Yz 250 change in performance?

[SKIDOOrider800]

:think:

Over the last couple rides I've noticed the engine on my bike seemed to be straining a little to make power. it just wasn't as crisp... you'd have to push it more anyway.

So tonight when I was riding I came off a little service road run, I noticed the bike sounded more throaty. It was less muffled more of a bRRRRRRRRattt vs. the late Bzzzzzzzzzzzt. Exhaust connections seem to check out.
I also noticed the power seemed better. It'd rev quicker, smoother, and hit the powerband more easily, didn't sound like it was trying so hard. back to what i believe was the original power.

trying to figure out what would cause this.

-The bike is an 02 with an FMF fatty, and homebuilt "shorty" muffler (looks to be a stock silencer cut 3" short?)
-I have an 05 engine in it, 7 hrs riding it myself (low hrs prior)
-it is still on 02 carb, but pipe and jetting match both engines according to the respective manufacturers
-I mix 33:1 Amsoil Interceptor, 91/92 octane gas, from a 5 gallon tank. I normally top up from 1/3 tank after every ride.
- I had some injector cleaner in there (10 ml's.. right amount for 2 gallons.)
-today was a few degress cooler than most

any ideas??


also,

 

[Chokey]

Injector cleaner? Why?

 

[John Cena]

Silencer packing in need of a change?

 

[racerx090]

The few degress colder leaned out your jetting slightly which in turn made your bike crisper and faster. It seems like if those other days are the normal then you should turn your air screw a bit farther out. This will lean the jetting a bit and give you that crisp throttle response that helps make the bike feel more energetic.

 

[SKIDOOrider800]

I will check that. the thing that gets me is that it wasn't like this the first 2-3 rides... maybe its perception, but I like it now.

the injector cleaner...well guy that had the bike before me was a bit of a grease monkey. couldn't find the right size wrench if it hit him in the back of the head if you get my drift...

Also it seems to idle high when i first start it.. then when it warms up the idle comes down. I knwo the idle screw has a mind of its own (vibration lets it change) but is there somethign i can do about this?

 

[kingbrian]

by your description and by my experience i would guess its time for a top end but you say its fairly fresh so maybe break-in didnt go so well? id check it out.... thats just my 2 cents though.. good luck.

 

[lastoman]

sounds to me like a sticky powervalve that has finaly come unstuck. my powervalve was stuck shut, or rather disconnected on my 95 and it sounded muffled. when I reconnected it, the bike got alot louder, more throaty, more resonsive, and a whole lot faster.

 

[SKIDOOrider800]

sounds to me like a sticky powervalve that has finaly come unstuck. my powervalve was stuck shut, or rather disconnected on my 95 and it sounded muffled. when I reconnected it, the bike got alot louder, more throaty, more resonsive, and a whole lot faster.

that was kinda my thought... I noticed after a few rides its had some oil sludge out the PV breather tube... that was mostly unburned oil.....lately it's only been trace black liquid... not enough to drip more than a few drops.

I'm just learning so I spend alot of time low and slow. Need to crack the throttle a little more I suppose.


maybe not stuck completely but sticky anyway?