1981 XS850 Midnight Special Engine Help.

[knightops]

Hey Guys, you have all been a great help to me in the past and I am hoping you guys can come through for me again. I am currently restoring a 1981 XS850 Midnight Special and I am nearing the end of my project. Went to start the engine today after filling it with oil and gas, got it to spark a few times and then the engine seized. Pulled off the valve cover, seems to be way too dry. Pulled off the oil line from bottom end to the top end, nothing was dripping from the line. The oil light went out when I was able to get it to turn over a few times, but the engine just seems to be on the dry side. I don't know why the engine won't continue to turn over. While it was turning over, I was working out issues as to why it wouldn't start, but the engine was not turning over for more than 1 minute total. I wouldn't think that this would be enough to seize the engine simply from a lack of oil. Please help. Anything I can do without having to tear the engine apart would be great. Thank in advance guys.

[DGXSER]

To Sieze or not to Sieze,that is the question

Ok,,I tried.....

Anyway, if it will turn over after you let it sit, the engine is not siezed from lack of oil. Siezing form lack of oil is bearing and mating parts melting together from lack of oil to cool them.

First thing to check of course is your battery. I have not worked on an XS750/850 in a very long time, but it should be the same as the 1100 in that th ebttery needs to have a minimum of 10.5 volts at the TCI to trigger the ignition coils and fire. From your description it sounds like your losing juice to the battery. When you go to restart it, after letting everything rest, does it turn over like nothing happened before?

Lack of oil to the top end. It is odd if your oil light is going off while it is cranking, this would signal your developing enough oil pressure at the switch to trigger it, which should be enough to send oil up that tube to the head. I wonder if your actually getting the oil pressure or if your just losing the battery enough to turn the light off.

[knightops]

Battery

Thank you for your reply. It definitely is not an electrical issue. I should have stated that in my original post, sorry. It has plenty of juice. The starter is definitely trying to turn the engine over. I thought maybe the battery was dying, so I jumped it with my V-star 1100 I have sitting right next to it. No Luck. I also have a kickstarter on this bike, it wont budge. I am not trying too hard because I don't want to cause more damage. I should also state that when the clutch is pulled in, the kickstarter and final drive turn very easily, so that should rule out any transmission/clutch issues. Thank you again DGXSER.

[mack]

Before you

Drain the battery, pull the plugs and try to crank the motor manually, you'll know right off if it's seized.

[knightops]

Not seized

I pulled the plugs and turned the engine manually on the timing side. It will turn clockwise, but when I try to turn it counter clockwise (the way the engine should turn) it locks up. Now that I have done that test, it seems like to me a possible bent valve, but the timing looks good. How would a valve bend other then bad timing? Could it be something else that is stopping the engine from turning?

[3Phase]

Knightops, like Mack says, have you tried backing off the engine? If something dropped into or jammed the engine it will still have to be found and fixed but it will let you know if the engine is seized.

Pull the spark plugs and put the transmission in 3rd or 4th gear, then try to roll the bike back to see if you can free the engine while you listen for any clunks or clanks.

If you can't or don't want to do that, remove the pickup coil cover and put a wrench on the flats on the timing plate on the end of the crankshaft, then try to turn the engine backward.

[cywelchjr]

Sounds to me like something in one of the cylinders and it stopped it when it hit the top. Going backwards works because it's moving the piston back down. I'm guessing that after moving backwards it will move back forward the same amount it went backwards? If not, it would be something else in drive parts (such as maybe the cam chain) that is jamming on forward rotation but isn't on reverse rotation. In any case, pulling the head may be required at a minimum.

[knightops]

I think you are right Cywelchjr, I will have to pull off the head and see if it will turn. If it does, I know it is something there that is causing it. 3Phase, I certainly appreciate your input. I think my latest post hadn't posted yet while you were typing your response. Thank you again gentlemen.

[3Phase]

Sorry about that, Knightops, but I'm glad the engine isn't seized!

I went and got something to drink and forgot to refresh the page when I got back before I hit the Reply button. Oops....

[mack]

Not sure if this

Is pertinent, but since your going to have the cams out again, make sure that the chain is properly seated in the bottom end. I know with the 11's it's easy to get it wedged next to the gear not on the gear if your not careful.