need advice

[motox31x]

Ok heres the deal i just bought a 01 yz250 that had only been riden 6 times from a buddy of mine he put v-force reed valve fmf pipe and race tech suspension i got bike for 2000$ not bad deal huh but heres the prob i wanted a 2002 yz250 the 02 has the modified ypvs power valve that
makes the throttle response crisper across the entire RPM range where as my 01 is just a beast on top end anyone have any ideas how i can make it more like the 02 can i mod my power valve? i know its probly a lost cause but hell its worth a shot

[Roostman]

That sounds like a pretty good deal. If your riding tracks mostly and not open desert, I would gear it lower by adding a tooth on the rear sprocket. Maybe even throw some new knobs on the rear to better suit your riding conditions.

[Roostman]

You may want to check into the Power Now gadget. I really dont know if they work that well or for the low end response, but its worth a look.

[Aus_Rider_22]

I think your 2001 YZ250 with the V-force reeds and FMF would be faster and more responsive than the stock 2002 YZ250!

So I wouldn't worry about having a inferior model when yours would probably easily match the newer bike.

[Woody_YZF]

I'm with aus rider. There can't be that big of a difference.

[ossagp]

Have you actually ridden a 2001 and a 2002 two at about the same time?? I have and could tell little difference. Just throw the magazines away and enjoy. If that wont work by a 2002 cylinder.

[motox31x]

I already got a larger rear sprocket and he had put new tires on it im in Ky so no desert here im a track rider hell have a 6 acre track in my back yard and yea i have rode a 02 and my 01 on same day my brother has a 02 it also has the v-force reed valve the bike just feels more controlable but its not a big deal i was just curious if there was some way to mod the power valve or maby put a 02s power valve in my 01 but like someone said its not that noticable hell most people probly couldnt feel a differance as long as i can still smoke his *** at the track im fine but thanks for the replys

[motojonny]

The 01 is a better bike in my opinion. In 02 the frame was stiffer and the suspension as a result felt stiffer.

I put an 11oz flywheel on mine. a gnarly pipe, v forse reeds, stock gearing. That in itself makes for a strong range of power.

I picked up on ebay an FMF OTF ignition with the boost/torque switch. It's like having two pipes. I prefer the torque setting everywhere except sand and loam.

It's one of my favorite bikes for mx and woods!

[motox31x]

FMF OTF ignition with the boost/torque switch never heard of it but im interested im gonna look into it more i ride my 01 the more i like it well thanks for the advice and if anyone is ever in ky send me a message i have a 6 acre track in mback yard and im at podeum 1 over in indiana every weekend thanks guys later

[Crogg]

Originally posted by motox31x
Ok heres the deal i just bought a 01 yz250 that had only been riden 6 times from a buddy of mine he put v-force reed valve fmf pipe and race tech suspension i got bike for 2000$ not bad deal huh but heres the prob i wanted a 2002 yz250 the 02 has the modified ypvs power valve that
makes the throttle response crisper across the entire RPM range where as my 01 is just a beast on top end anyone have any ideas how i can make it more like the 02 can i mod my power valve? i know its probly a lost cause but hell its worth a shot

The 02 has the exact same cylinder and power valve as the 01. (same part#) The head is different (has more compression) so they should run very similar if they are both stock....which they are not. The stock pipe is very torquey while the fmf units tend to trade some bottom (sometimes a lot of bottom) for more in the mid to top. The gnarly is an exception. Put the pipe from the 02, or the stock pipe back on and I think you will find that it will run just like an 02, unless however your 01 has been modified from stock form such as cylinder porting ect.

[mxrider]

your lucky that you got that deal..dam thats cheap!!!

[motox31x]

the power valves are different the 02 was even advertised as having a redesigned power valve "Newly reshaped YPVS power valve system features an all-new valve end collar and extra plate added to the back of the torsion spring, delivering improved airtight sealing for crisper low-end performance"
here is a diagram from yamaha of troy


[Only registered and activated users can see links. ]

[Only registered and activated users can see links. ]

also just for hell of it here are all changes to engine made in 2002 but like another guy said its not that noticable i still smoke 90% of the people at my local trackes
ALL-NEW FOR 2002

Engine:

* Liquid-cooled, 249cc, reed valve-inducted, 2-stroke engine is lightweight, compact and boasts numerous modifications and upgrades to boost its powerband.
* Newly reshaped YPVS power valve system features an all-new valve end collar and extra plate added to the back of the torsion spring, delivering improved airtight sealing for crisper low-end performance.
* All-new carbon fiber reed-valve petals improve throttle response and engine performance across the entire RPM range.
* All-new piston is stronger for improved performance with greater durability.
* New-design primary kickstarter features a reshaped crank and smaller-diameter shaft for smoother, easier starting action and reduced weight.
* New-design, large-capacity radiator features a 10-row core (up from 9 rows) with 4 louvers (up from 3) to deliver maximum cooling efficiency at all performance levels.
* All-new exhaust pipe with redesigned silencer features a reshaped tapered section for broader power delivery with stronger low-end hit for maximum corner-exiting muscle.
* Redesigned airbox features improved sealing for more efficient breathing and greater performance.
* 38mm Keihin PWK carburetor with power jet and throttle position sensor (TPS) ensures precise fuel/air mixing and extra-crisp throttle response throughout the powerband.
* Digital CD ignition system delivers precise spark and monitors engine speed to ensure optimal timing for faster, stronger response during hard acceleration.
* Smooth-shifting, 5-speed, close-ratio transmission with heavy-duty, multi-plate clutch.
* Trick, works-style clutch lever features race-spec barrel adjuster for on-the-fly adjustability.

[ossagp]

LOL,,all measured at the brochure!!

[motox31x]

all measured at the brochure? i have both bikes sittin in my garage along with a 2000 cr250 "for sale" $2100 and my newly acquired 04 crf450 i posted the specs to prove a point i can understand someone not seeing a differnce in 1999-2001 but i could tell a huge diffenance in 2002 maby its just me i ride many diffenant bikes almost everyday and i notice the small things but like i said before ITS NOT A BIG DEAL i was just curious if anyone knew if the power valves could be swapped but i have done tore both bikes down and discoverd NO not possible and i have seen up close the differance my 01 is the better trail-woods bike in my opinion but i think id rather have the 02 on the track, welp time for a new arguement my new crf450 is worst woods bike ever anyone wanna argue that point?

[psycho393]

Originally posted by motox31x
welp time for a new arguement my new crf450 is worst woods bike ever anyone wanna argue that point?

Sure sure I'll argue that point..... how did you want me to argue it?

[motojonny]

What is the problem with the CRF? Too much of a tank?

The 02 YZ did gain some extra HP, and also gained some extra flywheel wt.

The flywheel gives it the feel of having more torque.

[cowboyona426]

The CRF is the worst woods bike ever? I could fix it for ya... I'd even take it off your hands cheap

[motox31x]

i dunno im still tryin it out so far it just gets to damn hot im all new to the 4 stroke world so give me a few days in the woods but on the track i like it alot took a while to get use to it though so before i start *****in i better give it more of a chance oh and got 2 bikes for sale now the 2002 yz250 he is askin 3200$ and i have a 2000 cr250 for 2000$ i have pics of both bikes and all the junk done to them

[motojonny]

Is that your private track?

[motox31x]

yea but its nothin huge we have alot of kids that come out and ride we also own a small track in leitchfield Ky called blackrock but theres nothin like having a practice track in your back yard to fool around on