Valve float Question

[speedy400]

hey,
I was just wondering what does the engine do if the vavles float? As in.. say your going top of 5th pinned for awhile and the valves float. Would the engine just kill? Piston melt? ect. thanks-darren

[Chanman420q]

destroy the entire head, piston, cylender basicly its like setting an M80 off in ur engine

[speedy400]

:eek: :eek: I best get some stiffer springs sometime...its usually alright with hotcams though right?
thanks-darren

[cals400ex]

yeah, you can use the stock springs with the hotcams. i bet they will wear out quicker though and even more so if your running an aftermarket ignition box. i run my stock springs with my stage 2 without any problems to this day.

[2001400ex]

If they're floating it's gonna lose power too. Probably stutter, stall you should realize if they're floating...

[Chanman420q]

Originally posted by 2001400ex
If they're floating it's gonna lose power too. Probably stutter, stall you should realize if they're floating...

do u know what it means when the valves float? it means the springs stuck, holding them open at the wrong time, there for when the piston goes up on the up stroke it hits the valves and destoyes the head, its not like having wrong jetting and it only sputters on 1/4 cuz the air fuel screw isnt set correctly, ur valves float, say good buy to ur engine

[speedy400]

thanks for the info chanman, I am just trying to figure out why my quad died the other day when I was doing a plug chop. I went WOT for about 15 -25 seconds, then out of nowhere it bogged down and died. I checked the plug, it was white. I figured out that night I had finally forgotten to tighen down the carb all the way....*I'm retarded* anyways any ideas why it'd just bog down like that?BTW it ran great right after I tightened it down.thanks-darren

[Chanman420q]

im assuming you u checked all the basic things like, u didnt hit the kill switch, gas was on, choke was off etc..

have u gotten it started yet? if u did, u prolly just sucked in air threw the boot and it really leaned it out, which caused the plug to be white

if not i would clean the carb, make sure gas is flowing and all that. if still no go, ur gunna have to pull the valve cover off and the head and see if thats what happend. U may of just blown a head gasket or just need a new top end. Your just gunna have to check.

Maybe someone else can help you out.

[speedy400]

Right after I trailered her home(battery was dead). And jump started it it started right up no problems. I think I figured it out... now that I remember..I took the air hose to the whole carb that night, that why I never had anymore problems, probly just some water or piece of dirt in the main. thanks for helping, I guess I just forgot about the air hose thing..darren

[2001400ex]

Originally posted by Chanman420q
do u know what it means when the valves float? it means the springs stuck, holding them open at the wrong time, there for when the piston goes up on the up stroke it hits the valves and destoyes the head, its not like having wrong jetting and it only sputters on 1/4 cuz the air fuel screw isnt set correctly, ur valves float, say good buy to ur engine

Yes I know that you can ruin your whole engine if you allow the valves to float while your quad is running/you are riding it.

You should lose power the second they start to float though, right? Your engine isn't going to just seize the second they float right?

Yes I know that when the valves float that the springs are stuck open, can't they also move just a tiny bit when they're floating?

[400exdad]

Valve float will not destroy your motor. If you ever float your valves just once. :) Float is just what it says: The valves are not riding on the camshaft anymore because the RPM's and cam ramp angles have exceeded the ability of the valve springs to keep the valve/lifter following the cam profile. The indication of valve float is usually missing. It may even feel like you've hit the rev limiter. Now, please understand the valve float is still bad. While I do admit (with the close tolerances of these motors) that the valves may "contact" the piston in valve float, most likely causing no damage, the real wear/damage occurs when the float hammers its seat. This can be in the form or accelerated wear or valve/seat failure. Basically, if you are floating your valves all the time, you need better springs... especially if the cam manu. suggests it. But, if you are just floating them occassionally, it should be no big deal. If your cam is not one that is suggested to have better springs, you may just need to replace your stockers. There is a lot of heat in the top of the motor that probably derates the springs after a period of time. If your motor is older or has a lot of hours, it's probably time to change'em out.

[bmw500hp]

Originally posted by speedy400
hey,
I was just wondering what does the engine do if the vavles float? As in.. say your going top of 5th pinned for awhile and the valves float. Would the engine just kill? Piston melt? ect. thanks-darren

Lets say you are building your motor and your head is lying face up on the bench....just before you install it, your girl calls and tells of your best freind is now "the man"...:mad:

You are so mad, you take a claw hammer and beat on your beautiful new ported ex head with the hammer for about 30 seconds....

The head would now resemble one with valve float..:blah: :D

[400exdad]

That would be dropping a valve... kind of like the girl dropping you. Dropping a valve and valve float are not the same.

[JOEX]

LMGDAO!:p

dad, I liked your explanation for valve float, very understandable:)

Joe

[BSTURDIVANT]

And correct to the " T" !!