Diagnosis help

[pete]

Got some pic's? If they're 80 - 82 450 carbs I'll recognise them straight away

But good score either way!

[droyce]

So left side still isn't firing

The issue with it not firing followed the bad float bowl before. I have to assume its something with the jets or the gasket that I swapped over to the new bowl. Because the right side is still firing with the bowl from the '78 carbs.

I won't have time to look into it today.

[droyce]

I'm willing to bet if I can swap in the correct bowl, the rattling problem might disappear. Obviously the side with the wrong bowl isn't getting enough fuel and is causing an extreme lean condition. I try getting a video with lower idle.

Well we've solved the float bowl problem, both sides are firing now. So much so that I have the idle screw all the way out and I cant get the idle speed down.

The bad news is the clunking/rattling sound is still there.

https://www.youtube.com/watch?v=PgmU...e_gdata_player

[Mekanix]

Sounds like the chain slapping around against the guide at the last bit.

[droyce]

Sounds like the chain slapping around against the guide at the last bit.

Its only coming from the left side though.

[droyce]

Any chance its the piston slapping?

[Mekanix]

Yes it could be.

I have seen this on my bike.

I fixed it by swapping piston's from left to right.

Try pulling the cam cover off and see if you have any cam walk.

Check valve clearance to see if its too tight now that its been running,

What effect does pulling the plug off on that side or the other have on the noise?

What did you have for piston to wall clearance?



I went back and reread the build.

You only had one piston while waiting for the other one.

did you have both cylinders bored for that one piston?

If so, do you remember which side that one is on.

My theory is that: the piston they bored the cylinders for was good in either side and right now its on the right side. The other piston that cam later has a slightly smaller size and the tolerance is too high.

[droyce]

Yes it could be.

I have seen this on my bike.

I fixed it by swapping piston's from left to right.

Try pulling the cam cover off and see if you have any cam walk.

Check valve clearance to see if its too tight now that its been running,

What effect does pulling the plug off on that side or the other have on the noise?

What did you have for piston to wall clearance?



I went back and reread the build.

You only had one piston while waiting for the other one.

did you have both cylinders bored for that one piston?

If so, do you remember which side that one is on.

My theory is that: the piston they bored the cylinders for was good in either side and right now its on the right side. The other piston that cam later has a slightly smaller size and the tolerance is too high.

They had both pistons, they had me write which is which. There is always the possibility they got switched however.

The engine made this sound before I bored it, I originally did the boring because I thought it was the pistons. Now its all new. Could it be the lack of fuel on the left side tore up the bottom end?

[Mekanix]

there goes that theory. But yes its possible to have two different clearances for each piston but if it was making the noise to start off with, I'm leaning towards something else then.


The bottom end can't be hurt by lack of fuel unless you over heat it or really abuse it or wash the crank with gas and run it. Even then your dealing with a roller bearing everything. It takes much more to hurt i than with plain bearings.
If there is damage there, it was there before.


Assuming the pistons are fine, It could be:

connecting rod bearings
crankshaft walk
balance shaft walk
bad balance shaft sprocket springs
Starter clutch, or needle bearings it rides on.
Balance shaft main bearings
crank main bearings
thrust bearings
stator rattling around.
starter clutch bolts backed out
*Rear timing chain tensioner bolt loose*
The 4 cylinders have this issue.

I'd drain the oil and pull the cam cover and stator cover.
Shake everything around and look for something that makes a clunk noise.


Cam walk will be obvious.
To check the rear chain guide I'd loosen the tensioner knob and take up the slack in the chain, then wiggle the chain guide with something to see if it moves up and down.

Look for marks on the stator see if the rotor itself is moving around at all and rubbing on the stator.
Pull and push on the crank to see if there is any movement.
Try and wiggle the starter clutch, between the rotor and gear to see if there is any movement.
Hold the rotor and put a wrench on the balance shaft bolt. It should move back and forth about a 1/4 inch because of the springs but it shouldn't clunk, it should spring in both directions.


Rotate the crank back and forth and then turn it 1/4 turn and do it again, look for noises. Do that until you get around twice.

I'm running out of ideas without more info.

[pete]

Could it be as simple as one of the chrome cam end covers is loose and rattling? It was a bit hard to tell from the video for me.

I know mine are slightly loose even with the screws done up properly and loctited in place. Mine don't rattle but I see how they could.

[chef1366]

Exhaust leak???

[droyce]

This is where I'm at, I can't get the damn cases apart or the rotor out (don't have the special tool)



Everything look fine to you?









The crank rotates smoothly, I can't feel any play in the rods. Starter clutch is tight, no play.

Now putting a wrench on the balance shaft bolt, I can't get the balance shaft to spring at all, its tight. There is no play either way when holding the rotor, even putting another wrench on the rotor bolt, nothing, I'm just fighting myself.

There are a few grooves and notches on the crank...






Any trick to getting the cases apart?

[Mekanix]

Did you get the hidden bolts ?
I kmow there is a few.

[droyce]

Yep, got them all per the service manual, plus the two in the oil filter.

[Mekanix]

Grooves and notches are for balancing the crank. its in the manual.

To pull the cases apart you have to remove the clutch and the bits behind that.

If you look at the front and back of the engine you can see a notch cut into the one part of the case and a hole in the other half of the case. You could use a bolt and nut to push the cases apart.

Those are the spots for the actual spreader tool.

There is one in your first picture just under the mount hole beside where the timing chain is flopped over.



Go to page 92 of the clymer manual ( 95 of the pdf file ). From there It shows the balance shaft with the springs inside the gear. Its definitely supposed to have some spring to it but I don't know how much force it takes to feel it.



To get the rotor off you don't need the tool, Just a 14mm bolt with a 1.5 thread pitch. Put a pin inside that fits inside the crank threads without damaging them. Tighten it down and then wack the bolt with a hammer. After a few times it should pop off. Just get a good high grade bolt.

Don't use just the bolt without the spacer. IT ruines the threads on the bolt and you can't extract it without damaging the rotor .