I was riding my 400 last weekend pretty hard down at a nearby track. Toward the end of the day it kept shutting off when I would go over jumps. Before I made it back to my truck it made a clunking sound and just died. It will still turn over so the motor isnt locked up. I did notice my oil plug fell out sometime during the day, so pretty sure no oil was in the engine. Right now it will turn over but wont start, any suggestions.

 

Well let's see....... running an engine w/ no oil, hear clunk, & engine quits. Hmmm, shot in the dark here, but I'd say you wrecked it. I'd say you probably did damage from the crank all the way to the cam. Do a compression test, even with the compression release it should still have 80-100 PSI.

 

well you have 2 options, a complete rebuild or a new quad....its most definately blown up, unless its something real minor thats wrong with it, but im sure it was ran out of oil and was destroying ur motor like catman said

 

come on dude thats a no-brainer....

 

I know I messed something up, just didnt know how bad. I took the engine apart today and the only thing i seen wrong with it was the rings were gone and it needs rebored. Everything else looked pretty good, except for a little sand. I am going to go ahead a put a 440 kit in it. Do i need anything else with the 440 kit? Everything is stock for now, got a stage 2 jet kit and k&n powerlid waitin to put on it.

 

Well, if that's all that is scored you lucked out big time. Are you sure the crank bearings are smooth & tight?? Look very close at the cam lobes for wear. However, you might want to put in Hotcams anyhow to go with the big bore piston.

 

If you dont know enough to know what happened when your oil plug fell out then what experince tells you that it's only the rings. A little sand does more than a little damage to the crank. I would be hasitent to put any money into that engine. Good luck.

 

I knew something happened but not sure what. Thought somebody might have had it happen to them before. I knew something if not the whole engine would be bad. I know the rings are bad because pieces of the piston are melted onto the rings. My buddy is going to look at the bottom end. The crank is probably trashed but if not it would save me a lot of money. Hopefully luck is on my side.

 

Hell yeah, just had the bottom end took apart and looked at, everything be good. Got lucky as hell, piston fried before anything serious. Gettin a 440 kit next week, I found a good website for big bore kits a reboring if anybody is interested....http://www.lukesracing.com