Engine knocking

Just picked up this 77 kz400 today for 300 bucks and as I'm driving the antique home on the highway it just completely lost its power. I had the throttle wide open and it didn't respond..just acted like it wanted to die. I made it to the next exit and pulled off. Let it sit for a minute and cool off and tried to start it and the the kick starter barely wanted to move. I checked the little oil bubble and there was only a tiny bit of oil in the engine. I got it started but after cruising in 2nd gear on the way home the engine started knocking.. bad!!! Got it home safely, still fires up and seems to have good compression but why did all this happen you think?
Oh..and this bike has pods and the exhaust is cut down to collector pipe if that helps. And it's has been re jetted for those mods

If the bike was really that low on oil, could be a trashed bearing (crank, rod, cam, transmission, some combination), could be piston slap, but I'd put money on one of the bearings. Running an engine out of oil at freeway speed is one of the worst things that could be done to it.

You can drain what is left into a clean container, along with the filter, and look carefully for shiny bits. If they are present, you likely have a serious, expensive problem. The only way to know for sure how bad the damage is, is to carefully disassemble the engine with your factory service manual and some good measuring tools at hand.

+1

No or very low oil will kill an engine very quickly. Ed

Drained the oil. Only a thimble full was in it. I should of checked before I put it on the road. but oil is clean! Now on to disassembling the engine I guess

Where did the oil go?
Steve

That's what was in the filter
sorry for the pic quality but I wiped those shards of metal on the towel there

So you didn't fill it?
Steve

swest wrote: So you didn't fill it?
Steve

No. The guy I bought it from lives about 10 min away so I didn't bother with checking the oil. I just hopped on it and left.
Learned my lesson

WTF :ohmy:
I changed my oil on my Chevy one time, was putting in the oil but forgot to put in the drain plug. Lost three quarts before I checked it. Distracted by a low life again wanting beer. I'm now really good at throwing tools. All I have to do is pick up a wrench and give them that look. :evil:
On my own again. :woohoo:
I can hit a moving target at 300' with my rigging ax. :whistle:
Steve

I had a KZ400 for a while... nice little ride.
Does the crankshaft use plain bearings for rod and mains?
If yes.... OUCH X 100.
If no, you might have dodged a bullet on a major overhaul but if seized, your piston skirts will most likely be trashed and the cylinders will be scored like a MOFO. You'll probably be looking at a top end rebuild. Hopefully the cam bearing areas are OK.

I've seized my share of two stroke engines!!
A little acid in the cylinders to eat off piston skirt aluminum, a cheap honing tool from the local auto parts to clean/re cross hatch the bore and and a new piston with rings made them run like new again.

I lucked out on this one!! filled it with fresh oil and it runs fine.
Thank god!

Something is telling me to get in there and look around though because I did find a lot of metal bits in my oil filter :sick: so I must have done something internally.