TOPIC:

Does it backfire only at idle, or does it do it at higher rpm? Ed

Did you bench sync the carbs while you had them off again?

650ed wrote: Does it backfire only at idle, or does it do it at higher rpm? Ed

Seems to only do it at lower rpm

chconger wrote: Did you bench sync the carbs while you had them off again?

No didn't even think of it

Since the problem happens at low rpm I suggest you test the carb holders for leaks.

Make sure the vacuum caps are tight on the carb holder nipples.

Warm the engine up to normal operating temperature.

Temporarily set the idle as low as possible without stalling the engine. It should be down below 1000 rpm. The lower the better because when it is set low the carb slides are closed (or nearly closed) and this raises the vacuum level in the carb holders. The combination of the increased carb holder vacuum level and the very low idle amplifies the effect of the leak test.

Once the idle is set low, spray carb cleaner around each of the carb holders where they bolt to the cylinder head and where the carbs attach to them. If there are leaks, the vacuum in the carb holders will suck the carb cleaner in and this will affect the idle. It may cause the engine to stall. If the leaks are at the carb holder / cylinder head mating surface you need to replace the holders. If the leak is where the carbs attach to the holders you may be able to tighten the clamps enough to seal the leak. Some folks use starter fluid or other substances for the test, but carb cleaner works best as it doesn’t evaporate too quickly like ether and leaves no residue on the engine like WD40.

If you do need new holders just bite the bullet and buy them. Trying to seal things up with some kind of sealant or goop will only lead to frustration as it will at best only last a short time. Ed

Z1 has the holders for around $50 I believe....

You guys are a huge help for all us newbs thanks !

Tightened the clamps on the carb boots a little more and it seemed to fix the backfire out of the carb . But still backfires pretty bad out the exhaust

Lmmduramax wrote: You guys are a huge help for all us newbs thanks !

Tightened the clamps on the carb boots a little more and it seemed to fix the backfire out of the carb . But still backfires pretty bad out the exhaust

Check your valve lash.


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Nebr_Rex wrote:
Check your valve lash.


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Sorry not sure what you mean by valve lash ? Also it takes a little while for it to idle down ...very slowly drops. Having trouble to keep it running it just wants to die sometimes when I give it a little throttle.

Seems to run stronger when cold . How do I go about checking the cam chain ??

Air leak and do a valve adjustment. That's checking the valve lash. Not doing the routine maintenance like the valves is a common issue here. It's not done because it takes work and money. If not done, it will cost a lot more later.
When it runs better when cold, that can be a symptom of tight valves.
Steve

Lmmduramax wrote:

Nebr_Rex wrote:
Check your valve lash.


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Sorry not sure what you mean by valve lash ? Also it takes a little while for it to idle down ...very slowly drops. Having trouble to keep it running it just wants to die sometimes when I give it a little throttle.

Valve lash is the distance between the camshaft base circle and the valve follower. If there is too little or no distance, the valve can be prevented from closing when the engine is at operating temperature. The factory service manual explains the procedure pretty well, and even has some pretty pictures to help out.