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Eric Gorr yz134 vs 144

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20 hours ago, hpsailer124 said:

 

I’ve done the research on both just wanted to see what you guys think personally and what other mods you have along with it?

 

Back when we had 125's , man I miss them . I did alot of research on this and the 134 was what I was going to do when we had to do a new cylinder . It showed that it had less vibration and better woods capability . Now that's my 2 cents on what I researched . So hopefully some real experience will chime in . 

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Good YZ125 cylinders and powervalves can be hard to find. Most cores will have no powervalves in them or are unuseable.

I started out by asking the same question as you, and found that the answer in my case, was more about what was available at the time, than what was the best choice out of the two. That ended up being a freshly plated Eric Gorr YZ144 cylinder, head and powervalves 'sitting on the shelf'.

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Have you seen this article yet?
https://motocrossactionmag.com/mxas-yamaha-yz134-vs-yz144-big-bore-challenge/
I'm planning on doing the 134 at some point for my 06 YZ125, possibly over the winter.  It's the racing offseason here in CO so plenty of time to just have fun on the 125.

Yeah I’ve read it before. I just like hearing everyone’s opinion too and see what their personal experience was
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1 minute ago, Swappa said:

Good YZ125 cylinders and powervalves can be hard to find. Most cores will have no powervalves in them or are unuseable.

I started out by asking the same question as you, and found that the answer in my case, was more about what was available at the time, than what was the best choice out of the two. That ended up being a freshly plated Eric Gorr YZ144 cylinder, head and powervalves 'sitting on the shelf'.

Ah so you wound up going 144, cool - have you been able to try it out yet?

2 minutes ago, hpsailer124 said:


Yeah I’ve read it before. I just like hearing everyone’s opinion too and see what their personal experience was

I'm in the same boat :thumbsup:

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Based on what I've read, you pay for what you get.

If you want the best, go with a stroked HP perf, Millenium or Max Pwr YZ134 or YZ139. These are very expensive engine packages, IMHO.

Otherwise, I would stick with a straight big-bore YZ134 or YZ144.

Know that a big-bore YZ134 is never going to perform closed to the stroked YZ134. The stroked bike is more expensive and more powerful. Between the YZ134 and YZ144 BBs, I think the YZ134 is a little more mid-top and the YZ144 is a little more low-mid, but this is just from what I've read. Also, based on what I've read, the YZ144 can be tuned to rip/screen. The Eric Gorr 58mm BB YZ144 reviews are great.

Not all YZ144 BBs are equal. The Athena cylinder that I pulled off my basket case 2005 had poor casting/ports in my opinion, and I don't think it will perform any where near as well as the Eric Gorr YZ144 BB.

Edited by Swappa

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38 minutes ago, Tankslap said:

Ah so you wound up going 144, cool - have you been able to try it out yet?

I'm in the same boat :thumbsup:

My friend is helping me put the bottom-end together this week. I just assembled the new Eric Gorr 58mm cylinder last night, so I will let you know how it goes. Really excited to ride it! I'd really like to take it out this weekend, but I have a ways to go on the build and not much time after work/kids. At least I want to get it assembled and started and heat cycled a couple of times by Sunday night.

23432790_10213124875649526_1716194176_o.jpg

23439264_10213124876329543_848877215_n.jpg

Edited by Swappa
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15 minutes ago, Swappa said:

My friend is helping me put the bottom-end together this week. I just assembled the new cylinder last night, so I will let you know how it goes. Really excited to ride it! I'd really like to take it out this weekend, but I have a ways to go. At least I want to get it assembled and started and heat cycled a couple of times by Sunday night.

Awesome, post back here or PM me when you get some seat time on her!

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That mxa article is a joke my Eric yz 144 rips up top but I had it ported for more mid/top. It revs out like a 125 does they act like the 144 kit made it a slow revving trail bike. 

Everytime mxa tests a 125 or 134 vs a 144 they ALWAYS take the smaller bore claiming it revs faster. 

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2 hours ago, SmokinJoe said:

That mxa article is a joke my Eric yz 144 rips up top but I had it ported for more mid/top. It revs out like a 125 does they act like the 144 kit made it a slow revving trail bike. 

Everytime mxa tests a 125 or 134 vs a 144 they ALWAYS take the smaller bore claiming it revs faster. 

I wonder if they added one tooth to the rear sprocket :lol:

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Plus everytime they do a 144 build it's with the gytr aka Athena kit which has shit porting specs. No mention in the article if they did or what they did to the porting if anything. 

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Eric Gorr welds the exhaust port to widen and strengthen it before plating. There might be a small reduction in flow, but the upside is that there is much more material to cope with the heat and carry the ring load.  I think a YZ125 cylinder would last about 200 hours if it weren't for the cracked and worn exhaust bridge. When you hear YZ125 rings lasting 10 to 20hrs, it's because there is so much load on that bridge that it just chops a groove in the ring and wastes the compression in no time. On the other side, you hear of guys that love the reliability of the EG cylinder ... well that's where it comes from.
If you didn't notice, take a look at the transfer ports in both images. The porting is kind of extreme to the point where I'm going to have to trim the base gasket so that it doesn't interfere. I've never seem anyone chop that much out of a transfer.

The Athena cylinder is really blunt and the transfers are tiny in comparison. I'm sure Eric could get a lot out of the Athena cylinder too, probably even more than OEM, in comparison.

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35 minutes ago, Swappa said:

Eric Gorr welds the exhaust port to widen and strengthen it before plating...

...you hear of guys that love the reliability of the EG cylinder ... well that's where it comes from.

I'm sure Eric could get a lot out of the Athena cylinder too, probably even more than OEM, in comparison.

I understand the exhaust window bridge is a limiting factor when increasing bore size on the YZ125, so it is encouraging to hear E.G. has addressed the issue.

Luke's Racing offers a 59mm piston (vs the standard 58mm piston in 144cc big bores) to get 150cc's out of the YZ125. I wonder if Eric Gorr can adapt his process to make that piston work? I've also heard the Athena cylinder is beefier than the stocker, so perhaps that would be a better candidate for the 59mm bore... :thinking:

https://www.ebay.com/itm/YZ125-150cc-big-bore-Wiseco-kit-2005-17-59mm-piston-rings-pin-clips-yz-125/262058417934?hash=item3d03e61f0e:g:2gAAAOSwCL9ZteiV&vxp=mtr

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59mm piston not sure if I'd go that big but this is what happens to the piston like swappa is talking about. Piston was in longer then it should have was 50 hrs.

 

 

20170509_200109.jpg

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Lol the person that I got my bike from is stupid because he some how forgot to tell me that my bike was a 134 so when I put new piston rings in it they did not fit and this is my first 125 so I thought it was normal to be this fast

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