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Discussion Starter · #1 ·
I upgraded a trx400ex engine to the highest possible power output without a 460 kit. A complete Wiseco bottom end, 440 13:1 Wiseco top end, Advanced aluminum sleeve, ported polished head, Kibblewhite valve set with +1mm springs, stage 3 Hotcams cam, trx450r carb, 105 octane fuel, a CDI with the most aggressive timing, and a 16 tooth front sprocket and a 35 tooth rear sprocket. According to dyno numbers from different people with similar setups, I'm running something around 50 hp I think.

My stock clutch couldn't handle this amount power and would slip. I decided to do some research on clutch upgrades for the 400, and I found out that you can upgrade to better fibers, stiffer springs, or get an eight plate clutch kit (one more fiber and steel than stock, creating more friction area) from Gt thunder or Sparks racing. Well, under more extensive searching, I found out that these brands discontinued this product. Quite honestly I was bummed, but I found out that these kits were just 8 OEM trx400ex fibers and 7 OEM trx250r steels. So, I ordered 8 OEM trx400ex fibers and 7 OEM trx250r steels from Partzilla, because you can buy them separately but it did end up costing me over $200 (warning the 250r has 7 fibers and 6 steels stock, so don't buy a kit).

When installing them don't forget to soak them in oil, use jaso ma approved oil, and put the sharp edges of the steels inward. And don't forget that clutch plates need to be broken in.

After install and doing the break-in proceeder of the clutch. You can tell the difference between this setup and stock, It grips a lot better than before. Ultimately I think it was worth the money and time spent.

If you have any questions, please be free to ask.
 

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What year did they stop making 400ex?
 

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Discussion Starter · #3 ·
They stopped making the 400ex in 2014
But because there was so much of them left, dealers sold them as 2015 and 2016 models
 

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What year did they stop making 400ex?
Production of the TRX400EX ended in 2008 - in 2009 it was rebranded as the TRX400X - with sales lagging, production ceased and there were no TRX400X's produced in 2010 or 2011 - production of the TRX400X resumed in 2012 and permanently ended in 2014. 2014 models continued to be sold throughout the United States until all units were off the dealers floors. they were not sold as 2015 or 2016 units as that would be a violation of Federal law. Honda was guilty of retitle-ing leftover CB750's in the mid 70's and as part of the settlement of the class action lawsuit, Honda is required to place a sticker on their motorcycles and ATV's with the year model in characters no less than a specific height (about 8mm) so there would be no argument about the year model. Then in 1980 the universal World Manufacturer Index was established. It required all vehicles sold in the US to be identified with a 17 digit Vehicle Identification Number - the 10th digit of the number identifies the year model regardless of the date of manufacture. Typically vehicles manufactured after June 30 are manufactured as subsequent year models. Therefore a vehicle manufactured on July 1, 2001 may show up on a showroom floor in Sept 2001 as a 2002 model.

Here is an example: manufactured in June of 93; a 94 model that was the 2072 unit produced - the first digit of the production sequence is the production run year - 93 models were the first year of production and the production sequence was 100002 and up, in 94 it was 200001 and up, in 95 it was 300001 and up. In the powersports industry it is rare to have more than 100,000 units of a single model produced. The production sequence of my 04 CRF250X is 000126 - the first one produced was 000001, so mine was the 126th one off the assembly line, but over 100 were kept in Japan for testing and a few were given to Pro riders - according to American Honda, my CRF may possibly be the first one sold to the public. I ordered it in July 2003, it was supposed to be released in Nov., release was delayed until Jan. 2004 and I took delivery of mine in Feb.

Anyway, the TRX400EX was last produced for the 2008 model year and it became the TRX400X for 2009 - no units were produced for 2010 or 2011 - then they were produced for 2011 and 2012 then permanently discontinued. One major change occured; in 2005 the engine cases were redesigned and they got reverse.
 

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