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Changed my girlfriends top end

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Well this weekend i changed the top end on my girlfriends 2001 YZ 125.

this was my first time tackling this project, and i consider myself pretty mechanically inclined.

anyway it went without even a hiccup.

the companies made it so easy its insane.

the ring end gap was perfect, the piston size was perfect, the circlips were probably the hardest to get in, but not that difficult.

def an easy job, and the bike runs like a champ.

i took it around the block and will be trying to do a lot of heat-cooling cycles to break it in.

any tips on breaking it in i can tell her? when can she properly romp it out?

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I just did the top and bottom on my '99 YZ125. I heat cycled it a couple times up and down my block, then I took it to a small indoor track and rode it easy for about a half hour.

After that, I rode as normal

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Well this weekend i changed the top end on my girlfriends 2001 YZ 125.

this was my first time tackling this project, and i consider myself pretty mechanically inclined.

anyway it went without even a hiccup.

the companies made it so easy its insane.

the ring end gap was perfect, the piston size was perfect, the circlips were probably the hardest to get in, but not that difficult.

def an easy job, and the bike runs like a champ.

i took it around the block and will be trying to do a lot of heat-cooling cycles to break it in.

any tips on breaking it in i can tell her? when can she properly romp it out?

What kind of piston did you use? If it was OEM (cast), all it needs is a few minutes to seat the rings. If you used a forged piston, it should be heat-cycled a couple of times.

Regardless of the piston type, the engine should ALWAYS be warmed up to full operating temperature before riding.

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What kind of piston did you use? If it was OEM (cast), all it needs is a few minutes to seat the rings. If you used a forged piston, it should be heat-cycled a couple of times.

Regardless of the piston type, the engine should ALWAYS be warmed up to full operating temperature before riding.

i used wiseco (forged)

yes i make sure to warm it up properly before letting her ride :thumbsup:

id imagine she needs a bunch of heat cycles, and easy on the throttle for about 30-45 min before getting on it hard.

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Well this weekend i changed the top end on my girlfriend

Now much silicon did that take? Did she go from a 250B to a 450DD? How many strokes now?

any tips on breaking it in i can tell her? when can she properly romp it out?

If I post a question to that line, I think they'll kick me off the site! :banana:

Some of the other posts about "bottom end" work, heat cycles, cycling things up and down a few times.....geez....makes wrenching sound like fun!

:lol:

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Do about 4 heat cycles and you should be fine.

1. 0-1/4 throttle

2. 0-1/2

3. 0-3/4

4. let her rip!

Give the bike about 20-30 minutes to cool down in between cycles.

EDIT: When getting the bike up to operating temperature just wait until the cylinder is warm/hot to the touch and the radiator cap is warm/hot as well. Should take about 2-3 minutes while gently blipping the throttle.

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Do about 4 heat cycles and you should be fine.

1. 0-1/4 throttle

2. 0-1/2

3. 0-3/4

4. let her rip!

Give the bike about 20-30 minutes to cool down in between cycles.

EDIT: When getting the bike up to operating temperature just wait until the cylinder is warm/hot to the touch and the radiator cap is warm/hot as well. Should take about 2-3 minutes while gently blipping the throttle.

It's not throttle position that's important, it's load, temperature, and rpms.

From Moto814

1) Assemble the engine properly and torque all fasteners to specs.

2) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), shut it off.

3) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

4) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), shut it off.

5) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

6) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), take the bike off the stand and put it in gear. Take it for a ride. During this ride you want to keep the engine under a load at all times. Do not coast. Do not let the bike idle. Do not allow the engine to stay at one RPM. Riding on a mild slope is fine for this, as is slightly dragging the rear brake the entire time. Do this for about 15-20 minutes. Then shut the bike off.

7) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

8 ) Re-torque the head and base nuts.

9) Go ride.

The cool-down steps are crucial to this operation. You must let the engine cool completely for the break in process to work properly.

Also, do the warm up procedure I outline here before EVERY ride. Your top ends will last much longer if you do.

-Steve

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