Chainsaw Repair

It's only an assumption because I really don't know as fact .I assume however the 028 was most likely ported pretty close to the 038 in that it likely has around 99-101 degrees of opening on the exhaust .

From my observation it seems the later models had a little higher exhaust opening and slightly less squish as these earlier models and did have higher speeds and slightly less grunt .

That being the case one would naturally assume the transfer area on the newer faster models would also need a tad more area to sustain a bit higher rpm's .