Well, after I finished up installing a water temp gauge I rode it around the yard for a few minutes to test out the temp gauge and see if I could duplicate my earlier problem. After about 15 minutes of light riding, the problem started again. As I was rolling along at half throttle (maybe less), the engine began to bog drastically as if I was holding the brake on. my water temp never got hot enough to move the gauge up....Along with the heavy bog down, heavy smoke (more than the normal 2-stroke amount). I'm stumped. I've eliminated the rev Limiter and override switch bypassed.

I may have to bite the bullet and take it into one of the local shops when money allows. for now, it'll have to wait.

 

Sounds like what happens when the piston starts to seize. When it does this do a compression check. If less than 120 psi or so,could be what's happening.

 

I was thinking that as well, but, man, I certainly hope not. It's only got probably 30 hours on it since I did a full top end rebuild. I'll check compression to be sure though.

 

I haven't forgot about this one OPT. You just responded to my other project post (the 97 Sportsman 400L). I was hoping to get that one finished up and out of the garage this evening so I could get the trail boss back in to get on it again.

I may have the solution before I get back into it though. I asked my teenage son if he had done anything with it prior to me working on it last. He said he put some gas in it and rode it around the back yard for a while. What he didn't realize is I was putting oil in the fuel tank because I suspect the oil pump is not working sufficiently. He did not add oil b/C he didn't know to do so.

So I'm hoping if i put some oil in the fuel and run it a bit maybe I'll be okay. I just hope it hasn't caused damage. it cranks up and idle's just fine. I'll mess with it this weekend (compression checks, etc) and post results.

 

All depends on how long he rode it with straight gas.. Doesn't take long to have a partial piston seizure that ends up getting worse.

 

Finally got a chance to mess with this one again today. Checked compression......right at 118-120 which was expected with what happened. I mixed some oil in the fuel and rode for about 20 minutes. I can tell it has lost some power, so a top end rebuild will have to be done sooner or later.

Thanks for the advise OPT.

 

Ooops.. Wouldn't drive it to much until you do,plus when you tear it down look over the bottom end carefully as the lower rod bearing and crank bearings have been in the same situation as the piston..