New guy couple of questions

[97Yz250Rider]

Hi, I just joined TT and as always have a few new questions, as my name states I have a 97 yz250 J1, and first of all I know that the rings are semi-cooked and was wondering of i should replace the piston now or wait till i blow it, and when i replace it should i use a Wiseco or a different piston? I'm very new to replacing top ends and i am un aware of what are the "good" brands for piston replacement. And my second question is it has short or "sissy" (if i'm not mistaken then name) and i want to replace them, I came across a "fly" bar and I was wondering if anyone had any experience with them? or if i should just buy some Renthals and not take the risk with the "fly's? Thank you for reading I'm hoping that i will enjoy my time here on TT

[owainyz03]

I would pull the cylinder and check the condition of the piston and if it needs replacing then do it,or just replace the rings.

I haven't ever used fly bars as I can't get them but renthals are great bars

[97Yz250Rider]

thank you very much =)

[BDubb106]

I recommend replacing the piston anytime you buy a used bike. You never know how many hours are on that one. Dont wait till the piston lets go or it will cost you alot more $$$ to fix it. I prefer Wiseco because they are forged and last a little longer without the danger of fracturing if run a little past the recommended service life when compared to cast pistons.

As for the bars Ive personally never tried them, Im a firm believer in the Renthal Twinwalls as I have never bent a set. If I were you Id give the Fly's a shot if they are reasonably priced. If they are junk you'll know to get some Renthals or Pro Tapers next time around.

[1talbotj]

its almost winter up there in minnesota. use the winter months to repair and polish the bike...then in the spring you can ride problem free...you really dont want to tear your bike down in the spring...

[Ryderr]

Replace Piston, Weisco pistons are great and reasonably priced. Handlebars dont really matter. I have a pair of $25 Moose handlbars after I bent my renthals. Cheaper handlebars will bend easier, but they are cheap to replace. Renthals can and will bend as well. CR Highs are a great bend to work with.

[BDubb106]

If you bend a set of twinwall renthals you musta rode your bike off a cliff... Ive had some very very nasty get offs and Ive never bent a set. Well worth the money for a set that will never bend.

[cummins1320]

good bars are worth it especially if you race.

a set off bent bars could finish your day

[Ryderr]

No Im talking about standard bars. I had a pair of fat bars that fell off a 1500 truck and didnt bend. If you want the most use out of your money thats the way to go.

[97Yz250Rider]

thank all of you for your responses =) well i had stripped the bike down last night and went to bed, i took a look at the jug to day and its coverd with pits, and is 10 thousandths off of std, the piston is still within regs though, i could legitly wiggle the piston in the sleeve back and forth, so i was thinking ok well i will bore it this winter and put a 20 or a 40 over in it, my only question is that in the manual it said "waring do not bore sleeve" and this leaves me confused, any idea why it says that? and if i should still bore it or not?

[BDubb106]

Dont bore the cylinder... just send it out and have it replated. Dont go the sleeved route either.

[adam728]

The standard cylinder is plated aluminum. If you bore it then you remove the plating and have a bare aluminum cylinder. Many places out there will repair/replate the cylinder.

Now, if someone has bored it way out and pressed in a steel sleeve, then you can just have at it.

As for replacing the piston - Always! It may seem "expensive" to do at regular intervals, but letting it go too long can cost far more. Had a buddy that bragged about how great his bike ran for years, then it finally happened. Piston dropped a skirt, locked itself in the bore, breaking, bent the rod/crank and destroyed the cylinder. All said in done it was over $1K to have it fixed (he paid a shop), and then he had to sell the bike to pay the bill. A $100 piston didn't look so bad then!