Engine Knock On Start Up? Whats Cuasing this..

These bikes are designed to run on 87 octane as long as they are fairly stock, I used to run 92 but makes no difference and costs more. You really don't want to run it too long on the side stand for the reasons you just stated. I live in SoCal and it gets hot here so I run 20-50 year round with no problems. I also shimmed my oil bypass valve for a little more pressure, been working great for over ten years. You say it gets hot here, where is "here"?

Thats the octane im running. No sense in paying for more! I live in MO. Riding season averages about 95* id say. Has gotten up to 110 a few times. That sucks.

Bullitt03737 wrote:

Well. I put 20w50 in her. The first start up was brutal noise wise. But it imediatly went away. I dont think it has done it agian since then. No gas smell in the old oil either. No loss of power since Ive notiched this going on. Im at a loss to what is casing it. Oh my freind brought up a good point. What octane rating are these bikes suppose to use? Also this noise is the valve furthest away from the ground when its on the side stand so maybe it just because the oil runs away...

A valve or lifter usually makes a "click" or "tick" kind of noise. The only thing I have heard knock is a worn rod bearing.

Well it still makes the same noise on startup. But its no where near as bad or often. The valves do seem pretty noisy, ticking a lot. So I Have a new valve cover gasket on the way which leaks pretty badly. So I hope I can kill two birds with one stone. I suppose I should search for a thread on how to check these properly..

well there's ticking like clock work (normal) and ticking like a rabid coo coo clock on cocaine (not normal). Chain driven DOHC engines all make noises in the valve-train.

A "knock - knock" on start up is usually a loose rod bearing. As soon as oil pressure gets up it fills the bearing-to-crank gap and the sound stops.

Going to thicker oil usually doesn't help, it still takes time for the pump to get pressure up. Thicker oil helps if things start knocking when the engine gets really hot, not a cold start noise.

You might try some STP oil treatment or Rislone as they tend to stick in places better and might quiet it down a little.

Bullitt03737 wrote:

... 81 Csr...Ian

Thinking this bike is the same 1981 CSR 1000 mentioned in an earlier thread. With rods turning in needle bearings on the crank with 3 lbs or less oil pressure, same as the Z1 and KZ900.

Theres me Ian and another that I know of. I pulled the carbs last night cuase it started leaking gas back through #3. But the carbs were fine except when I pulled the plugs out of the pilot jet circuits there was another plug of rust behind it. Crazy. And the others had residue. Its a miracle it was running in the first place! But I cleaned that out and it idles much better now. Its the petcock that dosent work and it dosent shut off, and forced fuel in the bowls. The valves just seem abnormaly loud to me compared to our police crusiser kz. The valve cover gasket leaks something feirce. Is that common occurance in these bikes?

Bullitt03737 wrote:

Theres me Ian and another that I know of. I pulled the carbs last night cuase it started leaking gas back through #3. But the carbs were fine except when I pulled the plugs out of the pilot jet circuits there was another plug of rust behind it. Crazy. And the others had residue. Its a miracle it was running in the first place! But I cleaned that out and it idles much better now. Its the petcock that dosent work and it dosent shut off, and forced fuel in the bowls. The valves just seem abnormaly loud to me compared to our police crusiser kz. The valve cover gasket leaks something feirce. Is that common occurance in these bikes?

Old hard worn-out leaking valve cover gasket should be replaced with a new one.

Noise from camchain is often quieted by synching the carbs. And also attending to the other tuning items, such as assuring correct valve clearances, ignition timing, new sparkplugs, etc., all toward a smoother running better performing engine.

Petcock only allows gravity fuel flow to the carbs, and doesn't force the flow. Where fuel is coming out the floatbowl overflows, it's often because the float needle tip is failing to fully seal the orifice in its seat (usually resulting from crud or grit at the interface).

Good Luck!

Bullitt03737 wrote:

The valve cover gasket leaks something feirce. Is that common occurance in these bikes?

Not really, unless somebody warped the cover prying it off or chewed up the edge scraping the gasket off. Even if your cover is chewed up, you can seal it up tight with black RTV gasket sealer if the leak is a chronic problem.

Patton wrote:

Bullitt03737 wrote:

Where fuel is coming out the floatbowl overflows, it's often because the float needle tip is failing to fully seal the orifice in its seat (usually resulting from crud or grit at the interface).

Good Luck!

Yep, been there. The needle tip is a metal-to-metal seal against the brass seat. Take the needles out and chuck them in a hand drill and spin low speed and polish the tip with #600 paper until dead smooth and shiny. Use a Q-tip and chrome polish to polish the inside of the brass seat until smooth and shiny.

If tyhere is any roughness or burrs at the junction between the tip and the seat, it will leak like a fire hose.

It has new spark plugs. The cam chain dosent really make any noise. Just a valve or two louder than the others. I have a new gasket coming. So ill check out the valves while im in there. Whats really werid was the oil was seeping up past the outermost valve cover bolt. Its like its getting hot and "boiling" out. Is there anyway pressure could build up inside? Ehh. Ill probaly just ride it and wait for it to blow up. I dunno. I dont want this to turn into a money pit!