MUD707

Thanks.

I have a 81 XS 400 with bad rings. I tore down the top half of the engine to change them, but the size isn't marked anywhere on them. I was wondering if anyone knew what size the standard piston or rings are. I miked the piston and I am getting 68.8 to 69mm is that the standard or is it oversized?

So I stopped at the Miller's Yamaha of uniontown which is my local Yamaha shop today to get a estimate on my bike if I brought it in for them to do the work. Their head mechanic told me that they won't work on my bike b/c of how old it was. Is this the kind of service most Yamaha dealers have or is it just my local dealer. My wife suggested buying a new bike instead of fixing this one, but if I do I'm not to sure if it will be from them.

O.k thanks for the tips I'll check them out later tonight. meanwhile if anyone else might have any good ideas keep them coming please. By the way what is the differance between a xs400h and xs400sh?

How would you know if it was the valves? I know the engine taps, but would the valves cause the oil to smell like gas. I plan on draining the oil I just put in it after I let it run for a litte to see if it smell like gas also. this is the first bike I owned since my cr80 when I was 13 and my dad worked on that one for me, but he passed on a few years ago so I'm not real sure where to start. I like the bike and would take it to a mechanic, but I'm tight on funds right now.

I recently was given a 1981 xs400 to me from my father in-law. It ran fine for a couple of days (only went around my farm) and then started blowing white smoke and smells like its burning oil. I decided to drain the oil and I noticed the oil smells like gasoline and is it was gritty. So I think the rings are shot everything else seems good. Does anyone know what amount of torque I should use when I reassemble the engine. I don't want to over torque the bolts and strip them, or have them to loose where it will loose compression. Any help would be appreciated.