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Post by triesandluth on Apr 5, 2016 22:04:57 GMT -5
Here's some uncovered, still assembled shots of the cylinder, not too useful or pretty.   |
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Post by triesandluth on Apr 5, 2016 22:10:50 GMT -5
It had a bp7hs plug, it ran fine with a br8hs. Probably gonna have to change that by the time I'm done. Here's the head  From the surface that mates to the cylinder to the deepest point Is 14mm. This lip from the mating surface is 2mm. I can assume this can be considered a restriction, especially when you add in the almost .5mm head gasket.  |
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Post by triesandluth on Apr 5, 2016 22:14:07 GMT -5
The piston at tdc is less than a millimeter from being flush with the top of the cylinder, and the piston has a mild dome top.   Here's the exhaust port.  bdc lines up flush with the piston top and the bottom of the port. |
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Post by triesandluth on Apr 5, 2016 22:15:21 GMT -5
I have to refresh myself on getting port durations, then I'll take off the cylinder and try to make a port map and take some more pictures.
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Post by triesandluth on Apr 5, 2016 22:30:43 GMT -5
Getting 172 exhaust duration and 97 transfer duration. I'm going to triple check those numbers and attempt the intake duration.
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Post by triesandluth on Apr 5, 2016 22:34:24 GMT -5
Here's the intake at bdc  |
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Post by triesandluth on Apr 5, 2016 23:23:19 GMT -5
Oh yeah, 75mm diagonal measurement of the bolt pattern. 54mm straight from hole to hole, centered, perfect squared.
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Post by triesandluth on Apr 6, 2016 0:01:45 GMT -5
Quick, terrible, first try at port mapping.  Here you can see how much I'm going to open the exhaust port to match the header of the pipe.  Something interesting, the base gasket looks almost new, the head gasket was clearly not the right one, too small. I sure hope the little pieces that are no longer there aren't in the case. I'll go fishing in there tomorrow.  More pictures    I guess I'm going to start with opening and cleaning up the exhaust port outlet to the pipe, then research what would be safe to do on the actual ports. The ports on my malossi jug for the super 9 are similar size, if not larger! |
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Post by triesandluth on Apr 6, 2016 1:03:10 GMT -5
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Post by 190mech on Apr 6, 2016 3:56:13 GMT -5
Ports look verrry small for a cylinder of that size,head is a squish type,just needs some metal cut off to get the squish down,likely the best bet will be to buy a better cylinder assy than to try to mod the stock one...
PS,Ive got a BWS100 piston and crank here(maybe still a base gasket too) if you need any of that measured...
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Post by triesandluth on Apr 6, 2016 5:06:41 GMT -5
If the measurements I've looked up of the cranks are true then it should just be a 2.7mm difference. I know that even a millimeter difference in the stroke would throw off the ports (i actually don't KNOW that, I just assume), so some space will be necessary.
I am curious of the bws port map though, to see how badly genuine, or pgo, whoever, screwed this motor. Maybe just a few dimensions to give me an idea. Especially the bolt pattern, just for reassurance of fitment.
I'm sure that there's some other underlying issues that this motor had to make it perform so poorly. I don't like that the head gasket was clearly either the wrong one, or made wrong by someone. I was hoping to just find a need for reducing the squish band. It made me wonder how I had read of many people loving this motor stock, and getting pleasing results with a few simple mods, yet I was totally unimpressed. I have full faith in my super 9, it rocks, but I can't have It be the best scooter I ever built lol.
I'm going to treat this like I was treating the cheap morini kit that was on the bike in the first place... I'll do what I can to it, if it works, great, I'll use it until upgrade is possible. If I mess it up, not too much of a loss.
I'll try to get the squish down, use the copper spray and motoseal I bought today, open that exhaust port exit hole, clean up the rest of the ports and see what happens. Then the intake that ryanott is sending, and the carb that I bought from drc174. Hell, maybe I can build this the rest of the way just using parts from forum members lol. Clutch, variator, etc. It can be the second hand 49ccscoot bike lol.
So with my port durations, I'm going to read back into the two stroke tuning book and see if I can't try to figure out what I can do to the ports. I'll probably not be able to do much with my current tool sets, but I'm willing to try.
Any advice on where I can go with the ports?
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Post by 90GTVert on Apr 6, 2016 5:59:03 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/thread |
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Post by 190mech on Apr 6, 2016 7:07:10 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..
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Post by Deleted on Apr 6, 2016 10:32:12 GMT -5
So, where would be a good place for up to 5+/-mm thick aluminum? And the circle cutter I'll have to find. That's a great idea with using the hammer and such to tap out the cylinder on the gasket. I always just colored the gasket area with a lot of marker and hoped for a good enough ink transfer. I have machinery company near that throw away good chunks of aluminium. I asked if I can go through their junk and it was ok  (There's so much leftover it means nothing for them). Old Amps? Yes yes, I'm a cheapskate! |
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Post by triesandluth on Apr 6, 2016 16:01:05 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. |
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(There's so much leftover it means nothing for them). Old Amps? Yes yes, I'm a cheapskate!