yz250rider1

Member
Jun 10, 2007
13
0
i have a 1995 yz 250 nd it will not hit powerband ive bought fmf fatty pipe wit turbine core 2 silencer, v force 2 delta reeds, moose torque spacer,i dropped my front sprocket a tooth nd im running 12 49 gearing, nd it just will not hit power band its got power but not like a 250 should have i could stand it up in the first 3 gears wont come up in 4th or 5th. any suggestions!!! plz help!!!!!!!
 


yz250rider1

Member
Jun 10, 2007
13
0
sixds said:
maybe gunk in the carburator, maybe your powervalves are gummed up..


alright finally took powervalve side cover off todai nd ran it down the road threw all the gears only seems to be opening a tiny bit. could the shaft that goes down to the bottom case be causing this or is it just gummed up??? help!!!!!!
 

kx125412

Member
Mar 30, 2006
341
0
You didn't take the leftside cover off did you? That's your powervalve stop and prevents the powervalve from closing too much and venturing into your cylinder. To check movement take your right side cover off, but yeah this sounds like a powervalve issue. They're very easy to remove on these bikes.
 

yz250rider1

Member
Jun 10, 2007
13
0
kx125412 said:
You didn't take the leftside cover off did you? That's your powervalve stop and prevents the powervalve from closing too much and venturing into your cylinder. To check movement take your right side cover off, but yeah this sounds like a powervalve issue. They're very easy to remove on these bikes.


n i took the right side off but its not moving to much nd it moves when i move it wiht my hand nd it doesnt seem gumed up when i do that but hadly moves when i have the bike runnin throught the gears nd stuff is there possibility that it can be inside the case or no ??
 

kx125412

Member
Mar 30, 2006
341
0
Take your whole right side cover off and check the governor, see what shape its in, but first remove your powervalve its really simple, clean it, try it again. Ride the bike to warm it up then put it on a stand with the right side cover off and rev it up full throttle in nuetral. It won't sound good but as long as you don't hold it pinned for too long it won't hurt the bike. If the powervalve doesnt move then, it has to be your governor is messed up or something isn't connected properly down there.
 

yz250rider1

Member
Jun 10, 2007
13
0
kx125412 said:
Take your whole right side cover off and check the governor, see what shape its in, but first remove your powervalve its really simple, clean it, try it again. Ride the bike to warm it up then put it on a stand with the right side cover off and rev it up full throttle in nuetral. It won't sound good but as long as you don't hold it pinned for too long it won't hurt the bike. If the powervalve doesnt move then, it has to be your governor is messed up or something isn't connected properly down there.

took whole powwervalve out cleaned it nd everything stuck it bac in nd it still just opens a lil bit any suggestions plz help!!!!!!
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
Your powervalve should snap open about a 1/4 turn and at about half throttle to open.If it does not then YOU must use deductive reasoning and start at one end or the other and determine where it is worn,loose or not put together properly.If I remember correctly that set up sucks and is prone to wear and coming loose,maybe somebody that has one can help,or roll up the shirt sleeves and reference a manual!Have fun!
 

FNG

Member
May 2, 2008
97
0
I just got done cleaning the power valve on my 95. Before I cleaned it it "seemed" to move ok but now that it is clean, WOW was it sticky. I would not close all the way nor would it open all the way.

I have not ridden it since this as I am waiting on a new silencer, the previous owner had the baffle welded and, well you would have to see it to believe it:) Lets just say there was a large "restriction" inside the baffle, I.E. wire from the wirefeed.

When I bought it it seemd to be a bit flat on the bottom with a decent mid hit and no top. It kind of pulled like 125 until it laid down on the top. Hopefully with my findings I will have a 250 when I am done!

I have a Pro-Circuit pipe on mine with otherwise stock jetting with the needle dropped 1 clip.

What are you running for pipe/jetting?
 

XvXKx125

Member
Apr 29, 2008
6
0
Im having the same problem. But with my 1999 KX 125. The other day i filled up the tank with the same amount of oil and it suddnly stated sounding difrent. Its liek the bike cant hit its power band from 3-6. When i rev it up the revs come down really quikly. WHen i listen to the bike the sounds seems to be coming from the Air box..... Help!!!
 

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