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View Full Version : Engine rebuild take two



FixxxerKH202
05-26-2016, 05:20 PM
Well after buying a cheap "Niche Industries" cylinder and piston kit off of ebay and having it tear itself apart after about 4 hours of ride time post break in period which some of you may have seen in my other thread, I am now rebuilding the motor using genuine honda parts. Lesson learned and luckily "Niche Industries" honored their warranty and refunded me the full price. The rest of my parts will be here tomorrow, so this thread will start out a little slow and I will update it with a bunch of pictures tomorrow night of the process after I get done putting it back together. Not sure if any of you care much but I wanted to document the rebuild in case I sell the quad and for any newbies that are looking to rebuild an engine so they can get an idea of what they are facing. The task isn't too bad on these 400exs and really the most critical parts are the ring gaps, clocking of the ring gaps so they are staggered, and then setting the cam timing correctly.

Here are some photos after I tore it down and my bench with a mix of the parts that are still good and the bad ones, plus my oil tank after I got done flushing it out. I had the clutch and oil pump out, plus the stator side cover but had already put those back on before taking pictures. So everything is all flushed out and properly cleaned of debris from the failure which I suggest anyone does after any engine failure.

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FixxxerKH202
05-27-2016, 06:25 PM
Alright just finished up the rebuild here's some pictures. Didn't get as many as I would like due to racing daylight and getting a couple parts later than expected.

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FixxxerKH202
05-28-2016, 01:15 PM
Broke it in today, here's a quick vid of it running.

Just have to go back and double check the valves and then change oil to clear out the break in debris.


https://www.youtube.com/watch?v=-Cyy-VTtGLE

Diesel man 03
08-10-2016, 06:16 PM
Looks like you did a good job, now enjoy some riding.

honda400ex2003
08-23-2016, 08:27 AM
sounds like it runs good, nice work!

steve

joker11
12-19-2016, 11:01 PM
You didn't show what caused the failure of the Niche. I am interested in that.

Pictures?