So here is the story, ever since I was a kid I have wanted an off road Go Kart. I saw one in the movie little giants. Never ever did get one. I thought I might build one, one day. A couple weeks ago I came across this off road buggy looking thing at a garage sale. Had no idea what it was. It didn’t run but it looked complete and he only wanted $200, so I bought it. Turns out it was a 1983 Honda Odyssey FL250. It was sitting out side for years. I think it died on the previous owner and he tried to “fix” it and he didn’t have a clue what he was doing. So far I have stripped the cage off. Brazed 3 holes in the gas tank. Rebuilt the carb, replaced the ignition coil. Rebuilt the pull start. Cleaned and tested the CDI (Capacitor Discharge Ignition). Next I need to redo all the wiring. Next I need to fix the no spark problem and try to fit my aftermarket seat upgrade. Stay tuned for updates.

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Based on your screen name I thought you were from Rhode Island, Hawaii or Vancouver Island. Your English was good so I knew you were from North America or Aus.
You stated that you had no idea what it was when you saw it, so that tells me you are 30yrs old (late 20's or very early 30's).
You are tackling a stator so that tells me you work in the electrical, mechanical trade, possible welder. Possibly on construction, mining or sawmill areas.

Nice job on that fuel tank.
Two negative things. 1) Don't reuse those seat belts 2) That thing has no wrist restraints. It's an accident waiting to happen. I had a HUGE crash a few years ago in my oddy and broke my back (L1). The G forces were tremendous and words don't do it justice. Your not holding your arms in --- period.
You can get wrist restraints here: http://blueskyppg.com/index.php?main_page=products_new
I got a set from them and they are very nice.
I see you got a suspension seat for it. Your gona need it.
One other important point I want to make is that these machines have a deadly flaw. We sit low to the ground so there is no way to judge what is coming up. You must know the road BEFORE you go crazy. The quad and dirt bike riders are standing high and can see far down the road -- you and I can't.
You have been warned.

What is the compression of the Engine ??

Also the site has been very slow for a while now. Not many logging in and posting. So you may have to wait for answers. This site has everything you want to know about these machines, you just have to find it. Use the search box. I have a thread in the general section on how to use it. Here it is: viewtopic.php?f=2&t=17970

Your powers of deduction are astounding. I’m a 35 year old and I own a pluming company. Thanks on the fuel tank. I heard mixed reviews about people repairing them but I figured that it couldn’t get worse if I had to buy a new one anyway. I just saw a post about steering wheel wrist restraints a couple days ago. Your right it’s a must have. I heed your warning about visibility.

No idea what the compression is. I don’t have the tools to check it. The next issues I think will be exhaust. Trying to modify that to make more room for the seat. Also, there may have been a small rodent living in it.

Future upgrades: LED head light, some kinds of gear rack for a cooler and gas can for extended trips

Any tips on trying to mount an aftermarket seat?

1) You may be wasting your time right now. You need to know if it will even run. Buy a compression gauge and test it. Also note that some gauges are out of calibration, we have run across that issue on this site. Buy a good one. You may end up having to do a complete rebuild.
2) BEFORE you take it apart you MUST do a leak down test. This will tell you if the seals are still in good shape. There are threads here in the tech section that describes what you need for that.
3) Can't help you on the seat mounting. There was a member here from Spain that was looking for measurements and pics of the stock seat. May be post some of that if you got time. Hold the tape measure next to the seat and take pics if time permits.

Ok so stator coil wiring is repaired properly and reinstalled. I’m getting voltage at pullstart RPMs, exciter 34v, lighting 6v and pulse 3v. It’s at pull start RPM so take it as a grain of salt. I cleaned and lubricated the pull start, it pulls like new.

I did a compression test. It reads 140psi on the gauge. I did it three times, 4 pulls each time. Stock compression is suppose to be 128psi. I’m not sure why it’s more. Should I be looking in to this more?

Now I was having some trouble pulling the cord when the spark plug was in. No plug, it pulls fine and turn over like you would expect. I put the plug in and I could barley pull the plug at all. It seemed like something was plugged? I checked the exhaust it was full of water. I disconnected it and tried again. I was able to get it to turn over enough to get the compression test done. However it is still hard to pull, not impossible, but it doesn’t seem right. Could the intake be plugged? Not sure what to look at. With the spark plug hole open it’s super easy to turn over. Any ideas?

From what I see there I bet your whole bottom end of that Engine was full of water. Not good.
With that exhaust pipe full of water I would just strip down the Engine and start over.
Even if you do finally get it running you got no idea what shape those crank bearings are in or even what shape your rod bearing is in. Your heading for a lot of frustration I think.
Just my opinion.

Today I pulled the head and cylinder off the motor (( Internal Combustion Engine ? )) to see what the status was inside. Thre was water inside the bottom of the crack case. However there must of been oil in there also as there was no visible signs of rust. I sucked the water out with a siphon pump and sprayed the whole thing down with petroleum lubricant cleaner. I could see the inspection holes for the crank bearings no rust. I could see the bearings inside the piston arm, no rust. Piston cleaned up good. Top of the piston looks like it’s run very little. Here are some pictures. Let me know what you think.

Well there are two schools of thought here.
You could tear it apart and do a complete rebuild or you could try to run it and see how long it lasts.
I like rebuilding so that's what I would do. I don't know how mechanical you are. The reason I say this is because of the water. The ball bearing sitting at the bottom of each bearing will most likely be the one that is pitted and has a rust spot. At 8000 rpm this will not be good. The other issue is the rod bearing. Most people don't know or have the tools to do this job. Even if you tear it apart you probably can't do this part of the job. Your only saving grace here is that I bet the previous owner put oil in the cylinder to keep it for long term storage. It didn't work because he left it outside where the water could get in it.
You have a tough choice.

That clutch will have to come apart too.

By the way those are not bearing inspection holes. That's how the lube gets to the bearing.
If you need a manual I will post where you can get a free pdf when I get home. You can also use the search box and type in manuals. You will find a post.

You can get a free pdf manual here: http://oddatv.com/fl250-fl350-factory-manuals/

Thanks for the manual link. I did download it a few weeks ago and have been referring to it daily. The whole reason I don’t want to pull it apart is because I don’t have the proper tools. I have above average mechanical ability. I’ve always done all my automotive work. However, 2 stroke is new to me, so far it seems quite simple. But like you said the key to any jobs is having the right tool. I’m am also quite anxious to ride it. I think I’m going to leave it for now. I have an appointment with the motor (( Internal Combustion Engine ? )) cycle shop to check the cylinder and piston for wear, and make sure it in good shape. Then I’m going to hone it, put new rings on if required, replace the seals, and hope it fires up.

Yes, both the driven and drive clutch need to be rebuilt. They are very rusty. I’m hoping I can just clean them, oil it, lube it and put it back together. Crossing my fingers that there are not broken rusty springs.

So I went to a shop to have the cylinder and piston measured. As best we can tell privious owner installed an oversized piston kit. The piston cylinder and the piston was a match for each other. We honed it out and all looks good. I am ordering a new set of oversized piston rings and then I will be ready to rebuild. Best as we can tell is someone installed a 1mm over sized kit. So I ordered some 1mm over sized piston rings and I will start there.