Has anyone ever seen this weird factory exist port ?

[gary55]

Low, not in the middle

PK80 not that old as far as rod type with A type piston, but with that cyl. your probably right. I know I've never seen one.

 

[butre]

ZL rod might be 10 years old or it might be from a year ago. I wonder if it was a prototype casting, or if someone at cdhpower is a huge 2 stroke nerd and built a couple of fancy one offs

 

[Evan Frucht]

Hey, here are some more pictures and details.

There are a few other unique elements, aside from the bridged exhaust port, that make it different from the cylinder that came on my $90 shipped ebay engine.

1. Overall surface finish is much nicer than the one on my new ebay engine, it's actually very nice. There is no pebbly rough surface, it's very smooth. I'm not sure but I suspect it is heavier too.

2. There are some round casting marks on the one side of the fins (shown in one of the pictures)

3. Rectangular intake port with studs 40mm apart. My eBay engine is 35mm

4. Larger casting/mounting surface for exhaust port, larger port too... and bridged of course

5. Also, Not positive but I think it's a few mm shorter

Sorry! I haven't cleaned it yet

 

[machanic]

Wow!! you must have gotten one of the Not For Export engines.

 

[curtisfox]

Wow!! you must have gotten one of the Not For Export engines.

Or a original that were built in Russia i believe, that the china copied .............Curt

 

[Frankenstein]

Really looks like an experimental model, those strange round things on the fins look like fill and air holes from casting. At least now the exhaust port looks intentional, I would still be leary of the motor honestly looks cheap to me.. I could be wrong though.

 

[gary55]

Didn't notice the bridged transfers in the earlier pics. So how tall is it from base to top at the stud holes.Is it 47mm dia. how far down from the top of cyl. to the top of the exhaust and transfer ports. If the numbers work you should try it out. If it runs better than normal it might be a good cantidate to be nikasiled.

 

[curtisfox]

How about the rest of the engine? have a picture of it together and complete. I know a lot of older engines had them bridges, some 2, with round holes. But through the years they got bigger, if the port is bigger i would not cut it out..........Curt

 

[gary55]

How about the rest of the engine? have a picture of it together and complete. I know a lot of older engines had them bridges, some 2, with round holes. But through the years they got bigger, if the port is bigger i would not cut it out..........Curt

So you have seen this type of cyl. before? How did they perform? At first I thought the open transfers might lower case pressure and not work well on piston port intake. Then seeing the bridge in the transfers and how well it is directing at least 1/2 of the charge it really has me wondering. This thing might be a real screamer with a reed setup.

 

[curtisfox]

I believe the older snowmobile, chain saws, ice auger, and most had a bridge in the port. Performance was not a problem as far as i know. Oh yes even the old go-karts had MC. engines, some 2 or 3..................Curt