PE400 pinging at top of rev range

[rohan]

Premium fuel with a 25:1 mix - I know it should be 20:1 but this wouldnt be causing the problem would it?

[Mike52]

Premium fuel with a 25:1 mix - I know it should be 20:1 but this wouldnt be causing the problem would it?

Na

You have a large motor with a high compression ratio , older ignition and shit fuel .
It,s gotta ping , can,t do anything else.

You could prove a point by putting some AVGAS in it.
Betcha it stops pinging.

[rohan]

Avgas it is, next question - where can I get some on the Gold Coast?

[LWC82PE]

Premium as in 95? That is the minimum required for PE's back in the day as per the handbook but i honestly think you should use higher. Get some  BP98 or race fuel. Pump fuel is pretty crap these days, but really you should be able to tune it to suit the fuel.

[Mike52]

In the "OLD DAYS " the fuel had that ugly poison LEAD in it , guess what it was there for.
Avgas and BP racing fuel ( which is very close to avgas if not the same ) both still have lead in them.

Or as LW says start to detune it until it stops pinging.
Drop compression , retard the ignition , up the jetting until it blows black smoke.
I,me over stating it a bit but you get the general idea.
 
Avgas you get from the airport .

[rohan]

For those that remember, you used to be able to get AVGAS from the Tiger Moth hanger at the old Surfers Paradise Raceway on the Gold Coast about 15 years ago. The same location they used to have operation drag - where the cop’s would race the locals in a 400 chev powered VN cop car – great fun.
I was in my early 20's and used to put it in my VL commodore, fuel was around 55 cents a liter at the time and we used to pay 90 cents a liter for AVGAS (what a rip off  . Thought my VL was the fastest around with the AVGAS in her...

[oldfart]

Rabbit , can you remember a green 2 door Hatch back Torana that used to kick arse.
That was me .
You can buy AV gas at Auto Barn stores or try old mate at Oxenford opposite the pub

[rohan]

Unfortunately I don’t remember that Torry, now she would be worth 3 – 4 times what she was worth then.

[cheapracer]

How would hot exhaust gas cool anything?

http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

PR, try an equivalent but 1 grade colder ND brand plug (Toyota dealer) and glass bead blast your spark plug threads and plug seat as well as the head gasket surfaces on the head and barrel, the buildup of muck over the years can hurt heat transfer from the plug to the head to the barrel.
It's not thick with paint is it (head and barrel)?

[Lozza]

How would hot exhaust gas cool anything?

http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

Not anything there that remotely refers to a 2T engine.

[cheapracer]

Not anything there that remotely refers to a 2T engine.

2 strokes have a combustion cycle the same as a 4 stroke.

[Mike52]

Premium fuel with a 25:1 mix - I know it should be 20:1 but this wouldnt be causing the problem would it?

If you went to 20/1 Peter you would increase your chances of pinging because you would be running your bike leaner. (just a little )

[LWC82PE]

20 to 1 will bring it closer to standard specs and what the stock jetting was set up for. I would be starting at factory specs first. What is your compression like? did you use mineral oil for bedding in the rings? The thick paint is a good point. The guy on the PE forum with the same probs as you found a big part of his prob was caused by powdercoating on the engine which he ended up removing and just painting it. Apparantly some Canams came out with powdercoated engines had this problem too as it keeps the heat in.

[rohan]

Compression is good but havent checked it with a gauge,
Barrel and head were painted but not with an excessive coat,
Mineral oil was used to bed the rings.

[frostype400]

Sounds good well done now you can enjoy riding it, thanks Michael.