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Offline spencer.price3

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New YZ Project
« on: October 16, 2013, 01:47:04 AM »
Hey guys, so I am buying a 2001 YZ 125 on Saturday as a project. The bike is pretty beat so this should be pretty fun. Anyway, the bike needs a new cylinder, but the OEM cylinder is crazy expensive. What is your opinion on Athena's Big Bore Kit? I am looking at it, and it looks prett good. Any complaints or praises on Athena?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline cnrcpla

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« Reply #1 on: October 16, 2013, 05:43:07 AM »
I'm not shooting down the Athena kit idea (it would be pretty sweet), but is the OEM cylinder totally damaged beyond repair? Like did a rod go threw it or something? If not you should be able to re-plate it, re sleeve it at the worst for about $250 depending on where you go.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Stusmoke

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« Reply #2 on: October 16, 2013, 10:30:13 AM »
Hey guys, so I am buying a 2001 YZ 125 on Saturday as a project. The bike is pretty beat so this should be pretty fun. Anyway, the bike needs a new cylinder, but the OEM cylinder is crazy expensive. What is your opinion on Athena's Big Bore Kit? I am looking at it, and it looks prett good. Any complaints or praises on Athena?

Heard rave reviews about the 134cc kit. You won't gain much peak HP but what you will end up with is a broader powerband with slight HP increases. But like I said the two guys I spoke to said they bought it for the powerband, not the power, and they well and truly got their moneys worth. For peak output you're better off going to 144 or 167. Note: Both people had latest gen YZ125s, not the older engine you're working with.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline eprovenzano

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« Reply #3 on: October 16, 2013, 01:08:10 PM »
I had a buddy who bought a grenaded YZ125.  The cost of repairing the cylinder was more then the 125 Athena replacement kit.  Bolted right on with no issues.  It ran great for several years and then he drank the 4 stroke koolaid and it was sold.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Eric Provenzano
2019 KTM 300 XCW TPI
2000 KTM 300 EXC (Son's)
2001 KTM 380 EXC
Sold 1991 KDX 200... fun play bike
Sold 1999 KX250
Sold 1999 YZ125 (son's)
Sold 2001 Yamaha TTL 125 (son's 1st bike)
Sold but never forgotten 1974 Honda Elsinore CR250M
Sold 1974 Honda Elsinore CR125

Offline spencer.price3

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« Reply #4 on: October 16, 2013, 05:46:23 PM »
I have heard that when you install a Big Bore kit specifically on YZ125s that you need to modify the cases, does anyone know something about this?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline eprovenzano

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« Reply #5 on: October 16, 2013, 06:09:24 PM »
I have heard that when you install a Big Bore kit specifically on YZ125s that you need to modify the cases, does anyone know something about this?

I believe that is only if you go to a 144 (someone please correct if I am wrong).  The 134 does not require modification.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Eric Provenzano
2019 KTM 300 XCW TPI
2000 KTM 300 EXC (Son's)
2001 KTM 380 EXC
Sold 1991 KDX 200... fun play bike
Sold 1999 KX250
Sold 1999 YZ125 (son's)
Sold 2001 Yamaha TTL 125 (son's 1st bike)
Sold but never forgotten 1974 Honda Elsinore CR250M
Sold 1974 Honda Elsinore CR125

Offline Stusmoke

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« Reply #6 on: October 16, 2013, 09:35:31 PM »
I have heard that when you install a Big Bore kit specifically on YZ125s that you need to modify the cases, does anyone know something about this?

I believe that is only if you go to a 144 (someone please correct if I am wrong).  The 134 does not require modification.

x2 I THINK its with the 144 and its a little bit of clearance off hte crank cases. Definitely something to check though.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline spencer.price3

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« Reply #7 on: October 16, 2013, 11:13:47 PM »
Okay, so I think I have decided that I will order a used cylinder that comes with a powervalve already and send that off to Eric Gorr to bore out to a 144. I think it will be the cheapest option as the bike does not come with a cylinder and so I will need to buy the powervalve, which I priced out to buy brand new and is fairly expensive. So it is turning out that this bike will be pretty quick as I have heard nothing but good things of Eric Gorr's work.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Stusmoke

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« Reply #8 on: October 17, 2013, 05:33:06 AM »
I've heard a couple of very bad things about eric gore but many good things aswell. If you talk to premixed he will most liekly call you an idiot for even considering eric gore  ;D
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline spencer.price3

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« Reply #9 on: October 17, 2013, 05:41:54 AM »
Really...? What were these bad things?  ??? I guess I will have to do more research
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Offline Stusmoke

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« Reply #10 on: October 17, 2013, 07:28:39 AM »
Things like cylinder head bolts not being shipped back and being asked to fork out money for hte bolts to be shipped back to you and still taking over a month. Dodgey bore jobs, stripped threads things like that. Although hte last one could have just been teh owner trying to pin his ****ty torque wrench or lack thereof on someone else.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline spencer.price3

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« Reply #11 on: October 17, 2013, 07:48:40 AM »
I have priced things out, and the Athena kit is a much better option as it comes with a brand new head, piston, ring, gaskets, and powervalve assembly. The kit comes with everything I need for the top end. So in the end this is cheaper. I am sure that the Eric Gorr option will give more power but I am only a novice rider, so I will focus more on suspension and stuff like that. I will keep you guys updated and hopefully have pictures of the bike up on Saturday. This will be my first rebuild of a bottom end, and I am rebuilding the crank myself, so that on its own should be interesting. I am more than open to tips, suggestions and comments
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Stusmoke

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« Reply #12 on: October 17, 2013, 08:17:29 AM »
I have priced things out, and the Athena kit is a much better option as it comes with a brand new head, piston, ring, gaskets, and powervalve assembly. The kit comes with everything I need for the top end. So in the end this is cheaper. I am sure that the Eric Gorr option will give more power but I am only a novice rider, so I will focus more on suspension and stuff like that. I will keep you guys updated and hopefully have pictures of the bike up on Saturday. This will be my first rebuild of a bottom end, and I am rebuilding the crank myself, so that on its own should be interesting. I am more than open to tips, suggestions and comments

Sounds like you've got your head screwed on right. Makes a nice change... YZ suspension components are typically very good stuff. It won't be up to snuff with the SSS equipment on todays YZ line, but its still very good. The Yaba kit on my 01 YZ250 was better than any jap stuff I've tried since, not set up either. Jap stuff excluding the SSS that is :D And they were lightyears ahead of the stock WP components...
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Jeram

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« Reply #13 on: October 17, 2013, 08:36:03 AM »
good thinking with the athena kit... no point spending money on ported gore cylinders if you dont need it :)

Just on a side note: I think that now Gore is part of Millenium Technologies (Nikasil Platers), You might see a present increase in service and reliability as Millenium are simply great.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline spencer.price3

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« Reply #14 on: October 17, 2013, 08:23:30 PM »
I have done some research on the Athena 144 kit, and it looks like there are quite a few complaints about the kit, and it also requires modifications to the cases, which I would not be comfortable doing myself, so that would mean I would have to pay the local Yamaha dealer 100 bucks an hour to do these small modifications. So I found that Athena makes a 125 kit, it comes with everything I need, so I will be keeping the bike a 125. I really do not mind because I am used to racing a stock cr125 which is apparently in no comparison to a YZ125 motor.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »