I have a CFM air box and I am getting a fine mist of sand in the shoot and all the way to the carb. No sand on the reed side. The sandstops where the shoot makes the 45 to the box. I know that you do get gas blowing back a bit, so I know it's not coming threw the filter. I checked the intake boot for any rips, the carb cap, the cfm tube for any holes. It runs good and shows no signs of an air leak. Any ideas?
Any Ideas
- Thread starter Kgibson
- Start date
sand??? as in beach sand??? it's gotta be gettin thru the filter, do you have it oiled properly and tightened to the stem inside the box, i have the same box and use a uni filter oiled like a greased pig and just did a 34mm carb swap and didnt notice anything in the tube, better fix that soon or you'll be rebuilding that motor
tell me your not running a k&n filter <<<<<< known for lettin sand thru!!!!!!
tell me your not running a k&n filter <<<<<< known for lettin sand thru!!!!!!
Sand tracks in Florida Lol No I have a uni, I even got an adaptor so I wouldn't have to use the screwy one cfm sent. There is no sand inside the filter or at the beginning of the shoot. It all starts after the bend. And it is oiled good! Your right about the rebuild and the sad part I just did it. For the life of me I can not find anywhere it could be coming from. I even plugged up one end of the shoot and filled it with water thinking maybe when they welded it they missed a spot...no such luck.
Let me see if I can help you pin down that sand leak. Since you say the quad runs OK, without the engine behaving as if it has an air leak, it is safe to say that the sand is being sucked in upstream of the carburetor. You usually won't notice much sand downstream of the carburetor venturi, even if the leak is near here, because the velocity of the fuel/air charge coming from the carb. is powerful enough to whisk the sand away. It will tend to wind up in the crankcase, rather than sticking to the reeds.
That being said, I would first check the silicone/rubber hose that attaches the CFM airbox to the carburetor again. If this hose does not fit both flanges TIGHTLY, or if it has even a minute rip, you'll have a leak. If the hose looks OK, still take it off and bend it back and forth to expose any hidden rips/cracks.
Airbox-carb hose OK, and you're sure of it? Next, Id take a long, hard look at your air filter. What type of air filter are you running? Uni? No-toil? K&N? All of these filters MUST be oiled thoroughly in order to work properly. Just putting the filter in without any oil will allow sand to bypass the element. Also, the filter has to fit tightly against it's flange in order not to leak. Just because the sand appears to stop at a certain point in the intake tract does not mean that it isn't sneaking in past the air filter. Remember how fine sand particles really are. It doesn't take much of a leak to let 'em in.
OK. So, if you have a tight and properly-oiled air filter, and you're sure that the airbox is securely attached to the carburetor, take a long, hard look at the carb. I don't know what type of carb. you're running, but if the fitting where the oil injection line used to attach is not blocked-off, sand can come in through there. This is true even for aftermarket carb's that are supplied with a nipple on which to attach an oil injection hose.
Still can't find anything amiss? I'd remove the airbox from the quad, block off both ends of its intake tube, and put a pressure tester to it. You'll need to make a fitting on which to attach a pressure tester to one end of the intake pipe. Pump in a few psi worth of compressed air, and go after all the welds with a squirty bottle full 'O soapy water. Bubbles around any weld indicate a leak. While this condition is highly-unlikely, it is possible that one weld on your intake pipe was not done properly at the factory, and it has a slight gap present through which the sand can enter. If this is the case, the weld in question will have to be at least partially re-done.
Good Luck. Hope I gave you some ideas!!
That being said, I would first check the silicone/rubber hose that attaches the CFM airbox to the carburetor again. If this hose does not fit both flanges TIGHTLY, or if it has even a minute rip, you'll have a leak. If the hose looks OK, still take it off and bend it back and forth to expose any hidden rips/cracks.
Airbox-carb hose OK, and you're sure of it? Next, Id take a long, hard look at your air filter. What type of air filter are you running? Uni? No-toil? K&N? All of these filters MUST be oiled thoroughly in order to work properly. Just putting the filter in without any oil will allow sand to bypass the element. Also, the filter has to fit tightly against it's flange in order not to leak. Just because the sand appears to stop at a certain point in the intake tract does not mean that it isn't sneaking in past the air filter. Remember how fine sand particles really are. It doesn't take much of a leak to let 'em in.
OK. So, if you have a tight and properly-oiled air filter, and you're sure that the airbox is securely attached to the carburetor, take a long, hard look at the carb. I don't know what type of carb. you're running, but if the fitting where the oil injection line used to attach is not blocked-off, sand can come in through there. This is true even for aftermarket carb's that are supplied with a nipple on which to attach an oil injection hose.
Still can't find anything amiss? I'd remove the airbox from the quad, block off both ends of its intake tube, and put a pressure tester to it. You'll need to make a fitting on which to attach a pressure tester to one end of the intake pipe. Pump in a few psi worth of compressed air, and go after all the welds with a squirty bottle full 'O soapy water. Bubbles around any weld indicate a leak. While this condition is highly-unlikely, it is possible that one weld on your intake pipe was not done properly at the factory, and it has a slight gap present through which the sand can enter. If this is the case, the weld in question will have to be at least partially re-done.
Good Luck. Hope I gave you some ideas!!
Thanks for the replies. A new uni filter that i have checked over and over. A new silicone connecting boot, that I ordered the exact size and fits like a glove. I took the intake boot off and twisted a squezed trying to expose a crack with no luck. I do have a twist though...my son just told me when he came off the track two differant times the bike would be idling high. Air Leak after it got warm? If it were the reed cage leaking would it blow back towards the filter? The reed cage is all I can figure. It's a pj 34 carb. I've checked the box by filling it with water no leaks.Thanks
Haven't washed it yet. It;s just a fine mist, if you weren't really looking hard you wouldn't notice it. Thanks for the help.
Hmmm. You've checked everything obvious, alright. A high idle is definately a sign on an air leak, so.... Yeah, check your reeds again. Somehow, I don't think that's it, tho... An air leak by the reeds would result in the sand being drawn into the crankcase, not blown back towards the air filter.
Wait! I have another idea. How well is the throttle cable sealed where it enters the top of the carburetor cap?! There should be a rubber boot which slips down the outer cable and seals over the ferrule on top of the carb. cap. If this boot is missing and/or out-of-place, and air leak will be present. Also, unscrew the carburetor cap and be SURE that the 'O' ring is present, intact, and fully-seated...
Keep us informed! Yeah, check it thoroughly. If your carb. has a plastic cap (I know the PWK's usually have metal ones, but IDK about yours), check it carefully for cracks as well. Also, if the throttle cable gets pulled from side-to-side when the handlebars are turned, that rubber boot on top of the carb. cap can work itself loose over time. Re-route the cable as needed to keep it stationary while steering. I:I
The same sand was on the underside of the cap. Look at the boot it covers the metal insert but not over the top of the cap. I'll fix that and i think I'll put grease around the outside of all boots and even around the carb top. And the cleaning thing....****** don't tell me I should split the cases again. The carb and top end fine, but the bottom ****** . It was such a small amount, how about a good rinse job? Thanks you both for your help, I'm sure the top of the cap is the problem.
Hey! I bet you nailed it! Yeah, clean that carb. cap out really good, seal it up, and maybe that'll do the trick. I think your engine will be OK if you just fix the leak, maybe do a rinse job (NO WATER!) and run it as normal. I might run a few tanks of richer-than-normal 28:1 mix in it to help purge the sand from the crankcase, but apart from that... just go on with life.
As long as the engine wasn't run too long with an air leak, no damage should have resulted.
Oh! Keep in mind that nothing attracts grime faster than exposed grease on a fitting. Just a thought...
As long as the engine wasn't run too long with an air leak, no damage should have resulted.
Oh! Keep in mind that nothing attracts grime faster than exposed grease on a fitting. Just a thought...
Ya thats a good point about the grease. Only had about 10 min of ride time, and we are talking a real small amount. The motor is totally new top to bottom, so your right about lost $$$$$. Once again thanks to both of you for taking the time to help.
