79 runability problem.

[whatscooking]

Let me ask this, can a engine be out of time, cam to cam or cams to crank, and still have compression and run, I say not but I got to ask. Or can the chains be loose enough to slap around and make stuff happen. Like I have said if I stay steady on the throttle this problem hides but if your going down hill or letting off it reminds me of something whipping or slapping not a miss. I looked at the Honda Manual and checked timing of the cams when I did the valves and I thought things were right.
I have taken the coils and wires from another bike with no change and put another Dyna module on also. I can brake the bike and lug it to death when it does this and there has never been a miss felt.
I see evidence that the head has been off, nice clean black gasket and new head bolts. I know the compression is 130-135 checked hot. I do not know what has been done to the engine.

[daves79x]

Big question is are #s 1 and 6 plugs still sooty? If they are and all others are clean, then there's still an issue. That has to be resolved, whatever it is. If the plugs are all clean now, then you might be experiencing a leaness issue at that throttle setting. You can go up to 68 or 70 on the primary mains to help with that.

How many miles are on the bike? The bike will run a tooth or two off on the cam-to-crank timing and will run OK with badly stretched camchains, but unless you have 50-75K of hard miles on the bike, they are likely fine.

Have you adjusted the chains and verified both tensioners are working? Wish I could ride your bike, I'd likely have some more ideas.

Dave

[whatscooking]

Which way does the bolt that holds the advancer on unscrew, right or left hand threads? Yesterday I went back with my timing light to look at how the advancer worked and I am seeing that It goes to full advance way quicker than the chart on page 22-12 in the shop manual shows, around 1700-1800 which is where my problem starts, at that rpm it should be 10 degrees advance. I do not have the degree wheel but I can see that it jumps up way sooner than the 2300 RPM on the chart. I checked the other 79Z and do see a difference.
The bike has 18,000 miles on it. I adjusted the chains with the valve cover off and checked by rolling the engine backwards with very little slop\play seen.

[daves79x]

Advancer bolt is right-hand thread - nothing odd. You may find the advancer stuck on the shaft, however, once you get the bolt out. Be careful pulling on the shaft - it is keyed into the primary shaft and can give enough to pull out of there. Only requires removal of clutch cover to fix, though.

Dave

[whatscooking]

Tell me that the advancer, that has had the Dyna changeover, has two springs. The reason I ask this is that mine has ONE. What the hell one. It has the bolt with the jam nut on the button and a place on the advancer plate to hook a spring but no frickin spring. I have not fully opened up the other Z in my shop as it has the original setup with the ignition and so I couldn't just swap it anyway. This has got to be what is going on. The advance jumping up to full at the low RPMes matches now.

[EMS]

[daves79x]

As Mike's pic shows, there are two springs. The Dyna advancer is a little more fiddly to get them both on, but it should have two.

Dave

[whatscooking]

Part ordered.

[whatscooking]

I was waiting on the mailman this morning. Shortly thereafter I hit the starter. Very happy to say the bike is operating like It should. Very pleasant to run through the gears now with it running strong.

[NobleHops]

I was waiting on the mailman this morning. Shortly thereafter I hit the starter. Very happy to say the bike is operating like It should. Very pleasant to run through the gears now with it running strong.

Great persistence!

[daves79x]

Glad to hear it!

Dave

[whatscooking]

The ironic thing about all this is that I have seen motors act this way before. In my previous life I was a fleet mechanic for a delivery company. I have seen ignition distributors so worn out eating themselves springs gone acting like this. When it was suggested to look at the advancer I looked and saw what looked like brand new and clean thinking all was well. I want to thank Terry for a special part or two but mostly for sincerely listening to every call I made to him. I walked away from this several times but was not going to give up.