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400ex bad rocker arms

4K views 4 replies 2 participants last post by  Jsummerlin18 
#1 ·
So I picked up a 2005 trx400 for $1200. Guy said he bought it from a friend that blew it up but rebuilt the topend and then it wouldn't crank. Did a compression check and it's at 160 psi. So I bought it. First thing I did was check the timing, it was right. Then I looked at the rocker arms and they're extremely worn. I've never seen any worn this bad. Is it safe to assume that someone put at hardened cam in without hard surface rockers? No possible way the valves could open enough to run like this.

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#2 ·
You can assume anything you want to and be wrong, but after looking at the pics I will presume the TE was rebuilt with Chinese (probably NICHE) parts and the cam (if new) was not properly lubed and if the old cam was used it was not properly prepped and lubed when installed.

I have seen rocker arms worn worse than that in an engine that was still running, but the owner complained that every time he rode it the valve clearance increased and he brought it to me because he wanted longer tappet adjuster screws. I revealed to him the problem - fortunately for him 4 new rocker arms and a new cam was all it took to fix it.

You can buy cheap Chinese parts on Amazon to fix it, but get some Comp Cam cam break-in lube and then sell it after you have it running or be prepared to do a full engine rebuild within about a year. If it's a NICHE head, OEM rocker arms may not fit correctly and it's likely the rockers or sub-rockers will need to be shimmed in addition to the copper sealing washers. I had to use .020 steel shims under the head of the rocker arm shafts to keep the rocker arms from binding when rebuilding one Niche head - I would use either new or used OEM Honda head before using Niche and if someone brings me one with Niche parts on it, I will refuse to work on it.
 
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