KTM TPI Problem? Air Screw and IDLE for KTM Stroke TPI Bikes Explained

hey guys do you have a TPI bike that is too lean and doesn't want to idle properly I'm Kyle with dirt bike Channel today we're gonna talk about why that is and how you can fix it stick around contrary to what you might think the reason why KTM and husky went to these TPI bikes is not because they wanted him to run better it's because they had to meet the Euro four and Euro five standards in Europe for emissions they were surpassing the number of total production units that they that they had to to be able to you know be affected by these more stringent standards something the beta and chouriço don't have to do yet and so they had to figure out a way to make this bike leaner and have less emissions coming out of the exhaust in order to do that they had to control the amount of oil and gas don't forget about Eric I'll going into the motor thus we have TPI let's go over to the board and talk about why this is affecting you and why you might you might need to make some changes to your throttle body in order to make your bike idle properly and run properly okay this is actually what's happening inside of your throttle body which I've just taken off the bike these are not difficult to take off the bike the hardest part is to get the air boot to actually release off this there's other videos out there I also want to credit this diagram actually I took this off of two-stroke performances YouTube channel they have a video called KTM and Husky TPI throttle body adjustment go watch that video it's very good they explain this in detail so this is essentially their diagram there's really just two things that we want to talk about inside of these throttle bodies there's the air pipe a screw which is up here this is not an idle screw this is an air bypass screw and then on the bottom on the other side right here we actually have the idle adjustment screw the idle adjustment controls this butterfly inside of here that controls the air going through so from the factory KTM has basically a bolt lock tied it up in here which sets the idle from the factory because they're worried about the emissions thing to pass those Euro 4 and Euro 5 standards so the only way that they give you to adjust this as using the air screw and that is not correct the air screw the air bypass screw only only affects how rich or lean the mixture is down basically right around as you can see air is coming through like this okay if the if the butterfly is closed or nearly closed then air can come through this bypass circuit right the air bypass circuit to help this bike run properly and have the proper mix the idle screw down here basically I know this is a crude drawing but the idle screw basically just affects how far the butterfly will be open at idle right because that knot is how that works I'll take you over to the bench and show you in just a second but because that is locked itíd the only way that you have to adjust the idle is by using the air screw which is not what you want to do when you when you put the when you turn the air screw in essentially push this down you were rich in the mix because you're allowing less air to come through the bypass right conversely when you take that and go clock or anti-clockwise screw it out which is how they're telling you to get the idle to raise up what you're really doing is you're leaning out the mix which can cause additional problems so it's not a good way to control the idle but it's just the way KTM is doing it because of these standards that they have to adhere to what we really want to do if we really want to make the bike run properly and control our idle is actually fit a new idle screw down here not every bike needs this I haven't needed to do it on any of my bikes this bike didn't actually have to have it some bikes do some bikes don't but I'm doing it on this bike to show you guys and give you an illustration so go watch two-stroke performances video on this because he goes into this in detail but this is essentially what's happening inside of your throttle body so let's go over to the bench and take a look at how we install this air screw if you need or this idle screw to control the butterfly if you need it okay so here we are at the bench essentially when you take your throttle body off you're gonna this cover is gonna be popped on here like this you're gonna have to pop this cover off like that and that will reveal the idle set screw which KTM has put in there now this will be locked itíd in your bike because they don't want you they didn't want that to be moved so that it can pass those emission standards so we need to get this thing out now some guys have been able to basically just dissolve the lock tight with this stuff this Bob Smith industry stuff by just putting this on there and is in dissolving the lock tight very slowly I think you can do I ended up needing to put heat on this to get this to come out the other thing to mention is that your your your bolt in there is either a t10 Torx or a 2.5 millimeter hex or allen key bolt and it's very difficult to determine which one you have so you need to be very careful about that because it's easy for you to strip out that bolt and that's not what you want to do mine ended up being a two point five millimeter allen and so what I did is I just I dissolve some of the I use this which you don't have to use but I use this and dissolve some of that Loctite but it wasn't enough so then basically I just use my map gas torch here and a glove and I put some heat on this now you don't want to melt this so you have to put the heat right here so basically I just held this with the glove because I don't have a bison here and then I basically just put the heat right there it took around a minute and a half of two minutes of heating this area to where I had the Loctite where it would you know become liquid enough where I could get that bolt out but eventually after a minute and a half or two minutes of heating that very carefully because you don't want to melt this plastic piece then you can turn you can turn this bolt out right and the whole idea we want to get this bolt out is we want to put a bolt in there that we can actually adjust because again like we showed on the board see that's what the bolt looks like as we show it on the board this is actually going to control our throttle R this is our throttle body that controls the butterfly see that so this is how we actually want to control our idle now this bike actually ran totally fine the air the the air bypass screw I had out like four or five turns and this bike didn't have a hanging idle it was a little lame but I was totally fine with it it ran totally great what we're gonna do now is where I've turned this I this air bypass screw all the way in I've turned that all the way in clockwise and we're gonna start there I'm actually going to install this air screw this is this Jeff Slavens air screw right here he's the only guy that I could see that is actually selling these so he sells this air screw with this spring on it to keep it tight for thirty bucks twenty nine $29.95 or something like that so it's really it's really expensive I ended up buying two of them so I was $70 by the time I shift at $70 to get those two things but hey no one else is making it jeff has been making these for a couple of years and I just haven't needed to do it because not every bike needs this so this is going to allow us then to adjust the actual idle when we get this on the bike which is pretty slick something to note here though is these but these and you should probably measure this with set with a set of calipers you like my you guys like my RCBS calipers from my my days back in my reloading anyway you should take your calipers and measure this distance where this where the set screw is where that idle screw is set from the factory and I think it's going to be somewhere around four and a half to four point eight millimeters or something like that when you actually measure this so take your baseline I'm gonna set mine down to about four point six millimeters right there that's where I want it set and so I'll just put all this turn this in and I oh actually before I do that I'm gonna put a little bit of grease on these on these threads before I do that sorry getting ahead of myself I'm gonna put this is just some some a little bit of super-awesome grease that you get with your like levers so I'm just gonna put a little bit of grease on there like that now I'm going to put this in thread that in here and that should make it so it turns really well I also used a little bit of this uncured stuff to actually clean out my threads down in there and make sure all the Loctite was out so I'll do this and again we're gonna come down to where we're about four and a half so that's too far and back that off there's not a lot of adjustment in here but right see if I'm there I'm about what four point six four I think I'm gonna be fine right there so that's where I'm gonna that's my starting point and then you'll notice that the cover that you pulled off is gonna have to be drilled out so I've got all the tools here that I use use just a drill bit I drilled this thing out and then I basically just clip this off so that now when I when I put this whole thing back together once I get my throttle my throttles down in here my throttle cables this will actually just go and and snap over that little bolt that we've put in there because you will have to carve that out into kind of a kind of a u-shape in order to get this to fit once you're going back to install it but now the cool part is we've got an actual idle screw in here that is controlling our butterfly this is controlling how how far that butterfly is open so we actually do have an idle screw in there so that'll be pretty pretty slick to make to be able to tune the bike and then we'll tune the bike based off of our air bypass screw and our idle adjustment screw down here now I've had a couple of buddies that are that have done this and they've said some of them have left this air bypass screw all the way closed and in the bike ran great you know cuz that was the richest so they could get it others had to have it out maybe a half turn or three-quarters of a turn so every bike is gonna be slightly different and again your bike might not need this my bike this bike didn't have to have this it ran really well without it but some bikes are not gonna idle without putting doing this idle screw mod thing here so anyway we're gonna go stick this back on the bike as you can see when you take this thing apart you need to take your tank off and then swing your subframe up that's how you're gonna get these air boots to come off of this now that I've got the air screw or idle screw installed in this thing I'm been able to just put this back in the bike hook up my throttle cables and everything and finagle this back in there and then we'll be able to actually tune the bike correctly with our air bypass screw using using it as a true air bypass screw like is on the fuel injector four-strokes and then control my idle here and control the butterfly with the idle screw so that should be pretty sweet and make this bike awesome [Music] okay with the magic of film editing you've watched me kind of put this thing back together real quickly and there's gonna be have to be some tuning involved with this I'm gonna go ahead and put my air screw all the way in to enriching it as much as I can so that's what I've done is I've screwed it in all the way counterclockwise don't go too hard and then we're just going to be adjusting the idle down off of the idle screw down here on the bottom which we've installed I haven't started the bike yet so we're gonna see how close the idle is check it out okay that was the wrong way so we'll go the other way just a little bit look at that cool so what I'm gonna do now is I'm gonna go ride the bike well I can't do it right now but the next time out I'm going to bring a flat blade screwdriver and I might need to adjust this air screw a little bit because it might be too rich right now so I might need to adjust that out like a quarter turn or a half turn but I'm gonna tune that just like a carburetor air screw or a four-stroke air screw on the efi to tune this bike out and make it run right and I've actually got now an idle screw that I can adjust so this is gonna be pretty cool so that's how I've done this and that's how maybe you could think about doing it for yours again not all bikes are gonna need this one this one actually ran pretty spot-on even without this but now I think it's gonna run even that much better because I can actually truly tune this thing the way it's supposed to be the way the KTM couldn't do it because of the emissions restrictions so anyway hope you guys learn something in this video again go check the other video out that know how to link in this in the description probably what I got some of this additional information if you want to support their bike channel you can go to patreon right on my website dirt bike channel com I have a support thing where you can support me and eventually I give all the bikes away that I review so this bike will be one of the bikes that I'll give away at some point to you guys so anyway I hope you enjoyed this video and let's leave a singletrack thanks guys

Channel: Dirt Bike Channel

Views: 66,313

Rating: 4.8754029 out of 5

Keywords: enduro, motocross, dirtbike, ktm 2016, ktm motorcycles, shootout, ktm, range, erzberg, graham jarvis, johnny walker, best dirtbike, 125, 200, 250, 300, 350, 400, 450, 500, 525, exc, sx, how to, 2 stroke, 4 stroke, video, review, husqvarna

Id: Ivxr6nkQHos

Length: 13min 32sec (812 seconds)

Published: Sun Feb 16 2020