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2016 piston remap

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Have just put the 2016 piston and squirter in my 2015 yz250f just wondering if I need to remap for it as it seems like it has lost its bottom end and seems to stall alot more.

Any advice would be appreciated  cheers.

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1 hour ago, doolan said:

Have just put the 2016 piston and squirter in my 2015 yz250f just wondering if I need to remap for it as it seems like it has lost its bottom end and seems to stall alot more.

Any advice would be appreciated  cheers.

Timed correctly?

Oil pressure check bolt should create a small drip when backed out 1/2 way?

Did you clock your piston rings on rebuild?

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yip timing lined up correctly has oil pressure. done rings as per manual  just seems to have a flat spot now it never had before seems to hesitate a wee bit.

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Sounds like it may be a ring issue. Not that it was installed incorrectly but the rings might not be seated properly. Did you hone the cylinder before installing the new piston and rings? Was the cylinder wall glazed? Also, it never hurts to flash the ECU with a map just to make sure something wasn't lost when the ECU was removed. Stranger things have happened.

Edited by Enduro R Rider

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Sounds like it may be a ring issue. Not that it was installed incorrectly but the rings might not be seated properly. Did you hone the cylinder before installing the new piston and rings? Was the cylinder wall glazed? Also, it never hurts to flash the ECU with a map just to make sure something wasn't lost when the ECU was removed. Stranger things have happened.


Not an expert, but I just read in another post that the cylinders are not meant to be honed because they are Nikasil coated.
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2 hours ago, XRalways said:

 


Not an expert, but I just read in another post that the cylinders are not meant to be honed because they are Nikasil coated.

 

They are coated but can still become glazed. If you install new rings in a cylinder that has become glazed you can have ring seating issues. We have always honed our cylinders in order to create the recommended cross hatch surface. You are not removing metal when honing. Simply giving the rings a surface that they can seat to relatively easily. Take a look at flex hones.

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16 hours ago, XRalways said:

 


Not an expert, but I just read in another post that the cylinders are not meant to be honed because they are Nikasil coated.

 

Nikasil coated yes.  As stated above, you MUST run a hone thru the cylinder to create a cross-hatch pattern for proper lubrication of the rings while breaking them in.  Run in for 30 min to break them in. Change the oil, and run it like you stole it.  Just did a top end on a 450 this weekend, and that's how we did it.  No problems.  Some people will say the rings will break in and seat within the first 5 min of running.

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Just run a brown scotch brite pad through the cylinder with soapy water. 

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