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Post by 90GTVert on Dec 16, 2014 23:15:07 GMT -5
When matching the header, you would blend the outlet of the exhaust port in, but not carry it all the way to the port window where it enters the cylinder to change timing.
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Post by oldgeek on Dec 17, 2014 6:54:17 GMT -5
When matching the header, you would blend the outlet of the exhaust port in, but not carry it all the way to the port window where it enters the cylinder to change timing. Gotcha, I think I remember reading that now that you mention it.  I have learned so much around here, that I have started forgetting it now! |
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Post by 2TDave on Dec 17, 2014 7:23:27 GMT -5
I hear you in forgetting stuff. I did like Brent said and blended the port the best I could while trying to maintain the slope. So your not going to use the Orange stuffer crank?
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Post by oldgeek on Dec 17, 2014 7:41:46 GMT -5
I hear you in forgetting stuff. I did like Brent said and blended the port the best I could while trying to maintain the slope. So your not going to use the Orange stuffer crank? I am going to save the good crank for a nice long case build. I just don't have a lot of faith in this build, mainly the cases. |
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Post by oldgeek on Dec 18, 2014 22:22:07 GMT -5
I slapped the stock looking 45mm stroke crank in the cases using some slip bearings and test fit the cylinders I have. I am pretty sure I will need a base gasket to get it sealed up good, so using my thinnest one the durations end up as follows. Exhaust 183 transfers 132. This is the 52mm, 6 port, 78.5 tall cylinder.  I test fit the 54mm 8 port, 77mm tall cylinder, but it looks like a no go with that one. |
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Post by 2strokd on Dec 20, 2014 9:21:02 GMT -5
Those are good numbers outta the box! Looks like squish will be no problem either?.. Nice!
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Post by niz76 on Dec 20, 2014 10:27:19 GMT -5
I slapped the stock looking 45mm stroke crank in the cases using some slip bearings and test fit the cylinders I have. I am pretty sure I will need a base gasket to get it sealed up good, so using my thinnest one the durations end up as follows. Exhaust 183 transfers 132. This is the 52mm, 6 port, 78.5 tall cylinder. I test fit the 54mm 8 port, 77mm tall cylinder, but it looks like a no go with that one. I emailed Autotech355 about a week ago to ask if he has any of the 8 port 54mm "tall" cylinders. He doesn't. Would there be any advantage to using the 77mm cylinder but adding base gaskets/spacer vs. using the 6 port "tall" cylinder? I currently have a 50mm and wanting to go to 54mm and I have the "tall" 45mm stroke. |
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Post by oldgeek on Dec 20, 2014 10:28:53 GMT -5
Those are good numbers outta the box! Looks like squish will be no problem either?.. Nice! Thanks! I was hoping someone would chime in. I really don't know what numbers I am looking for. I want this to be a mild build. With that in mind, could I get away with using a stock style pipe? I really have not found a pipe for this build yet. I have one that should be good for a decent 90cc+ build, but I am saving it for a long-case in the near future. I also just noticed the crank I am using for this build has a small stub for the flywheel. I only have large stub flywheels, so I am looking for a small stub FW now. |
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Post by oldgeek on Dec 20, 2014 10:50:00 GMT -5
I slapped the stock looking 45mm stroke crank in the cases using some slip bearings and test fit the cylinders I have. I am pretty sure I will need a base gasket to get it sealed up good, so using my thinnest one the durations end up as follows. Exhaust 183 transfers 132. This is the 52mm, 6 port, 78.5 tall cylinder. I test fit the 54mm 8 port, 77mm tall cylinder, but it looks like a no go with that one. I emailed Autotech355 about a week ago to ask if he has any of the 8 port 54mm "tall" cylinders. He doesn't. Would there be any advantage to using the 77mm cylinder but adding base gaskets/spacer vs. using the 6 port "tall" cylinder? I currently have a 50mm and wanting to go to 54mm and I have the "tall" 45mm stroke. I am not sure, but I don't think the 8 port 54mm 77mm tall cylinder will work well with the 45mm stroke crank. Transfer duration was like 135 and deck height was pretty low when I checked it on my 45 stroke crank. I put my Hoca crank with the 39.5 43.5 stroke in for a test fit, and the 8 port 54mm 77mm tall cylinder looks good with it. Durations of 183 exhaust 130 transfer deck height looks great with 1 base gasket. I don't have internet access at the warehouse where I work on the scooters, so I dont have access to 49ccscoot.com there where I could really use it! I also just noticed the piston to cylinder clearance on this 54mm kit is kinda large. I can see the piston move in any direction I push it, so I don't know whats up with that? |
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Post by Corrosion on Dec 20, 2014 12:44:55 GMT -5
My Hoca 54mm 8 port, tall is a loose piston fit too. Probably for the cylinder wall are so thin, getting them to 54, there playing it loose. Just make doubly sure the ports are well chamfered, so as not to catch a ring
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Post by oldgeek on Dec 20, 2014 17:43:03 GMT -5
My Hoca 54mm 8 port, tall is a loose piston fit too. Probably for the cylinder wall are so thin, getting them to 54, there playing it loose. Just make doubly sure the ports are well chamfered, so as not to catch a ring Thanks, I will! Spent a while today installing and sealing the longer cylinder studs, and also blended the exhaust port to fit the header a little better. I likely raised the roof of the exhaust port just a little in the process, but I hope not by much if I did I brought the hoca crank to the house so I could work on polishing the crank journals for a slip fit in the bearings, but I forgot to grab the bearings.  |
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Post by 2strokd on Dec 21, 2014 8:58:37 GMT -5
We used to run a 103cc race engine with a 45mm/54mm short cylinder. Needed a couple base gaskets and some head work to get the numbers we wanted but it worked well in the end
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Post by 2TDave on Dec 21, 2014 9:18:07 GMT -5
Man that sounds good. A little familiar too.  |
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Post by moofus02 on Dec 21, 2014 12:51:08 GMT -5
I emailed Autotech355 about a week ago to ask if he has any of the 8 port 54mm "tall" cylinders. He doesn't. Would there be any advantage to using the 77mm cylinder but adding base gaskets/spacer vs. using the 6 port "tall" cylinder? I currently have a 50mm and wanting to go to 54mm and I have the "tall" 45mm stroke. I am not sure, but I don't think the 8 port 54mm 77mm tall cylinder will work well with the 45mm stroke crank. Transfer duration was like 135 and deck height was pretty low when I checked it on my 45 stroke crank. I put my hoca crank with the 39.5 stroke in for a test fit, and the 8 port 54mm 77mm tall cylinder looks good with it. Durations of 183 exhaust 130 transfer deck height looks great with 1 base gasket. I don't have internet access at the warehouse where I work on the scooters, so I dont have access to 49ccscoot.com there where I could really use it! I also just noticed the piston to cylinder clearance on this 54mm kit is kinda large. I can see the piston move in any direction I push it, so I don't know whats up with that? I've got a short 8 port i should mock it up and check durations with a 39.5 crank. If i get numbers like you did i think one of the rx8 might get a really bbk. Sent from my SPH-L720 using proboards |
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Post by moofus02 on Dec 21, 2014 17:22:33 GMT -5
Did i read the durations right? That was short 8 port 54 with stock 50cc crank?
Sent from my SPH-L720 using proboards
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