KTM Forums banner

1 - 20 of 21 Posts

·
Registered
Joined
·
40 Posts
Discussion Starter #1
My 2013 500exc was running very lean from the factory as they all are. I had a problem with the bike dying out at traffic lights and in tight single track riding. It did not happen all the time, mostly when grabbing some throttle when at idle and in first gear. I considered a jd tunner piggy back 200$. Then I read about this placed doing something called a magic mod 100$. You send in your throttle body and they change something (they wont explain) and then they send it back to you and suddenly your bike runs better and richer. ????? I thought about this a little and wondered if they were slotting the mounting hole on the throttle position sensor to trick the computer to richen the mixture across the entire rpm range. If you turn the throttle position sensor it will think the throttle is open further then it actually is and add more fuel. Just like changing a jet on a carb.

I pulled back the TPS cover on my bike and low and behold the throttle position sensor mounting hole is allready slotted. First the sensor is marked from the factory with a maker line in its original factory mounted position. I removed the sensor and checked what way the inside turns when the throttle is open. So if you loosen the T25 torx mounting bolt and the sensor housing is turned counter clockwise the computer will think the throttle is open further then it really is. This will make your bike run richer for free free free free!! No piggy back and no hard to find Euro tune fron a dealer. And no paying 100$ for a bull**** magic tune.
The difference is immediately noticable. If your go as far as possible it will be very rich and you will need to raise the idle speed. I am still playing with mine, but I can tell you my throttle response is much better. I can crack that throttle as fast as I can and it responds immediatly. I have found a guy on Thumper talk who gives specs using a so called tps sensor tool. I think it just a volt meter to help dial this in. He says his runs well at .64 volts compaired to the factory .60 volts. I think you will need to back probe the connector and use a volt meter to get these readings. But I am just going to try a couple of different settings and see what works best for me. I think I am a little rich now. Remember if you turn the sensor the wrong way (clockwise) it will get leaner and just make it worse. I just wanted to spread the word.





 

·
Administrator
Joined
·
14,818 Posts
Great write up.

I'm going to stick your post for others to find easier.
 

·
Registered
Joined
·
4 Posts
measurements

Where you able to take precise measurements as to exactly how many degrees or millimeters you rotated the TPS sensor.

I have a 2012 KTM 500 and I'm considering sending my TB off to have the MagicMod done.....But if I can get it done for free, that's even better.

Counter Clockwise or Clockwise and how many degrees or millimeters did you adjust it.....?
 

·
Registered
Joined
·
40 Posts
Discussion Starter #5
I took the bike for a short ride and let it get fully warm. I loosened the t25 torx that holds down the sensor and rotated counter clockwise until the bike idled very smoothly. It is very noticable.
 

·
Registered
Joined
·
40 Posts
Discussion Starter #6
After playing with this adjustment further over a longer time and in warmer weather. My bike runs best with the sensor set in the full rich adjustment. Turned counter clockwise as far as the slotted hole will allow. It does not completely eliminate the flame out problem, but it will GReatly reduce this annoying problem. I thought this may be a problem with the new fuel injection system. I was riding with a friend who has a carburated 450 and his was dying out more then mine.
 

·
Registered
Joined
·
6 Posts
tps problem

you may want to check out dirt rider page. when i perchased my 2009 450exc they had tested one and had the jetting solution for lean conditions and backfiring. when i talked to my lbs they new the solution i mentioned and it has been great for me from 30 degrees to 90 degrees. I am not a racer so i may not have your needs. i would put put with my 6yold and ride hard with c vets.
 

·
Registered
Joined
·
9 Posts
After playing with this adjustment further over a longer time and in warmer weather. My bike runs best with the sensor set in the full rich adjustment. Turned counter clockwise as far as the slotted hole will allow. It does not completely eliminate the flame out problem, but it will GReatly reduce this annoying problem. I thought this may be a problem with the new fuel injection system. I was riding with a friend who has a carburated 450 and his was dying out more then mine.

Came across this thread after mine 'died' a couple of times, and seemed very lean - especially low-down. Just done mine (Fully turned anti-clockwise) and will test later.

Will be sure to reply with my 'findings' !!

Also posted in your EXC headlight upgrade thread !

Cheers.
 

·
Registered
Joined
·
9 Posts
Well, tried my TPS in a few positions inc fully turned counter clockwise and same old story.

I've only had the bike a week, but at this point it barely ticks over. Trying to up the tickover when bike is fully warm makes little or no difference either.

Seeing as the bike was a year old, and only had 74 miles on it - and came with 3/4 of a tank of fuel: I also drained out the old and done 20 miles with fresh fuel in.

Bike is still awful from cold, and barely ticks-over when warm.

What next ?
 

·
Registered
Joined
·
9 Posts
Just to report back (In the hope it may help someone else), that on my bike the TPS set in the fully anti / counter clockwise position was truly awful, and made flame-outs more frequent.

As per unobtanium's earlier suggestion / post: The way i 'HOPE' ive cured my flame-out issues was to loosen the T25 torx that secures the TPS, and after warming the bike and slowing down the idle, i moved the TPS either way (Where running / idling was indeed a little rough) and then found the middle ground between the two where the bike idled at its easiest / smoothest point.

I then simply did the torx back up, and re-adjusted the tickover, favouring a slightly high idle in a effort to "stop the stalling" !

Fingers crossed........
 

·
Registered
Joined
·
10 Posts
I have a 13' 500 EXC. The first mod's I made was to add the 4.1 titanium muffler and FMF snap. After doing so I removed all of the smog components and blocked off the holes with an OEM XCW plug and a fastener on the intake end. The FMF parts completely woke this bike up. Instant throttle response and big low end power. To be honest I think I could have kept the bike like this and been happy.

After riding a while there is no doubt the bike was lean off idle which caused it to not want to lug high gears unless you were up in the midrange of the rpm's. I read about the JD tuner but saw mixed reviews. The next option was to adjust the throttle body myself or just send it out to Dave Simon at BestDualSportBikes.com. After reading a few threads about how adjusting the TPS wasn't an exact science and you would have to play around a bit to find a good setting, I again wasn't completely comfortable with the idea. So I looked into BDSB's webpage and youtube video's. They claim to have metered the throttle and watched the Air/Fuel ratio with an exhaust bung sensor. Along with checking the timing on the bike during and after making their adjustments. So I went ahead and searched online for some reviews and BDSB's previous history working with throttle bodies and tuning and I liked what I saw. It was also comforting to know that BDSB's and FMF were working on the EXC project's together. A staple in the industry with a long history of producing quality components.

I went with the magic mod and now the bike is running incredibly well and is getting a ton more fuel on the bottom end and rips right up to the rev limiter. Speaking of rev-limiters, before getting the magic mod I have never even hit the limiter. Now the bike runs so much richer and pulls so cleanly without falling off that hitting the rev-limiter without realizing its coming is happening often. thats a great sign that the sensation of power dropping off and the bike starving for fuel has been resolved. I'm also able lug 4th and 5th gears going really slow, and if I decide I want to make a move for it I no longer need to downshift. The bike will cleanly pull the gear at super low rpm's (with stock gearing) right up through the midrange. 1st gear flameouts has been reduced greatly. I only flamed out twice the entire day, when typically I would have flamed 25 times before the magic mod.

All in all Im not sure if BDSB's is adjusting more than just the TPS voltage but the bottom line is that I dont need to tinker around with the setup. A simple 125 dollars resolved 99% of my issues with the EXC stock mapping and im not sure I could be anymore pleased. The bike has the response and power of a motocross bike now (I also added the Megabomb). Is it worth 125 dollars though ?? For me it sure as hell is. Playing with the TSP sensor and using your seat of the pants feel to meter it just doesnt sit well with me. Hooking up a throttle meter, 02 bung, and timing gun to make your adjustments sure does though.
 

·
Registered
Joined
·
9 Posts
Playing with the TSP sensor and using your seat of the pants feel to meter it just doesnt sit well with me. Hooking up a throttle meter, 02 bung, and timing gun to make your adjustments sure does though.
Firstly mcg : Glad you got to the bottom of your issues :001_smile:

Im in the UK, and our bikes don't have all the smog stuff you do, so i didn't have that to contend with.

My bike also came to me with an FMF, but i didn't care for it and went back to stock. I've also never suffered any low-down issues you describe and mine has always pulled strongly and cleanly from low down. My only issue was the flame-outs, so perhaps your symptoms and problems were slightly worse, or at least slightly different to mine ?

All i can tell you is (And although im a mechanical Engineer, im certainly not a Automotive or Electronic engineer) i imagine the slot is put in the TPS; exactly for the reason of fine adjustment. And i can only imagine KTM wouldn't put enough adjustment in there so that a lamen (Or infact anyone) could do irretrievable damage.

I see it as akin to turning the distributor cap on a old car to finely adjust the timing. And having to listen for a happy engine is hardly 'seat of the pants'.
How do you think mechanics have been tuning combustion engines for the centuries and decades before O2 meters and electronic timing guns etc ?

All i can tell you is; for this bike, in this climate and during the last 100 miles covered yesterday afternoon and this morning: Its now running like a dream and to date i havn't had a single flame-out or hiccup from cold or otherwise.

I've also since lowered the tickover back-down, to a really solid, thumping idle as it appears to be fueling very well and doesnt need the additional 'back-up' of a slightly higher tickover. To be fair this was only ever MY 'insurance'.

Until something changes im one very happy camper right now, as at first the issue with the continual flame-outs was quite concerning, and the difference to now substantial..........

Good luck.
 

·
Registered
Joined
·
10 Posts
Firstly mcg : Glad you got to the bottom of your issues :001_smile:

Im in the UK, and our bikes don't have all the smog stuff you do, so i didn't have that to contend with.

My bike also came to me with an FMF, but i didn't care for it and went back to stock. I've also never suffered any low-down issues you describe and mine has always pulled strongly and cleanly from low down. My only issue was the flame-outs, so perhaps your symptoms and problems were slightly worse, or at least slightly different to mine ?

All i can tell you is (And although im a mechanical Engineer, im certainly not a Automotive or Electronic engineer) i imagine the slot is put in the TPS; exactly for the reason of fine adjustment. And i can only imagine KTM wouldn't put enough adjustment in there so that a lamen (Or infact anyone) could do irretrievable damage.

I see it as akin to turning the distributor cap on a old car to finely adjust the timing. And having to listen for a happy engine is hardly 'seat of the pants'.
How do you think mechanics have been tuning combustion engines for the centuries and decades before O2 meters and electronic timing guns etc ?

All i can tell you is; for this bike, in this climate and during the last 100 miles covered yesterday afternoon and this morning: Its now running like a dream and to date i havn't had a single flame-out or hiccup from cold or otherwise.

I've also since lowered the tickover back-down, to a really solid, thumping idle as it appears to be fueling very well and doesnt need the additional 'back-up' of a slightly higher tickover. To be fair this was only ever MY 'insurance'.

Until something changes im one very happy camper right now, as at first the issue with the continual flame-outs was quite concerning, and the difference to now substantial..........

Good luck.
i'm glad you made your bike better for you. thats really all that matters.

in my quote above I really was speaking for myself only. I wasn't comfortable making the changes and taking the time myself to figure it out, so I went ahead and bought the parts and service as a package deal, knowing they were all tested to work correctly together. If somebody can make the changes themselves without spending any money then by all means I think that is the more logical way to go. I just didnt go that route. :)

Also, just fyi, adding an exhaust on the EXC's without dumping more fuel or tricking the throttle body sensors makes the flame-out issue worse.

I would also like to add that, yes, I understand that you dont need to know your A/F ratio or the ignition timing to tune an engine to run properly, but the reality is that all I just spent 10 grand (all of us did) on the bike and if I have the option of the engine being metered while the throttle body is being adjusted, it just sits better with me personally.
 

·
Registered
Joined
·
9 Posts
i'm glad you made your bike better for you. thats really all that matters.

in my quote above I really was speaking for myself only. I wasn't comfortable making the changes and taking the time myself to figure it out, so I went ahead and bought the parts and service as a package deal, knowing they were all tested to work correctly together. If somebody can make the changes themselves without spending any money then by all means I think that is the more logical way to go. I just didnt go that route. :)

Also, just fyi, adding an exhaust on the EXC's without dumping more fuel or tricking the throttle body sensors makes the flame-out issue worse.

I would also like to add that, yes, I understand that you dont need to know your A/F ratio or the ignition timing to tune an engine to run properly, but the reality is that all I just spent 10 grand (all of us did) on the bike and if I have the option of the engine being metered while the throttle body is being adjusted, it just sits better with me personally.

Completely agree mcg, and i hear you on everything. I'd already read the exhaust would / could make flame-outs an issue, and over here where i ride: i didn't need the extra noise as much as anything. And i certainly dont 'need' an extra HP or two.

I fiddled with my TPS setting myself for a few reasons:

1./ I am the very reason the word impatient was invented !
2./ The flame-outs really narked me beyond belief. I didn't spend 10 grand to look a jerk at every junction i stop at.......
3./ (And probably the main reason): Im in the UK, and all the 'solutions' are in the US. I figure i could do something myself in the time the parts would take to arrive from "over there". Im also an inquisitive fellow......

3 rides in and still not a single flame-out so far - post TPS adjustment.

In retrospect, perhaps not the strongest or most confidence inspiring tickover i've ever had on a bike - but i guess thats the trade-off for a light fly-wheel and instant throttle response, not just a symptom of a lean idle condition.....
 

·
Registered
Joined
·
1 Posts
Just keep in mind that, for those of us who have already had the European map loaded into our ECU's (or for those of us who own a Euro-spec EXC-F) - the MagicMod will make your bike run way too rich!
A JD Tuner will work with the EU map, but the Magic Mod is a "stand alone" modification, and for use with the stock US EXC map *only*.
 

·
Registered
Joined
·
7 Posts
Would this trick also work for the 350 exc-f, i bet it's a different throttle body but is the concept the same?
Yes it should work on the 350exc too.

I think there are 2 parts to the problem, at leas with the USA bike. I got a 2014 500EXC and when you barely crack the throttle it would actually slow down, it was obviously extremely lean. I think it's caused by the little air valve under the throttle body opening and letting too much air in. Anyway, removing smog stuff and adjusting the TPS made an enormous improvement in smoothness down low. I went with .64V and just left it there. I used one of these for the adjustment, made it a 2 minute deal:

http://www.tpstool.com


I've still got the stock exhaust and love how quiet it is. Do you actually gain anything with something like an FMF-Q without increasing sound?
 

·
Premium Member
Joined
·
30 Posts
My 2013 500exc was running very lean from the factory as they all are. I had a problem with the bike dying out at traffic lights and in tight single track riding. It did not happen all the time, mostly when grabbing some throttle when at idle and in first gear. I considered a jd tunner piggy back 200$. Then I read about this placed doing something called a magic mod 100$. You send in your throttle body and they change something (they wont explain) and then they send it back to you and suddenly your bike runs better and richer. ????? I thought about this a little and wondered if they were slotting the mounting hole on the throttle position sensor to trick the computer to richen the mixture across the entire rpm range. If you turn the throttle position sensor it will think the throttle is open further then it actually is and add more fuel. Just like changing a jet on a carb.

I pulled back the TPS cover on my bike and low and behold the throttle position sensor mounting hole is allready slotted. First the sensor is marked from the factory with a maker line in its original factory mounted position. I removed the sensor and checked what way the inside turns when the throttle is open. So if you loosen the T25 torx mounting bolt and the sensor housing is turned counter clockwise the computer will think the throttle is open further then it really is. This will make your bike run richer for free free free free!! No piggy back and no hard to find Euro tune fron a dealer. And no paying 100$ for a bull**** magic tune.
The difference is immediately noticable. If your go as far as possible it will be very rich and you will need to raise the idle speed. I am still playing with mine, but I can tell you my throttle response is much better. I can crack that throttle as fast as I can and it responds immediatly. I have found a guy on Thumper talk who gives specs using a so called tps sensor tool. I think it just a volt meter to help dial this in. He says his runs well at .64 volts compaired to the factory .60 volts. I think you will need to back probe the connector and use a volt meter to get these readings. But I am just going to try a couple of different settings and see what works best for me. I think I am a little rich now. Remember if you turn the sensor the wrong way (clockwise) it will get leaner and just make it worse. I just wanted to spread the word.





Thanks for the heads up.
 

·
Registered
Joined
·
1 Posts
500 exc flame out?

I have a 2016 500 EXC with 1.9 hours on it and found that it will occasionally die when coming off throttle. It does not do it all the time and the dealer says they cannot duplicate the problem so they cannot fix it. It happens most when it has been ridden a few miles and is warm. If I ride at 4000-5000 RPM (a guess, no tach) and then come off throttle to very low rpm or to stop in first gear with the clutch in, the bike dies. It then doesn't fire right back up but will eventually start. Is this what ya'll are saying is a flame out and caused by the bike running lean.

The bike runs great under throttle but occasionally dies in the situation above, backfires a little more than it probably should, and does not like going slow like on tight single track. When going slow it is not real smooth, it wont poke along at 7 mph, it fluctuates between 7-9 mph with a constant amount of throttle. All the dealer says is everything is in spec. Any help would help me like KTM again.
 
1 - 20 of 21 Posts
About this Discussion
20 Replies
14 Participants
KTM_SFL
KTM Forums
KTM Forums is the forum community for dirt bike motorcycle enthusiasts covering the KTM Duke, Sport minicycles, Off-road bikes, KTM 1190 RC8 and all KTM Motorcycles.
Full Forum Listing
Top