new please help

[cookie123]

Hi, im new here i was registered a while ago i guess because i dont rememebr making this account, but its ok because i need it now.

I recently purchased a 95' yz250 it has an fmf pipe, i think its called a fmf turbine core 4 the person i bought it from said i needed a new spark arrestor, is this a tough thing to replace or could i do it myself? and he said one day he blew everything in the pipe out. im guessing that means the fibers and such. but havent been able to find the fibers online, so if someone could send me a link to that it would be much appreciated. also i keep seeing like silencer packing. Do i need this also? i live in ca if that makes a difference with laws or anything.


Thank you for your time.

 

[oldfrt613]

If you can't change the silencer or change to a spark arrestor, you probably shouldn't own a dirt bike - translation - it is a simple procedure. What he probably means by he blew everything out is that the packing is bad. Packing is the fiber material in the silencer which actually muffles the noise - good idea to replace as loud bikes are becoming a big issue for off-roaders. It is readily availible from most any off road motorcycle parts supplier ( try searching ). I'm not sure what the exact rules are for older bikes in CA, but the YZ is designed for closed course competition, I'm not sure how that whole green sticker thing works - but I bet your going to be limited where you can operate it.

 

[cookie123]

ok thanks, so i replace the spark aresstor and get silencer packing? and should i get a couple orders of this packing just for backup?

 

[oldfrt613]

All you should really need is packing, unless someone "gutted" the spark arrestor. The spark arrestor is usually a series of screens or baffles to suppress exhaust flaming. They may need cleaning, but should still be functional, unless removed by the previous owner. Check the FMF sight and see if the silencer you have is a combo silencer/arrestor or simply a silencer. FMF makes add-on arrestors for most of their silencers.

 

[cookie123]

oh ok, well when i start it up it smokes alot, and the guy said its the spark arrestor. so ill check it out, and try just replacing the packing first

 

[ecy063]

I recomend that you buy the book.

 

[cookie123]

which book? the manuel i have that for the bike and i guess this is the pipe https://www.fmfracing.com/products/catalog.aspx?CategoryID=62&ItemID=020358

 

[ecy063]

Eric Gorrs' Motocross and Off Road Motorcycle Performance Handbook.

 

[fizzle]

If it is a FMF Turbine Core II silencer, I seriously doubt the actual spark arrestor would wear out. The spark arrestor part of the silencer looks like a propeller (or more correctly, a turbine) that is riveted to the canister of the silencer. It is made out of fairly thick sheet metal w-holes, not screen like most spark arrestors. If anything it might be gooey, but doubtful that it would ever have to be replaced. If you have a bunch of closed end rivets sitting around, you can drill out all of the existing rivets, take out the end cap and spark arrestor and see for your self...then rivet it all back together (I did with mine,it wasn't a big deal, but wasn't really necessary to take it apart either). Most likely all you need to do is change the packing, which doesn't even require rivets...just undo the 2 allen screws on the front end of the silencer, pull the pipe and old packing out, replace with FMF or whatever brand material you want, and put it back together.

Hope this helps.

 

[cookie123]

thanks alot, yea i think ill try replacing the packing first. could that cause it to smoke up as much as it does

 

[fizzle]

I'm not an expert....but in my experience, the silencer has never created smoke, in fact it doesn't even get that hot. If anything, the silencer gets all "spoogy" from unburnt premix oil, and that's what usually ruins the packing, not heat. If it is smoking a lot, you should look to your engine or carburator. There are many problems that could cause it, such as carb being too rich, seal/gasket leaks in the engine etc... It is normal for them to smoke on startup, with the choke out and engine cold....and maybe a slight amount when you are really on the throttle. Other than that, I would suggest the troubleshooting tables in your owner's manual, Eric Gorr's book, or searching the forum for"excessive smoke" threads or something like that.

Here's a link for the replacement packing material. Even though it's probably not what is causing the smoking, it's good to change the packing every 20-30 hrs of riding (or sooner) to keep the bike nice and quiet.

Good Luck

 

[cookie123]

ah ok ill have to look into it then. thanks

 

[cookie123]

sorry to bring back an old thread i started but i thought it would be better then making another.
I finally got the 250 in my possesion, now i have never ridden a 2-stroke i have always been on 4 strokes, when i get this thing going. is it going to be as "zippy" as everyone says, where right when i put it in gear and go im going to be suprised from this new amount of power, that i will fall off the back? :whoa:

 

[xcracer72]

running too rich will also cause mucho smoko

what color is it?

 

[cookie123]

the smoke? its like a grayish whiteish color i guess. its also real hard to start not like im weak that kind of hard, like it just wont even get the chuga chuga chuga to it.