouble this is most likely why it happened.

I jammed a couple of resistors (would have used one but I didn't have one of the correct resistance value) wired in series into the connector plug for the EXUP servo.
It's been working since I first got the bike, 2,600 miles ago. :)

http://www.thumpertalk.com/forum/showthread.php?t=793736&highlight=exup+eliminator

It's so simple, you don't even need a wiring schematic. :)

When I first did this, my CEL (Check Engine Light) would sometime light up, but after a couple of days, it went out for good and hasn't returned in a couple thousand miles of riding.
I'd try this trick first and give it a shot before you do anything else. :)

If you read through entire thread you'll see that one guy had issues with it.

I wonder if he ever got it worked out?

One 5 cent resistor vs. a $65 doohicky from Graves????

I want to know what Gargoyle ended up doing.

for what it's worth, the graves one has a nice connector and looks alittle more official than a resistor jammed in the plug. is that worth $65, not to me.

motokid wrote:

If you read through entire thread you'll see that one guy had issues with it.

I wonder if he ever got it worked out?

One 5 cent resistor vs. a $65 doohicky from Graves????

I want to know what Gargoyle ended up doing.

I was curious too, so I sent him a pm over on Advrider. He's happy with the Graves. I'd love to try the resistor trick, but have no doubt I'd screw it up. I know absolutely squat about such things.

Sarah