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Post by repherence2 on Jan 3, 2021 13:02:42 GMT -5
fartin' round with the 28mm OKO (genuine taiwan). was just planning on making templates for venturi dividers but i went a little overboard. this time around the plan was to make dividers for pre-slide and post-slide portions of the carb. repurposed a used box of Natural Ice for templating. once i got the venturi profile matched in card stock, i transferred it to some hobby plastic. it is clear, initially i thought it was sheets of polycarbonate but the package says it is polyethylene. 1. templating  2. prototype build. went a little further than i wanted to, but i guess i needed a proof of concept for myself. the first divider i made for my Chinarelli was made of 1/16" aluminum and it was only in the horizontal plane in the venturi, pre-slide.  3. mock up, front divider, no slide.  4. mock up, front divider, with slide.  5. mock up, rear divider.  6. mock up, rear divider, front divider and slide removed.  initially the plastic was clear and smooth. after assembly and gluing, i decided to sand down the surfaces because they were too smooth in my opinion -- thoughts of Surface Adhesion Effect. Sanding it also made it more visible for picture taking. the plan is to glue it in with some Automotive Goop. this is Prototype 1. plans for Prototype 2 already include 2 more intermediate dividers on the front assembly. a small divider at ~1/4 throttle and ~3/4 throttle. i have a feeling that the 1/4 throttle divider would really help with the low throttle tuning/response of this 28mm carb. I would like to trust the Taiwan OKO over the China fOKO but they are very very similar in appearance, so i would suspect the low throttle gremlins of the fOKO carries over to the real OKO, inherent of it's design. working with and cutting polyethylene plastic is so much easier than working with 1/16" sheet aluminum, i hope the poly holds up the gasoline... we find out later. ...more brainstorming until then. |
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Post by repherence2 on Mar 7, 2021 12:48:58 GMT -5
some works. picked up a Malossi Torsion Controller (2512828) and a Contrast yellow spring (29 7042.Y0) from 808Cycles.  wrapped the rear half of the Arrow chamber. prior to wrapping the rear half, i painted the pipe and the front half of the wrapped section with high temp Rustoleum black gloss. the fiberglass wrap needed to be encapsulated because every time i handled the pipe, i was getting itchy. the rear half of the pipe was getting the surface rust under the clear coat that looks like rusty veins/capillaries. so i decided to paint the whole thing for preservation. went to the hardware store to buy the metal zip ties, it's the same stuff that is sold for header wrap at the auto parts store. for sh!ts and giggles i put each tie 2" apart along the whole chamber. then i painted the whole assembly with more high temp Rustoleum.    still need to spray 1 more can of high temp Rustoleum to seal it all up. ...make anykine, experiment. i was getting tired of see the pipe getting that surface corrosion under the clear coat because of all the salt air/breeze where i live. painted the CVT cover red, just for fun. i had a can of metalic red sitting around so i painted the cover to see how it would look on the engine.  glued in my venturi divider into the OKO 28mm a while ago. there are dividers on both sides of the slide. i used some oil resistant sealant that was left over from work. we'll see how that holds up.  opened up the gearbox to remove and replace the old gasket because it was leaking oil. i counted the gear teeth for the SYM DD50 and came out with 12 x 32 and 12 x 47. from my calculation i get 11.0972. fiddled with some calculations for gearing ratios that i see available on craigslist locally, but all of the available gear sets put the gear ratio into a seemingly rediculous region. 15 x 42 would put me at 7.93324. i seen a recommendation somewhere that the perfect target ratio for the DD50 was 8.4:1 to 8:1. i guess that would be okay, but i didn't feel like chancing it, neither did i fell like pressing gears. i want to see what this MHR Replica does on stock gearing, do some tests and log some speed/rpm. see how well this MHR rep performs with the Arrow. i seen a JISO stainless steel chamber pipe at the shop when i bought my Malossi torsion controller and contrast spring yesterday and it's selling for $350. i really want to get one of those and port the MHR rep cylinder, run it on stock gearing and then change out the gears later. ...day dreams and make anykine. |
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Post by aeroxbud on Mar 7, 2021 14:55:25 GMT -5
Great work.
Living by the sea, I feel your pain about corrosion.
If you ride in the wet. The water can lay between the pipe, and wrap. Making it corrode worse.
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Post by repherence2 on Mar 7, 2021 21:55:34 GMT -5
Great work. Living by the sea, I feel your pain about corrosion. If you ride in the wet. The water can lay between the pipe, and wrap. Making it corrode worse. Yes yes, very true. I have accepted that corrosion is inevitable. "...nothing lasts forever in the cold November rain..."  I've seen the Arrow labeled as a potential toy pipe on other forums. I guess it's a 10.5k pipe, not really high revving. I'm guessing that's where the MHR Rep lives for power. I told the the owner of Qwik Fix Garage that i had an Arrow pipe. He went behind a cabinet and dug out a 1st gen bore (single exhaust port). I took that as, that's what he felt was best for the Arrow. Having accepted that the Arrow will rust, the next best thing is to put several layers of paint for some preservation. Having seen the JISO chamber pipe at 808Cycles this weekend for $350, that is my next target purchase. It's shorter than the Arrow, ...so i will assume it will rev hig her than the Arrow. It is Stainless Steel too! Hot Damn! Port the MHR Rep exhaust port to compensate for the shorter JISO chamber, swap the gearing, and call it a day. I have been eyeing a set of aluminum machined and anodized sets of wheels at 808Cycles for $250 (dio/dd50). But im thinking that the JISO stainless chamber pipe will take priority. Eyes on the pr ize. Just gotta run the JISO exhaust, figure out what Rpm the pipe sings at, and tune every cylinder to those timings after i kill the MHR Rep. Im at a point in life where it's Zen style. Mujou - no Permanence. Mugen - "infinite". no Limit. Mushin - no Mind. I know i say "make anykine", but don't get me wrong, it's not uneducated guessing. It's Something; it's more about the Journey, the Learning, Sharing of knowledge, and Helping those of less experience. The Hawaiians always told me, "Always leave a place better than it was then when you got there." I figure, Learn, Build, Share ...this forum is a cool place and i Appreciate Everything about the People on this forum, and i appreciate everything about this forum. |
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Post by aeroxbud on Mar 8, 2021 4:29:50 GMT -5
I wish more stainless steel options were available for scooters. I just have to paint whatever I get. And every year, clean and paint again.
I brought a DD50 for my wife years ago. Only had it a week. She didn't really like the small size, and brought a yamaha.
I didn't really know much about the tuning potential then. Or I would of kept it. Standard they are a quick little bike.
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Post by repherence2 on Apr 21, 2021 15:38:16 GMT -5
Did some brain storming for a couple weeks. Yesterday was 4:20 and i fiddled with some parts in the irie laboratory. When it comes to large bores, greater than 47mm, for the Honda vertical motors, the largest bores for stock stroke are the 50mm and 51mm bores by Char-mo or Ruima. I'm tinkering with the thought of fitting up a 54mm Hoca/SSP-G minarelli bore onto the SYM dd50 block. My idea is based on the fact that the Jog90 stroke is very close to the af16/dd50 stroke. 0.2mm difference. Piston from the 54 Hoca fits up nicely to the dd50 crank because its a 12mm pin. However, the piston cannot go to BDC because the piston skirt hits the case casting. The outter diameter of the lower skirt of the Hoca bore is 2.238". The case bore is 2.200" as measured with a Mitutoyo dial caliper. I have a cheap digital caliper but i rather trust the accuracy of the Mitutoyo knowing that i was formerly calibrated/checked annually. --probably going to find a large ratchet socket at work of suitable size, stick some nonskid tape on the outside of the socket, and use it to bore/lap the case. Open it up to about 2.240" from the 2.200" it currently is. The stud holes on the Hoca will need to be modified. They have to be brought in toward the center of the bore 1.5mm. --i will probably use a small "rat tail" file for that. Upon initial mock-up and brainstorming in the irie-lab, i will probably modify the piston skirt instead of removing material from the case. I want to see how a 54mm 94cc vertical Honda-type engine compares to a 54mm 94cc horizontal Minarelli. |
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Post by 190mech on Apr 21, 2021 19:16:15 GMT -5
What is the distance from the deck to the bottom of the transfers?If its 42mm you are good,45mm and its a no go..Ive tried many times to adapt a jug designed for a 45 stroke to a stock 42 stroke crank..Gotta add a spacer to the cyl base to get BDC even,then there is a huge squish that must be taken care of by step cutting the head or decking the jug top,both lead to a thin/poor sealing head joint that leaks badly!
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Post by repherence2 on Apr 21, 2021 21:06:41 GMT -5
What is the distance from the deck to the bottom of the transfers?If its 42mm you are good,45mm and its a no go..Ive tried many times to adapt a jug designed for a 45 stroke to a stock 42 stroke crank..Gotta add a spacer to the cyl base to get BDC even,then there is a huge squish that must be taken care of by step cutting the head or decking the jug top,both lead to a thin/poor sealing head joint that leaks badly!
thank you for the input 190mech.
oh goodness... after taking the measurement that you pointed out, it is 45mm from the deck to the bottom of the transfers.
darn, i thought i had a good idea going. i did notice that the Hoca was significantly taller than the MHR Rep.
something interesting is the pin location on each of the pistons.
my initial idea when i noticed the difference in jug heights was that it gave me material to machine away to get the ports set to functional nominal height and then tune/port it to suit.
i know you used the words "45mm and its a no go". is it in the realm of "impossible"? i did notice that (like the shipyard Jedi's i worked with) you described the need for a bottom spacer and modification of either the head or the cylinder deck. maybe i am reading between the lines too much in thinking that it is "possible" but i gotta put in some work to achieve it.
the machinist at work that i learned from in my later 20's straight up told me, "Boy! Dis da Shipyard! Nothing is impossible if you put your mind to it." so that is the way i approach things. if it involves machining, i can probably make it happen or find someone to make it happen. im up for a challenge. the way i see it, most of the work has to take place on the jug. if it does not pan out, i always install the MHR Replica.
this is one of those things for $hits and Giggles. it's my way of taking a jab at the Honda moped crowd here on Oahu. i was just at a shop yesterday and the mechanic was telling me how he's tuning a Corsa mated to an Arrow pipe to race a guy on a 84cc 2Fast4Race jog. i hinted to the guy that he might want to run a Scorpion instead of the Arrow, but he attributed the Scorpion pipes to "hype". little does this mechanic know that a Taida 54mm bore can out run most Honda set ups, even the mighty Corsa. Because of people like that in the Honda scene here, i really wouldn't mind building this hybrid as a means of silently shit talking. no one runs a stock stroke 54. all the 54mm bores here have to run full stroker cranks. ...i want to take BIG jabs. |
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Post by repherence2 on Apr 21, 2021 21:40:43 GMT -5
the pictures of the ideas... 54mm Minarelli bore versus 47mm Honda MHR Rep.  54mm piston in engine case so i could see what it would look like.  54mm piston, wrist pin installed, at TDC. MHR Rep piston on side as comparison of size.  Hoca bore on dd50 case. some metal removal is necessary.  metal removal tools acquired. small rat-tail round file 6mm dia. 1-5/8 CHINA 3/4" drive socket. 3M Safety-Walk nonskid tape. 3/4" male to 1/2" female adapter. the socket measures 2.200". a single layer of the nonskid is 0.025". double that up because the socket will have strips of the nonskid around the circumference. that brings the tool to a cutting size of 2.250". the skirt of the bore is 2.240". 0.005" diametrical clearance might be a bit much, but not bad being that the MHR skirt it 2.140".  |
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Post by jbjhillbilly on Apr 21, 2021 23:41:15 GMT -5
I want to say I remember someone taking a stab at this here on the boards.
But maybe I ordered the wrong kind of mushrooms.
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Post by oldgeek on Apr 22, 2021 6:40:16 GMT -5
I was working on fitting a Minarelli Top Performances 86cc cylinder to vertical Kymco cases, using the minarelli 44mm stroke crank fitted with a 90mm con rod. It requires a lot of modifications but I think it will work out. I will get back to it eventually. I talk about it in this THREAD if you want to take a look. |
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Post by repherence2 on Apr 22, 2021 23:24:25 GMT -5
What is the distance from the deck to the bottom of the transfers?If its 42mm you are good,45mm and its a no go..Ive tried many times to adapt a jug designed for a 45 stroke to a stock 42 stroke crank..Gotta add a spacer to the cyl base to get BDC even,then there is a huge squish that must be taken care of by step cutting the head or decking the jug top,both lead to a thin/poor sealing head joint that leaks badly!
do you think a 43.2mm ministroker crank would be better suited?
Oahu CL has 2 ministroker cranks at 43.2mm and both are full counterweight. one is listed at $160.
all i know from research is that these 43.2mm ministrokers do not require case cutting. and the 43.2 gets me a lil closer to the 45mm range.
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Post by 190mech on Apr 23, 2021 3:46:09 GMT -5
Still gonna have to deal with 1.8mm if the cylinder is 45mm from the top deck to bottom of transfers..
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Post by stofzuigalpacca on Apr 25, 2021 6:00:39 GMT -5
Hi can someone help my find that airfilter for the sym dd50 or 1 that fits on it aswell? I have a dd50 myself but its been standing in the backyard for 5 years or more and i want to clean it up and rebuild it but the airfilter broke and i dont know where to find 1
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Post by repherence2 on Apr 25, 2021 9:31:14 GMT -5
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