Engine knock :(

Ok so here's the story: Bike was running with no real engine noise before I took off the carbs to clean. Didn't open anything else up, only changed the radiator. Got my cleaned carbs back, put them on, fired her up, and now there's a savage knock coming from the front left cylinder (rider's left). I took the valve cover off and looked at the cam lobes, and didn't see any pitting or scouring, etc. There is oil getting to the top as everything was coated.

Could something have fallen into the cylinder when I took my carbs off, and now be stuck making that noise? (I thought it would just seize the engine or hole the piston), or is is something upper head related?

Thanks

EDIT: Checked to see if it was a "clutch chatter" like mentioned in some other posts, but it remains regardless of the clutch being engaged or not.

 

Lets make sure it's a knock and not a solid ticking sound. If it is a deep knock then pull the spark plug wire off that cylinder and see if the noise changes in depth or goes away. If so possible problems are wrist pin or rod bearing. Sounds very unlikely for something like that to happen so sudden.

I'd guess something like a small screw, nut etc fell in to the cylinder or may be sticking the valve open/not letting it close all the way and it's just hitting the piston.

Take the spark plug out and bring the piston up close to TDC and see or feel w/wire if something is in there or embedded in the piston top. Possible it's still on the carb side of the valve and not dropping thru.??

I hate those type of noises.

 

So when you pull the spark plug, see if it is damaged. it could be a carbon knock?
but the best plan is to Check all cyls comp. and go from there ..:thumbsup:

 

Believe it or not, but if one cylinder is not firing, it'll have a knock noise.

Check the plug from that knocking cylinder...if it's wet, your plug isn't firing. If it's dry and Very clean! then your not getting fuel.

I doubt anything fell in.....it would have caused more damage by now.

Report back

LL

 

Ok. Took out the plug, looked inside, the top of the piston looks rusty (the small part I can see at least) I didnt' see any damage though, tried it with out the plug in and no sound change to the knocking noise.

It is getting gas and firing, as the plug has spark and the exhaust pipe is hot. I took the valve cover off again in better light and turned the crank a few rotations, still no visible damage to lobes, but I don't know how to inspect the valves and springs really.

I will shoot a video to see if that helps, and will upload it asap.

Thanks for the tips guys!

 

Here is the video:

Knocking Video

 

Sounds like a valve is out of adjustment big time. Or the cam chain tensioner is broke. Check your valve lash on 2&4 cylinder. If OK then your tensioner is bad.

I'm betting on a valve adjuster came loose. That's all.

By the way that's more of a ticking noise compared to an engine knock.

 

I see. How do I check the valve lash and what specs should I adhere to?

The video doesn't quite give the intensity of first hand, as the sound kinda maxed out the mic on my digital camera, but I will be taking it all apart anyways.

 

If you have a fax number I could fax you the section from the manual. I haven't been able to find a down loadable service manual for the 83-85.

You need two .005 feeler gauges to use at the same time.

 

Ok so I found the problem. Small washer or something must have made it's way down into the cylinder. So it's outta there, but now I'm trying to put it all back together, but I can't seem to figure out how the cam chain tensioner works to get enough slack to put the cam sprockets back on.

And on the cam chain tensioner assembly, should there be a rod sticking out from the bottom facing the front, coming in contact with the chain?

 

Ok. So doing pretty good considering I don't have a manual. I got everything back together, and the cam sprockets lined up to what I thought were the right markings, but I guess not. I guess I just have the cams upside-down? When I turn the crank at the alternator, it only goes about 3/4 of a rotation, before it refuses to move.

On the front head at TDC, cylinder's no. 2 and 4, when looking from the rider's right side (throttle side) the intake cam was as close to 7 o'clock as I could get while still having the markings line up, same with the exhaust at 1 o'clock.

Should I just ignore the markings, and go for what the cam lobes should be at according to the book? Or should I ignore the lobe position and just line up the markings (which is what the carl parker tutorial has (but his were marked before hand, where as I was just stupid).

Thanks for everything!

 

I got everything back together, and I can crank it a full 360 degrees in either direction. But I must have messed something up as it won't even fire on the front two cylinders. I'm guessing that valves are open during the compression or ignition stages.

This is with the timing indicators matched up to what the clymer manual says, and I checked the markings many times, and made sure I was at TDC. I've had enough for today I think, but I wanna sort this out tomorrow, it's supposed to be nice this weekend

Thanks guys.

 

Time to fire up that RD??
no valves, no cams, no timing chains.......

 

Haha yeah no kidding, easy to work on. Only problem is: tiny gas tank, heavy drinker = not good for touring, and I gotta trip to the west coast coming up :s