KTM and Husky TPI throttle body adjustment and Idle Bolt installation by Two Stroke Performance
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- Опубликовано: 25 ноя 2019
- Explanation of the air bypass screw and the idle screw on the TPI throttle body. Plus from 9:50 onwards we show you how to install a new idle bolt into the throttle body.
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OK now this is the LAZY BOY option. I didn't want to tear my brand new 2 week old 2021 Husky 300 TPI down so this is what I did. First I removed the single retaining screw and popped off the throttle cover (I did not need to remove the exhaust to do this, I just GENTLY pushed it from the OTHER SIDE on it's edge at the top with a broad bladed screw driver and it popped off). Secondly I could see the blue Locktite on the screw and I sprayed it 4 times with ordinary DISC BRAKE CLEANER, 30 minutes apart, and left it overnight. Next day all visible blue Loctite was gone, an encouraging sign, but I knew that some would still be active in the threaded section of the housing. I then removed a 2.5 Allen/hex from a folding bicycle Allen tool set which have those big loops at the end when you take them out of the set (the loop is critical for leverage, a standard Allen wrench will not work) I then fitted that to the idle screw and once in place, used a bigger Allen wrench handle through the loop in the 2.5 as a lever (any handy short lever would do just as well).Very slowly I kept pressure on it but TIGHTENING it, not UNDOING it. ( So many people go wrong trying to loosen reluctant engine setting screws, tighten them first whenever it is possible because the wrench is being pushed in, much less chance of stripping the hex).
Just as the 2.5 Allen started to twist a little under strain, it gradually turned the idle screw a fraction so I stopped and warmed the engine to full operating temp. Whilst doing that I plugged in my OB2 diagnostic unit (dirt cheap on Ebay but get the convertor plug made in England by Lonelec to connect to KTM/Husky) and via my mobile on the free OB2 App, watched the ECU rev count NOT the ENGINE rev count because that fluctuates too much on a 2 stroke, the ECU RPM count is the AVERAGE reading and THAT is the one to set your idle by if you have the choice to do so. It is is easier to get the really fine adjustment on a 2 stroke this way.
After much experimenting on my bike I found 1775 ECU RPM (easy number for you Yanks to remember! My Husky must be a Republican!) to be the optimum for my bike with the Air Bypass Screw totally SHUT. There is ZERO reason for using the air bypass screw, it is ONLY there because manufacturers cannot use any other method to adjust idle without effecting emissions. It is a total bodge because the TPS has not been moved so the ECU has not been 'informed' of a change. That is why despite raising the idle speed you get 'flame outs". My bike used to do it all the time and always in the worst situations which caused me to fall off several times on steep hill climbs etc. The Air By Pass bodge works kind of OK on cars and even to some extent most 4 strokes but the 'work around' was never intended for high performance 2 strokes which have totally different "needs" to deliver optimum power delivery characteristics. Trust me, just screw the stupid POS Air By Pass SHUT and experiment with getting a perfect setting with the idle screw which moves the TPS and 'informs' the ECU to adjust the mixture accordingly
Your bike might vary on it's perfect RPM average but now mine pulls really cleanly off the bottom (quite critical on the RPM reading I found, higher or lower RPM settings were not optimum) and is NOW great at ultra low speed manoeuvres like "figure of 8" at walking pace, but also goes like a f**cking missile when cracked open. Honestly, it is like riding a totally different bike.The first time I gave it a whiff of throttle the front wheel came up so fast in a power wheelie that I nearly fell off, I just wasn't expecting that much sudden performance increase from fiddling with an idle screw!
Lastly, remember to drill a little hole in the plastic cover before you put it back so you can adjust the Idle screw without removing it. I will get around to replacing the Idle screw with a 5 X 50 mm next time I am in a hardware store ( I am certainly not paying $35 for one! 10 cents and an old spring from a Beretta shotgun more like!) but for now I haven't bothered as I don't want to disturb my perfect setting and there seems to be enough Loctite still on the screw to prevent it unscrewing in service. i.e. the idle adjustment is quite stiff in both directions which is perfect. So guys, that is a lazy-arsed Brits way of achieving exactly the same result with 10 per cent of the effort. No heat, no rebooting the oil pump or anything.
And if you do get it WRONG and strip the hex head you are no worse off because you were going to strip the entire bloody bike down anyway, in which case you can release the screw with a pair or pliers once you have melted the Loctite. Worth trying! Less hassle, more riding time!
Hello, I have a 2022 husqvarna, it consumes me a lot of gassoline,can you help me please?
I want to mention that I walked on the air and idle screw
Just did this modification and it works just like he describes it. Took me 45 min to strip, do the mod, reassemble and test ! Awesome video.
Did you remove the TPS from the throttle body when heating it up?
Dave you make an great Job,teaching those people fundamentals !!! you are a Serious Smart Bro, greetings to Australia
Thanks for the video. I get it done within 1.5 hr and the bike runs perfect with idle adjust.
The best video i have seen on this subject...so if the bike running fine and no issues the is not necessary 👍🇬🇧
Good info. Thanks for sharing. Look forward to putting to the test on my 2023 Husky 150
Great modification, works wonders on Mt TE250i, 2018 vintage
Great video and excellent explanation. Thanks!
Excellent explanation. Many thanks!
Just done this mod today works a treat
Great video!
Best one out there for sure.
Mine I didn’t have to heat. It was loose enough. Probably because I use an engine blanket when I snow bike and maybe it caused enough heat to break down the thread locker? Your kit is fantastic and transformed the bike. Kudos yo South Bay Moto for their excellent service!
Good video. To the point and well explained
Great video thank you. I’m new to TPI and made a idle adjustment with the bypass by mistake. Bike is very boggy and not very crisp. This mod sounds like it’ll fix my problem.
Done this mod myself on my 250 tpi 2020, bike would not idle an kept stalling, tried adjusting the air screw as instructed by Ktm (upto 6 turns out) but bike started fouling the spark plug with oil, Ive now adjust the air screw back to around 1-2 turns out an raised the idle with this screw, perfect
Hi great explanation! I've installed the adjustment bolt in my Husky TE250i 2018 and messed around with the TPS calibration as well. Can you tell me which are the factory basic settings in the TPS and throttle position for my bike?
Excellent video thanks my 2020 ktm300tpi has been a dog from new cuts out on idle when warm thank you for the video i will definitely in time order the mid comp head and ecu flash cheers 🍻
Thanks you for this informative video. I have a 19 300 XCW, and while it runs perfectly, the low idle just bugged me. I was hesitant to make this mod, but after watching this video, I took the plunge. I pulled the throttle body, and made the necessary preparations. I set a timer for two min and fired up my torch. After 90 seconds the lock tight began to bubble, after 2 min I was able to turn the screw (with a T10 tork bit) 1/2 a turn. Added heat for another 30 seconds and the set screw came out without resistance. I've set the air screw to 1/2 turn and tuned the idle to my liking. Total time was around two hours, which included a lot of cleaning. (since it's apart, you might as well clean parts you normally can't get to...) I'm on old 2-stroke guy, who always jetted his bikes just a tad rich, so this mod gives me piece of mind. Again, thanks for the video it's greatly appreciated.
Excellent video. 👍👍👍
Thank you
Thanks for the video. It has to be an alloy bolt or a stainless steel one with some anti seize grease does the job?
Great vid Dave,3.5 /4 turns out on the 2020 too is that about right do you think
Looks like you could drill out the cover and have it surround the bolt. It might help keep dirt off the threads and make adjustments easier but would definitely look nicer.
Then you’d have to remove the idle bolt ages reset the idle if you wanted to remove the cover
I’m one of the small percentage who has to do this. Do we need to use the “wake up “ plug to prime the oil pump when we re connect the oil tube?
hey do u guys ever remove return throttle cable on ktm tpi bikes to make throttle easier?
Hi. For 2020 models at 2000 meters elevation. What number of turns you recomended. Thanks
What dimensions are the spring ? 0.5mm thick / 35mm long / 7mm diameter ?
Hola si cierro el tornillo del bypass del aire del cuerpo de mariposa la moto consume menos gasolina o más???? Gracias
I have a 2020 300tpi
I have the two stroke performance head and re-map
I have set the throttle position sensor to 600mv as suggested and my air screw is 3 turns open as per the TSP instructions but my bike isn’t idling too good. Any ideas please ?
What size spring do you use?
Great video Thanks 🏁🏁🏁👍
So, basically you are tuning the idle and part throttle mixture by adjusting the TPS value (by resetting the idle stop screw) and closing off or opening the air port.
Q. What happens if/when the system resets the TPS 0% value?
Some odd information here.
The 'air by-pass' named in the video is actually the Idle Air Screw.
The 'idle screw' is the factory pre-set throttle stop.
Moving the throttle stop should be avoided as it affects the idle TPS reading which only takes small movements to make large changes to idle fuelling. Any movement of the butterfly stop should also be followed up by a TPS zero position reset.
The air required for Idle will arrive at the insides of the engine from either the throttle butterfly or the idle by-pass port, it does not care how it gets there. Only the volume of air is important for the idle speed. Fuel is added into the transfer ports, so there's no problem with air 'not mixing' at the butterfly plate from bypassing through the idle port.... There's no fuel at that area.
Dangermouse none of it is odd, it’s just different to the tech info KTM release... the change in the TPS reading with a small adjustment of the idle screw makes negligible difference to idle fuelling on the TPIs in the real world, and it makes zero difference once the throttle is opened even slightly. On the other hand the air screw setting DOES impact air fuel ratios at all throttle positions, with the biggest impact being at low throttle and idle... much greater than any change in idle TPS value makes.
The reason for doing this adjustment is due to the fact that there is a wide variation in how TPI bikes run, even though they have the same fuel maps, they will give different air/fuel ratios. By adjusting the air screw you can make small adjustments to the A/F ratios, especially at part throttle.... once part throttle running has been tuned via the air screw in SOME cases it will result in a higher or lower idle speed than ideal. In THIS case you’d fit the idle bolt to bring the idle back to normal (and therefore bring the total amount of air at idle back to normal). Of course I’m aware that there’s no fuel mixing in the throttle body.
No question what I’m suggesting is different to the tech info KTM release but after having tuned over 200 TPIs by reflashing the stock ECUs I can tell you that it works.
@@TwoStrokePerformance
Other that 'Map shifting' by moving the throttle shaft in the TPS, there is absolutely no difference to the air coming into the motor.
The MAP sensor will see the same vacuum signal in the manifold if air passes under the throttle blade, or through the Idle Air Screw.... it's just air.
If the TPI runs the same as every other small bore bike and runs off the TPS for Idle and slight throttle, then the ecu has no way of knowing which path the incoming air came via.
It will just do a volume calc based on the current TPS setting, the RPM and the other sensor data and add fuel to suit ...
I can't see why you think that Idle Air Screw air is special.
This all changes when you drop the Idle Air Screw down and choke off air, then you'd have to crack open the throttle stop to raise the idle.
This moves the TPS value to a richer section of the idle map and 'cures' your part throttle problem.
Moving the TPS idle setting is something that we used to mask the horrible flameouts in the TE449 factory mapping before we had access to the tuning app we have now. It only take a tiny (0.05v) adjustment for it to correct the problem.
I'd suggest that's what is happening.
Dangermouse you’re thinking about it wrong. They don’t run a normal
MAP sensor and fuelling is mostly determined by RPM vs TPS.
By adjusting the idle bolt we are only changing the closed position of the butterfly , there’s no change to the relationship between the throttle and tps.
At any given TPS vs RPM point the ecu will add a calculated amount of fuel. The calculations assume a fixed flow of air through the air bypass at that TPS value. By changing the air bypass setting we can influence air fuel ratios.
The TPI TPS doesn’t have any means of adjustment. It’s fixed, unlike most other EFI bikes and there’s also no mapping software commonly available.
But again this doesn’t matter as we’re not changing the factory TPS setting, only the closed position.
@@TwoStrokePerformance
Mate, I stand corrected.
I wrongly assumed that KTM might actually be using a proper EFI system, not something off a piece of lawn equipment.
I'm now understanding why they won't run right.
There is no way for the system to make a sensible decision on what fuel to deliver to the engine without knowing vital sensor info.
Just another KTM cheap nasty solution.
Your comment regarding the throttle adjustment not affecting the TPS makes no sense. The sensor is on the end of the throttle shaft, if you adjust the stop position, the shaft moves and the TPS value changes. If it doesn't move, there's no point in having a sensor.
All the best.
Dangermouse
I have to agree with you. I’m an old retired automotive tech. Factory trained Chrysler technician. Been awhile, but have a pretty good idea how fuel injection works. Considering that was one of my specialties.
I’ve watched several of these tpi throttle body videos. Including Jeff Slaven’s. I’m at a loss of what this is supposed to do. Air passing through an adjusted orifice or around the butterfly valve is just air flow, no difference. The only possible positive outcome is if opening the throttle butterfly to achieve enough air flow for the engine to run/idle would be if the tps changes enough for the ecu to change fuel mapping, fuel injector pulse width. Cars have an idle speed motor that controls the air to control idle speed this way. Would be interesting to see if the tps value changes do this mod. And/or if injector pulse width changes. The other part that I don’t understand. The explanation of the “cold start” control. Per Jeff Slaven. “Don’t need or use it”. The cold start control does not control fuel. Does not richen the fuel delivery. That is done by the ecu calculating the amount of fuel needed, using sensor values. Cold engine, baro etc. what the cold start does do is raise the idle speed. Engines run better with a high idle speed when cold. Cold start your car engine and pay attention. The idle speed will be higher for a calculated time controlled from the ecu. Even carburetors have a high idle cam.
Dangermouse, I agree with you!
You might like to use an electrical hot air gun rather than the blow touch - better control and less chance of melting anything.
wel done
I have the Coober ECU. Would your head work with it?
Will a heat gun work?
Instead of using a flame, try using a Sodering iron, you can direct the heat directly on the screw.
Just finished the procedure. All is perfect except a bit of sputtering in wide open throttle in 2nd gear?
Guess I need to play with air bypass and idle for a bit? Any suggestions.?
I did the idle screw mod but missed the part about only adjusting that if necessary after adjusting the air bypass screw. I have no idea now where it sits relative to the stock setting. How can I set that back to near stock setting? As I recall you can measure voltage somewhere and set accordingly. Any tips?
Hello, I have a 2022 husqvarna, it consumes me a lot of gassoline,can you help me please?
alors je doit légèrement fermé l'air screew ou faut ouvrir?
Actually that screw is the throttle stop point right? We should not mess with it right?
Hi, Does it harm more fuel in TPI engine Crankshaft oiling? so If we make mix rich does it will be harm for engine oiling?
Why is nobody answering that question? nobody know it worldwide? ))
Do we need to remove the TPS from the throttle body when doing this mod? Would the heat effect the TPS?
No. Heat is isolated to the area behind the set screw. Nowhere near the TpS
So the factory manual is wrong when it tells you to adjust the idle bypass screw to adjust the idle speed?
Yes and no. When the bike is leaner, it will idle faster. Indirectly it controls idle speed. It would be like using jetting to control idle speed.
Is this mod still relevant for a 2023 300xcw? I read that idle speed would require only a small idle air screw adjustment due to revised (closed) butterfly plate position on recent year Dellorto TB. The article also stated the 2018-2019 bikes were the ones that needed the grub screw changed for an adjustable screw. I cant remember where i read it. RacerX, Vital mx...not sure. I have the 2023 and it runs good. It just idles low and will shut off if you arent blipping throttle constantly. Just curious since this vid is 4 yrs old.
My bike seem to be getting flooded every time i start it up i have a 2020 xcw tpi is this something i should consider doing ?
Yes, and if it is bogging better check your crankcase sensor mine ran fine for a year and starting flooding and bogging
Not sure if anyone can help. My bike is running rich based on the colour of my spark plug. Low revs the bike is running ok but mid throttle seems to be really boggy and chuggy. Whats best to do?
Mine did same thing, crankcase sensor, RUclips it
Ty for the info. Probably will buy your flash/head kit.
But my 2021 seems to run fantastic at stock settings. Did they make changes from 20 to 21?
Thx again
Just bought one as well 2021 te300i and wondered same thing... Still waiting for delivery tho...😉
I don't doubt anything you say, but it confuses me that you say the flat blade screw is not to be used for setting the idle. KTM says the contrary and recommends to set the idle speed by turning this screw. 300 TPI owners manual page 22....
He said the screw will let more or less air in at idle but use it to adjust running at half throttle then,
if the idle is to high / low use the new idle screw to re-adjust idle not that screw.
Does this apply to the 2020 TPI bikes?
Yes
Where should the air screw be when starting out after mod on TE 250i 2018?
watch the video again👍🇬🇧
~4.8mm gap mate
I will vouch for this modification, having just done it on my 34 hr. 18' 250 TPI.
That, and replacing the CCP sensor at the same time while you're in there. Bike now runs totally as one would expect it to.
Is there any issues with fitting this with a stock ECU?
No, you can fit it to a stock bike and its very effective at adjusting the tune.
Hi I fuck up and didn't count the bypass and now I can't start my bike 😅 . Do you know what a ktm 2012 air bypass start at please?
How long was the bolt
m5 x 50
curious about spring and drill hole size
Do you know what dimensions the screw ism M5 by how long? Like to be prepared before I start it
He said 50mm long M5
Ridiculous KTM didn't have this done at the factory.
This is making me not want to buy one of these...
That comment is the equivalent of self harm.....they are phenomenal bike, by not buying one you will really miss out on a great experience. If you’re not mechanically apt, then maybe go for Honda....and be left behind.
Part of having this type of machine is getting to know it, understand and recognise it’s complexities and learning something new every day.
I’m in my twilight years, approaching the last stepping stone before greeting St Peter but I just love this bike, it has transformed my riding skills and look forward to new challenges on every ride.
I’ve ordered the idle screw and about to get out the tools in readiness.
Just go for it Scott.....live a little.