Jump to content
Sign in to follow this  

Does it sound like it's running right?

Recommended Posts

Hey guys, semi long time lurker and first time poster here. I picked up a 1999 YZ125 as my first bike a few months ago, knowing that it most likely needed some work. I tore it all down to take care of some aesthetic bits a month ago, and it's on the way back to being rideable again.

Since I'm new to dirt bikes and 2 strokes, I'm not too familiar with the normal sounds that one should make and how it should feel all of the way through its powerband.

I took a quick video of myself riding, using my phone (sorry for it being pointed too far down). After watching a lot of other 2-stroke videos on youtube and comparing them to mine, it's got me wondering if mine sounds "healthy".

Give me your $.02.

The video starts after the bike cut-out since I was riding with the gas 'off'...

The previous owner couldn't tell me how many hours he had on the top-end, but it's on top of my priority list to replace asap. Here's a shot of what the piston looks like, which might give you further indication of how the motor's running:

Piston.jpg

Head.jpg

And here's a picture of how she looks right now, after painting the bars/frame and some other bits. (I know the left suspension "leg" is rotated backwards)

YZwithmotor.png

-Nick

Share this post


Link to post
Share on other sites

Overall doesn't sound too bad. Sounds fairly tight and fresh.

It started kind of hard. That might be because you had just ran out of gas and the float bowl wasn't filled yet.

It has a little bit of a hesitation or stutter on the low-to-mid transition. Notice how you had to keep blipping the throttle in the tight corners to keep it running, like it was trying to load up and maybe foul the plug a little or stall.

Might be slightly rich on the pilot or needle. Check the reeds and make sure they aren't chipped or cracked. Make sure the air filter is well cleaned and properly oiled.

The pics of the head and plug make me think it's slightly rich as well. What gas, oil, and ratio are you running?

Share this post


Link to post
Share on other sites

+1 Id check the reeds out as well! They can make the bike hard to start and cause some odd symptoms. Once its wound up it sounds pretty darn crisp though.

Dome of the piston looks pretty good, your a tad rich but not horrible. Side pics, and a pic of the underside of the piston would give us a better idea though.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×