pinging sound in polini kit

Just put a Polini kit onto a za50 and on the first kick it started with a pinging noise. the head is at enough of a distance that the piston is not hitting against it, and the piston goes through the cylinder flush. Any ideas what this could be?

Re: pinging sound in polini kit


How is the crank doing? Are you using the stock con-rod? Is there any slop in either end of the con-rod (in the direction of piston travel)?

Have you split the case, replaced the crank bearings, and/or replaced the connecting rod?

If you jiggle the flywheel back and forth, do you hear parts tapping against each other?

Re: pinging sound in polini kit

you put the piston on upside down?

Re: pinging sound in polini kit

same set up, mine never seemed to be hitting the head, but when it was running it was.. once upon many years ago

Re: pinging sound in polini kit

I'm going to assume this is Willie posting on Justice's profile, and I'm going to assume this on Jeff's ZA50.

No matching? Come on you know better then this, but I'm not going to get into it, you know better.

Check to make sure your bolts that hold the intake on are not over tightened and causing the cylinder to warp; to do this take off the cylinder and piston while leaving your intake and reeds installed, then make sure the piston slides smoothly through the bore (while you got it off at least put in the boost ports).

Did you chamfer at all?

Are you running all the gaskets?

Re: pinging sound in polini kit

everything worked out alright, the case wasnt chamfered yet, and all the gaskets were used. this is justice by the way, made the post to help jeff out....butthead

Re: pinging sound in polini kit

So case match and chamfer (the cylinder not the case) and report back. At a minimum put in the boost ports.

What carb and pipe is he running?

Did he rebuild the ZA or just slapped it on? Actually never mind on that I know the answer.

Did you guys check the intake bolts like I said?

Re: pinging sound in polini kit

Same problem. Here's my experience so far. Mine is case matched, ports chamfered, and yet you can still here the pinging with or without a head gasket. Definitely not hitting the head and it's not the timing because retarding did nothing. Guessing it's the crank that has some slight play. Running and going strong till I can replace the stock crank. Good luck

Re: pinging sound in polini kit

It's the Polini 'happy' sound.

Mine did it for over 1000 miles and was fast and awesome.

AS long as you're confident the crank is good, just run it. It's fine.

Re: pinging sound in polini kit

yeah, it's my ZA. i have the 15mm bing on there and (for the next few days) the stock pipe. the kit was a wee bit off center and when we got it perfect the ping when away (or a least diminished for a while). now it's back. we'll get to the case matching / chamferring and see what happens.

any other suggestions?

Re: pinging sound in polini kit

roadent$ craig /

i got a ping noise too... no problems. ive heard its normal... the "polini ping". my points were shit and i was misfiring a ton and i still blasted it. just mix rich the first couple miles and your fine.

Re: pinging sound in polini kit

Aluminum kits are louder (pingier) then Iron, your probably fine; but seriously you should case match, those boost ports are crucial to the life of kit.

If the pinging really bothers you take some little (like 1/4")chunks of cut up tire and stuff them between each of the fins on the cylinder.

Re: pinging sound in polini kit

i'm so fucking sick of wasting my time reading posts like this. 'i put my shit together all janky and now its not running right... why!?!'

stop wasting our time.

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