HELP! dying under throttle

Okay, how do i get 1 and 4 to top dead center? If it was a truck I would just use a big socket to rotate the crank, but how do i do that on my bike? I suspect the advancer is on wrong. Cause the bike will only start w/ the magnets white stripe out, but wont rev up. thanks

anybody?

I would have thought a 550 owner would be trying to help. I haven't owned a 550 for 25 years so from memory, I think it works the same as a larger bike... take off the right hand points cover (where your ignition pickup coils are). There will be a hex bolt. This bolt holds the mechanical advance. Under the head of the bolt is another hex bolt. This one is larger and the one you turn to turn the engine over. To find TDC, remove your plugs and turn the engine over with a socket (easier to use than a wrench because of the location of the pickup coils). At TDC for 1/4, you can stick your pinky or a pencil in the #4 plug hole and feel the crown of the piston at the top. I can't see how the advance can go on backwards but I am not familiar with your bike. Keep in mind also that this might not be the actual TDC but the second TDC as your plugs fire twice for every combustion cycle (lost spark). It doesn't matter since the 1/4 T mark should line up with the mark on your case when the #4 piston crown is all the way to the top. (#1 will be also but it is on the other side and harder to check).

Here's the manual:
home.comcast.net/~loudgpz/KZ5mnl.pdf

On page 60 (page 70 of the pdf), it describes the ignition timing. The timing marks are the same for points or electronic. Further details for the electronic stuff is a few pages later. You have to look through the little window with a flashlight, to see the marks.

You need to verify the motor-versus advancer alignment. When the 1-4 pistons are at Top Dead Center TDC, the timing mark should be at the line next to the T. At the same time, the rotor point should be pointing toward the rear pickup which is the blue/black pickup.

You can turn the engine over easy if all the plugs are out. That can be turned by the big nut on the advancer. The big nut is not an actual nut, but is keyed to the advancer which is roll-pinned to the crank. When you turn the big nut, you are turning the crank. Only turn it the same direction as the wheels. That is forward rotation. Don't use the small nut, it can shear off because it is smaller, and that is the bolt that holds the advancer on.

I'll respond more as needed, but work is a little busy right now.


Post edited by: loudhvx, at: 2007/05/02 14:06

So #'s 1 and 4 are the outside two plugs? What is the plug wire order? I want to verify they are correct too. I can't find the plug wire order in my clymer manual. thanks again.

As you sit on the bike, they are 1 to 4 from left to right. Number 1 and 4 pistons go up and down in unison, and the 2 and 3 pistons go up and down in unison. 1 and 4 are 180 degrees apart from 2 and 3.

1 and 4 both spark at the same time, but only one cylinder combusts at a time, alternating every rotation. The other cylinder is on its exhaust stroke. It gets spark, but there is no fuel to burn. The same happens with the 2 and 3 pair.

The firing order is not necessarily important to ignition timing since they spark in pairs. 1 and 4 spark 180 degrees from 2 and 3.

The advancer can only go onto the crank one way. It is keyed by a roll pin. However, the rotor can go on either of two ways (correct, or 180 deg out). The rotor is the pointy iron slug that rotates on the advancer. Looking at where it points is how we make sure it is on correctly. It points toward the blue/black pickup when the 1 and 4 pistons are near the top of their motion.

Post edited by: loudhvx, at: 2007/05/03 01:50

So the cylinder are 1-2-3-4, from left to right? I"m just checking, cause some of the threads I searched said 1-2-4-3, left to right. I just want to be sure. Thanks a bunch, I think that either the rotor is on wrong or the plug wires are. thanks again

Post edited by: tcbradbury98, at: 2007/05/03 11:14

1234 is the physical layout of the cylinders. 1243 is the firing order of the cylinders.

thanks got checked and at least a couple of the wires were switched. Would the bike idle if the wires and magnets were switched? Got it all fixed now. Gonna exchange the battery and fire it up. thanks to everybody, especially loudvhx and wiredgeorge.

okay, bike is good to go now. 1 and 2 are hotter that 3 and 4 so I am gonna adjust all the fuel mix screws to 1.5 turns and adjust the idle down and see what happens. Thanks again. Just to check, the coil w/ the black wire fires 1 and 4 right? green wired coil fires 2 and 3 right? The idle should change if I disconnect a plug right? thanks again

tcbradbury98 wrote:

Just to check, the coil w/ the black wire fires 1 and 4 right? green wired coil fires 2 and 3 right? The idle should change if I disconnect a plug right? thanks again

Correct on the colors.

The magnet polarity thread has a post with the details of what wires go to what coils etc.


If you disconnect a plug wire, you must short the wire to the engine by sticking a bolt or some other metal into the wire cap. It needs to go to the engine in order to complete the circuit for the other plug in the pair to fire.

EDIT:
I changed the page so the polarity can be confirmed through using a voltmeter instead of using the stripes/dots as the polarity test.
Details here:
home.comcast.net/~loudgpz/GPZweb/Ignitio.../PickupAndRotor.html

okay, new info. Bike starts easy on choke when cold. Idle is low though, 1 and 2 are still hotter that 3 and 4. Fuel mix screws are all at 1.5 turns, but changing them on 3 and 4 doesn't seem to do anything. On 1 and 2 the screws make the idle go up when fully seated. Does screwing the screws out make the carbs richer or leaner?

I checked the plugs and 1 and 2 are whitish, indicator of lean condition and plugs on 3 and 4 are carboned, sign of rich condition. Rechecked compression and all are within 10% of 150psi.

Bike has will rev as high as I want when on choke, but won't take any throttle on idle. Power on choke is way better than before, but issue off choke is still the same.

Idle screw has little to now effect.

HELP!