Which cylinder head for malossi 220

[bogs]

I have had problems with my malossi 220 pinging in mid range.
I've tried , lots of jetting set ups, had it tested for air leaks , tried ignition retarders and it still does it , so I'm considering changing cylinder head.
The set up is malossi 220 sesc tuned, mmw head with 2.3 mm recess, cases matched, jl pipe and standard carb.
What does anyone suggest to have successfully used on a similar set up???
Ta

[LI150]

I had issues with the malossi head and have used the Sip one to good effect.

[Jack221]

To me it still sounds like a jetting issue. If its only pinging mid range and not full throttle then its just jetting. Keep moving the needle clip down. If you get all the way to the bottom clip of your X13 and it still does it you will need the next richer needle (X2).

[mick1]

Worth a trip to your local Dyno. I'd say it's jetting and the Dyno will either confirm or prove that wrong. Cost of a Dyno is probably the cheaper option as well

[fastfrog]

... mmw head with 2.3 mm recess...

What do you mean? an almost 2,3mm squish clearance?

[bazman]

I'd say he means the head has been altered to sit in barrel by 2.3mm.?
If not then squish is very large!

[bogs]

It has a swish of 1.25 mm , the head is machined to allow for the 60 mm stroke, base gasket and no head gasket .
As far as jetting goes, the air corrector is 160, it just four strokes with a 140, it makes no difference to the pinging however rich emulsion tube I use.
Good advice about the dyno.... If it was pinging due to hi comp head or combustion chamber shape would this be evident on a dyno?

[bazman]

Is it ok full throttle?
Could be fuel flow , with a standard carb I had issues when petrol got below half a tank.

[bogs]

It has a fast glow tap and a cosa float bowl and larger needle valve.
I set the m tech to be at about 14 ' btdc at about 6000 rpm which is where it pings.... Didn't make any difference.
After 6500 rpm the pinging reduces

[bazman]

What size atomiser ?Be3/4 ?