Fixing The Biggest Problem With Honda 2 Strokes!


Welcome back to the channel guys. My name is Cameron. And today we’re gonna be tinkering on this beauty back here it’s a 2003 CR250 that I’ve been building and Today we’re gonna be discussing one of the biggest issues with these bikes and that is how the air boot seals to the airbox A lot of you have probably heard of this. It’s a really crappy design and Could lead to a serious engine failure. So definitely worth looking into you so the problem with this design is that all that seals the boot to the airbox is This little foam gasket and that’s definitely not enough So when you tighten the screws that hold the boot on to the airbox the boot will actually warp maybe not quite to that degree, but it’ll create a gap there and That allows air and more importantly dirt to go through there and into the engine. This design was used on the o2 207 co2 50s, which I have here and also on the 2002-2007 cr125 as well. So if you have either of these bikes Definitely something you want to consider. There’s another issue with this design as well. And that’s inside the airbox. There’s all these little nubs Where the air filter sits on the airbox and it’s supposed to seal right there and obviously having those nubs Doesn’t create the best seal and a solution for that is a gasket called the pro seal It’s like a rubber or foam type gasket. It just sticks through the airbox You can see it’s a little bit thicker and has all the cutouts for the nubs so basically just raises up that surface there to the top of the nubs and Allows the air filter to steal a little better and later in the video I have a better kind of more permanent solution for that This is kind of a quick fix, but I’ll link this little gasket down below in the description Now the most important issue here is the air boot to airbox seal so discuss the three solutions I have for that and the first one being the cheapest and easiest way to fix it and that Involves using some Permatex liquid gasket like gasket maker. This is the ultra black basically, what we’re going to do here is put a generous amount on the lip here all the way around the airbox and Then we’re gonna mate up the boot onto there Let it tack up before tightening it down. See what the Instructions say here. Looks like it tacks up in an hour and then you want to let it dry for 24 hours before use so Once again, get the sealant on there put up the boot don’t tighten it down all the way let it dry for an hour and then snug it all the way down with the screws and That’s not going to be a hundred percent guarantee that it’s gonna seal and last But literally it’s like a five-dollar solution and I’ve heard of a lot of people having good luck with this Basically you want enough sealant on there, too When you put the boot on it uses out the edges just a little bit But keep in mind this isn’t going to be the cleanest or prettiest solution, but it’s effective now The second solution is a bit more involved, but the end result is a lot cleaner and it’s more effective so the basic concept here is to adapt an air boot and the air filter mounting plate from a 97 to 99 cr250 onto this air box that design was a lot better and pretty much foolproof It’s something that Honda should have stuck with so how we do that is by cutting out the center portion of the air box here Dropping that out And then the 97 to 99 air boot has a dual lip just has an extra flap that comes out One lip goes on the inside the air box and one goes on the outside So it’s like the perfect seal and I don’t have a dual lip air boot to show you guys what that looks like so I’ll put a picture on the screen so you guys can see and As far as the air filter mounting plate, it’s metal and replaces this cheap little plastic one inside here so it’s not gonna flex like this one does and that has studs that come through and Bolts the air boot onto it so a really solid solution, but it takes a little bit more time and you have to find the 97 to 99 air boot the air box and all the Components inside as well and I’ll actually drop a link down below that explains more about this setup. It has pictures Right up. This is a really comprehensive tutorial on how to do this modification keep in mind this mod only works for the C or 250 s because the air boot only fits on the 250 carb and not the 125 card now the third solution and the one we’ll be using is This one that has aluminum plates one goes on the inside the air box one goes on the outside and in my opinion this is the most effective way and You don’t have to do much in the way of cutting So the basic idea with this solution is you have two lumen plates. You bolt them together with the air boot in between they’re obviously not gonna flex they’re pretty thick and They’re not going to create any air gaps between the air boot in the air box or between the air filter and on top of that you shave off these little nubs inside that I was talking about earlier and That creates a good seal between the air filter and the air box And before we get started got to make sure all of the old sealant Gasket dirt grease all that stuff is off the air box in the air boot now the first step is to drill out all the mounting holes for the air boot and the size we’re using is a 257 so 2.25 7-inch. It’s One size up from quarter-inch. So we’re gonna drill all the way through these holes obviously try to be as straight as possible and all the way through The nub on the other side since the air box already has little holes there Those will act as pilot holes and that should make it pretty easy After drilling you’re gonna have some birds around the holes. So you want to trim those off with a scalpel or a razor blade and Make sure all of these nubs are the same height when you’re all done trimming So now the hole should look something like this now The next step is to go inside the air box and trim off these nubs that we drilled through You want to trim them all the way down to the surface? You don’t want anything poking up Got all the nub shaving down not the Tydeus job kind of takes a while, especially with these lower ones It’s pretty tough to get down in there. But the tool I found that works best for this is a little scalpel I’ll link it down below. It’s pretty nice for shaving gaskets, too I’m gonna go ahead and test fit the plate make sure it’s a snug fit Sweet stroll the holes line up All looks good Now before I slap this together, I’m gonna seracote these plates black. I want them to match the air box I think that would look pretty good The plates are looking good all done with sarah coding and now we can slap this whole kit together So we’re gonna put sealant on the inner lip of the air box here as well as this lip around the outside And then seal that’s going to go on this side of the ring too as well as the inner lip of the air boot The sealant should look something like that when you’re finished up every bit of that surface should be covered and Then the inside of the air box should have a nice fat bead all the way around as well It’s got to make sure there’s no way dirt can get through that now I’m going to get this plate set in place in the air box and then get to work sealing this side All right, I think we’re ready to slap this thing together just gonna line up the boot here Gonna start popping in some bolts here make sure everything lines up Damn glove got stuck in there get out of there So things weren’t lining up the greatest so what I did was put all the bolts in from the inside get that inner flange lined up with the air box and Now I’m gonna line up the air boot. Hopefully this works a little better this way Honestly this outer plate really isn’t lining up too good for the holes Look like they’re fine. But this fifth hole right here is a little bit off and That’s holding us up from being able to put this together looks like an got it Lined up right now if I can get this one on the rest of them should be pretty easy got that one lined up This one looks like it’ll go All right So we got all the bolts lined up took a bit of work to get him to go But I would recommend doing these two bolts first These are the harder ones once you get those lined up the other three should be pretty easy So now that we’ve got all the nuts on I’m gonna tighten them all down evenly so I’m gonna go in a crisscross pattern Here kind of like you’re tightening a five lug wheel Got everything tightened down and looking good and within an hour before that sealant starts to dry You want to clean up the excess around the edges? Looking pretty trick now for the filter cage you want to make sure that it fits Snugly against this inner flange. You don’t want to see any air gaps there Looks like it’s pretty tight seal all the way around won’t need to do any trimming to get it to fit better So that looks like a go. I think we’re all set So just let that RTV sealant dry for 24 hours before using the air box and then we put an air filter on You want to grease the inner lip here at the air filter where it fits against the air box? So that’ll ensure even further that no dirt gets past your filter The very last thing I want to do this air box is make it look good and keep it looking good So I’m gonna get rid of some of these scratches Son fading and kind of pitting back here so I’m gonna hit it with like 800 grit sandpaper just for a little bit and then finish it off with the Seracote trim coat. This will give it a nice shine and it says it lasts for up to 200 washes So let’s give it a shot. I’ve got the air box all sanded down Now before that coating can be applied the air box has to be clean with dish soap and completely dried there Can’t be a speck of water on it So basically just wiped down the air box with the cloth inside and then to give it a consistent finish You just wipe it in the same direction like this to finish it up All righty guys air box is all finished up looking absolutely Amazing honestly looks better than new and works better than new too so like usual I will have all the products they use throughout the video including the aluminum plates the seracote the trim coat all Link down below in the description for you guys to make it easy and one thing I didn’t mention about the trim coat It’s a ceramic coating So it has anti stick properties and you guys know how dirty the inside of these air boxes get over time So I actually think the trim coat will help keep them clean. I’ll keep you posted if that works or not Here’s another look at the finished product here Literally looks brand new. This stuff is freakin incredible Definitely worth a shot and I believe seracote offers a free sample on the website I can find that. I’ll drop a link down below Thank you so much for watching the video guys and like always if you enjoyed it. Make sure you go ahead and share it I really appreciate that. So expect to see a lot more videos with the cr250 coming out pretty soon in the next couple weeks We got some really cool parts showing up. So that thing should be done sooner than later. I’m excited That’s all I got for you today until next time keep it brand You

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