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GYTR heads on YZ250F


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I would like to know if anybody here as use one with or without Hi-comp piston? I'm looking to getting back into racing for 2011 (can't ride for 2010) and I want to please myself with a nice motor package (suspension will come also). I'm looking to some other avenues but I friend of mine pointed me this option.

I know I can send my head for porting and other options but I want to know how it's Vs the original head (with dyno chart if possible). Peak power doesn't mean anything much in my opinion.

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So you're saying he is stupid? I checked williams' website, for 1600$ you dont get much more, and you dont have your oem head to keep as a backup or sell on eBay.

I think the OP was asking for comments from someone who tried it.

Nope he's not stupid now, but he may feel that way after he spends $1500 for the GYTR head.

This is not the place to start stuff with comments like yours. Keep it to yourself why don't you?

Williams does good work and the website does him no justice for what he produces, you shouldn't need a back up head with his work, unless of course you have issues putting your own bike together.

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This is not the place to start stuff with comments like yours. Keep it to yourself why don't you?
I know I can send my head for porting and other options but I want to know how it's Vs the original head

My comment was legitimate. I was wondering the same thing as the OP, and telling someone he's stupid for not going the same route as you doesn't answer the question. Maybe we just have a good reason for choosing something you wouldn't have, and just want some hands-on feedback on something you don't know. In this case, you don't need to reply.

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My comment was legitimate. I was wondering the same thing as the OP, and telling someone he's stupid for not going the same route as you doesn't answer the question. Maybe we just have a good reason for choosing something you wouldn't have, and just want some hands-on feedback on something you don't know. In this case, you don't need to reply.

Maybe he should have said, "you might have a hard time finding someone who runs a GYTR head that isn 't sponsored and gets them for free". 👍

Either way it's an opinon and opinons are welcome here (or I thought) . Brap!

Edited by duhameister
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You might have to contact yamaha for a dyno graph. Not many people are stupid enough to blow $1500 on a head when you can get Porting, Cams, valve springs, ignition, piston, transmission gears polished etc for the same price from a motor builder. www.williamsmotowerx.net

Tell me where you get all of this for 1600$ and a spare complete head?

If you read correctly, I know there's other avenues possible but I want to check this one. So no I'm not stupid.

You're probably the stupid one since you can't understant this simple question wich was ''I want to know how it's Vs the original head (with dyno chart if possible)''

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WOW THey do have a head for the 250f now.

Damn its complete too. That head probably out does most motor builders as well. More resources and each head is exactly same.

Did you try getting Yamaha to send a dyno? I would love to see the before and after.

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WOW THey do have a head for the 250f now.

Damn its complete too. That head probably out does most motor builders as well. More resources and each head is exactly same.

Did you try getting Yamaha to send a dyno? I would love to see the before and after.

You can take that GYTR dyno run and flush it down the toilet, that will show you absolutely nothing, but some numbers on a graph that are different that everyone else's dyno run.

Builders can add and take power and put it different places (somewhat) depending on what your using the bike for and your riding style i.e. upper or lower RPM range.

Just something to think about. I have yet to even see or hear of anyone that's running one, maybe there's a reason for that, not sure.

Maybe you can be the first and give us the rundown, but that's a lot of money to drop off of a dyno chart.

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You can take that GYTR dyno run and flush it down the toilet, that will show you absolutely nothing, but some numbers on a graph that are different that everyone else's dyno run.

Builders can add and take power and put it different places (somewhat) depending on what your using the bike for and your riding style i.e. upper or lower RPM range.

Just something to think about. I have yet to even see or hear of anyone that's running one, maybe there's a reason for that, not sure.

Maybe you can be the first and give us the rundown, but that's a lot of money to drop off of a dyno chart.

You're right except if you run your test on the same dyno with weather comparable. It's give an idea of before and after. I'll try to contact some guys at yamaha that I met last year when I tried the YZF450 2010 at the montreal SX.

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Engine builders do not have the equipment or resources a big company does.

unless we are talking about pro-circuit or another huge company like tokyo mods. Their price though woowee yeah. Be up there too.

Sure that engine builder can pnp a head and make it have a great power curve but duplicating it. I wouldn't under estimate a manufactures.

Argue all you want. I have a williams Motowerx motor and carb, yet I woudn't be surpised one bit if the gytr head performs better.

It all comes down to what you are looking to get. These bikes come race ready stock. It cost a lot of money to get a tiny bit more out of them. Do you really need that tiny bit more power? Chances are you are not even using all of the stock power.

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Engine builders do not have the equipment or resources a big company does.

unless we are talking about pro-circuit or another huge company like tokyo mods. Their price though woowee yeah. Be up there too.

Sure that engine builder can pnp a head and make it have a great power curve but duplicating it. I wouldn't under estimate a manufactures.

Argue all you want. I have a williams Motowerx motor and carb, yet I woudn't be surpised one bit if the gytr head performs better.

It all comes down to what you are looking to get. These bikes come race ready stock. It cost a lot of money to get a tiny bit more out of them. Do you really need that tiny bit more power? Chances are you are not even using all of the stock power.

I bet you Jesse's head works better...or equal.

You'd be surprised at the "size" of Jesse's company and just "how small" it isnt.

But the bigger picture and more important question is: What is required to make more power...

Certainly flow numbers are extremely important, however more important is where these flow numbers are.

Port volume is critical, and that goes beyond just port velocities.

Some people will make a head flow HUGE upper lift numbers respectively to a stock head...and it will not perform better.

Some heads that only look marginal on the bench make great power.

The single biggest area in development IMHO that MUST be addressed is matching the head to the cam and "scavenging" or suction characteristics of the engine.

The yz has been around in the same basic package for a long while now...and thus even mom and pop guys have had enough time to develop it thouroughly. I hate to say it but regarding some of the "larger" companies...I have not seen many customer heads that perform much better than stock from many of these companies...be it on the bench, or on the dyno.

Often companies wont sell truly good cams...and you might question why. Put simply stock motorcycles are already pushing the "reliable" limits to valve opening and closing velocities, bucket velocities etc.. To make a cam better reliability often needs to sacrifice. If a "big" company sold every single customer a cam that on a good day only goes 15 hours of run time before failure of some valve part...they will get a bad rap...

Are the GYTR products good? Sure.

Are other individuals products good?

Definately....

So spend your money where you wish.

I personally think spending it here in the U.S. with business owners who dump the money back into the U.S. economy is a good thing:thumbsup:

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I bet you Jesse's head works better...or equal.

You'd be surprised at the "size" of Jesse's company and just "how small" it isnt.

But the bigger picture and more important question is: What is required to make more power...

Certainly flow numbers are extremely important, however more important is where these flow numbers are.

Port volume is critical, and that goes beyond just port velocities.

Some people will make a head flow HUGE upper lift numbers respectively to a stock head...and it will not perform better.

Some heads that only look marginal on the bench make great power.

The single biggest area in development IMHO that MUST be addressed is matching the head to the cam and "scavenging" or suction characteristics of the engine.

The yz has been around in the same basic package for a long while now...and thus even mom and pop guys have had enough time to develop it thouroughly. I hate to say it but regarding some of the "larger" companies...I have not seen many customer heads that perform much better than stock from many of these companies...be it on the bench, or on the dyno.

Often companies wont sell truly good cams...and you might question why. Put simply stock motorcycles are already pushing the "reliable" limits to valve opening and closing velocities, bucket velocities etc.. To make a cam better reliability often needs to sacrifice. If a "big" company sold every single customer a cam that on a good day only goes 15 hours of run time before failure of some valve part...they will get a bad rap...

Are the GYTR products good? Sure.

Are other individuals products good?

Definately....

So spend your money where you wish.

I personally think spending it here in the U.S. with business owners who dump the money back into the U.S. economy is a good thing:thumbsup:

Nice write up, worded well.

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Hi, to I'll give it a try to get back to the start of your tread and actually try to answer your question, as to what the GYT-R head will do. I have one on order and expect it in a fiew days, I'll try to post some graphs after we run it on the dyno. Of course we will run the oem head first for comparison.

Ride safe

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Hi, to I'll give it a try to get back to the start of your tread and actually try to answer your question, as to what the GYT-R head will do. I have one on order and expect it in a fiew days, I'll try to post some graphs after we run it on the dyno. Of course we will run the oem head first for comparison.

Ride safe

I will really appreciate your feedback from the track also.

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Hi, to I'll give it a try to get back to the start of your tread and actually try to answer your question, as to what the GYT-R head will do. I have one on order and expect it in a fiew days, I'll try to post some graphs after we run it on the dyno. Of course we will run the oem head first for comparison.

Ride safe

Thanks for taking the time.

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just to stir things up..i just picked up a tokyo mods head off of ebay at an ebay price....unfortunatley, i do not have access to a dyno..talking to tokyo mods though..they say that the stock bike runs around 36 horse and i can expect an increase to 43 horse??..guess the seat of the pants dyno will tell...wohooo!!!!

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Hi, to I'll give it a try to get back to the start of your tread and actually try to answer your question, as to what the GYT-R head will do. I have one on order and expect it in a fiew days, I'll try to post some graphs after we run it on the dyno. Of course we will run the oem head first for comparison.

Ride safe

What is the price you paid for it? I see people writing $1600, but the yamaha website says $2245.95...

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Engine builders do not have the equipment or resources a big company does.

unless we are talking about pro-circuit or another huge company like tokyo mods. Their price though woowee yeah. Be up there too.

Sure that engine builder can pnp a head and make it have a great power curve but duplicating it. I wouldn't under estimate a manufactures.

Argue all you want. I have a williams Motowerx motor and carb, yet I woudn't be surpised one bit if the gytr head performs better.

It all comes down to what you are looking to get. These bikes come race ready stock. It cost a lot of money to get a tiny bit more out of them. Do you really need that tiny bit more power? Chances are you are not even using all of the stock power.

Anyone on TT who knows Jesse "Williamsmotowerx" knows he does a superior job for the price. I know way more people running Jesse's stuff than GYTR. GYTR is just over priced product from Yamaha. And yes Jesse does have the proper equipment to do just as good a job if not better than the "big manufacturers. I wouldnt run PC stuff either as it is expensive to maintain. Jesse is very good at making a powerful engine package that is very reliable. I guess my point is if you have deep pockets and can afford to be replacing valves every 10 hours than by all means go with PC or one of the other high end performance engine builders. I think for $ per hp you will get a better deal going through Jesse. JMHO.

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