Question about 1982 Yamaha XJ 650

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83 Yamaha XJ550 hesitating and losing power at higher speed

Once warmed up, at higher speeds starts losing power, open choke to keep it running but runs rough, enough to get it home. No problem when cold or at lower speeds.

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I had a 1981 XJ650 and I can tell you carburetion is a nightmare on these bikes! While every manufacturer on the planet used Kehnin carbs Yamaha decided to contract with a company that NEVER made carbs before - Hitachi...
Because of the year, it could be several different things, let's start with the easiest/common.
#1. Grab a STRONG flashlight, open the tank and look inside...if you see ANY rust, I recommend removing the tank and Kreme it. #2. Remove the carbs, if you can...take a good look at the carbs "boots" the black manifold(s) between the carbs and back of the engine. If done carefully, it's not too difficult and shouldn't take more than 2hrs. Check the boots for cracks or damage that allows air too leak into the engine during operation...if they are damaged, you'll have to Google carb-parts for Yamaha's? #3. The easiest way to clean the carbs is to go to Advance Auto Parts and buy a can of "SeaFoam" and add it to a tank of gas per instructions (more is NOT better).
Good Luck

Posted on Jun 21, 2009

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Posted on Jan 02, 2017

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