2 stroke no tool compression test ?

MotoX Luca
For a yz125 is there any way of telling if the compression is low without any tools. I've heard if u can push down the Kickstarter with one finger its to low but I don't know if that correct. Do you guys have any other methods ?
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NWmx756
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NWmx756 7/3/2019 8:18pm
7/3/2019 8:18pm
just pull the jug and look at the ring. anytime I used my hand, if it goes through the stroke easily it was time for a piston.
kb228
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kb228 7/3/2019 8:42pm
7/3/2019 8:42pm
If its low enough to push with a finger or not start you let it go too long. Invest in the tool until you can feel it with a kick.
Spudnut
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Spudnut 7/3/2019 8:48pm
7/3/2019 8:48pm Edited Date/Time 7/3/2019 8:48pm
X2 for pulling the jug
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gsxr6
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gsxr6 7/3/2019 9:10pm
7/3/2019 9:10pm
Pull the spark plug out, plug hole with finger. If u can feel heat, not just pressure but some good heat when it blows your finger off the head, it is plenty to run.
77Moto
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77Moto 7/3/2019 9:12pm
7/3/2019 9:12pm
If its too low they start hard or wont start. I know because back in the day I rode my practice bikes till they wouldn't fire.

A compression tester is less than 30 bucks online.
bvm111
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bvm111 7/3/2019 10:37pm
7/3/2019 10:37pm
Take plug out and stick your tongue in the hole and jam on the starter... if it hurts you are good to go!
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mxtech1
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mxtech1 7/4/2019 11:08am
7/4/2019 11:08am
bvm111 wrote:
Take plug out and stick your tongue in the hole and jam on the starter... if it hurts you are good to go!
I thought you were supposed to put use your wiener not your tongue?
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bvm111
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bvm111 7/4/2019 11:13am
7/4/2019 11:13am
bvm111 wrote:
Take plug out and stick your tongue in the hole and jam on the starter... if it hurts you are good to go!
mxtech1 wrote:
I thought you were supposed to put use your wiener not your tongue?
WoohooWoohooWoohoo
JustMX
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JustMX 7/5/2019 3:15am
7/5/2019 3:15am Edited Date/Time 7/5/2019 3:18am
bvm111 wrote:
Take plug out and stick your tongue in the hole and jam on the starter... if it hurts you are good to go!
mxtech1 wrote:
I thought you were supposed to put use your wiener not your tongue?
This only works on a Yamaha if you use yamalube.

If bore and stroke are compatible you may learn a whole other way to love your yz125.
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chuck356
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chuck356 7/5/2019 2:14pm
7/5/2019 2:14pm
Working in a bike shop for 40 years, I am not too bad at guessing compression by how hard it kicks, but even I get fooled from time to time. Barrow a guage or pay someone to test it for you. Or just disassemble and inspect.
Paw Paw 271
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Paw Paw 271 7/5/2019 2:27pm
7/5/2019 2:27pm
You can get a loaner compression tester at Auto Zone.

Paw Paw
Texas Built
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Texas Built 7/5/2019 9:54pm
7/5/2019 9:54pm
MotoX Luca wrote:
For a yz125 is there any way of telling if the compression is low without any tools. I've heard if u can push down the Kickstarter...
For a yz125 is there any way of telling if the compression is low without any tools. I've heard if u can push down the Kickstarter with one finger its to low but I don't know if that correct. Do you guys have any other methods ?
If you don't have $125 for a top end, then the compression is "just fine". If you do have $125, then you should change it.
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