Dracus124

Member
Jun 18, 2007
45
0
I am planning on buying a 94' RM250 for $500

It comes with a 5 gallon desert tank AND the stock tank

FMF silencer and i believe an FMF fatty pipe.

And an extra frame.

:nod: :nod: :nod: :nod:


One thing is wrong with it. The power valve is jacked up Thus making the power band weak as hell.

1. Where can i get the power valve/kit from?

2. Are these hard to replace?

Thanks alot!
 

Bunya

Member
Apr 26, 2007
147
0
You can get OEM parts at Bike Bandit or Yamaha of Troy but they're gonna be pricey.

A second option would be Fleabay. You're more likely to find a complete cylinder rather than just the PV assembly, but even so it will probably be cheaper than just the OEM PV.

Lastly there's classified ads at various motorcycle related web sites.

As far as difficulty, that all comes down to your ability. To me, it's about as simple as it gets. OTOH, my bro-in-law would spend half a day on it, bend and break a bunch of stuff, then call me to come over and 'help' him get it together.

A final bit of advice is to pick up a service manual for the bike so you'll know how to set the PV, have all the torques, etc.
 

DougRoost

~SPONSOR~
May 3, 2001
720
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Oftentimes the PV mechanism just gets gummed up or carboned up. Sometimes an actuator rod could come off, it could be out of adjustment, etc. Get a manual (or Eric Gorr's good book on offroad maintenance and performance) and open 'er up to see what's wrong. My guess is it'll just need a good cleaning, which is best done by removing the cylinder. At that point you can put a new top end kit in it, too.
 

DougRoost

~SPONSOR~
May 3, 2001
720
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BTW, that book of Eric Gorr's has a great section at the beginning on buying used dirt bikes. Lots of good advice in what to check for. You can order it from him or many shops stock them.
 

Dracus124

Member
Jun 18, 2007
45
0
oo la la

Sounds good, The guy says the bike has a fesh top end, 190+ compression.


He rebuilt the top end and the pv went poo after an hour.
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
3
Dracus124 said:
oo la la

Sounds good, The guy says the bike has a fesh top end, 190+ compression.


He rebuilt the top end and the pv went poo after an hour.

Power valves dont just "go poo". They either gum up, or weren't installed correctly, or the actuator rod comes loose. Worst case is it fell into the piston. If he did a top end he should have cleaned and inspected the valve. I wouldn't buy any parts until you pull it down and see whats boogered up.
 

DougRoost

~SPONSOR~
May 3, 2001
720
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_JOE_ said:
Power valves dont just "go poo". They either gum up, or weren't installed correctly, or the actuator rod comes loose. Worst case is it fell into the piston. If he did a top end he should have cleaned and inspected the valve. I wouldn't buy any parts until you pull it down and see whats boogered up.
Yep. The brand new Dirt Rider mag that just came out has an article on a bike they called the money pit. It was a KX250 that was beyond restoring. Not saying this bike is the case, but the gears in that bike's KIPS (Kawasaki's name for their powervalve system) were sheared off, which is the type of thing you could end up dealing with. Perhaps the reason the guy decided to put in a new top end was more about the powervalve than worn rings, but I agree that he sure should have cleaned and inspected the KIPS mechanism.
 

unclefista240

Member
Apr 23, 2007
36
0
power valve kit

Dracus124 said:
UPDATE!!!!

Called the dealer, the whole kit is $141.25!!

seems like i am buying this bike :)
i have a 1995 rm 250 i bought for $1000. recently a head o-ring let go and it lost enough compression that now it wont run. when i took it all apart i found that the entire power valve assembly was gone. its hard to believe,i thought the bike ran pretty good.its like $500 worth of parts missing. ive looked everywhere for a used power valve. i have the money to replate the cylander and buy the top end rebuild kit, but i cant afford a new valve assembly so i made a block off plate. it looks like two circles side by side. did you mean a power valve kit is $141.25? if so could you please let me know where? ive lost sleep over how much a new one cost. do you know if its the whole assembly? thanks for your time
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
unclefista240 said:
still losing sleep. i seriously need your help here. did you buy the bike yet?
I realize you do not know where you live but,you have some sort of connection to the internet,have you ever tried a search? Fleabay and Pro source come to mind,along with those already mentioned. Blocked off the pv openings,unbelievable,and yet???
 

unclefista240

Member
Apr 23, 2007
36
0
yeah fox i blocked off the openings, do you not think it will act like an old bike that wasnt offered with a power valve? iwas gonna install a flywheel weight but this might actually create the low end power i want.i mostly ride woods and trail, along with some agressive street riding to get to the areas in my neighborhood where i can actually ride.so... what i was asking dracus124 was where did he find the kit for $141? and was this a top end kit or power valve kit.the reason i ride a bike so old is because it ran good i thought ,my wifes dad owned it, and back when i went to prison in 94 it was what i lusted for every day till i got out. ill post pics and write a detailed report on how the block out plate works or dont work AND YETT????
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
I would think coming off bottom would be like dragging a car engine behind you! I would not commit to the detuning method of a heavier flywheel till you get the engine running correctly first!
 

unclefista240

Member
Apr 23, 2007
36
0
found power valve

i found a power valve in the united kingdom. dont know how long to get here. langcourt raised theyre prices so ill probably go with u.s. nicom for the cyl. plating.
 
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