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Post by tsimi on Mar 31, 2018 4:11:09 GMT -5
Busy day today. The boost port was really a tough one. And removing the rips with a disc grinder wasn't a walk in the park either. The engine material was really hard and sturdy.     |
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Post by benji on Mar 31, 2018 11:26:41 GMT -5
Busy day today. looking good! Remember to use clear coat on that wheel. |
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Post by PIG on Mar 31, 2018 14:43:45 GMT -5
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Post by pitobread on Mar 31, 2018 15:14:04 GMT -5
And remember, you don't want it polished. Finish sand it with 80-120 grit sand paper in a random pattern. Leave it "rough"
Or if you have access to a media blaster a nice glass or sand blast is good too.. just wash it REALLY well and qtip out all the threaded holes and pipe clean oil passages. ( make sure to tape off the bearing areas, you dont want to do them)
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Post by 'O'Verse on Mar 31, 2018 17:36:20 GMT -5
Only Crank, bearings, gears, oil, clutch, variator, td, grease, reeds, intake, carb, and a spark plug left. Haha!
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Post by tsimi on Mar 31, 2018 18:30:00 GMT -5
I didn't polish it. I used those sanding drums and left it that way. About that trenching stuff. I am gonna grind off the sharp edges and make it smooth and all but I won't be doing a 5BM engine style trench. I just can't risk to mess up that engine. Too unique over here. Any other Jog engine would be no problem I can get tons of em over here.
If that means that I loose 1-2 hp then it is so. Still should have more than enough hp to get me flying away.
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Post by 190mech on Mar 31, 2018 18:42:47 GMT -5
WOW!Thats strange,,I was just starting to ask about some trench work..Even some mild smoothing would be a lot better than hoping the mixture will travel across sharp angles..Here is Brent's link to different methods; 49ccscoot.proboards.com/thread/10404/case-carter-porting-trench-cuttingRemember the flow is subsonic so vision a fast WW2 fighter plane,no way for air to tumble,just to move smoothly over all of the surfaces... |
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Post by tsimi on Mar 31, 2018 18:46:44 GMT -5
Wow, that's strange, i was just reading that trenching thread.
Brent's "basic" trenching looks good to me.
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Post by ryan_ott on Mar 31, 2018 19:54:43 GMT -5
It actually takes some effort to cut through the cases, I wouldn’t be too worried about it but best to plan ahead and back fill. I’d recommend some sort of trench work just for more effective cylinder filling.
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Post by tsimi on Mar 31, 2018 21:00:19 GMT -5
Can you guys take a look at the following images and tell me if the marked area is the correct area to grind off. I also added the unedited image for better view. If you think there should be a different area worked on can you please use the unedited image and mark the area? Thanks. Meanwhile I'll jump on my scoot and go get some JB weld.     |
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Post by 'O'Verse on Mar 31, 2018 21:41:44 GMT -5
Just from seeing other trench work I'd round all edges in green. Then go grab the biggest reed block you can find and shove it in there. And if necessary take any material away in yellow to fit the new reed cage.  |
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Post by tsimi on Apr 1, 2018 0:36:41 GMT -5
Went to the store to get JB weld and... they didn't had it anymore. They said they'll get more in 2 weeks.  I will go to another store tomorrow they should have some since I saw it just few days ago. Meanwhile I started to take apart the Prebug and I need your guys help. Check here...BTW. Wonderful weather over here. 20+ degrees Celcius! Haven't sweat that much in a while. Can't really imagine some people mentioning something about snow.  |
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Post by pitobread on Apr 1, 2018 1:38:27 GMT -5
Devcon is another great epoxy filler that can work in this application.. It is what I use. Probably get it at industrial supply stores.
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Post by 190mech on Apr 1, 2018 4:00:46 GMT -5
Here is another method,although a vertical mill is used,the same could be done with a hand grinder..Cant understand a word he says,but the visual is a good education.. www.youtube.com/watch?v=DE7840g3z04The metal chips start at around 2 minutes.. |
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Post by 190mech on Apr 1, 2018 6:08:31 GMT -5
A wedge shaped reed spacer mounted under the reed will help direct mixture flow toward the transfer ducts(like the 5BM) instead of crashing into the spinning crank.. Some space between the sides of the reed tips help also as flow is there;  |
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