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Post by rehabkymco on Sept 4, 2020 14:53:50 GMT -5
With flash and without. Still 34/92 jets and Shut down at 7500rpm. Also went down to 7 grams. Revs from dig now just over 6k instead of just under. Also went from 1mm to 1.1mm shims. Feels a little better. Still weak tho. Gonna go to 5 grams like Every other stock contra 139qmb gets set to and see how she likes that.
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Post by rehabkymco on Sept 5, 2020 4:40:16 GMT -5
5 grams is what she likes. 7500 from the dig. And i hit 51.1(8500 rpm) on the GPS. And it probably would benefit from a 1k contra and a set of sliders (5 to 6gram) Only minor issue is between tests the speedo decided to go back funky. Gonna have to go to a digital speedometer like the koso or stage6 if I want reliability and accuracy.
Gonna go read threw some other threads. Try to come to a decision, cause I want more power. I've got 2 different 83cc kits here. An Airsal and a flattop. I know that I can use the flattop with my ported stock head without the need for race gas. Not sure about the Airsal. Although part of me wants a proper BVH to go with the Airsal
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Post by rehabkymco on Sept 5, 2020 8:42:55 GMT -5
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Post by rehabkymco on Sept 6, 2020 8:46:27 GMT -5
Put about 45 miles on Kym yesterday. Fastest ive seen (on its own) is 51. I did get 54.5 drafting behind a minivan. I can tell 2 things thou. The 738 belt has done amazing things for acceleration, even with 9.36 final. The 2nd is that 72cc isn't powerful enough for 9.36 final. I feel it hit a wall around 50 mph. Which this set up with 10:1 gearing and the drum brake would still pull to 55. I don't think anything is causing drag. And with this engine only having now 2920 km on it and well at least the gearbox bearings felt good, so I don't think there's any issue there. The only crunchy bearings I know about are in the swingarm/torsion thing.
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Post by aeroxbud on Sept 6, 2020 16:47:52 GMT -5
That's is some tall gears. Do you know what revs it's hitting 50 at?
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Post by rehabkymco on Sept 7, 2020 1:24:37 GMT -5
That's is some tall gears. Do you know what revs it's hitting 50 at? According to the "factory" tach I'm at 82-8500
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Post by rehabkymco on Sept 8, 2020 17:50:03 GMT -5
Well been thinking something has been wrong well now i know. The spark plug threads has disappeared. Need a new head. Or switch to my 50mm kit and matching head
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Post by Zino on Sept 8, 2020 22:24:00 GMT -5
Good to know below 10 to 1 hits a wall with big tires and a 70 cc .
11 to 1 is always been the go to target what you have just proved that it is pretty spot on .
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Post by rehabkymco on Sept 9, 2020 5:13:46 GMT -5
Good to know below 10 to 1 hits a wall with big tires and a 70 cc . 11 to 1 is always been the go to target what you have just proved that it is pretty spot on . 11:1 is great for 2T. 10:1 is doable on 4T(more torque)but it comes down to how hard will it twist up. My 9.367 (16/52 pri 17/49 sec) should get me to 60 if I could get it to pull to 10k rpm. With my need of a head now, I'm going to put my generic 81cc kit with matched head on. Hopefully it will have the power im looking for. Of course, the devil is on my shoulder saying quit fucking around, throw the Airsal on and SEND IT
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Post by rehabkymco on Sept 9, 2020 5:19:47 GMT -5
The ports on my 18/16.5 valved 50mm chamber head that came with the generic 81cc kit. Yea it's used but by me. The only thing I see that it could use is just a little more work to the exhaust port.
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Post by rehabkymco on Sept 9, 2020 16:01:15 GMT -5
Out with the old and in with the new. Fresh honed 50mm bore kit with flat top piston and the big bore head are ready to be installed. Would already be but I live in a swamp and the mosquitoes are attacking in swarms today with the rain.
Probably best, the 47mm piston has some scuffing on the skirts and the head gasket was just about bare metal. Put about 1800km on this kit between the 2 engines.
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Post by rehabkymco on Sept 9, 2020 19:29:27 GMT -5
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Post by aeroxbud on Sept 10, 2020 6:57:18 GMT -5
Small capacity scooter lights are rubbish. Riding down dark country roads is scary.
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Post by rehabkymco on Sept 10, 2020 7:00:53 GMT -5
Small capacity scooter lights are rubbish. Riding down dark country roads is scary. Agreed. Although when I had this 18w led hooked up threw a relay off the battery my output was 10x better. Still kinda scary on moonless nights none the less
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Post by rehabkymco on Sept 11, 2020 9:16:22 GMT -5
Ended up having to order a new head. Going with a 47mm universal parts piece. Should keep the compression ratio pretty high with the 50mm bore and when I eventually put the Airsal Hi comp kit on as well
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