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Discussion Starter #1
I found on JEs website that they have pistons available for the wr's. Here's the problem. They told me there wasn't enough of a demand so they pulled production. They said they could make me a piston. But I'd have to get 2 made. I have no use for 2. So it would be 520.00 for 2 pistons, rings, pistons, and locks. So if anyone wants to put a high comp. Piston, please email Brian weaver at JE so we can each get one for 260$.
 

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Discussion Starter #3
yeah man, dudes name is brian weaver. i just got on the site and emailed sales. hes the ont ive been talking to. he said he could only do it if they made 2. i want to do it badly but theres no way i could get rid of a second kit. i cant believe they dont have a single other person to sell one piston to. seems like wr owners are trying to squeezae power out any way they can. youd think theyd be hot sellers. oh, well. let me know though.we might be the only ones with them. so far.
 

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Hey Steve, try to find out more specs about this piston... My main concern is how much it weighs, if it's a significant difference from stock. And I'd like to hear some people tell me why I shouldn't do this....

But really, I would be very interested. If we can get more people, you think the price can go down even further? I haven't really ever seen this piston being advertised on SMJ, and the majority of wrx owners who want to upgrade their bikes come here to get ideas...

Let's get some comments on this, people...
 

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Discussion Starter #6
i couldnt tell you all the specs. youre going to have to ask someone at JE about it. but the bore and stroke are the same in the wr and the yz. of course the yz has 5 valves and probably alot less weight in the crank and flywheel, as well as just the whole bike being lighter. but the yz comes with a 13.5:1 compression ratio and a 5 speed and they scream. theres no way anyone can convince me that going from 11.8:1 to a 13.5:1 with a fuel injected 6 speed wont be a signifigant wake up call to the wr. it probably still wont be as fast as a yz.. but closer..
 

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That would be a big improvement to the stock motor, however, I have always been told anything higher than 13:1 needs race fuel. I would not run the crappy pump gas with ethanol additives in that motor.....just my 2 cents:rolleyes:
 

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Discussion Starter #8
ive always ran 93 pump gas in mine and i think it would be ok. i have quite a few friends that run 93 in their race quads with 13.5:1. and the yz runs perfect on 93 also with 13.5 so thats what im going to go with.
anyone ready to do it yet?
 

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Dude Steve,

Seriously, I'm pumped about this new piston. But I have to check how feasible it will be for me to whip out $250 bucks plus the cost to get that thing installed. How difficult is it to install a new piston on the motor? How many hours would you guys estimate it would take a pro mechanic to do this?

I so want this! I think there is a potential for big gains is what I think...
 

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Discussion Starter #12 (Edited)
Dude, it's easy. You need a service manual. But the design of the bike is supposed to be you just disconnect everything from the motor, ant the part of the frame that the motor is bolted to, actually seperates from the rest of the frame. then you just put the motor on the table, follow the service manuals torque specs and everything. And it's good. Even a pro mechanic needs to refrence the SM for specs But novice wrenchers can do it. The manual tells you how to do anything on the bike step by step.
 

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Damn I'd be so scared!

But seriously, I'm loving this idea.

On the big bore kits available, how much does the compression change? Anyone know?

I don't know but I think this would provide a significant improvement. Significant... I could be wrong though.

It would be nice if we could get a good 3hp on top with something like this. Not to speak of a great improvement on the low-mid range... No?
 

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Discussion Starter #14
I really don't know man. It would probably have to be all retuned and everything for the big bore kit. Not to mention just the sheer price difference. I would imagine the piston would really wake it up for around 260 bucks vs the what? 900 pr so for the 40 more cc's with probably close to the same compression and the exact same amount of work. But I could be wrong. I'm happy with the wr. Would just like a little more grunt and top end power.
 

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Discussion Starter #16
Yeah, with just a Quick search, 290 kits are like 750-950$ and I know power comander only has one map for it and it's with the fmf slip on.. So just let me know when you're ready
 

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not trying to rain on any parades here but anyone care to say what YZ comes 13.5 comp ratio? averything i find states 12.3-12.5... on a 450 10.xx on a yz250?

z
 

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Go to yamaha motors.com and look at the 2010 yz. Click on specs. Come factory wth 13.5:q
ahhh i saw the yz250 not the yz250f

z
 
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