Has anyone ever seen this weird factory exist port ?

[Evan Frucht]

Has anyone ever seen this. The exhaust port has a vertical bar in it and it looks like it came right out of the factory like that. Its part of the casting. Could this "design" have any purpose that would affect performance in a postive way? I'm thinking it would only hinder the engine...

 

[Street Ryderz]

Has anyone ever seen this. The exhaust port has a vertical bar in it and it looks like it came right out of the factory like that. Its part of the casting. Could this "design" have any purpose that would affect performance in a postive way? I'm thinking it would only hinder the engine...View attachment 79639

That's pretty cool and referred to as a bridged port,some will say that it can create a hot spot but they are used by many manufactures and cut out by tunners,Interesting that the transfers are open like the B.T. engines also that port looks good compared to most stock cylinders.Witch engine kit is that?

 

[Frankenstein]

Looks like the computer/person cut the mold wrong before casting. All these are are Styrofoam examples of the metal part, they pack it in a box of sand and pour molten aluminum into it, the Styrofoam immediately melts and the aluminum takes its place.

Somebody forgot to remove that bit and the metal was left in its place lol...

Just cut it out with a dremel, something that thin could end up burning and warping, then say bye bye to your rings and chrome.

 

[butre]

haven't seen it on a china girl before. lots of mopeds have such a feature though. they're meant to improve ring life.

open transfers too, where'd you get this top end? I want one

 

[curtisfox]

haven't seen it on a china girl before. lots of mopeds have such a feature though. they're meant to improve ring life.

open transfers too, where'd you get this top end? I want one

for sure if the port is bigger then stock, it is meant to keep the rings in place..........Curt

 

[crassius]

first I've seen of it - am also wondering who makes it

even more interested to hear how it runs

 

[machanic]

first I've seen of it - am also wondering who makes it

even more interested to hear how it runs

DO NOT REMOVE!!!! the bridge, they are used when exhaust ports are wide enough to swallow a ring, they should be slightly concave .003-4" deeper than the bore to allow for expansion also there should be two holes 3/32" in piston in line with the bridge for lube and cooling.

 

[Street Ryderz]

DO NOT REMOVE!!!! the bridge, they are used when exhaust ports are wide enough to swallow a ring, they should be slightly concave .003-4" deeper than the bore to allow for expansion also there should be two holes 3/32" in piston in line with the bridge for lube and cooling.

That port currently is Not big enough to allow the ring to expand into the port,It allows the port to be enlarged in width and not let the ring catch the top or bottom edges,the bridge should be flush to the bore as being concaved would promote the ring expanding into the port.

As you can see on this one the port width exceeds 3/4 the bore width so the bridge is needed to keep the ring flush with the bore and the bridge is also flush with the cylinder wall.If your not going to enlarge the port width then the bridge can safely be removed to aid in flow.Also two holes inline with the bridge makes no sence at all!

 

[machanic]

That port currently is Not big enough to allow the ring to expand into the port,It allows the port to be enlarged in width and not let the ring catch the top or ,the bridge should be flush to the bore as being concaved would promote the ring expanding into the port.

.Also two holes inline with the bridge makes no sence at all!

The bridge being in the middle of the hot exhaust gasses and with no cooling gets hotter than the surrounding metal, it expands more and will bow into the cylinder pushing the piston back against the intake side wall of the cylinder, it will get ugly. The two small holes in the piston will allow a small amount of the cooler fresh charge of intake gasses from the bottom end to cool and lubricate the bridge somewhat. The exhaust port doesn't have to be wide enough to swallow the rings but only wide enough to allow them to bow in a small amount, catch 6-7ths. if ring in a port at 6000 rpm and it gets real ugly fast.

 

[machanic]

From the experts.