VHM 2005-2021 Yamaha YZ125 Cylinder Head and Insert
Yamaha YZ125 Performance Cylinder Head
VHM has been the world leader in Two Stroke performance heads since 1978. In that time many World, National and Regional Championship Titles have been won in Motocross, Kart and Road Racing.
Heat is the enemy of especially 2 stroke engines, as the race goes on and the engine gets hotter, the power drops off. You have probably noticed your engine seems to have less power towards the end of the race, or you can’t clear a jump you were making at the beginning of the race.
The engineers at VHM looked at the problem and noticed that because stock heads were made by casting , the water jackets were small and rough, not at all conducive for optimal coolant flow. So it was that the idea of machining the head in two pieces was born to achieve a much better flow and thus better cooling.
THE BENEFITS OF A TWO PIECE DESIGN ARE NUMEROUS
*By machining the head out of billet aluminum it could be lighter because a lot more internal material could be removed.
*Bigger and smoother water jackets could be machined to greatly increase the coolant flow through the head and to the radiators
*The next natural evolution was to look at the insert, by using a higher grade Missile Grade aluminum/alloy billet , the combustion chamber insert could be machined much thinner increasing coolant volume.
*Heat from the combustion chamber has less distance to travel thru the thinner insert so is dissipated quicker.
*VHM inserts not only limit power loss to heat, they also make power. VHM Engineers spend countless hours on the dyno, at test tracks and at the races perfecting High Performance heads and inserts.
*Because of the extremely high grade aluminum/alloy used, VHM inserts are far more detonation resistant than stock heads.
*Inserts are easily interchangeable and are offered in SX and MX versions. The SX insert has a higher compression and works well on tighter tracks with lots of jumps. The MX version is a slightly lower compression and works better on more wide open and sandy tracks.
*Heads and inserts are sold separate and at only $63.99 we would suggest you take both inserts.
* VHM heads run on good quality pump or race fuel.
* Custom inserts can be produced by VHM to tuners specifications, or we can supply what we call “Blind” inserts that tuners can machine to their own specs. This is way more cost effective than buying a new stock head every time you want to try a new modification. Blind inserts cost $47.99 and custom made inserts cost $94.99. Contact email@example.com to find out how to order special inserts.
*VHM heads are easy to install and usually use stock OEM gaskets or O Rings. In the event VHM change their head to better design your head will come with all relevant hardware.
*Langston Motorsports USA offers a ONE YEAR Guarantee against faulty workmanship. This does not include gaskets or O rings for obvious reasons.
* Finally there is one last benefit of having a VHM fitted to your bike, and that is Psyching your buddy out when you pull up next to him on the start line with that trick looking Golden Head on your bike.
* To order the correct head for your Two Stroke engine please use the drop down menu below. NOTE: Heads only come Gold Anodized.