This is a follow up question to another thread I started when I thought I had a bad rear wheel bearing on my 2004 Yam BB 400 ATV.  The issue has turned out to be a worn out wheel hub and axle splines.

I have found the new axle for $237 plus shipping online at Extreme Powersports Flemming Yamaha in NJ. http://www.partforyamaha.com/pages/parts/viewbybrand/2/Yamaha.aspx  That is much better than the $378 I was quoted from a Yam shop here locally.

I do need to find a repair manual that will walk me thru the steps to remove old axle and install new axle and any associated required work or parts.  I have tried several of the online repair manual sites that have been mentioned and found only a supplemental manual and not the real mechanical repair manual for ATV model YFM400FWS.

Has anyone done this repair/replacement?

Thanks, Dave

 

It seems this is a more common failure than I thought.  A friend of mine with a Kawasaki ATV has the same problem.

I found the axle for my Yam Big Bear 400 4WD ATV online for $237.  That is alot cheaper than the $378 I was quoted from a Yamaha shop here locally.

Now, if I can find a repair manual or similar that will walk me thru the steps to change the axle.

Anyone ever done this?

Dave

 

No end to the story yet.

After cleaning it all up, reassembling and tightening, as described, I took it to the woods for a test ride.  Afterwards I found the wheel hub has loosened up again and the hub is again wobbling on the splined axle end.

Not sure, but guessing that I am going to have to replace either one or both the wheel hub and/or axle shaft.  To replace the axle shaft appears that it will be a major deal possibly having to dissassemble the entire rear end.  Not sure that replacing only the wheel hub with a new one will cure the problem.

Any good ATV mechanics out there?  I need some accurate guidance and advice.

Thank, Dave

When I removed the rear wheel and hub, I discovered the hub was a splined assembly, and not a hub with inner/outer bearings.  The problem was that there was no cotter pin to lock the hub nut tight and keep it in place.  The nut had backed off a ways which allowed the hub to be loose and wobble on the splined axle.  That wobbling around did wear the splines significantly in both the hub and on the axle, but it did not appear to be terminal.

I used a small SS toothbrush and brushed and cleaned all of the rust and corrosion out of each part inside and out, reassembled using a good grade of marine wheel bearing grease on the splines, tighened the nut up, and placed a new heavy duty cotter pin.  Hopefully this will be the end of the story but I intend to keep an eye on it and see if it will remain tight.

Anyone else ever encountered this problem?

Dave
 

I have a 2005 Yamaha Big Bear 400 4WD with manual transmission that has what appears to be a bad rear wheel bearing on the non-brake side.  I noticed the wheel was loose, shook it from side to side, found some slop, looked on the rear axle and could see the bearing has worn to the point the wheel hub is not perfectly centered on the axle.  Hopefully it has not ruined the bearing surface or axle.

I have never had to replace the bearing assembly.  How do I remove old bearing and replace with new bearing assembly?

Thanks for any information.

Dave 

The fitting or gromet that screws into the side of the carb has broken so it has to be replaced.  I order the arts called a "Starter Set" from Yam dealer and now have to figure out how to disassemble and do the R&R.

The cable is still attached to something inside there and the broken piece will have to be removed.

Dave

I have a 2005 Yamaha 400 Big Bear 4 WD atv that developed a problem this weekend. Engine began to run rough at slow speed, would cut off at idle, black smoke out the exhaust, etc. indicated it was choked and/or getting too much fuel.  PLug was sooted black.

I got to looking it over and noticed that where the choke cable enters the side of the carbrueter, it is routed thru a small black plastic or rubber gromet looking fitting that appears to be screwed into the side of the carb and the choke cable goes thru it. That black plastic or rubber gromet looking fitting has broken or separated and the choke cable housing and spring had pushed backwards out of the carb. I pushed it back in and it cranked and ran OK but it needs to be fixed.

Called my Yamaha dealer and they said that fitting is called a "Starter Set" and is about $17, labor to replace is about $70 if nothing else is wrong.

Anyone have this problem before or have any knowledge of it or the necessary repairs?

I see what has happened but am wondering why it happened.  Is the choke plate gummed up and not opening and closing easily inside the carb which creates back presure on the cable and housing which in turn caused the rubber gromet to break or separate???

Thanks for any info, Dave