Determining which carb is leaking

[cowboyup3371]

Honestly, set your screws at 3 turns out and get rid of that homemade manometer. Get a decent one and test your settings again. Afterwards, set your idle at 1500 or 2000 and adjust your screws by the highest idle method listening and watching for that needle to move.

[scott]

I think I'm missing something. First of all, the Clymer manual says for 82 models and earlier to line up the mark to the left of the T for the TDC mark. Mine has a mark to the right of the T (and no mark to the left).

My pics didn't come out great for some reason:


My pic doesn't look exactly like the the Clymer manual so maybe I don't have a stock unit? It does look newer than 30+ years.



Also, with the marks lined up as above, my chain doesn't seem to be lined up anything like the manual. It's definitely not in a position for me to count the pins between 2 and 3.



I must have screwed up somewhere so I'll do some more reading. Anyone have any tips? Or is this indicating something is wrong and is causing my back pressure issue?

[scott]

Reading the Clymer manual and the service manual from BassCliff, I didn't see anything obvious (other than my TDC markings don't seem to match). The service manual does say "While holding down the timing chain, rotate the crankshaft" which I'm not sure what they mean but it is in the re-assembly section so I was assuming it's because the crank sprockets aren't installed yet.

A side note, this is what my spark plugs looked like while I have them out checking the cam chain. If this is only showing the last state of the engine, it was doing the vacuum synch so it's showing the idle state (unless they're so badly charred that my recent mixture changes are not showing). The plugs are only a month or two old if that's relevant. If I'm reading this right, Carb #1 is lean, Carb #2 is ok, Carb #3 is ok, Carb #4 is rich.

[scott]

I found a post in another thread that seems relevant:

Remember - 4 cycle motor, so the cams CAN be 180 out, give it another rotation (I assuming you did this) to see if something lines up

So I rotated it until the 2 was near vertical and noticed that there was a different notch on the ignition plate so I lined those notches up. It seems closer at least. Here is the ignition plate position (it looks slightly misaligned in the pic but maybe that's the camera angle):



And here is how the sprockets look:


I count roughly 23 pins, not 20. Could it be this far off and still run?

[tom203]

I think I'm missing something. First of all, the Clymer manual says for 82 models and earlier to line up the mark to the left of the T for the TDC mark. Mine has a mark to the right of the T (and no mark to the left).

My pics didn't come out great for some reason:


My pic doesn't look exactly like the the Clymer manual so maybe I don't have a stock unit? It does look newer than 30+ years.



Also, with the marks lined up as above, my chain doesn't seem to be lined up anything like the manual. It's definitely not in a position for me to count the pins between 2 and 3.



I must have screwed up somewhere so I'll do some more reading. Anyone have any tips? Or is this indicating something is wrong and is causing my back pressure issue?

Your signal generator looks like the ones on the 80 550 (later models had hole cutout, instead of big slot) "T" mark is TDC for #1 and #4 unless the japs are out to confuse me (very likely!). My clymer manual for chain drive 650 indicates 19 pins ( between mark 2 and 3 ) but 20 pins for shafty 650- I will take a wild guess and say that the 550 and chain drive 650 are identical.-but I often leap to conclusions so beware. That pic you show of chain with mark 1 facing forward and mark 2 vertical, is that with crankshaft on "T" mark ? Looking at that pic it seems to me that mark #3 should be about vertical and 19 pins from #2, not 23 pins. Would it run? apparently yes! Intake camshaft appears to running behind. What does this mean? At bottom of piston travel after intake stroke, piston reverses and starts to compress mixture, but intake valve has to be closed or the mixture can shoot back thru intake valve and then thru carbs.
Are we having fun yet???

[scott]

Your signal generator looks like the ones on the 80 550 (later models had hole cutout, instead of big slot) "T" mark is TDC for #1 and #4 unless the japs are out to confuse me (very likely!). My clymer manual for chain drive 650 indicates 19 pins ( between mark 2 and 3 ) but 20 pins for shafty 650- I will take a wild guess and say that the 550 and chain drive 650 are identical.-but I often leap to conclusions so beware.

The manual seems to indicate it should be 20 pins.

That pic you show of chain with mark 1 facing forward and mark 2 vertical, is that with crankshaft on "T" mark ?

No, that's with the crankshaft on the "F" mark. I assume that's 180 degrees off but according to Big T's post in the other thread, that may not be a problem (could be wrong).

Looking at that pic it seems to me that mark #3 should be about vertical and 19 pins from #2, not 23 pins. Would it run? apparently yes! Intake camshaft appears to running behind. What does this mean? At bottom of piston travel after intake stroke, piston reverses and starts to compress mixture, but intake valve has to be closed or the mixture can shoot back thru intake valve and then thru carbs.
Are we having fun yet???

Hehe - well it's looking like you were right about the cause of the problem! Pretty impressive! I have to wonder how it would have gotten so far out of alignment though. It's not clear to me how to get it into alignment either. The stuff in the manual seems to be coming from the perspective of having everything disassembled. Is that what I'm going to have to do? I hope not.

I'm wondering if I should post a new thread in the Engine/Drivetrain/Clutch - while I thought I had a carb overflowing problem it seems to be something else entirely.

[tom203]

The manual seems to indicate it should be 20 pins.


No, that's with the crankshaft on the "F" mark. I assume that's 180 degrees off but according to Big T's post in the other thread, that may not be a problem (could be wrong).


Hehe - well it's looking like you were right about the cause of the problem! Pretty impressive! I have to wonder how it would have gotten so far out of alignment though. It's not clear to me how to get it into alignment either. The stuff in the manual seems to be coming from the perspective of having everything disassembled. Is that what I'm going to have to do? I hope not.

I'm wondering if I should post a new thread in the Engine/Drivetrain/Clutch - while I thought I had a carb overflowing problem it seems to be something else entirely.

If manual says 20 pins, so be it- it that's wrong, one of the gs members should have dove in by now and said otherwise. So, your intake camshaft is running behind. Someone probably fiddled with it years ago, and left you to fix it. The cam chain tensioner is an odd device- if not installed correctly (with lock screw released ). the chain would be too loose and could skip on the gear, but who knows. Low mileage, so chances are good that this is an old problem causing poor running.
If you removed the cam chain tensioner, I don't know if there is enough slop in chain to let you relocate chain on gear. Remove all spark plugs, and turning the 19mm nut on crankshaft, you might be able to do it. Usually, you should only rotate crankshaft clockwise, but with tensioner removed, you maybe could rock it back and forth to get more slack. And you got valve spring tension to add to fun!

First bike, keep up the good work! next bike will be alot easier!