Ported cylinder

Duffman

Member
Dec 29, 2018
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Hey fellas I recently purchased a used engine and this cylinder was on it. It had a CDH OZ reed on it. I removed the cylinder and it seems to me someone had done some extensive port work on the cylinder but to me it doesn't seem to be completed. The third transfer port doesn't seem complete. I'm hoping to attach a picture or two in hopes that someone might know why it is the way it is. I had the engine running barely, no power under load, but also realized during disassembly that the engine had quite a bit of rust in the crankcase. I haven't been able to get in touch with the seller, that's why I'm reaching out to you guys.
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Shelburne Troy

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Nov 5, 2020
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If your piston wasn't windowed than I dont get it! If im seeing correctly the 3rd transfer port was only starting above the intake and not brought down to bottom of cylinder. If piston was windowed than maybe they thought this would give a little more gas/air flow and maybe it did but if I were you I'd complete the 3rd transfer port and also if the piston isn't windowed, id do it also. A lot of guys go with one or the other but them together ive had amazing results
 

Duffman

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Dec 29, 2018
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Thanks Shelbourne the piston is a dual window and even though the piston was windowed I couldn't understand that the 3rd transfer wasn't completed. I have another bike that is reed and has the completed 3rd transfer. I'm new to the higher performance engines and rely on guys like yourself that have far more knowledge about these engines. I guess I'll practice on a couple of cylinders and hopefully be able to finish this port job.
 

Shelburne Troy

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Nov 5, 2020
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Awesome Duffman, just remember if your going with a dremel and carbide bit, take your time its not a race. Tape off the rest of your cylinder good just incase your bit kicks back and hits where your not trying to but go with lower rims and take your time. Let me know how she goes and keep me updated on your progress. You can never go wrong with watching YouTube videos, there's a lot on there about this stuff and may save you from grave mistakes, I only wish I had YouTube when growing up and learning my small engine skills lol good luck my friend
 

Duffman

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Dec 29, 2018
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Thanks Shelburne for the advice and encouragement as well. I'll let you know how it turns out!
 

Shelburne Troy

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Nov 5, 2020
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Awesome, look forward to hearing from you. As we speak, I currently am staring at my crank. I did a complete tear down and am doing a crank balance. Nothing to scientific, just following some YouTube advice from Zeda Motor Sports. You should check out some of their stuff on YouTube, there very helpful. Also another very helpful guy on YouTube goes under 2stroke stuffing, look some of his stuff up and you may find some stuff that interests you especially if your looking for some hp gain. Again good luck
 

Duffman

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Dec 29, 2018
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Thanks Shelburne. I have watched Zeda and 2stroke Stuffing as well. I have learned a few things but have much more to learn and enjoy doing so. I haven't started to finish up the 3rd transfer yet, still looking into exactly what carbide burrs I'd need. I'm also concerned what when removed the head there were 2 head gaskets 1 copper and 1 aluminum. Also 2 base gaskets, 1 thin one and 1 thicker one? Any ideas I'd like to hear. I hope the balancing of your crank goes well. I'll see if I can find that on YouTube. Take care!
 

Shelburne Troy

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Nov 5, 2020
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So after doing a little research, the notch above you intake port may not be a bad idea. It is there to help direct the gas-air mixture to spark plug, helps with quicker throttle response but me personally if your running reed valve, id complete 3rd transfer port. From what your telling me with the double gaskets and the notched cylinder you may have a fred engine or someone copied how he builds his engines because that's what he does and if your head is an aftermarket high compression head, with the doubled gaskets , its probably a 7.0 head. They double the gaskets to elongate the cylinder which could help with top end speed. I dont quite understand exactly why that helps, ive just come across some videos stating that. You should look up some Fred videos, I know the guys at Zeda seem to like to bash his engines but he has been doing engine builds well before Zeda so I take what he says as knowledge and truth. By the sounds of it, you may have got a great deal on a nice engine, those copper gaskets alone will run ya $20 a pop. Some time when you can, id love to see a oil of it. Listen I haven't been doing Bicycle engines very long, ive spent a lot of my life in the country working on and racing 2 strokes, sense ive moved to the city, this is about all I have room for lol but I love it. These little engines are a blast to work on and sharing info with you and others makes it even better. I haven't got my engine back together sense balancing the crank, my gaskets won't be here until tomorrow but I just spent the better part of the morning running around finding good aftermarket bearings for my engine. Its a good idea to replace the bearings with good aftermarket one because though the bearings in these engines aren't that bad, their the life line of these engines and upgrading them is a good idea. Anyway let me know how your making out and ill do the same. Cheers my friend
 

Shelburne Troy

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Nov 5, 2020
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Also Duffman if your interested in doing some port work and need carbide bits, I get mine off Amazon for a great price and they are as good as you can get. Before I ordered them off Amazon I was paying big money for individual bits at princess auto or Canadian tire. I was paying near $10 for a bit and they were nothing special. They bent very easily. Man I was going through 2 a week but the wife showed me some on Amazon , a 10 pack for like $13 I thought they were gonna be trash but what did I have to lose lol well I ordered my first pack, I got them 3 days later on Amazon Prime, buddy they are amazing. Ive been using them steady and only bent one. I ordered 3 more packs because there a great investment. Their called Luter 10pc tungsten carbide bits. They won't let you down. If you decide to go that route just remember to keep the rpm's down when porting , its much easier and less chances of bending bits or skipping across your cylinder and running it. Slow and steady, its well worth the pay off
 

Duffman

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Dec 29, 2018
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Thanks fellas for your shared knowledge and suggestions. I had a machinist finish the third transfer, which he did lickity split! I have a Zeta Firestorm bottom end I'm going attach the cylinder to, hopefully it'll work and hold up.
 

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MedicWill

New Member
Oct 25, 2010
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Most guides say you want the boost port to be smaller than the transfer port.
With a angle on the top to shoot the charge upward.

If you check most porting being done and sold, the boost port is much smaller.

Will be interesting to see your results :)
 

Duffman

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Dec 29, 2018
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Yeah Medicwill, I had some concerns as well about that. I'm gonna run it once I figure what base and head gaskets to use. I'm a newbie and have much to learn.
 

Shelburne Troy

New Member
Nov 5, 2020
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Ive had success with them both (big and small) and they both ack differently. The first port i ever did was a wider one like duffman's and it worked great, it had great bottom end and good top end but I noticed that most cylinders you buy with a boost port already in it are smaller so I tried that also, keep in mind that both boost ports were tapered at about 60 degree angle at top to allow for good upright air fuel transfer. The difference from big and small boost port for me were noticeable. Big port more bottom end little port i felt like it was hitting better at top end. Im actually doing another cylinder tonight, I blew er up a couple days ago and this cylinder im going in between lol gonna make it a bit smaller than duffmans but a bit bigger than my smaller one but this time and for the first time im taking out my transfer port walls to see how that works, I see a lot of guys doing it so here goes, keep ya posted
 

Duffman

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Dec 29, 2018
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Thanks Troy! I'm just waiting now for some copper head gaskets after reading post on Squish. I checked using solder and had a squish of .98. After checking my Californiamotorbikes pro hi performance engine and had a squish of .59 I figured I should shoot for the same on the Zeda. I hope all goes well with your project and if you don't mind let me how it goes and I'll do the same!