750 4 cam timing

Well, as many of you know i had a top end problem with my 810 so i pulled the head. Before i spend a bunch of time and money on fixing this head, i want to be sure that the valves were the problem. So i threw the old kz head on it, and timed it. I have checked everything over and over. It refuses to fire, or even pop. I just pulled the valve cover and checked the cam timing again. It is right on with the motor at tdc. Now, i am thinking that maybe the cam sprockets arent bolted on right, as there are three different sets of holes to bolt it to. Also, my buddy was helping me tear it down, and said that the timing was off from where it should be in the old head. Does anybody have a picture, or know of which cam sprocket holes i should be bolted into.

Right know, with the cylinders 1 and 4 at tdc, z7ex is level with the head on the exhaust camshaft, and in is level with the head on the intake camshaft. They are spaced the right number of teeth apart(45-46). But the exhaust cam sprocket is bolted on with the square mounting hole, and the intake cam sprocket is mounted with the circle mounting holes. Does anybody know if this is wrong and what is the correct way????

The only thing the motor will do when cranked over is backfire and shoot a flame through the carbs once and a while

your cam spockets are in the right holes it sounds like they are timed right it if its backfiring you may have reversed your ignition pickups try reversing coils it sounds like your ignition timing is 180 degrees out

Coils are inthe right order, checked that too. Borrowed my buddy's compression checker today, and tested each cylinder. I had between 30-55 psi in each cylinder! I couldnt see how that could happen as all of the head bolts were tight. Then i realized that the new head gasket i threw on was from my 750 gasket set, and not the wiseco 810cc head gasket. Would this cause a large compression drop? WOuldnt using a head gasket that was too small sever the crush gasket around the cylinders and cause it to lose compression?

??????

did you check the valve clearence, the space should be .33MM or .013 in, if the clearence is not right the valves won't close properly and cause loss of compression, also time the cams at 105degrees (109 for exhaust, the valve cover will bring it back to 105). Every time you change cams you will have to go through clearence and timing, it's not just drop them in and go. there are pills under the cam followers that are different sizes but you can grind the tops of the valve stems to get the right clearence

I NEED HELP!!!!

I have never seen anything like this. Its probably just something stupid that i am missing but i dunno. I threw a head gasket for the stock 750 motor on my 810 to get it running like said above. Now i just put on my wiseco 810cc head gasket to correctly fit, and i tightened down the head pretty good with the ratchet, but have not yet torqued it. The cams are not in, just the head bolted down. I am still getting only about 30 pound of pressure in each cylinder! What might be my problem!!! It has not been running for a while know, and all i want is to ride again.

Thought i found the compression problem, but was once again let down. I rememvered that i did not have any of the stock washers under the head nuts, and thought maybe the nuts were bottoming out. So i used my deep APE head nuts, and tightened those on there. Still only getting a little over 30 pounds of pressure.

ANY IDEAS????

jordan wrote:

Thought i found the compression problem, but was once again let down. I rememvered that i did not have any of the stock washers under the head nuts, and thought maybe the nuts were bottoming out. So i used my deep APE head nuts, and tightened those on there. Still only getting a little over 30 pounds of pressure.

ANY IDEAS????

Leakdown test should determine source of compression loss.

Good Luck!

I will try a leakdown test. Can the tools to do a leakdown test be bought at most autoparts stores? The wierd thing is that this head was just removed from a perfectly running motorcycle. My buddy just replaced it with a GPZ head

In this instance, might be able to have an assistant use a rubber tipped air nozzle pressed into sparkplug hole to pressurize the combustion chamber, while you listen for air escaping at suspect areas (exhaust; carb intake; crankcase vent; head gasket).

Of course not up to standards of a real leakdown test tool , but fast and cheap!

Good Luck!

jordan wrote:

I will try a leakdown test. Can the tools to do a leakdown test be bought at most autoparts stores? The wierd thing is that this head was just removed from a perfectly running motorcycle. My buddy just replaced it with a GPZ head

Can the tools to do a leakdown test be bought at most autoparts stores? -- Yes, and also at Z1E.

Good Luck!