New Rings?

[Bryan300EX]

I recently bought a '01 400EX. After I got home I took the spark arrester out and rode it. I noticed smoke coming out of the exhaust when I let off the gas. It isn't a whole lot but enough that I want to fix it. It wasn't noticable with the spark arrester installed. I was thinking that it needs a new set of rings. Any help would be appreciated.

Also I was wondering how time consuming it would be to put on a set of new rings, and if it is difficult.

[enduro400rider]

it takes a while to do a rebuild ( a few days ) if you replace the rings you will need to take your cylinder to a machine shop and have it honed. you might want to get a valve job done while your in there. you will also need a top end gasket kit and possibly a new piston depending how bad your stock one is. i would recomend you do this project with someone who knows how to work on motors and you will definatly want a service manual. if you dont think you can do it plan on spending 200 to 300 at the honda shop

[mikeminyard]

If you are going to go to all that trouble I would recommend spending an extra $120 and put in a high compression piston. A little smoke is nothing to be worried about though, especially if you are not noticeably buring oil.

[prepracing]

Bad rings or wore valves, valve guides and seals could cause a little smoke. I would get new rings and hone the cylinder and let a machine/motor shop check your valves out. As far as time goes, it just depends on your situation. If all parts are available I would say about 2 days if you have someone else doing it. My local shop did my valves and honed my cyclinder in a few hours and I put it back together myself.

[cracer250]

When you took your S/A out did you rejet? That most likely leaned your jetting out a little causing your bike run hot. You can ruin rings that way depending how hard you rode it. What kind of oil do you have in it? I've heard of people switching from honda oil to a good synthetic and their smoking problems went away. Regular oil like the honda oil will break down easily at high temps. Just my opinion.