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Post by leze23 on Aug 11, 2012 10:06:03 GMT -5
Okay, this is my first project where I only speak english. My english skills is bad.. Starting point is only empty cases. But also i have crankshafts, reed valves etc. Stock morini cylinder It is really narrow I take the dremel to my hand and now its little bit wider. But it is not ready! Also reed valve really suck. so I will modiflie the piaggio reed valve body. Here is plan: I will cut the section avay and fill blue areas. for filling I use chemical metal. Now the actual cylinder project: Here is stock portmap: It is not really good. Paper moved little bit inside the barrel and it is little bit skrewed.. Im thinking to modifie exhaust port to: Here is small challenge. ;D The cylinder: ;D Parts that i cutted away. Exhaust port modiflication.. Little bit information what Im thinking: Max power will be @ 9000-9500 exhaust duration: 182 transfer duration: 132 Lot of work.. Sry my bad english, im finnish guy..
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Post by 90GTVert on Aug 11, 2012 10:34:02 GMT -5
Ambitious project. I'm interested to see how it turns out.
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jonik
Scoot Member
Posts: 58
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Post by jonik on Aug 11, 2012 11:39:58 GMT -5
I would aim the reed cage more towards cylinder transfers. Direct flow is always better.
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Post by 2strokd on Aug 11, 2012 17:03:48 GMT -5
Good work man! You are not afraid to dive right in and cut away! Nice to see another build
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Post by leze23 on Aug 15, 2012 12:45:31 GMT -5
Thank you for really positive feedback. okäy here is little update: modded intake side: It is really unfinished.. Barrel right side is tuned and left side is almost stock. also back transfer is tuned. It is little bit enlarged.
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Post by leze23 on Oct 6, 2012 14:04:17 GMT -5
Little update. I have been working cylinder and piston little bit more. cutted down piston, little bit 1200 sand paper and now its raeady to roll. :lol2: There is three section exhaus port. next week i will do it 100% complete. Piston law lowering. I will lower it more in next week.
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Post by 90GTVert on Oct 6, 2012 14:27:13 GMT -5
Excellent work!
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Post by aeroxbud on Oct 10, 2012 16:57:31 GMT -5
Good project
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bare
Scoot Member
Posts: 55
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Post by bare on Oct 16, 2012 15:48:56 GMT -5
Ambitious project. I'm also sensing a Very limited knowledge base though. Shame, as there is mountains of info on the internet just for the reading... some of which is even correct. It's genuinely Unlikely/improbable that Cylinder could Flow up to the max of the Stock Reeds.. let alone More. But hey.. stuff in a V force if that makes you happy. The sheer thickness of the Rings on that piston say: low speed Low performance. Rpms require thin and v strong rings. Adding extra ports is seriously advanced modifications. Often unsuccessful even when the people attempting it are decades experienced 2 stroke tuners. Power in a cyl is centred in the angle , direction and flow of EACH of the inlet ports. That is where experience tuners focus their energies. Suggest you bone up on that aspect... before... cutting off even more huge chunks of metal
Not trying to disuade just suggesting giving a good think to what you are attempting
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Post by waltinhawaii on Dec 26, 2012 23:04:27 GMT -5
Lese23, he has some points so you might re-think what you are doing. But knowing english is not your strongest language, I think you will have a hard time understanding him.
I LOVE your spirit and that you are attempting such things with what looks like minimal tools and not too much experience. But reed valve work is probably not going to get you increases like you are wanting... you should probably attack the weak points in your engine build first. The reeds don't give you much of an increase in the best case, so in your case, with stock engine and mild airflow, you probably will see little increase. You probably should look to make sure your ports are aligned properly and balance these out. Remember you are not only after port timings; try to make the ports flow better by obvious things like smoothing out bumps and making the turns gradual and sweeping in the transfers. taper the edges closer to the piston. You have stock rings, which are heavy and thick, this will limit your upper rpm, but this is a small cylinder anyway, so you can get away with a lot. make sure you cut your ports so they are sweeping and close gently to move the piston rings back into the grooves. Measure the width of the port and the diameter of the cylinder, your width divided by the diameter will give you a percentage that probably should not exceed around 65%, but this figure can go up or down depending on the shape of the port. Your port is rather squarish, so you should tend to a smaller number, maybe closer to 60%. a more oval port can go near 70% and race ports are higher still but piston rings don't last more than a couple races. forget about adding exhaust sub ports. This will require removing the cooling fins, welding the cylinders to add more material, then re attaching the cooling fins; before you can drill yours for subports. so unless you know how to weld cast iron and can mill these ports accurately, you probably can't do that. i have seen people make their own bridge across an exhaust port so they can widen it a lot; this might be possible for anyone with very limited welding tools and a honing machine or even a drill and honing fixtures. look for pictures of ported cylinders on the web and pay attention to how they blend the transfer passages down near the case, and how smoothly the upper arches are near where they enter the cylinder. The two streams of air from the left and right transfer MUST enter together at the same angle because the two streams must collide with each other. They are pointed away from the exhaust port and up toward the head. Both these angles are important and will decide if your engine makes more power down low or up high. You will have gREAT fun, I'm sure. Try everything. Take a lot of notes. reaD READ READ everything you can find. What I know about 2 strokes will rattle around inside a thimble, it is so little, but this board is a great resource. Good luck my friend.
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Post by skuttadawg on Dec 28, 2012 23:28:40 GMT -5
I too want to port my 49cc 2T since the exhaust port is a D shape where my 72cc BBK is shaped like an O . I think the exhaust port limited to RPMs at top end . To truly get the most out of porting you will need a tuned pipe , Uni or K&N airfilter and larger main jet and replace the intake and reeds with HP ones
I read about a guy who uses JBWeld to fill in the ports then cut out the excess . JBWeld may help you if you remove too much material
If you using the oil pump replace ASAP with a Mikuni pump and new throttle cable part #159-26 or premix
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Post by 90GTVert on Dec 29, 2012 7:20:01 GMT -5
I've seen JB Weld used on the intake of a GY6 150 to sorta reshape the curve, but I wouldn't think that's a good idea for a 2T's ports. The intake isn't subjected to the heat that the ports would be, especially exhaust.
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Post by kevin55950 on Dec 29, 2012 13:00:39 GMT -5
I've seen some JB weld used to block the boosters on Malossi MHR Replica cylinders to make them way smaller (only 2 small holes were let there ) to after enlarge the central exhaust port, and it lasts. The one in two tubes that you mix at 50/50 ratio stick well, the one in a kind of paste in a plastic cylinder isn't great on our small applications: I've got problems with it.
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Post by waltinhawaii on Jan 1, 2013 15:44:03 GMT -5
I prefer welding as a more permanent way to add metal; but this requires machinery that not everyone has access to. Aluminum is hard because these cylinders are a LOT Of material and requires a lot of heat to do a job well (preheat required) and cast iron, well, is a big PIA if you ask me. I've welded cast iron before but it makes the added material behave strangely, the welds turn out SUPER hard and impossible to tap (although they can be ground down), but although strong, they are brittle and easily snap if under large stresses. An old shipwright once told me an alternative method is to weld up cast iron using stainless rod as filler material as the stainless remains a relatively workable temper.
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