'97 Prairie 400 -- I need some help!

[Ant-Knee]

I recently picked up a '97 Prairie 400 4x4 that didn't run. I didn't get much information from the previous owner except that it was running a couple of weeks ago, then started losing power. After that, it just wouldn't do anything... no crank, no start. The electric start didn't do anything and the pull start seemed locked up. When I got it, it had no fluids whatsoever—no oil, no coolant, nothing. I figured the engine was seized. I took the pull start recoil off and tried turning it with a wrench but it didn't move. I took out the spark plug and put some lubricant in the spark plug hole. After a while, I was able to get it moving and it turns now but isn't super easy to turn. I put oil and coolant hoping it would fire up but still nothing. I took out the starter and tested it and it worked perfectly. I tested the starter solenoid and it clicked so I assumed it is working. The battery is good and holding a charge. I also put in a new spark plug as the old one was somewhat corroded but didn't look that bad. After I tested the starter, I put it back in and ran some power directly to the starter. It started cranking the first time I gave it power but didn't do anything after that one time.

Any ideas of what I should do next would be greatly appreciated. Always wanted a quad so I really want to make this work but not sure if it is do=able.

[Gwbarm]

Sounds like you may have several things going on here. You are not getting power to the starter which indicates an electrical issue. I would be concerned it had no fluids in it. If he ran it out of oil or coolant the engine may have seized although you got it freed up, that doesnt necessarily mean no damage was done. That shouldnt have anything to do with no power to the starter unless it overheated to the point that it took out relays. Does it have spark? 

I think what i would do at this point is keep working it with marvel mystery oil down the cylinder untill you get it freed up where its not so hard to turn, and it may not free up. If you do get it freed up where it turns over easily do a compression test to see if the rings have been damaged. 

[Ant-Knee]

Thanks for the response. I will do that. I can tell that the previous owner messed around with the electrical and I am having a hard time trying to figure out where each wire is supposed to go. If there is some internal damage do you think it is something that can be fixed? Although I consider myself mechanically inclined, I am not a mechanic for sure, especially on small engines. A couple of people (who are also not mechanics) have told me that it is dead and I should scrap it. 

Suppose I don't get it freed up any more that what it is, could I either do a rebuild or take it to someone to have it done? I have no idea yet how much it would cost for something like that but I am willing as long as the cost doesn't outweigh the value — it is a '97. This is all new to me. There is a series on YouTube, I think from Mid Nebraska or something like that, and his videos make it look straight forward. Is that any other major part that I should look to see the condition of?

I really appreciate your help!

[Gwbarm]

You can definitely do a rebuild, i probably wouldnt take it to a mechanic because of its age you might put more in it than its worth. I would hope the lower end is ok no burned main bearings or crank. You wont know that until you get the cylinder off and see if it turns freely, but even so you can split the case and put in new bearings. Thats all jumping the gun a little until you know whats going on. Learn that from compression test., just keep oiling the cylinder and turning gently for a while 

[Mech]

Yup, what Gw says, get the engine free and test for compression. If it has no compression then pull the head and cylinder off and check the crank bearings by moving the rod sideways and then pressing down hard on the rod and rocking it on the bearing as you slowly turn the crank. You are checking for any rough spots on the crank. If the crank seems ok, get on the end of the crank shaft and try lifting and moving it down looking for play in the main bearings. If the crank and rod seem ok, then consider fitting a piston and/or rings and/or new cylinder. When you are lifting the cylinder, make sure the piston is at the top and then only lift the cylinder as little as possible that will allow you to wrap a rag around the rod and into the crankcase hole.. to stop and broken ring falling into the crankcase.

Compared to all that, the electrical issues should be minor.. 

[Ant-Knee]

Thank you both. I don't mind putting in the work, I just wanted to know that it would all be for not. I will keep working the cylinder and take it apart later this week. I may be back with some questions once I get it apart. I know it is a 28 year old machine but I am also using it as a learning experience. 

[davefrombc]

There is a service manual for your quad in the downloads section  that will help sort your wiring problem and any rebuilding you might need to do.

[Ant-Knee]

Thank you Dave. After a few more posts, I will be able to download the manual. I am looking forward to that. 

I started pulling the engine apart. I still have one stubborn bolt keeping me from getting the cylinder off but I have penetrating oil soaking down into it. I am a little confused about what I found so far. One of the rocker arms is concave instead of convex. Any ideas what would cause that? Valves adjusted improperly? I will add some pictures. Also the cutouts where the cam sits is worn with some deep ridges.

 

[Gwbarm]

Yes That rocker looks badly worn and the other doesnt look that great either. Getting the broken bolt out can be difficult  keep wet with penetrating oil if you can get vice griips on it turn it back and forth short strokes to see if it will loosen you may have to add a little heat that will help.

[Ant-Knee]

What would cause the wear on that rocker arm that badly? You think it was just time and usage or is there something that I should look out for? 

[Gwbarm]

No! That is a typical sign of no oil, and from the looks of it was run quite a while with very little oil until it just wouldnt go any further. Im afraid you are going to find more off the same in the cylinder and piston deep lines in cylinder and piston. 

[Mech]

Yup, with that blueing it will be lack of oil getting to the top end. And it must have been running short of oil for a while. Since the other rocker and the cam bearings don't look as bad I'd suspect that rocker is the last place the oil gets to and so it ran dry. A lot of over head cam engines have a restrictor/restriction in the oil supply to the head to stop it taking all the oil pressure away. The restriction, because it's a small hole, can get blocked. The restrictor is generally down on the crankcase..  A manual or a parts diagram should show it.

Edited July 25, 2025 by Mech

[Ant-Knee]

Ok, good to know. I will see if I can find the restrictor. I don't understand why people aren't more diligent about making sure there is enough oil. Seems so basic! I did see a complete rebuilt top end on powersportsnation for about $400 which seems like a deal. However, I have to get past this one bolt to see if the damage goes deeper. If it is all top end, I will feel like a winner here.

[Ant-Knee]

Ok, so I was wrong, it wasn't a bolt, it was TWO bolts that were seized. I did everything you guys suggested and after about the fourth day I decided it was time. I stayed on them for about 6 hours straight and I finally got the mofos out of there! I can't tell you how good it felt to finally bust them loose but you probably have had similar. So, now I would like your opinion about what I found inside. What is that wrinkly brown stuff? I will have to chip it off because it is solid.

And the pistons...

Everything down below looked ok but to be honest, I don't know what I am looking for. The shaft itself seems to be pretty solid. Is there a predefined way to check if it is holding up other than wiggling it around and determining that it seems good? That was about all I could do.

Any help and opinions are always appreciated!

 

 

[Gwbarm]

Thats great you got them out without breaking them. I see some pretty hefty scratching on the cylinder hard to tell how deep they are as to wheather they will hone out or not. The piston look fairly good i dont see any scratches on the piston but sometimes photos are deceiving. The rings look free they are not welded to the piston as i would have suspected. Overall it doesnt look as bad as i expected. Hard to tell much about the valves without seeing the sealing surface. The dried wrinkly stuff will come right off.

Hows the bottom end does the crank rotate freely, take the rod in your hand and push down you should feel very little resistance as the crank turns. Then take the rod at its highest point and wiggle it up and down you should have no play there, but you will have a little play side to side.

If everything checks out after a cleanup check the ring gap by putting in cylinder one at a time and measuring with a feeler guage to give you an idea of the wear and check to manual to see if it is within specs. If the scratches do not clean up you may have to get a rebore with oversized piston, or top end kit that comes with everything.

[Mech]

Well done. Perseverance always wins, giving up never does.

To check the rod bearings you put at the top and move it side to side. That shows up play in the bearing. It will probably move about three mills side to side, but five mills is too much. The manual will probably give specific measurements. Then, to check for wear on the crank pin you rotate the crank a few degrees after top dead center, about fifteen degrees after, and then holding the crank from moving you push down hard on the rod and rock it forwards and aft feeling for any roughness. Then turn the crank again a little to about twenty degrees and check, then turn it to about twenty-five degrees and check it. If there is roughness on the crank pin it will be in that fifteen to about twenty five degree range.. perhaps even up to thirty degrees after top dead.

I think I see some black aluminium oxide in the bore which is caused by an over heated/ near seized piston. Turn the piston so we can see both sides of the skirt and show us what they look like.That carbon build up isn't too bad and could be left there. As Gw says, check the ring fit in the grooves. Check all the way around looking for any part where the rings have more clearance that the other way around.

The bore looks a bit scratched but that may buff out with a hone or wet and dry paper. If you can get it so you can't feel the scratches with your finger-nail it will be ok if the piston is reusable still. Put a top ring in the bottom of the bore and square it up with the piston then measure the gap. Then put the ring at the top, not right at the very top but just below where the top ring was rubbing to in use, and measure the gap again. The difference between top and bottom measurement, divided by three, will be close to how much wear/taper the bore has. If everything checks out ok I'd probably put it back together with new gaskets, rings and a valve lapping and valve seals.. 

[Gwbarm]

You will need to replace the rocker arms, how are the cam lobes.

[Mech]

Right.. I forgot about them..

[Ant-Knee]

You guys are awesome! I could not have done any of this without you. If you are ever in Apple Valley, CA I will buy you a beer!

I spent a little time cleaning some of this up but still have some work to do there. Here is the piston with shots all the way around. I don't see any obvious issues.



Here is the cylinder. I can't really feel anything with my fingernail. It is all pretty much smooth but you can tell some areas are more worn. I haven't done used the feeler gauges to test the space because I have to do that when the piston is put back together... right? I tried to get the best pictures I could but it is still hard to see.

 

 

Here is the other piece with the lobes? I still have some cleaning to do here as you can see.

 

And here is the cam. In the pictures it looks like deep grooves but it is actually pretty smooth. Not sure if there are any issues here.

 

I THINK I followed your directions with the rod. I moved it and it all seems pretty smooth. There wasn't much play from side to side and it moved down with ease. I also looked inside the bottom of the motor to see if I could see anything obvious but it all looked good to my untrained eye.

So how am I doing so far? Can't tell you how much I appreciate you guys!

 

[Gwbarm]

You have been busy, very good cleaning job. Everything looks pretty descent, except the cam but you said the photos looked worse than it really was, so hard to judge, i can see signs of heat damage. I would take the rings off the piston put them in the cylinder one at a time and measure the ring gap or just put in new rings. Of course you can mic all the parts and see if they are in spec according to the service manual.

[davefrombc]

To  measure the  ring gap,use the piston to  push the ring  down in the cylinder to easily  align the ring to the bore.. Measure the gap at the top, middle and bottom  of the travel  area to find any taper worn into barrel.