XT 550 engine noise / rebuild???

Found a nice 83 XT 550  2 owner today. 8K miles Great condition with a box of NOS spares included but the engine has a piston slap/wrist pin kinda noise in it. Noise is low on the cylinder slightly louder when fully warmed up.  Any one here have any insight on rebuilding one of these hard to find parts for engines? Suggestions?


Bob V



Which parts are you referring to ?

Need to find out what is causing the noise first

There's a good amount of spare parts available (cmsnl.com, dealer, ebay, etc.), but as always not everything. So it depends on what you need. Tear it down, check everything, and see whats needed.

I am interested in the engine noise, post a video so we can listen!

I have located another bike with no title that has only 5K miles on it...Will try to purchase that bike and will use it to repair the knocking motor cycle.

Will keep you all posted ... thanks!

Bob V

These motors are easy to rebuild , several piston kits , valve options ect. .. Biggest thing to learn is that most of the motor is the same as the next models , XT600's . While the head has only 2 valves , and the 600's have 4 , they can be bolted right up to the 550 cylinder , but is best done with the 600 cylinder as well ,up to '86 model , '87-'89 they added a bolt on the end of cam chain tunnel and the 2 main stud pattern got wider so the whole topend must be used then . There is a nut on the right side of the crank that is known to come loose and it will make a knocking sound , that's the first place I'd look and if loose check the key behind it for being damaged .  

If a person wanted to you can bore the cylinder out to the 95mm and use a 600 piston kit which has a ton of options. Or if you find a good 600 motor it'll bolt right in and be good to go . Frames are entirely different and I wish Yamaha kept the oil reseravoir in the frame instead of that bulky thing hanging below the seat on the left side.

There is a bunch of other things that can be swapped over , some with minor mods , other requiring more 600 parts to go with .


the 550 has 4 valves just like to 600,s (not 2)

Ya, your right , I was picturing the 500 head . The 550 was changed to the 4 valve setup.




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