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790 Big Bore Kit Installation Instructions

Submitted by Lora B on Thu, 03/14/2019 - 16:34
DR650 790 Big Bore Kit Installation Instructions


DR650 790 Big Bore Installation Instructions

(See Available PDF for printable version)

  1. We recommend using a factory Suzuki service manual for engine teardown and assembly procedures.
  1. Note: The factory manual may have an error regarding head bolt installation. The head bolts are 3 different lengths. Mark the bolts so they go back in their original positions. (Note: Example - our shop copy of the factory manual has the bolt positions confused.)
  1. Sleeve to Cylinder interference fit should be 0.004”.
  1. Piston to bore clearance should be 0.002”-0.003”.
  1. Piston Rings must have the end gap properly measured/adjusted per the instructions included with the piston before installation.   
  1. Piston to Valve clearance must also be checked prior to final assembly. This is a minimum of .050” for the Intake valves and .070” for the Exhaust valves. Here is a link to a video that explains this well. (Yes, the video shows it being done on a car motor, but it is just the same for a DR, only you just have to do one cylinder!)
  1. The Cylinder Head and Cylinder surfaces must be clean, smooth and flat.
  1. When installing the head bolts, be sure the threads are very clean. Oil the threads generously with engine oil before installation. Head bolt torque is 29 ft/lb.
  1. We like the ‘MotoMan’ method of break-in for piston rings. 

See: for details.

  1. Change the oil immediately after break-in.