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Discussion Starter · #1 · (Edited)
After stacking my Cag, I had time on my hands to do some porting and polishing. I ported & polished the exhaust port to match the IP2 pipe I will do the transfer ports when I've decided exactly what I want to do with them.



I'll try and post more at a further distance.

Demtoofast.
 

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Discussion Starter · #5 ·
I havn't tested yet, I hope to today. I've chucked in a Rocket Key and 1.4 clutch springs too, so whatever differences/improvements will be as a result of all mods. But we'll see.

Demtoofast
 

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I see the porting but not the polishing, lol. Regardless good job on the porting. It looks as if you did not port all the way through the port and just the opening. This is good because if you ported it like that all the way through I bet you would have lost power. If you port all the way through, you are really only supposed to port the sides and in some cases the top but never the bottom.

Let us know how it runs.
 

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Discussion Starter · #9 ·
Ok Ok, I know the polishing isn't 100% yet. But I only used 400 grit paper. When I port the transfer ports, I'll finish off the exhaust.

Demtoofast
 

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Discussion Starter · #10 ·
Well, I tested the bike today, and boy was I dissapointed. It seems that I have made myself a 49cc bigbore ashtray. My porting has robbed the bike of all of its bottom end, some of the mid range, and most of the topend. All in all, the bike has dropped in top speed by 8-10mph. You gotta laugh though!

Is the cylinder a dead duck? Or can something be done to rescue it, like maybe porting the transfer ports to counter this loss??? In honesty, I think probably not. Oh well, back to the drawing board.

Your suggestions are welcomed.

Demtoofast.
 

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Yeah you ported it way too much. I'm surprised you didnt burst through the port.

Try this out...put the cylinder back and and turn the flywheel. Look through the exhaust port at the piston where it reaches BDC (bottom dead center, lowest point) and look to see how the piston is in referrence to the exhaust port. If the top of the piston is still showing from the exhaust port, try lowering the exhaust port by porting matching it to the top of the piston. Don't go too far or you'll burst through. Doing this mod will make sure that all the expended gas/air will be released at the piston's BDC.

Also, try messing around with the squish. Add more gaskets to see how the engine reacts to this, or don't use any gaskets at all. If you don't use any gaskets, make sure the piston won't hit the top of the head.

This is why I tell everyone, more isn't necessarily better. I know first hand from porting the case and head.


Demtoofast said:
Well, I tested the bike today, and boy was I dissapointed. It seems that I have made myself a 49cc bigbore ashtray. My porting has robbed the bike of all of its bottom end, some of the mid range, and most of the topend. All in all, the bike has dropped in top speed by 8-10mph. You gotta laugh though!

Is the cylinder a dead duck? Or can something be done to rescue it, like maybe porting the transfer ports to counter this loss??? In honesty, I think probably not. Oh well, back to the drawing board.

Your suggestions are welcomed.

Demtoofast.
 

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quote
"Try this out...put the cylinder back and and turn the flywheel. Look through the exhaust port at the piston where it reaches BDC (bottom dead center, lowest point) and look to see how the piston is in referrence to the exhaust port. If the top of the piston is still showing from the exhaust port, try lowering the exhaust port by porting matching it to the top of the piston. Don't go too far or you'll burst through. Doing this mod will make sure that all the expended gas/air will be released at the piston's BDC."

This doesn't make sense,how are you gonna lower the port to match the piston's top if it is already higher than the port?

However,your cylinder isn't a total loss,use high temp epoxy and fill the areas of the ports that are cut too much,not the best way to go but it does work.Also do not port the transfers too much ,you will loose velocity in the transfer and drop your peak rpm,best thing to do is widen the exhaust port slightly to increase area,then raise the port in the center like a notch in the middle,this should increase power delivery and keep the exhaust gas velocity high even to know you now have a larger port area.

Tom
 

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Sh*t you're right. My bad. I got confused there for a sec.

I have used JB weld to fix mistakes of porting done on my head. Works fairly well. No cracks at all on the epoxy.

Another good product is this other High Temp Epoxy that you can buy over at Kragen or Autozone. Its a product made for Ace Hardware actually. i forgot the name of the epoxy, but it can withstand temps twice the max temp of the JB welds.




Bulldawg racing said:
quote
"Try this out...put the cylinder back and and turn the flywheel. Look through the exhaust port at the piston where it reaches BDC (bottom dead center, lowest point) and look to see how the piston is in referrence to the exhaust port. If the top of the piston is still showing from the exhaust port, try lowering the exhaust port by porting matching it to the top of the piston. Don't go too far or you'll burst through. Doing this mod will make sure that all the expended gas/air will be released at the piston's BDC."

This doesn't make sense,how are you gonna lower the port to match the piston's top if it is already higher than the port?

However,your cylinder isn't a total loss,use high temp epoxy and fill the areas of the ports that are cut too much,not the best way to go but it does work.Also do not port the transfers too much ,you will loose velocity in the transfer and drop your peak rpm,best thing to do is widen the exhaust port slightly to increase area,then raise the port in the center like a notch in the middle,this should increase power delivery and keep the exhaust gas velocity high even to know you now have a larger port area.

Tom
 

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Discussion Starter · #18 ·
Thanks for all of your input guys. Its help lie this that makes our scene so strong.

Now that you've mentioned JB weld, I remember when my Dad's Kawasaki strimmer blew up about 13 years ago. It blew a ring and scored the cylinder up real bad. He filled all of the scratches and scores with JB and that thing was like new. No compression loss. It still performs well to this day.

If you rememver the name of that high temp epoxy, please let us know.

Thanks a bunch

Demtoofast.
 

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http://epoxyputty.com/thermosteel.htm

For us people in the U.S, we can buy it at Kragen or Autozone. For the U.K, not too sure. You might have to special order it.

The JB weld I have used is holding up great so far. Also, I have seen racers use JB weld to shape their ports in their car's heads, so I know JB weld would work well in your case.

Hmmmm...this just gave me a good idea ;)


Demtoofast said:
Thanks for all of your input guys. Its help lie this that makes our scene so strong.

Now that you've mentioned JB weld, I remember when my Dad's Kawasaki strimmer blew up about 13 years ago. It blew a ring and scored the cylinder up real bad. He filled all of the scratches and scores with JB and that thing was like new. No compression loss. It still performs well to this day.

If you rememver the name of that high temp epoxy, please let us know.

Thanks a bunch

Demtoofast.
 

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I'm currently using that "Thermosteel" on two primaries of a header on my car to patch up a crack that occured because they used a mild steel brace to connect the two stainless steel tubes. The Thermosteel is probably about 6" away from the exhaust port on my heads. This stuff is awesome!!!!! Before using it you must clean the area or it won't stick well when it's heated up. It's great for a temporary fix. And being 6" away from the exhaust port, this stuff see's some extreme temps.
 
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