1987 lt250r shakes alot. Handel bars make hands hurt after riding it. Anybody have an idea what the problem is?

Balancer bearing is probably bad and has a lot of slop. My 91 shakes a lot because it's ported and I have a cool head which eliminated the head mount. But check that balancer bearing because with a frame that old it may start to crack due to the shaking.

Here are a couple photo's of mine




http://i59.photobucket.com/albums/g286/Jas...wheeling014.jpg
http://i59.photobucket.com/albums/g286/Jas...wheeling012.jpg

Possibly was taken apart and the balancer is not in sync with the crank.

I had a 84 250r that I thought I could gain some hp by eliminating the balancer(took the gear off), what a mistake that was, you could not hold on to the bars for anything, shook worse than a jackhammer. My logic was the tecate didn't have a balancer and they were faster, so I gave it a try. That was 23 years ago, if I only knew then what I know now!! LOL

did you put any sealant in the tires?

My buddy had the same problem and he noticed another timing mark. I am not sure where the mark was but he was only lining up two marks and there are three. You might look for an extra timing mark that you are missing. His manual didn't even show this timing mark that is the reason he was missing it but he won't miss it again I bet ya. Good luck but I would start there.

maybe you need a new powerband, thats what happened to mine.

bingo

I've dealt with this a few times. Either your counterbalancer is malfunctioning or your crank timing is off one tooth.

Take your flywheel cover off and a look at the counter balancer. A lot of times there is a little piece of metal that wears out that helps position it on the shaft. If the shaking just started it is not your timing and something has worn out in regards to your counterbalancer.