YZ 125 VHM Head inserts

Burger745
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Location
Whitinsville, MA, USA

My son has a 2024 YZ 125. We just bought a VHM head with SX insert which has higher compression than stock. We run straight C-12 32:1 with motul 800. Looking for an insert designed for race fuel only. Anyone know a part number that has gone that route?

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MxAddic
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9/13/2024 8:44am

You can only get it so high. It's not like a 4 stroke where you can really crank it up.

Any racing 2 stroke with higher than stock CR is in race gas territory and so are many stockers. They are just jetted rich so they they don't go boom.

1
Burger745
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90
Joined
12/16/2018
Location
Whitinsville, MA, USA
9/13/2024 8:54am
MxAddic wrote:
You can only get it so high. It's not like a 4 stroke where you can really crank it up.Any racing 2 stroke with higher than...

You can only get it so high. It's not like a 4 stroke where you can really crank it up.

Any racing 2 stroke with higher than stock CR is in race gas territory and so are many stockers. They are just jetted rich so they they don't go boom.

Hello,
 
 
Yes for VP C12 you can run a much higher compression insert, partnumber AE32327-097
 

This is directly from VHM response yesterday so hopefully it goes well Lol!!!

 

1
MxAddic
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5308
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9/13/2024 9:03am
MxAddic wrote:
You can only get it so high. It's not like a 4 stroke where you can really crank it up.Any racing 2 stroke with higher than...

You can only get it so high. It's not like a 4 stroke where you can really crank it up.

Any racing 2 stroke with higher than stock CR is in race gas territory and so are many stockers. They are just jetted rich so they they don't go boom.

Burger745 wrote:
Hello,
 
 
Yes for VP C12 you can run a much higher compression insert, partnumber AE32327-097
 

This is directly from VHM response yesterday so hopefully it goes well Lol!!!

 

Is he looking for more low end?

Burger745
Posts
90
Joined
12/16/2018
Location
Whitinsville, MA, USA
9/13/2024 9:19am

Looking to get gains through out. We went to a 50t rear and that helped not having to abuse the clutch as much. So far we have done FMF factory fatty with shorty silencer, v-force, GYTR jet kit and just bought VHM CDI and head. Probably doing full race motor this winter. TMR has good reviews but talking with Tom he is a one man shop and he’s booked out for awhile, Lynks racing is my other option because I live in the northeast and can deliver the motor to his shop. Heard good things about STIC carb mod also

The Shop

MxAddic
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9/14/2024 4:18am

Lynx is a real racing engine.

Just raising the CR is going to give you more bottom to mid but will shorten the powerband. Nothing across the board.

1
12/11/2025 10:28pm
MxAddic wrote:
You can only get it so high. It's not like a 4 stroke where you can really crank it up.Any racing 2 stroke with higher than...

You can only get it so high. It's not like a 4 stroke where you can really crank it up.

Any racing 2 stroke with higher than stock CR is in race gas territory and so are many stockers. They are just jetted rich so they they don't go boom.

Burger745 wrote:
Hello,
 
 
Yes for VP C12 you can run a much higher compression insert, partnumber AE32327-097
 

This is directly from VHM response yesterday so hopefully it goes well Lol!!!

 

Any feedback on this dome? Do you know what CC it is? 

Burger745
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90
Joined
12/16/2018
Location
Whitinsville, MA, USA
12/12/2025 11:09am

Contact VHM and give them the part number for specs

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