Quantcast
Jump to content

  • Join Today, It's Simple and FREE!

    As a member, you can post in our forums, upload your photos and videos, use and contribute to our downloads, create your own member page, add your ATV events, and even start your own ATV club to host your own club forum and gallery.  Registration is fast and you can even login with social network accounts to sync your profiles and content.

Jeff Wolf

kawasaki bayou 400 piston

Recommended Posts

Bought a nonrunning 1996 bayou 400. Tore down engine and found major problems. Piston is damaged and cylinder liner needs replacing. Looks like cause was a broken oil pump gear.

 

Question is can a piston from a prairie 400 be used? Is it the same engine? I assume the liner is replaceable?

 

 

Share this post


Link to post
Share on other sites


Welcome to quad crazy. The piston would probably fit but it’s not worth using it. There are two ways to go about it. You can bore the cylinder out and go with a bigger piston and rings and maybe have to re-jet the  carb. 

Or you can buy a used one from eBay but I would buy a new piston since it’s all torn down.  I just looked and found a used jug in great condition for $166. I rebuilt one of the same bikes about a year ago. Water cooled bike was super strong.  I think I paid $45 bucks for a full gasket kit on amazon. I would also do the valve seals while your in there.  

But this all depends on the condition of the bike and if it’s worthwhile. Also are you sure the oil pump gear was the problem? Because here’s my question.  The oil pump brings oil to the head to oil the top end valves, cams etc not the cylinder walls.  That’s done by the oil that’s in the lower end.  The piston could have just blown because it was beat on or the bike was ran out of oil.  

 

  • Like 1

Share this post


Link to post
Share on other sites

When we took off the right side cover, the plastic oil pump gear was deformed and not attached to the keyed shaft that drives the oil pump, so that for sure needs to be replaced. Could have been run without oil though because the roller bearings on the connecting rod at crank are totally shot, with some of them in the bottom of engine.

The bottom of the piston sleeve has a chunk of metal out of it, half moon about .5 inch.  Piston is all busted up. One valve looks like it might need to be redone.

Trying to get the flywheel off now. We don't have the special puller. Does it take a 33mm puller? Tried the pry out with screwdriver and tap on slightly undone center bolt with no luck so far.

Share this post


Link to post
Share on other sites

Yes you will need a wheel puller to get that off. I’m honestly feeling like the engine is blown and may be beyond repair.  You really have to take a good look and see what happened.  The engine could have locked up and came to a complete stop and broke that oil pump gear.  Best bet is to take it all apart and see what the main bearing looks like.  Worst case is you lost time.  

  • Like 1

Share this post


Link to post
Share on other sites

got it all apart. Bearings look good... in fact everything in bottom end look good except for connecting rod and bearings. There is a chunk out of rod and bearings blew up.

So... we have a used crank with connecting rod, and used cylinder and piston on the way. Also a used oil pump gear.

Plan on cleaning everything up real well and reassemble. 

Will get some new seals for valves and clean up head well and reassemble. Also some new seals for side panels.  So far it has been a fun project for my son and I.

Any suggestions on what I may be missing?

Share this post


Link to post
Share on other sites


Awesome stuff.  I would recommend changing the water pump while your in there.  That bike was fun to work on. The valve cover bolts 8mm  there are quite a few different lengths that go on that cover so be sure about the way they go back.   Be super careful with the water temp sensor wire, they break off easy.  Use a lot of grease on the parts, cam, lobes etc  prior to start up and crank the engine without the spark plug in for a few seconds each time so you pump oil up to the head.  Other then that I think your  right on par.  

Good luck. 

Post some dam pics I love pics!!!!

Share this post


Link to post
Share on other sites

Worked on quad some more this weekend. I've included pics of damaged piston, jug, and connecting rod. Also a bent valve.

Have the case back together with replacement crank and connection ng rod in. Put crank in freezer for 4 hours and propane torch on case (225f) and it slipped right in. Pretty cool. 

New valves should be here thursday and it will be back together.

Plan on turning it over by hand a few times before installing plug or spark.

Next will be electrical evaluation.

20190611_071059.jpg

20190611_071116.jpg

20190611_071141.jpg

Share this post


Link to post
Share on other sites

I know right? Crazy damage... still not sure how it all happened.

Drive shaft and transmission gears look great and parts not strapped in engine look like they are new. Who knows.

Hopefully electrical stuff will work.

Share this post


Link to post
Share on other sites


Probably...I'm surprised these machines dont have low oil alert lights...(maybe they do and I dont see it yet). Would have prevented a lot of damage.

Picked up some cheap 10/40 oil for when we get finished.. was thinking run it a couple of hrs then change oil and filter just in case?

Share this post


Link to post
Share on other sites

Yes for sure. Always a good idea to do a secondary oil change after a job like that.   Plus I like to add grease to the lobes of the cam and valve rockers etc and run my finger around the cylinder with a little grease as well. This will relieve some initial start up friction. 

Share this post


Link to post
Share on other sites

When the ignition key is on and transmission is in neutral the "neutral " light should come on whether the engine on/off switch is in either position right?

Need to find a wiring diagram I guess... anyone know if the bayou 300 wiring is the same?

Share this post


Link to post
Share on other sites


If so take the light green wire coming from the harness not from the wires coming out of the switch and add a ground to it and see if the bike cracks and the light comes on. If so there’s a problem within the neutral safety switch or contact point on the reverse cam. 

Share this post


Link to post
Share on other sites

You are the MAN! After grounding the green the neutral light came on.. also with the starter disconnected we could hear the starter relay clicking on and off when pressing the start button.... so now to re-evaluate that switch... see how expensive to replace.

Share this post


Link to post
Share on other sites

Ok so what’s bad most likely is the reverse cam, not the neutral safety switch.  

Ive attached pics of the reverse cam.  On that revers cam there is a small pin that’s spring loaded. That spring loaded pin is what touches the electrical tab on the neutral safety switch.  Over time the spring collapses and does not make contact. 

Good news: it’s cheap to fix parts wise 

bad news: the bevel gear housing that covers that switch can only be removed with the engine raised up off of the frame or the engine pulled.  

 

Share this post


Link to post
Share on other sites


Ok... after further inspection the neutral light came on when lifting shifter lever. Sensor was removed again and rotated slightly and functions properly again..whew!

 

Now just waiting for valves to arrive and top end can go back on.

Getting closer....

Share this post


Link to post
Share on other sites

That’s good but It will work intermittently so be sure it’s good.  That spring loaded pin inside the reverse cam gets week over time and it gets lazy and will only work sometimes.  It would suck if you did all this work just to have to pull the motor again.  

One of my recent posts on my bayou I had to change the reverse cam. There were some good progress photos of the old and new reverse cam differences with regard to the spring.  

Share this post


Link to post
Share on other sites

Got it back together....turned over by hand fine then by starter.

We are getting spark. Now we are cleaning carb in hope of firing this thing up.

Share this post


Link to post
Share on other sites


Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Similar Topics

    • By Arizona
      So a few weeks ago ended up buying a 02 Bayou 300 for 100.00
      Get there to see it and motor was gone through and parts missing, stuff not connected
      and a big freekin bucket of parts and bolts. He said had no power and mechanic said it was
      the wrist pin. Ended up leaving it in pieces and left like that. I end up getting most of it back together
      and manage to get it to fire up. I drive it and has no power! No missing just no power. I figure check 
      the timing chain as he did replace that. Well I spin the motor over and guess what!
      A blind guy could have done a better jobs. Just one question, I  loosen the top bolt on the tensioner then remove it
      right? Nothing is gonna fall inside the motor is it? just making sure, need this out before I can move the cam gear 
      to the right location. Thanks in advance Az
       
       



    • By mike costa
      Has any one tried using the Harbor Freight Winch mounting plate on a 2001 Kawasaki 300 4x4 Bayou? 
    • By Mudrecon
      Haven't got a service manual for this yet so I'm flying by the seat of my pants I made myself a shifter extension to go up by the gas tank took my foot shifter off to weld it and now when I put it back on I don't seem to be able to find neutral. Is there some asinine reason that you have to do something internally when you change or remove the foot shifter? It was a simple take off weld put back on and dog bite my pecker it's not working. I hope this is something simple I've done and that's something I need brain surgery for. Cheers fellas I know y'all will have the right answers
    • By weblex
      Problem: The ATV starts and runs at idle perfectly. But as soon as I open the throttle, the engine starts to slow down until it stops. On the attached video you can hear the sound of how it works: see video below
      Prehistory: there is a Polaris Sportsman 500 1998, which for about 1.5 years stood in repair, including also replacing CDI with one taken from the same ATV. Finally, the vehicles were on wheels, traveled several kilometers and overheated - forgot to fill the antifreeze Came back home in small moves. The next trip started well, but after 10 km there was a feeling of a small drop in power (even as the vehicle got warm completely) but still drives. Next trip - the situation is repeated. The next test of ATV through time and a huge loss of power from the very beginning. The engine sneezes, does not want to go more than 5 mph.

      What has been done: the carburetor has been replaced with a new one (inexpensive, $ 40), a new spark plug, a new ignition coil, the engine head has been removed, the piston is in good condition, valves were corrected - but the problem was definitely not in them.

      Ignition control unit is suspected. Who faced similar? Please help in solving the problem.
      Thanks in advance.
       
       
    • By Kelby 746
      I have a 1987-89 (not sure on the year) Kawasaki bayou 300 that has electrical issues, I have replaced the entire harness with a proven good/used one, new CDI box, and two brand new coils, problem is that it tests no charge at the pickup coil, so I replaced and tested again with a so called good one that had been salvaged out of a blown up 220/250 (not sure which, the left side cover is smaller than my 300) in Missouri. It has a proven good OEM stator. I am trying to avoid buying a new start and pickup coil because it is so expensive so if anyone has a suggestion please let me know.
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...