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turning a yz85 into a 105

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we are making my yz85 into a 105, but we are not sure on the best way to do it any suggestions? :confused:

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The best way is to spend $400 and send it to eric gorr. I did that route myself for my yz85. The piston is 52.5mm. Send the cylinder, head and both empty crankcases- they need clearanced for the larger piston. He does the plating, head modification for the larger piston as well as modifying the cases, all for $400. A really great deal.

I did the low/mid porting and race gas. Turned out great muh more power and gets to the powerband quicker which was my concern.

I just pulled my piston out at 17 hours. Planning on 15-20 hours from here on. It's a good reliable kit

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hi i have an 05 yz85 that we bored to 105 and it is sweet and it pulls wheelies in 5th but the only issue is that i have no low or mid power.

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That's the only problem with the yz85- no powervalve unlike the other bikes in its class.

Mine is significantly better at lower and mid with the low/mid porting then when it was a 85cc.

Also advancing the ignition timing from stock .9mm to 1.2mm helps. Running a shorty silencer helps alot. Throw on a flywheel weight and that's about all you can do. I only use mine for woods riding and its a blast!

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