Tell me what you think of this motor work

D

Dagwood834

Location
Kansas
Tore into the motor that came in my square to reseal everything tell me what you think of the work done to the porting and crank best I can tell it’s a 4 mm stroke and the domes were re cut looks like quite a bit has been cut off of the sleeve at the transfers and the exhaust port has been raised way up. Gtg run it or start fresh with unmolested parts?









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Storbeck

Location
Minnesota
fastgtfairlane said:
just curious why they would have opened up the side of the sleeve by the bottom of the transfer ports and not done something to the intake side of the sleeve.
Click to expand...

That seems strange to me as well, and I've seen other posts saying that exhaust port shape is a Protec thing, but it makes zero sense to me. It looks like all of the disadvantages of a wide exhaust port without gaining much blowdown time area.

I'm not a pro engine builder so I dunno.
 
kevbo

kevbo

Location
dfw
Thats an OLD 650 race motor. Sell all that garbage and get a newer 62T engine. If you want to use it then measure the exhaust port. If its less than 70%, blend the sides and run it till it pops.
 
TheBuzzard

TheBuzzard

Location
the jetski grave yard
I had a cyl with that exact wing port in the middle but I sold it on ebay ages ago. A guy I know has one with the wings at the top and that sj rips. Raising the sleeves up increases the flow into the transfers with a straighter shot. Its an additional cost since it's a lot more work grinding hard sleeves.
 
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