raceready99
Member
- May 5, 2003
- 35
- 0
I got a YZ134 that hasn't been ported. I was thinking of getting head mods done. Is there any benifits from doing this? If so, should I choose to run race gas since I have access to it?
Head Mods
- Thread starter raceready99
- Start date
Eric Gorr
Engine Builder
- Jun 29, 1999
- 384
- 12
Its nearly impossible to grind on an aftermarket cylinder. Head mods will adjust the head for pump gas but race gas was intended to be run in a YZ125 because the ignition map is very aggressive and they're suseptable to detonation which can damage the piston and cylinder.
The most important thing is that the head is flat, you can slide it across a sheet of fine emery sand paper spread across a flat surface like a metal or granite plate. A granite counter top would work in a pinch too. The Wiseco piston is trimmed to fit in the stock combustion chamber, and depending on the exhaust port height, that will determine if your bike will run on pump gas with a head mod.
The lower the exhaust port height the higher the compression ratio, the center of the exhaust port should measure 28.5mm from the top edge of the cylinder in order for the compression ratio to be in pump gas range.
The most important thing is that the head is flat, you can slide it across a sheet of fine emery sand paper spread across a flat surface like a metal or granite plate. A granite counter top would work in a pinch too. The Wiseco piston is trimmed to fit in the stock combustion chamber, and depending on the exhaust port height, that will determine if your bike will run on pump gas with a head mod.
The lower the exhaust port height the higher the compression ratio, the center of the exhaust port should measure 28.5mm from the top edge of the cylinder in order for the compression ratio to be in pump gas range.
raceready99
Member
- May 5, 2003
- 35
- 0
- Thread starter
- #3
To be honest what you said makes no sense to me. Pro-Action Suspension is like right next to my house and they do head mods. I just wanted to know if I could do that without having to do anything else to the cylinder. I want to start running race gas no matter what because the power valves really seem to be getting gummed up with oil. I don't want to touch the cylinder at all, I just wanted to get the head work done. If I were to get the head work done, would I need a flat top piston also?
Perfect sense, well explained, whats the question? Oh and proaction, I wouldn't even let them touch suspension much less an engine! The best engine and suspension guys on the planet, here, in and out of these forums and in archive,and they get doubted, I feel bad!
Try to Change your premix ratio a little and it couldn't hurt to clean the powervalves every once in awhile. They need to be tended to ocasionally. It's general 2 stroke maintenance. What knd of oil are you using? What kind of riding do you ride? Make sure the engine is good and warm before riding/loading the engine. I don't think race gas is going to help you in your sitiuation. It is going to be a waste of more $. I don't want to come off like a jackass but I truly do not have any experience with the yz125, just about everything else though. If I was you I'd listen to what Eric says.
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