wr 426 blowing smoke


8 replies to this topic
  • pete76

Posted December 28, 2008 - 10:05 PM

#1

hi, just wondering if anyone can help me with this problem im having. Every time my bike sits in the shed for a period of time, i have trouble starting it. It seems to foul the plug. After taking it out, cleaning it and putting it back in, it starts with choke on for 30sec. Press choke in it runs rough, so i have to hold the rpm up probably 4000rpm. It also blows blue smoke when i get on and off the throttle. Could the valve clearance be out causing these problems or could i have a bigger problem? The bike has 2000kms and has been looked after.
Regards Pete.

  • NateJacobs

Posted December 28, 2008 - 10:21 PM

#2

How does the bike run after 10-20 minutes? Does the smoke go away? My bet is that the oil in the head is seeping down throught the valves into the cylinder. Check your oil level and make sure it's not too high. Be sure to follow the instructions in the manual so you don't overfill. Overfilling will cause excess oil in the head and drainage into the cylinder. This of course would cause the smoke and the fouled plug.

  • brad the best

Posted December 28, 2008 - 11:32 PM

#3

when ever your having any smoke problems always check to see if the crank case breather is plugged , its should be a black pipe on the left side of the bike the end of it is near the flywheel .

probably not the problem your most likely looking at a valve problem , but excessive crank case pressure can push the oil .

its just an easy fast possibly cheap check .

  • pete76

Posted December 30, 2008 - 02:42 AM

#4

After 10 to 20 min, the bike runs fine and it doesn't really blow smoke. But sometimes when i open it up on a ride, then roll of the throttle it starts blowing smoke. The bike runs strong apart from this problem.

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  • gregwr450f

Posted December 30, 2008 - 10:51 PM

#5

2000kms on a 426, are you the original owner?

Probably stale fuel.

  • pete76

Posted December 31, 2008 - 12:16 AM

#6

Fuel is always drained when bike has been sitting for a long period of time. I am the second owner and have had the bike for over 3 years. They are original kms.

  • brad the best

Posted December 31, 2008 - 01:25 AM

#7

2000kms on a 426, are you the original owner?

Probably stale fuel.


i have never seen stale fuel burn blue , blue indicates oil burn off .

  • WR_Dave

Posted December 31, 2008 - 06:10 AM

#8

With only 2000 kms on the bike I suspect a very poor break in procedure was done on this engine. This would lead to rings not seated properly and possibly valves or valve guides that may have been damaged during break in. You say it has been looked after, if that means the bike was treated gently, being too easy on these engines doesn't help them break in properly. I suggest setting the valves and then doing a compression test or a leak down test on the cylinder. Rolling off the throttle creates a high vacuum above the piston in the intake tract and it will pull oil past the valve seals or the rings. Pull the carb and have a look down the intake runner for signs of oil coming from the valve guide area. You may only need to try new valve seals due to the small amount of run time on this older engine. Also get into the habit of setting the engine at TDC when it is not being used so all the valves are closed and at the most relaxed position. Once you have the problem figured out, repair it and ride more often, 2000 km's on a 426 is way too little riding. :busted: :moon: WR Dave

  • acarter92

Posted January 01, 2009 - 05:16 PM

#9

2000 km's on a 426 is way too little riding. :busted: :moon: WR Dave[/QUOTE]


Agreed, heck i think i put on that many this week! Well... maybe not but that bike's like new yet




 
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