Does anyone have and EVO thats modified and have ping or piston knock in the 3000 to 3800 rpm range.
Mph ranges from 75 to 85, noise changes with throttle -quieter wot and when easy back off gas.
I am trying different plugs, have been using the Iridium tip but since the cam change have noticed more noise, back to H-D brand.
1991 E Glide 10.5:1 SE pistons .020, ported heads, Crane 286 grind cam, HI-4 ignition, HSR42 with 180 main and 1 size richer needle at top groove, VH classic slip ons with true dual set of head pipes.&nbsp\\;\\\\\\;&nbsp\\;\\\\\\;Bike runs very good all around-no hesitation or boging out at all. PLugs are light gray with just a very faint tint of red and gets mid 30's at 75-80mph.
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Greg

 

I had the same thing. Only my knock would happen between 2500 and 3000 RPM. I would have to keep it under 2500 RPM. Then someone suggested I add some Seafoam to the gas and oil. The knock went away never to return. No idea why it was knocking or how Seafoam fixed it, but glad it did.
Quigley

 

&nbsp\\;Two thumbs up on the Seafoam!!!!

 

What is seafoam? I've heard of it before, but never really gave it much thought. There's so much crap out there on the market. I gather that it's an additive for oil and gas, but what is it doing? When should you use it?

 

Try running your ign. in race mode with voes hooked up if not already doing so. I have simular set up just 10.1 and daytona twin tech ign. in street mode it pinged slightly went to race mode ping gone also 91 or better octane gas.

 

Set the rev limiter way up and advance way down and always use 91 or higher octane.

 

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Its an additive you can get at just about any auto parts place.&nbsp\\; I use it in my vehicles yearly.&nbsp\\; For cars you can suck it in through the vaccum on the brake line - about half a can.&nbsp\\; Let it sit for 5 minutes and then start it back up.&nbsp\\; It smokes like crazy (fun to do just to see the neighbors freaking out!) and after a few minutes all the carbon build up is out the tailpipe.&nbsp\\; You can also add it right to the gas tank to clean out the gum and stuff in the carb/injectors.&nbsp\\; It also works in your oil (although I never leave it in there long myself - maybe 50-100 and then drain).&nbsp\\; it's like the Windex of additives - just cleans anything.&nbsp\\; It really is good stuff.&nbsp\\;

 

Took a timing light with adjustable dial and set it to 25 degrees, noise is quieter but still there at 80.
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25 at what RPM? the manual states 15 at idle (1000 rpm) and max at 35 degrees?

 

25 degrees at 2200 rpm with the advance curve in the middle, according to the crane timing graph that is part of the instructions.&nbsp\\;\\\\\\;www.cranecams.com