Question about pistons

Architeuthis dux · 01-24-2006, 11:19 AM

I see some cheap wiseco piston sets on ebay for like 10 bucks No Reserve. They are brand new for my 91 cr 125. Is it worth buying one of these just to have for so cheap for when i need to replace it. It says its 54mm. Is that the stanadard size that i would need or are there different lengths or what?

Maynard_002000 · 01-24-2006, 11:22 AM

You running Nawwwwsss or something? I've never had back-up pistons for anything. I'd save your money

blndebmbr · 01-24-2006, 11:36 AM

I completely disagree^^^^

You bought a used bike so you have no idea how long that piston has been in there. I replace the top end in my 80 AT LEAST once a year. I would def jump on it if it is brand new!!! It doesn't hurt to have one on hand, especially if you ride hard. (Mine is a race AND a recreation bike...lots of hours in different climates) You may as well see if you can't get some rings and seals on hand too. Especially with the 125's...most people ride the piss out of them. I would bet that top end is going to need a rebuild sooner than later anyway. If it's not kicking your ass when it hits...odds are it's going to go.
I'd buy the spares if it were me.

blndebmbr · 01-24-2006, 11:38 AM

Oh and one more thing...
Do yourself a HUGE favor and buy an owners/service manual.

You may end up having to actaully take the motor apart and measure everything to be sure of sizes. Again, because it is used you don't really know what previous owners did to it. I wouldn't assume anything. I would take the time to measure first. This would also give you the opportunity to see what condition the piston is in anyway.

Dr Honda · 01-24-2006, 11:53 AM

Quote:

Originally Posted by Maynard_002000

You running Nawwwwsss or something? I've never had back-up pistons for anything. I'd save your money

you've never owned a 2 stroke... have you??

As long as it's the right size for your bore... get it.

Carolyn · 01-24-2006, 12:51 PM

I agree with BB...

Nothing wrong with having extra parts for your bike, especially since you have an older 125. When I had my 125, I had a handful of extra spark plugs - ya never knew when a plug would foul

And a pluse on the bike manual. If you're not familiar with dirtbikes, they can be tricky

Krazy Hawaiian · 01-24-2006, 04:25 PM

Most likely you still have the stock bore since the cyclinders are nickle plated or haed chromed as they call it so boring it is not a good idea. The thinking is the hard bore doesnt wear the piston does so getting a spare would be a good idea if you intend to own the bike long. Make sure it comes with rings and wristpin and bearing.

A piston set with all the parts uasually runs about 100.00 bucks.

Architeuthis dux · 01-25-2006, 10:36 PM

yeah i got the manual and i was thinking i could def do a top end and replace the piston until i got to the party where it talks about measuring and boring out the cylinder and stuff. I dunno maybe i'll just have the dealer replace the piston when needed? You think someone with decent mechanic skills could do one? How much does the dealerships charge for a new top end?

blndebmbr · 01-26-2006, 12:26 PM

Replacing the piston is a lot easier than you would think....at least in my YZ80 it is. Mike (hawker) is not a certified (auto/motorcycle) mechanic but he is a maintenance mechanic and can do it without any problems. After watching him do it, I think I could do it too.

Krazy Hawaiian · 01-27-2006, 10:38 PM

Hell it's so simple. Don't worry too much about the measuring. Like I said late model (1990 and up) 2 strokes have a hard chrome cylinder you CANT bore it! Well you can but only to install a new sleave in the cylinder that is hard chromed like the original. The only teason to do that is if something scored the cylinder badly like a broken ring or chunk of metal got in the cylinder and tore the walls up.

Clean it up good decarbonize the head and exhaust port and clean the power valve make sure the linkage is operating correctly and make sure its adjusted correctly. The power valve is a under a small cover above the exhaust port. It alters port timing by raising and lowering the gate. It makes a huge difference in the way the engine runs.

Architeuthis dux · 01-27-2006, 10:44 PM

hhhmmm maybe i'll look at it again but thanks for the info it sounds doable. I absolutely love this bike, I cant get over how much ive progressed in just 3 riding sessions. Its all starting to click a little. I have more fun on the dirt then I had with my street bike. I like the freedom you have with the dirt bikes, no speed limits or cars.

Krazy Hawaiian · 01-29-2006, 12:56 PM

Quote:

Originally Posted by Architeuthis dux

I absolutely love this bike, I cant get over how much ive progressed in just 3 riding sessions. Its all starting to click a little. I have more fun on the dirt then I had with my street bike. I like the freedom you have with the dirt bikes, no speed limits or cars.

Yep dirtbikes will teach you more about riding in a weekend than you will learn from a year on the pavement.

I like the no cops and go as fast as you can handle part of dirtbikes... plus the places they can take you once you get proficient riding them is just mind boggling!

I've been to places on the Island that there is no other way you could get to see unless you were on a bike.