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Post by triesandluth on Apr 6, 2016 16:04:04 GMT -5
Transfer ports are tough to deal with unless you have a very small right angle rotary tool or handpiece. Most of us raise the cylinder to get transfer durations up. 97 is pretty low so I'm not sure raising it to more standard numbers (usually closer to 120 anyway) would be practical without needing a bunch of work to deal with the issues that creates elsewhere, like squish, compression, and exhaust duration. You may just need to see how far you can go and keep the other variables reasonable for a compromise. By the time you raise it, the exhaust port will probably have plenty of duration without needing any opening up vertically, but you could widen it. 49ccscoot.proboards.com/post/30179/threadAgain, something I've read here before but needed to revisit. I also just read all that early this morning before bed in bells book. You just make it a bit easier to take in and applied to our situations. It's easier to get to without going through the 3rd chapter of the book 3 times lol. Thanks again, Brent! |
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Post by 190mech on Apr 6, 2016 16:32:45 GMT -5
The cylinder does look like has little wear,,get me a cylinder bore dimension and a distance measurement to the bottom of the transfer ports.I'll plug that into my porting calculator after work and come up with some numbers to think about.. Are we talking from the base or the bottom of the skirt? I'll try to get something before I go into work tonight. Sorry that wasnt too clear!Distance from the top of the bore to the bottom of the transfer ports,(I think its 50mm from your port map,just gotta be sure..For a low buck hop up,it'll likely need the Ex port raised and widened,cylinder spacer to raise the transfers and a possible step cut head to get the squish right,will know for sure after I run it thru the port calc.. |
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Post by triesandluth on Apr 6, 2016 17:04:22 GMT -5
That's cool, I'm learning the terminology, or trying. Yes, measures 50mm for the transfers, just a tad over for the exhaust. 52mm bore, 50mm stroke. If we raise the cylinder to get the transfers better, maybe file the piston a little to avoid setting the exhaust port off too much? And besides milling the head, maybe I can mill a little off the deck of the cylinder? It has a raised area that is just asking me to get rid of it.  It's harder to see in the picture, but it is a millimeter plus. Maybe could take a millimeter off there and 2 from the head, leaving 2.5mm minimum to raise the base of the cylinder without destroying the already shitty squish and compression. |
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Post by triesandluth on Apr 6, 2016 17:06:52 GMT -5
Now I wish I would've set up the cvt better before doing this to have a good base to start with.
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Post by 190mech on Apr 6, 2016 18:34:57 GMT -5
Heck!Slap it back together and tune that CVT!Ports can come later..I dug around in my pile of stuff,no BWS base gasket,but I did find a head gasket,,52,5mm stud spacing FWIW..Porting the exhaust is super easy,transfers are a bear..I'll report back on the port calc findings..
PS,Just ran it,your stock is Ex 30mm,Tr 40mm........Desired Ex 28mm(182.5 degrees),Tr 38.5mm(129.8 degrees),so we need a 1.5mm spacer(.060"),Ex port will need to be raised .5mm and widened 1.5mm each side,then the squish will need to be adjusted after those adjustments,,Yeah,the head and cylinder have plenty of meat that can be removed to get the right squish...This still isnt the super race ideal setup,but should run a heck of a lot better!!
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Post by triesandluth on Apr 6, 2016 21:16:56 GMT -5
Hell yeah, I'll definitely owe you some beer money after all is done.
I think I may do the cvt after I attempt to weld a plate over the hole in the exhaust and figure out a silencer mount.
That stud spacing is different than mine. I got 54mm each way, going from center of the holes.
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Post by 190mech on Apr 7, 2016 11:53:43 GMT -5
Bet the BWS100 jug will fit though,,the studs are 7mm,holes in head and jug are 8mm..
Ive got some .063" aluminum at the shop,can send you a piece with the cylinder skirt hole already cut if you give me a size..
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Post by triesandluth on Apr 7, 2016 13:55:55 GMT -5
Right on. I probably won't be doing much until Monday, between work last night, my gfs daughters softball game this afternoon and her house tonight, my daughter and gf with me all weekend, and riding to Charlotte to get together with the club Sunday, I'm pretty booked up.
I try to avoid extensive periods of scooter wrenching when the gf is over. We used to get into it about me paying more attention to other things when she was around, she hasn't ever flipped over the scooter obsession (she thinks it's cute and that I'm good at it :/ ), and I'm trying to keep it that way lol.
I'll measure the piston skirt here in a minute.
Sent from my VS985 4G using Tapatalk
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Post by triesandluth on Apr 7, 2016 14:13:58 GMT -5
I measured 60mm for the outer skirt diameter, might be safe to go 60.25 or so. Like I said though, no rush
Sent from my VS985 4G using Tapatalk
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Post by triesandluth on Apr 12, 2016 17:08:23 GMT -5
The shock riser came in yesterday. But I've gotten way off target for this project. I guess taking a little break doesn't hurt. Just passing by it in the driveway, looking under it to think of things to do with the mounting of the motor and vibrations. And looking at that cylinder on the counter. It's time will come go under the knife....soon....
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Post by 190mech on Apr 12, 2016 17:17:40 GMT -5
I'd say going under the cutter!As I have no base gasket,whats a safe dimension around the 60.25mm skirt hole for the spacer??
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Post by triesandluth on Apr 12, 2016 21:15:08 GMT -5
I'll measure when I get home from work. I still am going to put it back as is, minus the head gasket, to get a quick tune on the cvt. I need to either order some clutch springs or just get a whole new clutch and bell. If I do the latter I'll most likely switch to the smaller clutch and bell.
First, I'll be getting a small gauge piece of steel from a friend to fix that hole in the pipe. Oddly, right after the break, I stumbled across a thread talking about these prima pipes breaking at the welds. But that person's experience was a break at the header. I don't know which would've been worse for mine lol.
I'll get some time these next few days. Get back after it...
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Post by triesandluth on Apr 13, 2016 9:17:33 GMT -5
I'd say going under the cutter!As I have no base gasket,whats a safe dimension around the 60.25mm skirt hole for the spacer?? If you could manage 95mm each way that would be great |
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Post by 190mech on Apr 15, 2016 19:54:40 GMT -5
Before I cut,is this kinda what is needed??  |
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Post by triesandluth on Apr 15, 2016 21:15:04 GMT -5
Before I cut,is this kinda what is needed?? That would be perfect. Thanks! I started attempting to take that lip off the head with sandpaper and glass. It's going to be a long process, I may get with a machine shop up the road that I sorta got in touch with. I'll see if my hands will make it through it. Also bought a thin sheet of steel. Gonna try patch up my exhaust hole. That also may turn into an outsourced job lol. |
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