TOPIC:

Have you checked compression?

Timing might need to be adjusted. The timing marks are only a suggestion. Especially if your compression is low AND gas is nothing like it was 40 years ago.

Hi guys. Solved the problem with the carbs (leaking float...).
But now I have a different problem with the engine. Last time I went for a ride it worked perfectly. But few days ago I've noticed a major problem...as I pop into 1st (or any other gear) and release the clutch lever, the bike won't move at all... first I suspected that there is something wrong with the clutch. Then I removed clutch plates and it seems that there is a problem somewhere else. If I turn the rear wheel with my hand, the inner part (clutch center) doesn't move. I'm not much of a mechanic, but I assume that if I turn the wheel something should move, right?

Take a look at the engine sprocket to ensure it has not come loose. It is the sprocket at the forward part of the drive chain. If it is not secured properly it can cause the symptoms you described. Ed

650ed wrote: Take a look at the engine sprocket to ensure it has not come loose. It is the sprocket at the forward part of the drive chain. If it is not secured properly it can cause the symptoms you described. Ed

That's exactly what happened, thank you 650ed! It looks like the thread on the shaft was damaged and some wise guy tried to fix it with teflon tape....I will try to turn a new nut that will fit the lightly damaged thread...

Be SURE to use a new, correct lock washer on that engine sprocket so the problem never happens again. Ed

Hi guys,

I have some troubles here....for some time I tried to figure out why my bike in running pretty well when the tank is full, and start to run on only 1 cyl when the tank is half full. Then I took apart petcock and installed new gas tubes and it worked fine. Yesterday I reset the ignition timing with strobe light. Today I went on a ride but the engine doesn't run well. It vibrates a lot and it doesn't have the right kick when I open the throttle. I wonder if there is maybe something about ignition timing...since the instruction manual was written 40 years ago and I suppose that gasoline back then was a bit different? Does octane rating affect ignition?

Hi guys, I think I found the problem. Today I removed needle jets and one is considerably more worn than another. How much play should the needle have in the jet? Should the needle completely close the needle and prevent flow of the gasoline?

Here’s a photo of needle inside the jet.

Photo

if the needle jet or needle are worn they should be replaced. what state are the diaphragms in? Did you figure out your ignition problem? is your advancer rusty?

Is that a pic of the needle and seat or the needle jet and jet needle?
Post a pic that is 90 degrees of the one you posted.


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DoctoRot wrote: if the needle jet or needle are worn they should be replaced. what state are the diaphragms in? Did you figure out your ignition problem? is your advancer rusty?

Yes I know but I have problem finding the correct one (Z-4), but I do have machines to make new ones.
The diaphragms are in good shape, they are not torn or damaged.
The ignition works fine, breaker points and capacitor are new, advancer cleaned and lubricated.

Here’s the pic (I hope it will upload from mobile phone...)