lose the 07yz450f!

[KJ790]

First off, the dirt getting past the filter is not the manufacturers fault. You were using an aftermarket filter. Either the filter was junk, you didn't oil it enough, or you went too long without changing it (my guess is one of the second two). Second of all, have you taken off your valve cover to see if the vent tube sucked dirt into the top end? If you haven't then you have no room to complain because you are not taking care of the bike properly! If I ever thought there was any chance that dirt could have gotten in my top end I would pull it apart and look immediately. The breather tube blows out as much as it sucks in. Most of the time it will suck dirty air in about an inch or two and then blow it back out. This makes the first inch or two dirty, but there are then 12 inches of clean tube where no dirt could have gotten. If it is such a bad design and Yamaha should be sued, why aren't they all blowing up in the first couple hours? I'd imagine that if all the YZ450s out there were sucking massive amounts of dirt into the top end then there would be a massive amount of engine failures, yet there aren't. I don't see a problem here.

[Polar_Bus]

ive owned countless 2 strokes. i know how much maintainance it requires. i have learned that my 250 2 strokes air filters don't need to be cleaned every ride if its not dusty. because they don't suck as much air

.

My experiences are completely opposite to this claim.

cc's being equal, a 2 stroke draws air every SECOND stroke. A four stroke draws air once every 4th stroke. So a 2 stroke requires much more air than a 4 stroke. This whole post sounds like a disgruntled rider crying sour grapes. My '02 WR250F was the most reliable bike I owned (i've had 10 bikes over that past 23 years). As for my '07 450, I only have about 50 hours on it, but so far has been perfect. Neither Yamaha bike ever "sucked dirt" through the breather hose, this claim is a crock of BS.

[Yamaha4lyfe]

kj. i wouldent have brought this up if i havent checked under my valve cover.

first shim adjustment i have had to do, i found a few fingers full of gritty sand. not on the cams, not on the lobes, not on the chain. but around and near the valve springs. i oil my filter correct. i dont under oil it. and i change it after every ride. no exceptions

maybe i am wrong that a 4 stroke draws more suction then a 2 stroke but a 450 does draw alot more air at 1 time then a 2 stroke does, because of the such large displacement. i have been using stock and no toil/twin air filters. so far haven't had a problem with the twin air. but the no toil and the stock have not shown me anything to be happy about

i dont think yamaha has had their bike testing in places where that breather tube is exposed to such harsh elements. my opinion would be that they only test their 450f racers on motocross tracks. because thats what the bike is designed for. now being a woods rider also. and riding in gravel pits may have side effects. but that should be no reason to have something such as this. but for the time being, i am neutral about this air breather tube. like i said i installed a filter on it. hopefully that will work. as for the air filter no toil it out of the question i will be experimenting with different brands

Ryan

[blue9red9]

I ride here at my house track always. The dirt can get like talc powder if there is no rain. There is sometimes so much dust you can't see somebody in front of you. You have to back off and we can't race each other if it's like that but we still ride. I've had my valve cover off. There's nothing there but clean oiled stuff. No dirt, sludge, nothing. I've owned three yami 4 stokes here with hours and hours on each. Never had anything under the valve cover but clean clean. I don't know where the stuff you are talking about would come from. The breather tube is to release compression blow by from combustion gasses getting by the rings. It shouldn't suck in anything. And the carb air boot thing... there must be something wrong with your air filter. There's no way with the design they have if it's all buttoned up like it should be, stuff like you speak of could get by. Here's a picture of some of the dust for giggles. The picture was taken 10 minutes after we stopped riding. It just hangs there when there's no breeze. We called it off after 3 laps today for just this reason.

[KJ790]

Every manufacturer has a vent tube from the valve cover to the outside. it is a must for the engine to function properly. If the dirt was on the valve springs and not the cams or buckets, then it entered through the airfilter. If dirt were to enter through the vent tube it would be on the cams and buckets, not on the valve springs. Your filter failed for some reason, either manufacturer or user error. Since the manufacturer of the air filter you were using was not Yamaha, and we don't know how you oil your filters (everyone always says they oiled it properly, yet many people don't), or whether or not it was installed properly, there is no way Yamaha could be at fault.

[Yamaha4lyfe]

Every manufacturer has a vent tube from the valve cover to the outside. it is a must for the engine to function properly. If the dirt was on the valve springs and not the cams or buckets, then it entered through the airfilter. If dirt were to enter through the vent tube it would be on the cams and buckets, not on the valve springs. Your filter failed for some reason, either manufacturer or user error. Since the manufacturer of the air filter you were using was not Yamaha, and we don't know how you oil your filters (everyone always says they oiled it properly, yet many people don't), or whether or not it was installed properly, there is no way Yamaha could be at fault.

i don't believe that beach sand size grits can get in though the air filter and yes it can get in though the breather. that valve cover gasket has it sealed off. that little compartment beside the spark plug hole. where the breather tube connects. i don't know how the stuff got in their. only way i can see it, is from the breather tube. i have dumped my bike on the left side into a corner (sandy) when i had not re-routed my breather tube. maybe thats what did it because it stalled?

[BergArabia]

I ride in sand.. in the desert to be precise.

So I have been a bit paranoid about this sucking sand up through the breather especially for when I fall off and the bike is running lying down with me lying somewhere else (happens more than it should).

My solution has been to reroute the oil breather hose into the air box (outside the filter of course). I then use a bit of panty hose (soaked in filter oil) over the breather hose end. This helps me rest easier..

[Yamaha4lyfe]

I ride in sand.. in the desert to be precise.

So I have been a bit paranoid about this sucking sand up through the breather especially for when I fall off and the bike is running lying down with me lying somewhere else (happens more than it should).

My solution has been to reroute the oil breather hose into the air box (outside the filter of course). I then use a bit of panty hose (soaked in filter oil) over the breather hose end. This helps me rest easier..

yeah i did the same thing, but i put a K&N harly crankcase filter on it. from canadian tire! cost 17 bucks. ill have pictures tomarrow. right now its time for bed i get to work on thanksgiving day STat baby!

[ttr125l95]

now you went and screwed it all up.

[BergArabia]

yeah i did the same thing, but i put a K&N harly crankcase filter on it. from canadian tire! cost 17 bucks. ill have pictures tomarrow. right now its time for bed i get to work on thanksgiving day STat baby!

Actually, to be fair, on looking back through your earlier posts on this thread I can see that you did mention the breather hose reroute.

So it looks like you have been pretty careful in trying to keep te air getting into the engine clean. I can see why you would then be upset to see that gunge in there since you have been vigilant in trying to keep it out..

So what about this filter from Canadian tire?

Is that the culprit?

[Yamaha4lyfe]

here is the picture for the valve breather tube filter

and how i oil my air filters

[02YZ426]

Not sure why you are getting dirt past the filter, but I would check every seal from the box to the engine. I have an 07 myself and ride in the dustiest conditions around, NO dirt gets through to my engine. I also use No Toil air filter and oil. I personally would take that vent tube out of your airbox.. not sure why you would put that in there anyway. I've heard of guys doing it, but I'm yet to see the need to put it in the dustiest component of your bike.

http://i2.photobucket.com/albums/y7/02YZ426/Oshweken%20RND3/DSC_0157.jpg

[Yamaha4lyfe]

so it doesent suck up water or sand if i flop it to the left side.

[rexbond007]

i don't know what your doing wrong, i have have been using no-toil for 5 years on 3 bike different bikes with stock air filters, and UNI filters. my 07 450 has 55 hrs on it. the breather intake tube is still in the stock position. but i sniped it 3" back at the elbow for going through swaps. I never sucked any swamp water back before i sniped it. my guess is your not using enough oil on your filter.

[02YZ426]

so it doesent suck up water or sand if i flop it to the left side.

I understand that, but I still don't think its necessary. I'm almost positive that nothing will make it up that vent tube into your motor in the stock position. Wasn't there a vid somewhere around here where a guy put that tube in a bucket of water, revved the bike up and it was making bubbles in the water? That tells me right there that nothing is going to get sucked up that tube. Is your airbox sealed tight where the big clamp is in the airbox?

[Yamaha4lyfe]

wel i have never checked the seal on my air boot. but, i had a picture of the dirt in my engine, but my gf deleted it!!!! it was still on the camera, and i forgot to upload it. so its true i had proof. but i dident watch it happen so i can be 100% clear on how it go in their. but ill leave this filter on it, and it nothing is in it. then i know for sure it came in the breather tube.

[grayracer513]

I understand that, but I still don't think its necessary. I'm almost positive that nothing will make it up that vent tube into your motor in the stock position. Wasn't there a vid somewhere around here where a guy put that tube in a bucket of water, revved the bike up and it was making bubbles in the water? That tells me right there that nothing is going to get sucked up that tube. Is your airbox sealed tight where the big clamp is in the airbox?

While the engine is running, there is from zero to a net outflow of air from the breather. This is because even at idle speeds, there is not enough time for the upstroke of the piston to draw a load of anything up the whole length of the tube before ti reverses direction and blows it back out.

The problem comes when the tube is stuffed into something small enough to be vacuumed up, and the engine is cranked, or the last stroke it takes at a stall is up. The right way to fix this, if you think it's a problem for you, is this:

https://www.thumpertalk.com/forum/showthread.php?p=4054651#post4054651

https://www.thumpertalk.com/forum/showthread.php?p=4956573#post4956573

[Yamaha4lyfe]

Sweet i got gas! its mine dont nobody take ie mahaha:p

thanks

[Wiz636]

I understand that, but I still don't think its necessary. I'm almost positive that nothing will make it up that vent tube into your motor in the stock position. Wasn't there a vid somewhere around here where a guy put that tube in a bucket of water, revved the bike up and it was making bubbles in the water? That tells me right there that nothing is going to get sucked up that tube. Is your airbox sealed tight where the big clamp is in the airbox?

All the other stuff aside, I can positively say that dirt WILL get sucked up the breather and right into the valve cover...at least on my '06 it does. I have seen it (and it was not just a few grains either) and had to clean it out. It is a problem that I had to address with a re-route and a PCV valve filter from an auto parts store.

[mattwatson]

so it doesent suck up water or sand if i flop it to the left side.

I think you will find that the breather will blow engine onto the filter, this will do two things dilute the sticky filter oil, also the extra oil will carry the dirt through the filter with it. Also when rideing in wet conditions, or you water blast your bike, cover the side cover holes,water will also wash dirt through.I have a 06 450 and stalled with water just over the breather, becouse I knew it could suck up water, (when the engine not running and the crankcase is cooled by the water), I started it then checked the dip stick,found water, so had to ride 10 minutes back, I have left it standard, but thought that a check valve setup,with a small 5mm tube above it to equalise the pressure, with the small tube in the air cleaner box, makeing sure the discharge is not on the air cleaner.