Power valve?

[lannyLT250R]

I was wondering what the power valve on the 88-92 quadracers does. And in another forum i heard someone say something about not to use a synthetic oil because it gunks them up or somelthing? what's the difference in oils and is golden sprectum a synthetic oil?

[Suzukispeed18]

Go with a semi-synthetic oil and i believe spetro is a semi-sythetic,i run spectro in both my blaster and lt250 and havent had any problems

[Banshee]

Spectro is a Semi. Yes Full Synthetic does gunk up the powervalve. How long does it take to gunk it up I really couldn't say.

To explain a powervalve you need to understand the stroke of a 2-stroke, up and down. Basicly the powervalve makes the exhaust port closed when you intake is feeding the motor gas and air so that you are not losing any gas and compression out the exhaust. When the motor fires and the piston goes downthe exhaust port will open and exhaust will go out then it closes and repeats. Let me know if this makes sense.

[370banshee]

ok i'll try this tell me if anybody is confused or if i'm a dipshit!!

ok a power valve is just that it's a vavle. (i know only 4 strokes have valves right. not true but thats a totally differnt page long post lol)
the powervalve regulates how much exhaust the engine will let out. at low RPM the exhaust pressure is lower due to less air fuel mixture in the engine. therefore you have less exhaust to push out. think of it like this the smaller the passage the higher the pressure. so if you try and push this little bit of exhaust gas out a big exhaust port then the engine is running at that point very inefficent. the key is to have exhaust that equals your intake. to much exhaust mean not enough back pressure and threrefore no low end. the powervalve regualtes the exhaust back pressure. no back pressure or little back pressure is only good for high end power. the back preesure that a powervalve gives the engine down low makes torque. there fore youir low end power is there too. the powervalve runs off of engine RPM. at full throttle the vabvle is completely open. i hope this is helping and not confusing everybody.


oh yeah about the powervavle getting gummed up or clogged up from synthics. that because nobody has been looking at amsoil. interceptor and dominator are both great for powervalve engines.


somewhere on this site in the forums there is a good explaination taht i wrote bout the powervale thing. i'll try and find it

[lannyLT250R]

Thanks guys, i get it now. i was wondering why it moved when i opened up the throttle. I was wondering how hot shot the engine get when i'm riding? like the outside case? it was cool enough to touch but felt kinda warm...even the bottom end is that normal? it was really hot, i mean i could hold my hand on it. I ask this because today when i was riding i slowed down and hit the throttle hard and it started to stall out(it was real boggy) ..i pulled the clutch and it reved up fine and i went again fine...i was wondering if it could be because of it being warm. I also was wondering if anyone could tell me how much gas is in the tank when you have to use reserve b/c that could have been the problem aslo but i had enough gas on normal to get about 200 more yards to park it.... thanks

[370banshee]

were you at low RPM you may have had it loaded up.

[suzuki LT250R]

Thats the good thing about 2 strokes you have to stay on the gas and keep the rpms high. If you want to ride slow you better go buy a 4 poke. j/k

[OhioLT250R]

I dont think its abnormal to bog when you are low on gas. Mine does it when I'm real low. I just let of then goose it and it's usually fine.

[LT250Racer87]

I would like to take mine apart and clean it out, cause i think i might be losing some power (im redoing the topend to so this might make it easier).. im shavin the head, polishing that, new piston kit, port polish the rest of it, and i wanna take the pv out to clean that, how would i do that

[LT250Racer87]

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