Engine knocking

I think your intuition is on the right track.

The 400 twin has a plain bearing bottom end and I believe, no cam bearings. The cams spin in carefully machined bosses in the head and cam cover, with nothing but a healthy supply of oil to keep those bosses from getting wallowed out.........

TexasKZ wrote: I think your intuition is on the right track.

The 400 twin has a plain bearing bottom end and I believe, no cam bearings. The cams spin in carefully machined bosses in the head and cam cover, with nothing but a healthy supply of oil to keep those bosses from getting wallowed out.........

What do you think those bits came from? I know its probably hard to say but have any ideas? I havent done to much with motors

The crank and tranny get the oil first, then the top end. It would be prudent to open it up and asses the damage.
Steve

Drafter89 wrote: I lucked out on this one!! filled it with fresh oil and it runs fine.
Thank god!

Hmmm.... I've never seen an oil exam with that much metal where there was not some significant engine damage. Just be aware.

... 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.

Sounds like heat seizure due to lack of oil. the plain shell bearing bottom ends and camshaft bearings 'float' on high pressure oil, as well as taking heat out of bearings.

If it sounds really rough it is likely to be serious engine damage, if it was run low on oil before and seized up previously then the damage was probably done already.

My ex gf ruined a really nice Honda late 70's 125 twin learner bike, she changed the oil but didn't tighten the sump bolt enough, a steep hill and the sump emptied followed by engine seizure. The motor was scrap metal and not economic to repair.

Putting fresh oil in it and having it work is a bonus.......now I suggest before any more damage is caused by running it and hoping all is well......that you strip that motor down and find out exactly what happened. At the very least you will know that motor inside and out, as mentioned do not attempt this without a manual and preferably a factory one.......and post pics too......good luck

Yeah, I agree there is obviously some internal damage. 400/440 engines are a dime a dozen and parts can be hard to find and expensive. I would just drive that one and shop around for another engine or a parts bike.

The crank runs on plain bearings, if I recall the rotating counter-balancers run on the aluminum housing directly, and they may have been damaged as well,

swest wrote: 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

"If you can dodge a wrench, you can dodge a ball!"
LOL sorry couldn't help myself Steve, just reminded me way too much of that!

Sorry to hear about the lack of oil, I did that in a nasty old truck once that I wanted to get rid of and it sure did the job. Best of luck on the rebuild and hope your 400 gets riding again soon!

- Irish