1990 GS500E - Motor issues

[EastCoast]

I am brand new here and trying to fix a bike for a friend. She bought a 1990 GS500e in pretty good shape but wont start. I checked the spark and fine, getting gas also. Feel like the exhaust valves are not shutting or bent. Previous owner said he rode to a cookout and then went to leave and it started for about 3 seconds then stopped and hasn't been able to start since. Then it sat for 6 months. From looking around on the net, I have read about this situation before and points to the exhaust valves. I can tell you that it has a nice aftermarket pipe on it and the carb did not appear to be jetted. Perhaps that is the reason for the burnt or bent valves? Her boyfriend ordered new exhaust valves and tried replacing them but bent the new ones so now has lost interest but she still wants it running. Any help would be appreciated. Would it be easier to replace the whole motor and have this one for parts? Any have one available? Any other motors fit into this bike? Again , any help would be appreciated. If I can fix or find another motor....the carb needs jetting to match the slip on....suggestions there also please.

 

[Nessism]

Wow, this reads like a train wreck.

First of all, exhaust valves don't just fail. Some idiots don't ever adjust the valves and eventually they hang open and burn, but this takes quite a few miles and when they do fail it doesn't happen suddenly. Regardless of the misdiagnosis, it seems that another fail occurred by the so called mechanic that replaced the valves. At this point I'd pull the head back off and figure out what's going on for yourself. Replace the valves as needed and get the cam timing right so they don't bend again. This is all quite simple for someone that knows their way around a tool box. There is no reason to change the engine.

 

[EastCoast]

Yeah it is a trainwreck....the guy said he could replace the valves and set the timing but I guess he didn't know what he was doing..evident by the fact that he bent the new valves he just put in. I know I am going to have to jet the carb to keep it from happening again. My guess is that it was run too lean and it cause the exhaust valves to stick open or burn and warp. I wasn't there to see them when removed. Anyway, the new ones bent and that indicates to me that he didn't get the timing right as you stated. I am trying to become as educated on this as much as I can before attempting to fix the mistakes that already took place. Where can I look to learn about setting the timing when I get it back together. I have a lead on a complete head for pretty cheap so might go that route but would still need to set the timing correctly. And would still need to jet the carb to keep from running lean....any suggestions there...jet kit preference?

 

[Nessism]

Even if you buy a complete head you still need to pull it all apart and check everything and replace the valve stem seals, so I don't see the point in purchasing the head complete. Just get the parts you need and go from there. It's hard to say what's going on without seeing for yourself. For example, if the valves truly burned the valve seats may be toast too.

Check this link for a service manual. Better yet, go buy the factory Suzuki manual for the bike in question. You can't work on a bike without the manual. http://members.dslextreme.com/users/storagecliff/images/more_manuals.html

 

[Big Rich]

East Coast, look around over on the GSTWINS site as well. It is dedicated to the GS500, so there should be plenty of specific info for you.