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2002 Honda trx400ex
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2 Posts
Discussion Starter #1
How’s it going fellas? So I have an 02 400ex and last Saturday about four hours into riding I noticed that when I was at WOT it wouldn’t really come up in the RPM and seemed to stay steady at roughly 3-5k RPM. It happened randomly and I can’t figure out why. Has this happened to anyone else? Here’s the specs- 440 big bore with possibly a stock cam (didn’t really pay attention when I was putting it back together. I bought the quad in five million pieces) I know for a fact the timing is right and I know for a fact my clutch is good. Put a Brand new plug in it right before I went riding Saturday. And I’ve rode it pretty hard for about twelve hours total and never had a problem until this. There’s no smoke no back fire no bogging problem and it idles perfectly fine. It fires up as soon as I hit the start button. It just seems to stick at 3-5k RPM like I had previously mentioned. Any ideas?
 

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2020 520 rubicon foot shift
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198 Posts
The lift arm on the carb slide comes unscrewed sometimes, happened twice to mine. It will only rev up a bit if this happens but will idle all day, I made it home when it happened but it was a slow trip lol.
The main jet can also get plugged with dirt causing similar issues.
 

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2002 Honda trx400ex
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2 Posts
Discussion Starter #3
The lift arm on the carb slide comes unscrewed sometimes, happened twice to mine. It will only rev up a bit if this happens but will idle all day, I made it home when it happened but it was a slow trip lol.
The main jet can also get plugged with dirt causing similar issues.
The lift arm on the carb slide comes unscrewed sometimes, happened twice to mine. It will only rev up a bit if this happens but will idle all day, I made it home when it happened but it was a slow trip lol.
The main jet can also get plugged with dirt causing similar issues.
yeah I actually took the carb off today and checked that and sure enough the screws backed out and it was loose in there. But here’s the kicker, I screwed the lift arm back to the carb slide and put my carb back on and fired it up, same exact issue. Wont rev all the way out and no power. I’ve been riding for a little over 20 years and have always fixed all my shit considering im a master mechanic and own a performance and off road shop but I’m stumped with this one for sure.
 
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