Cheapest DIY Servo Bypass

cool thanks, i'm reading that some of the guys think it helps performance if you do it the way they made the circuit boards but nobody can seem to say for sure or not. i built one of those boards and my code 18 came up which is exup motor stuck so i may just have a loose connection but if i cant figure it out i'll just take a 10k and put it in between the 2 wires as suggested.

Thanks SheWolf! I solder prongs from a car fuse to the resistor and plug it in. NO MORE CEL!!!!!!!!!! silicone the crap out of it and taped it up today ;)
Great forum, thanks again!

i had 1 wire screwed up on the circuit board i made, took a close look at it and figured it out put some solder in place and light went out seems to be working fine now, i taped it up and tucked it away behind the battery area.

Gotta say, I did this 25 cent mod and I have not thrown a code yet!!! Thank you SheWolf!!!



(of course I siliconed the shiite out of it!)

some say its not doing the correct things with the electrics by doing just that mod, the circuit board does something different i guess but either way works i guess.

It must be doing something right because I've had this thing in for almost 3 years; water, mud, dumps, etc and not one code.

cant complain about that i guess. there was a whole big writup about it causing the ecu to overwork itself or something along those lines. who knows, if it works run it.

Stubbz wrote:

cant complain about that i guess. there was a whole big writup about it causing the ecu to overwork itself or something along those lines. who knows, if it works run it.

A big write-up where? Can you post a link?

I just finished making the full blown servo sub. I was going to do the single resistor, but I couldn't find any 7.5k. I was going to use a 10k which several people have used and apparently works but I had to buy a pack of 5 for a whopping .99.
For an extra $4.37 I was able to make this one. Haven't taken it for a ride yet, but no code on startup.
Likely overkill, but what can I say, I'm a geek and haven't soldered a circuit together in a while. It was fun.

I've not heard of anyone having an issue with the resistor mod, or of the ecu overworking. I don't think the electronics is that complicated. The CEL comes on if there is an error with the exup motor, & it gets that by reading a range of resistance (presumably from the pot in the exup control). Obviously, the 7.5 works, & has been used for years with success. The 10k one also has worked, & it also falls in the range of resistance to fool the ecu into not throwing a CEL. I've been going on 2 years with no issues with a 10k resistor. If someone wanted to experiment, i'm sure the range of resistance will extend beyond 7.5 to 10k, & perhaps someday some enterprising individual will do that. But for now, it has been shown to work with the 7.5-10k range. The ecu looks for an acceptable range & finds it, & does not throw a code.

Here's my procedure, going on 2 years now. I think i had a writeup for it on this forum, but maybe it was on TT, which i haven't visited in months.. :(

http://rydnseekbike.blogspot.com/2010/03/exup-removal-resistor-mod-ais-removal.html

I don't see how it could overwork anything in the ecu. It's just a software program & simple switch. ECU checks for a range of resistance. IF there, CEL light is off. IF NOT, turn on cel light. I can't imagine Yamaha making it more complex than that, having multiple checks for other variables. Plus it just flips on the cel.. nothing else. I rode mine for quite a while with the cel on.. but finally got around to putting in the resistor. I would have gone with a 7.5, but they were not to be found, so i experimented with the 10. I think quite a few others have had success with the 10's also.

Anyway, i like wroldman's comments about truth to be found on the internet, & i throw my reasoning in the ring with the same reckless abandon.

OK, so long story short..now that I have my FMF programmer and FMF Q$ pipe in place, all I need to do to take out the whole Servo gizzmo, is take it out and stick the earlier rec'd resistor in the wire harness, seal it up and call it a day??

Yep! Just make sure you don't start up the bike before you put the resistor in or you'll throw the code.

OK, good deal. Next mod/ weight savings.

Is there a good write up somewhere for removing the whole apparatus??

Here is what is bothering me...if all you need is a simple resistor, why would people bother to build servo subs??

http://www.wrrdualsport.com/tech-guide/electrical/84-exupremoval

No idea, when this does the same job without the headache of building that.

OK, so after a little internet research, this is what conclusion I have come to:

I was a little worried by reading the linked TT write up on WRRdualsport. The guy making servo subs was assuming the fuel curve was impacted by where the valve position was. BUT, since there was no feedback, it just did not make sense to me.

Doing some more research, it seems the system(valve) is more closed at lower RPM's for both sound and torque building. As RPM's increase, the valve opens.

After market exhausts have no valve and are obviously set up for more breathing at all RPM's and do not really worry about sound levels. The fuel programmer compensates for the need for more fuel.

So, I am gonna go with the resistor and not worry about it. My guess is that is all the Graves on is anyway..in a nice neat package.

Be happy and ride that little screamer!

DougZ wrote:

OK, good deal. Next mod/ weight savings.

Is there a good write up somewhere for removing the whole apparatus??

Simple:

remove side panel that hides battery
directly under battery sits servo
It's held in place by two screws - same screws that the battery retention strap bracket is connected to
remove those two screws and servo motor will fall into your hand
disconnect plug from back of servo motor
insert resistor
check to make sure you've got resistor connected to the proper places
check to make sure you get no error light on dash
secure resistor using method you approve
replace battery strap retention bracket and side panel
go for ride
be happy

motokid wrote:

DougZ wrote:

OK, good deal. Next mod/ weight savings.

Is there a good write up somewhere for removing the whole apparatus??

Simple:

remove side panel that hides battery
directly under battery sits servo
It's held in place by two screws - same screws that the battery retention strap bracket is connected to
remove those two screws and servo motor will fall into your hand
disconnect plug from back of servo motor
insert resistor
check to make sure you've got resistor connected to the proper places
check to make sure you get no error light on dash
secure resistor using method you approve
replace battery strap retention bracket and side panel
go for ride
be happy

awesome, thanks.

wildbillhatchbac wrote:

The EXUP valve report on R1 forum . . .

I stopped reading after I read this.

"Honda's VTEC switches between two and four valves per cylinder based on revs, but isn't really variable as valve lift and duration is unchanged."

As a Honda tech for over 9 years and building a few high compression camed out motors I know that statement is completely false.

Makes me very curious about all the other info.

This is somewhat misleading as honda as more than one "vtec" system. Their cars do change the valve timing, however on the vfr800 the vtec does indeed run 2 valves per cylinder at lower rpm and higher rpm starts running 4 valves per cylinder. Doing a valve adjustment on one of these is a little complicated! There is a definite "hit" in power when those other valves kick in!

Bottom line: THIS MOD WORKS!!

I just got an 8.2k 1/2 watt resistor from work.

Can you say FREE BABY??????

Get that thing in there and ride it. It's pissing down rain here and I won't ride on dead skins...not to mention food poisoning doesn't help.

Best two minute mod eva!!!

I used a 1/4W 10K resistor from Radio Shack. No codes, no problems.