Intermittent "tick" that slows engine 81 kz650

Recently have noticed an intermittent "tick" sound from the engine when I'm sitting at an idle like a red light or stop sign. I have cleaned the carbs several times and every time I have found a rusty looking grit in all 4. I don't know what it's coming from as my tank is clean and the fuel filter rarely gets little bits in it. But the tick happens randomly and the bike Boggs down slightly every time it happens. I have also noticed that after I clean my carbs when I first start it of course I have to use choke then as it warms up I have to turn it off or the bike will want to die. Is this normal? Before carb cleaning It would take much longer before I turned the choke off. I was also wondering about the fuel/air mixing valves. The manual only states to put them back to the original position it was in when you took it apart, me not knowing if anyone has ever messed with them which I'm guessing they have, I don't know the original position. How would I figure out how to get it set properly?

Valve tick wouldn't come and go and wouldn't really affect operation much.

I suspect it's more likely a spark issue. A cracked aprk plug wire etc can cause the spark to jump to the head instead of going to the spark plug. I would try to run it in total darkness and look for sparks wherever the plug wires get near the engine, and look at the plugs to see if a spark runs along the outside of the spark plug. Also check the coils for a similar spark running on the outside of the coil.

Does the problem get worse as you try to open the throttle?

Could be an gas blow by into the intake port/carb that sounds like a "tick" or "hiccup" from the engine.
Check your valce clearance and cam chain tension.

Oh, lots of questions there, the guys have given you pointers re ticking, I cant think of anything else that would cause that.
Re choke, Full choke to start then slowly ease it off to maintain required tick over. If you leave it on full it will be over rich and the engine will stop.
Airscrews, starting point is 1 and 1/4 to 1 and 1/2 turns out from lightly seated. Then fine tune with a colourtune or by ear. By ear means you will have the bike warm and ticking over. Slowly turn ONE airscrew in or out to get maximum revs. Re adjust the tick over back down using the thumb screw, then do the next airscrew. Repeat for all 4 airscrews several times. It's a faff to do it that way but if you don't have a colourtune its the best way.
To ensure you have the correct jets in the carb and mixture at higher revs you will need to run it for a good few miles and see what colour the plugs are afterwards and adjust accordingly.
Gunk in the carbs, it can only have come through the fuel system. Either its dirty fuel from the gas station (do you use the same place each time?), or your tank is not as clean as you believe or your fuel pipe is not modern fuel proof and is getting eaten by the fuel from the inside out. I would suggest replacing the fuel pipe as its cheap and ensuring it is modern fuel resistant.

The grit getting into the carburetors doesn't make sense to me if a new in-line motorcycle fuel filter was installed.
You should only have to clean the carbs once.

Have you vacuum synchronized the carburetors?
A vac sync can make a significant difference in how good it starts & runs, especially when the engine is cold.

How many miles are on the motorcycle? It may be do for a valve clearance check. just something to keep in mind & not put off.
Doing the check is fairly straight forward. changing shims is more work but should be doable.
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agrestixrock wrote: . . . have cleaned the carbs several times and every time I have found a rusty looking grit in all 4. I don't know what it's coming from as my tank is clean and the fuel filter rarely gets little bits in it . . . .

The stock fuel filter is inadequate.

Would add an aftermarket inline fuel filter.



Good Fortune!

I was thinking he installed an in-line fuel filter already, but I'm probably wrong about that. doh. :blush:

So, as Patton says, install an in-line motorcycle fuel filter. some from the auto parts store don't flow enough fuel.
The correct size for the 81 650-CSR is 5/16. The tank is probably full of rust at the bottom.

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The type of filter that flows with a gravity feed fuel system won't filter very fine (like that type with the gold stone inside), so it doesn't surprise me that rust dust is getting through. And by virtue of finding rust in the carbs that's evidence that the tank is not properly clean, even though you may think it is by peering inside the tank through the cap.

I'd derust the tank first thing. Evaporust works good and is safe for the paint. There are other derusting products that will work just as well and are cheaper, but they are harsher. Before derusting you have to fabricate plugs for all the various openings such as the petcock hole, main filler, and any fuel gauge that may be present. There are tons of derusting threads so I'll stop here and encourage you to search out more info if you need it.

Good luck

Derust the tank for sure. After that use a good fuel filter. I use a Golan Super Mini 5/16" fuel filter (70-312G 5/16 Barbed Fittings). They are not cheap, but one will last a lifetime; I got mine from ronayers.com. They use a stainless steel filter element that can be cleaned. They filter out very small 10 micron particles but still pass fuel at a rate of 6 gallons per minutes – MORE than enough for any bike. They are very small so they fit well under the tank. Also, I used a 5/16” stainless steel elbow to make the bend from the tank to the cabs so there is zero chance of the fuel line pinching. I got the elbow at a place that specializes in propane supplies. Ed

Thank you everyone! I will look into derusting the tank. I am just using a red plastic filter I got from the parts store but maybe the bike shop will have something better. As for the tick, after cleaning the carbs it didn't really happen that much but it is getting colder and I noticed it more on hot days. This morning I did notice my #2 spark plug was shaking a bit while running and when I grabbed the cable to see if it was loose I got a good shock. Guessing it's got to be that. I will look at the plug and make sure it's tight. Looks like I'll be getting some new spark plug wires. For the leaky gas, it hasn't been as bad still occasionally drips but I'm guessing it's the float bowl gaskets.

loudhvx wrote: Valve tick wouldn't come and go and wouldn't really affect operation much.

I suspect it's more likely a spark issue. A cracked aprk plug wire etc can cause the spark to jump to the head instead of going to the spark plug. I would try to run it in total darkness and look for sparks wherever the plug wires get near the engine, and look at the plugs to see if a spark runs along the outside of the spark plug. Also check the coils for a similar spark running on the outside of the coil. [hr] Does the problem get worse as you try to open the throttle?

Loudvhx nailed it a week ago. A carb issue normally doesn't come and go at a stop light. OR tick, for that matter. (usually it will consistently run like crap)

A cracked / arcing spark plug cap or rubbed through plug wire, or possibly a cracked plug porcelain will all cause a noticable "ticking" sound. Carbs don't tick. When it bogs down, you are more than likely dropping 2 cylinders since 2 plugs fire at the same time on different compression strokes. All it took was a good zap to find it. I call that free therapy. lol The plastic caps screw onto the solid plug wire, UNLESS someone already >improved< the spark plug wires by "upgrading" them to a automotive resistor wire. (Totally wrong) I really doubt billy-bob in AZ or a bike shop is qualified in vintage kaw repair.

in chasing this demon, I hope you aren't causing more problems for yourself in the fuel / air department from your mis-diagnosis. OR sealing a bunch of crud into your gas tank for eternity by coating it without actually removing the rust and scale first. Coatings are meant for leaking tanks. I posted a few links to some good non-toxic gas tank cleaning articles a while back. For cheap too.

Metal rescue is kinda pricey, but it works well. There are others that are cheaper, but it will not harm the paint, unless it has ferrous metal in it. (red iron oxide). The "wood bleach" stuff is cheap on ebay, but I have never used it.





One last note, if you are going to start changing out igniton parts blindly, instead of finding and fixing the problem, you will cause more self induced future problems if you use the wrong ignition parts.
My bike uses copper core, non-resistor wires and STOCK NGK BR8 plugs with the 5K resistor plug caps. If you start mixing and matching a bunch of oddball parts, you will soon need to buy new coils (wrong primary winding resistance), then a new igniter from using the wrong el-cheapo coil, etc.

Not trying to slam anyone, just trying to point out the pitfalls of using mismatched parts in a attempt to fix something SIMPLE. Research things before you start changing out parts. In just making this posting, I and others before me have tried to steer you in the right direction. I did not see any prior posting that was wrong, concerning carbs, except carburetors are not problem. Of course like a lot of neglected bikes, they tend to have multiple problems. the question then becomes.. where to start. It ALL needs to function properly.