WR400 hesitation on high revs

5 replies to this topic
  • mikie

Posted January 04, 2006 - 01:51 PM


After about an hour or two of riding I got into some slow 1st gear single track, when I emerged the bike hard a very bad hesitation when I got on the throttle hard.

I changed my oil today, used Mobil 1 Gold cap 15w 50. I've always used the red cap but they were out. When I got home it I compared an old Mobil 1 bottle and they appear to be the same, full Synth 15w50 (so maybe the cap just changed colors :applause: ). This is the only mod I've done in the last week.

Also, I noticed some oil on the left bottom frame. Some if from the oil change but it looks as though some is comming out of a breather hose on that side.

Could all these factors be linked? Are they obvious signs that something is going wrong? 4Strokes are rather new to me, I know I need to adjust valves but what else should I do?

  • RichBaker

Posted January 04, 2006 - 03:30 PM


Oil from the breather hose, a little bit, is OK...LOTS of oil is bad. What year, how many hours will help with the diagnosis...
Oil type won't affect carburetion...sounds like jetting, maybe an accel pump adjustment.

  • mikie

Posted January 05, 2006 - 11:14 AM


I was thinking the same thing. There is a few drops of oil on my garage floor, VERY little. So I think I'm ok there. Ive had it for about 2 months now and am going to proceed with a valve check/adj. pronto!

I'm also pulling the plug on it today to check for fouling. It runs great, so I never thought it to be to rich, but maybe those very slow tech trails were enough to foul it up. :applause:

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • mikie

Posted January 05, 2006 - 12:39 PM


Just pulled the plug and it was perfect, nice choc. brown. Made sure the plug cap was on snug, put her back together and took it for a couple laps around the block. Ran great, no hesitation at all.

Does the big WR400 have issues with overheating in trails? It wasnt a hot day and my coolant levels are up to par. I do have Devol guards though.

I'm stumped.

  • jbrooks26

Posted January 05, 2006 - 08:51 PM


Are you sure it wasn't hitting the rev limiter? I know this is a dumb question, but it could be a possibility. Hope this helps,


  • mikie

Posted January 06, 2006 - 10:50 AM


uhh, no. :applause:


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.