Detonated my WR426 need suggestions

5 replies to this topic
  • Macombcountyrider

Posted September 09, 2016 - 06:47 PM


I recently detonated my motorcycle due to bad gas and I,m looking for suggestions what I should do to the bike when I tear it apart ? Any information would be helpful ,thanks Gus

  • bodge

Posted September 10, 2016 - 04:31 PM


I am sure there is many things you can do but I would check the wr forum.

  • tcmII

Posted September 15, 2016 - 12:57 PM


You need to be more specific on "detonated" your engine.  What are your symptoms?  WR really do not like "bad" gas (who does!), but wouldn't necessarily destroy your engine.

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  • Macombcountyrider

Posted September 15, 2016 - 01:19 PM


I lost all compression, Dont need the decomp lever kick start kicks right thru, and motor stalled on me and when riding it home it lost most of its power when on the throttle before it shut off on me .. my mechanic said it detonated and its about $1500 to fix on the high end

  • tcmII

Posted September 17, 2016 - 04:54 AM


Loss of compression is not likely related to fuel. Have you actually confirmed low compression with a gage?


Start with the simple and work toward the complex;


- Check the spark plug, make sure it is not loose (also check the plug has the compression gasket).

- Make sure the intake and exhaust are not plugged.

- Check the decompression function to make sure it is not stuck open. (Follow the cable to the front of the engine there is a lever, you should be able to see if move back and forth when you pull the lever on the bars.

- check for spark (remove plug ground against the engine and kick over. Look for a blue spark.  If there is none, try with a new plug. 

- check fuel in carb

- check jets (pilot and main - simplified, pilot is for idle and main is for 1/2 to full throttle)


This one is a little more difficult.  Did you add oil recently?  If so, try draining the oil and replacing it (WRs have two drain plugs one on the engine and one on the frame).  WRs are dry sump motors and store the oil in the frame, but when they are sitting oil can drain down into the crank case.  If the oil level is checked incorrectly you can over fill which could make this problem worse.


From there you need to do compression tests.




  • Macombcountyrider

Posted September 17, 2016 - 07:30 AM


Thanks for this info , I will have the bike checked for these things when I get a minute!!!


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