Gorr 05 YZ144 project is a success

jake949

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#31
have you looked into ceramic main bearings? I see that eric has a stroker crank ready to roll on his web site, you should get it :) ;) . I have been thinking of a few weight saving ideas. but one of them i need to proto type. IF it worked it should save weight and help cooling. but i have to find some parts to butcher and i need to see about laying up some carbon.


Have you drilled out the fins infront of the rads? you know for that ultra factory look.
 
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#32
Ceramic main bearings are a nice addition in a high rpm engine that runs in super clean conditions like asphalt kart racing. The downside is, introducing even small amounts of dirt into the engine can destroy them quickly, which makes them a really poor choice for a dirt bike. ;)
 
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#34
How is the mo power porting working out. I thought it wasnt a good idea for 125's? Ideal for 250 and 500's. How is the power delivery? Have any idea on hp?
 
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#35
jake949 said:
thanks Rich. I thought Eric said they worked good. but i might have been mistaken.

They work great in the correct applications. Dirt bikes just aren't one of them. :cool:
 
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SpDyKen

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#36
Thank you, all, for the great information! Having recently returned to the fun of playing in the dirt, I have been contemplating building a lightweight '05 YZ125 woods bike to harrass my big bore buddies with.(they keep encouraging me to ride their KTM 300s & 450s) It's now become a plan. Please continue to update us with your progress. You all have saved me the embarrasment of bothering Eric & Rich with a bunch of elementary questions! Thank you again.
 

SpDyKen

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#37
By the way, glad I stumbled on your EGFM website, Eric. I appreciate the info. there, bought the book, and found DRN. What a find! Probably haven't seen you since the first (my only) Santa Fe Speedway speedway race. Was that '79 or "80? Again, I appreciate all you have and continue to do for the sport (business) and us all! I'm enjoying catching up on some of it here. Keep up the great work and keep those chips and shavings flying! KW
 
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#38
If anybody has info on that Racers Edge quick throttle let me know, I want one for the same reason.
 
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#39
On the yz144, do you have to do any mods. to the bottom end, or can you just send the cyl. and head? Also, do you think the stock pipe and silencer is ok to use with the 144?
 

steve125

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#40
Lonewolf said:
On the yz144, do you have to do any mods. to the bottom end, or can you just send the cyl. and head? Also, do you think the stock pipe and silencer is ok to use with the 144?
On the 05 even more so than the previous YZ 125 models. The front of the main engine cases need to be relieved 1-2 mm or the piston will hit. This can be easily done after taping off the crankshaft area, with an air die grinder. I usually follow this up with a pre-mix flush of the lower end, as its just about impossible to not have some chips enter into the lower crankcases.

The stock pipe and silencer while not ideal, will work fine with the 144 kit.
 
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#41
If I decide to go with the 144 on my yz can I ever change it back to a 125 again, or will the mods that have to be done to the bottom end prevent this? What about the power valve does that need modified as well?
 

Eric Gorr

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#43
SpyDyKen,
Robert Blalock and Brian Browning are 2 of my customers in the Atlanta area who are running 144s on 05YZ125s in enduros. They are both 40+ and switched from 250s to the 125 for the handling and weight savings. Look them up at the races. Robert is a product developer and tester for Yamaha.

Only one track has a track of clay, Santa Fe Santa Fe! Rich and I had a lot of fun at that track, we tested our proto low CG bike there is 1982. The track is gone now, the space is filled with million dollar houses. So much history, so few brain cells left to remember it all!
 
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#44
Thanks for the responce Eric. I think I will send in my motor for the 144 kit this up coming winter, I don't want amny down time during the summer.
 
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#45
Eric, I also wanted to ask about 144 maintence, are top and bottom end rebuild intervals much different than a standard 125? If I decide to go with the 144 I would probably have you port it Mo Better if that makes a difference.
 
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