About to explode, cam timing problems!

Hey my name is adam and I have been lurking for about 6 months and thought ya'll might be able to lead some insight into my problem. I bought a 75 z1 in original condition about 6 months ago and just recently got done doing a rebuild. I'm a very experienced mechanic and this problem is driving me up the wall. The odometer was missing, but I would say it had about 20-30k miles on it. I didn't replace any cam timing components. Only thing that semi-worried me was the cam chain auto tensioner, I figured the spring might have weakened over time. Anyways I was driving one day, and i started hearing a small amount of cam chain noise.. I figured it might go away. I took it home and figured the cam chain just needed to be tightened.. I thought it was weird it loosened up, I figured it might have been because I ride it like i stole it. So, i proceeded loosened it up and let it take up the slack. Started it back up and the noise got louder. I did it agian and it got even MORE loud. I thought maybe the the auto tensioner got stuck in the slide and it wasn't taking up the slack. I took it out and put it back in, started it once more. It made a hell of a fucking racket. I figured I better reset the cam timing and take the cams out. I did it once already, when i rebuilt it so I figured it would be a sinch. I pulled the cams out, pulled the chain taut, placed the exhaust cam in, placed the intake cam in, tightened everything back down to spec. Made sure i was 28 links from the mark to the 28 , the arrows were flush with the head. Put in the auto tensioner and turn the motor over with the tensioner untightened to make sure all the slack was taken out of the chain ( per manual ) Then the real troubles began. After turning the engine over with or without the cam chain adjuster tightened down, the marks will be totally off. I made some pictures as its quite confusing to explain

I have taken the cams out of this thing ATLEAST 50 times, Trying different ways to get it set. I have failed and im afraid if I tighten down these cam caps anymore I'm going to end up with some stripped bolts. Think i need a manual tensioner? New cam chain? Any help would be appreciated

I notice in the photo it looks like the chain has been replaced with a masterlink type chain. Did you recently replace the chain or is that how you bought the bike?

You're timing is correct. Cam chain wear will cause situations like this. You won't get the marks any closer than what they are now if the cam chain or idlers are worn out.

A 75 wouldn't have had an auto tensioner. They were manual adjust tensioners. Consult your service manual for adjustment procedure.

As you turn the motor over, watch the cam chain up by the top idler. See if you get slack sections passing through there.

I would also pull the top idler and see if the gear wobbles around.

Another probelm area is the little shoe in the front of the block. They break or wear through. No amout of cam chain tensioner adjustment will correct that situation. Look down inside there and see if you can spot a problem with the shoe.

larry is the guru hear for engines so i can't add anything...

but my first take was that the marks were for checking clearances and the end of the cam marks are the ones used most often for installation...eggs level and facing out ....

larrycavan wrote:

I notice in the photo it looks like the chain has been replaced with a masterlink type chain. Did you recently replace the chain or is that how you bought the bike?

Thats not a real picture of my bike, I didn't replace any cam chain related peices.

You're timing is correct. Cam chain wear will cause situations like this. You won't get the marks any closer than what they are now if the cam chain or idlers are worn out.

A 75 wouldn't have had an auto tensioner. They were manual adjust tensioners. Consult your service manual for adjustment procedure.

I was saying auto tensioner as in, it has a spring that automatically takes up the tension when you loosen up the screw. Not like an ape where you have to manually adjust

As you turn the motor over, watch the cam chain up by the top idler. See if you get slack sections passing through there.

Yes, about every half turn on the crank there quite a bit of slack by the top idler.

I would also pull the top idler and see if the gear wobbles around.

It has side to side play, but no up and down play

Another probelm area is the little shoe in the front of the block. They break or wear through. No amout of cam chain tensioner adjustment will correct that situation. Look down inside there and see if you can spot a problem with the shoe.

Are you speaking of the peice that the adjuster pushes on, that then pushes on the cam chain?

Adamsz1 wrote:

larrycavan wrote:

I notice in the photo it looks like the chain has been replaced with a masterlink type chain. Did you recently replace the chain or is that how you bought the bike?

Thats not a real picture of my bike, I didn't replace any cam chain related peices.

You're timing is correct. Cam chain wear will cause situations like this. You won't get the marks any closer than what they are now if the cam chain or idlers are worn out.

A 75 wouldn't have had an auto tensioner. They were manual adjust tensioners. Consult your service manual for adjustment procedure.

I was saying auto tensioner as in, it has a spring that automatically takes up the tension when you loosen up the screw. Not like an ape where you have to manually adjust

As you turn the motor over, watch the cam chain up by the top idler. See if you get slack sections passing through there.

Yes, about every half turn on the crank there quite a bit of slack by the top idler.

I would also pull the top idler and see if the gear wobbles around.

It has side to side play, but no up and down play

Another probelm area is the little shoe in the front of the block. They break or wear through. No amout of cam chain tensioner adjustment will correct that situation. Look down inside there and see if you can spot a problem with the shoe.

Are you speaking of the peice that the adjuster pushes on, that then pushes on the cam chain?

The shoe I mentioned can't be replaced without pulling the block off. It's in the front of the block. It's held in by a screw from the bottom side. Quite common to see them broken.

They're difficult to verify with the motor in the frame because it's hard to see down in there. You can pull the cams out, move the wiring aside and shine a light down inside the cam chain tunnel for a visual inspection.

That chain slack every half revolution isn't good. I wouldn't ride the bike with that situation going on.

bikebandit.com has schematics that will show you the components if you don't have a manual.

Everything is solid.. rollers, shoe, idler assembly, tensioner assembly. Do you think a manual chain tensioner will remedy the situation. I find it hard to believe the cam chain got so far stretched in the 300 miles since the rebuild. What would you replace to be safe

Edit... assumed due to 300 mile stretch... My bad!........ Not trying to insult, just asking the question in case....

Which chain did you order/install.. 122 or 124 link?

OMR

I said that is not a picture of my bike and I did not replace any cam chain related pieces.

What I ment in the above posting is, the chain was the original chain, but it was working fine 300 miles ago. Though, I do remember it had alot less slack under the idler pulley when the crank was turned.

Oem advancer should look like the image below.
Be certain about location of the T mark, as differentiated from the numeral "1".

Before adjusting the tensioner, use 17 mm nut (NOT 13 mm bolt head) to hand rotate crankshaft to TDC, aligning T mark with permanent case mark. This puts most cam chain slack at rear where the rub block presses against it.

Adjusting the automatic cam chain tensioner:
The "automatic" refers to pressure against the rub block which reduces chain slack.
Loosen the lock nut, then loosen the bolt. A spring inside the advancer is calibrated to set the correct pressure on a rod that presses against the rub block (that's the "automatic" part, otherwise equivalent to "finger tightening" a manual adjuster).
Then tighten the bolt (which holds the push rod in its freshly automatically adjusted position), and then tighten the lock nut to secure the bolt. "Snug" is sufficient for both the bolt and lock nut.
The automatic tensioner cannot be adjusted too often.

Good Fortune!

[Click on image to enlarge view.]

Yes, my advancer is the one to the right. I have 3 manuals that tell me what you just told me. I understand how to do it. The problem is once I get it set and spin the motor over by hand with a 17mm wrench. The marks are not aligned on the head anymore. It seems its jumping a tooth when I spin it over. Like theres too much stretch in the cam chain

Here's a diagram for ready reference in the thread.

[Click on image to enlarge view.]





[Add checked items to Pick-List] REF NUMBER PART NUMBER DESCRIPTION QUANTITY US CA CN REMARKS
[Add to Picklist: 12057-001]
1 12057-001 IDLER ASSY 1
[View Supersession]
[Add to Picklist: 112G0635]
2 112G0635 BOLT-UPSET,6X35 4
[Add to Picklist: 92027-155]
3 92027-155 COLLAR 4
[Add to Picklist: 92075-119]
4 92075-119 DAMPER RUBBER 2
[Add to Picklist: 92075-120]
5 92075-120 DAMPER RUBBER 2
[Add to Picklist: 12057-002]
6 12057-002 IDLER ASSY 2
[View Supersession]
[Add to Picklist: 12052-005]
7 12052-005 SHAFT,GUIDE ROLLER 2 Z1-A/B, Z1
[View Supersession]
[Add to Picklist: 12052-003]
8 12052-003 SHAFT,CAM CHAIN GUIDE 1
[Add to Picklist: 92075-232]
9 92075-232 RUBBER,GUIDE ROLLAR 4 USE WITH 12052-005, USE WITH 12052-002
[Add to Picklist: 12048-001]
10 12048-001 TENSIONER ASSY,CHAIN 1
[Add to Picklist: 12055-002]
11 12055-002 ROLLER,CAM CHAIN GUID 1
[Add to Picklist: 92075-123]
12 92075-123 DAMPER RUBBER 2
[Add to Picklist: 21070-003]
13 21070-003 CHAIN,CAM SHAFT 1
[Add to Picklist: 12054-001]
14 12054-001 PUSH ROD,CAM CHAIN 1
[Add to Picklist: 92081-107]
15 92081-107 SPRING,TENSTIONER 1
[View Supersession]
[Add to Picklist: 11009-1980]
16 11009-1980 GASKET,TENSIONER 1
[View Supersession]
[Add to Picklist: 12049-1003]
17 12049-1003 HOLDER,TENSIONER 1 Z1, Z1-A/B
[View Supersession]
[Add to Picklist: 410B0600]
18 410B0600 WASHER PLAIN 6MM 2
[View Supersession]
[Add to Picklist: 112G0620]
19 112G0620 BOLT-UPSET,6X20 2
[View Supersession]
[Add to Picklist: 311B0600]
20 311B0600 NUT 6MM 1
[Add to Picklist: 92003-093]
21 92003-093 BOLT,TENSIONER ADJUST 1
[View Supersession]
[Add to Picklist: 12053-019]
22 12053-019 GUIDE,CAM CHAIN 1 E/NO. 062686--
[View Supersession]
[Add to Picklist: 220B0610]
23 220B0610 SCREW PAN HEAD 6X10 1