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Post by pinkflames420 on Mar 24, 2017 23:18:13 GMT -5
Speaking of, PartsForScooters just released their Athena selection. Sucks we still need to find a 12 pin piston somewhere else though... Plus i've been referencing this post ( www.pedparts.co.uk/blog/tecnigas-exhaust ) on exhaust performance lately... Considering my circumstances now, I think the technigas would be good to first consider and then the yasuni r with the Athena bbk sounds like a nice and pretty setup  of course we're thinking a bit ahead |
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Post by AtariGuy on Mar 25, 2017 0:06:00 GMT -5
Its a venture. I'm still doing my first full build completely from bare case halves. I don't even know how my 2 stroke runs, it never ran while its been in my ownership. So my first ride will be on a 70 kit right off the bat. I wanted to start with something a little more forgiving on my first assembly, then as i start understanding the deeper bits, the devil in the details, then i'll be more confident setting up my own stage 6 90cc LC hyper race with 190mech's peace pipe and 28mm dell carb... (trails off...) |
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Post by pinkflames420 on Mar 25, 2017 14:12:28 GMT -5
Its a venture. I'm still doing my first full build completely from bare case halves. I don't even know how my 2 stroke runs, it never ran while its been in my ownership. So my first ride will be on a 70 kit right off the bat. I wanted to start with something a little more forgiving on my first assembly, then as i start understanding the deeper bits, the devil in the details, then i'll be more confident setting up my own stage 6 90cc LC hyper race with 190mech 's peace pipe and 28mm dell carb... (trails off...) I applaud you for taking such a dive! Your first 2 stroke build will be fun I'm sure Have you tried getting it to run stock? Or I suppose some parts need replacement anyways right. Its so awesome the forum has there own pipe builder!! How busy are you anyways 190mech ? |
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Post by AtariGuy on Mar 25, 2017 15:35:35 GMT -5
Its a venture. I'm still doing my first full build completely from bare case halves. I don't even know how my 2 stroke runs, it never ran while its been in my ownership. So my first ride will be on a 70 kit right off the bat. I wanted to start with something a little more forgiving on my first assembly, then as i start understanding the deeper bits, the devil in the details, then i'll be more confident setting up my own stage 6 90cc LC hyper race with 190mech 's peace pipe and 28mm dell carb... (trails off...) I applaud you for taking such a dive! Your first 2 stroke build will be fun I'm sure Have you tried getting it to run stock? Or I suppose some parts need replacement anyways right. Its so awesome the forum has there own pipe builder!! How busy are you anyways 190mech ?  🙂   if you check my tng venice build section thread, it shows pictures of what i started with, there was no way it would run when i got it, so its been a full rebuild. I atill have framework/electrical to do outside once it warms up enough for it. I have hundreds more pictures on my phone if you want more details. 49ccscoot.proboards.com/thread/17018/tng-venice-project-first-scoot |
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Post by AtariGuy on Mar 25, 2017 17:33:08 GMT -5
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Post by pinkflames420 on Mar 25, 2017 18:26:16 GMT -5
It might be a dumb question, but on the 49cc printed degree wheel, when your checking your durations and you pass the 180(BDC), then the numbers start dropping down 170, 160, 150 so on. Would I be looking at 170 as 190, and 160 as 200, 150 as 210 .....? I took of my previous durations with the single head gasket and this is what I got. If the stated above makes sense then it would make more sense that my numbers were depressing and not increasing since I was reading it wrong. It would also be good news for me then my durations will be a bit higher and but then I totally woulda screwed this up because then I would need to think of lowering the durations... hmm. So the pic, i thought the wheel said 164, but does it say 196? If someone can please correct me.  |
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Post by niz76 on Mar 25, 2017 19:39:11 GMT -5
Head gasket will have absolutely no effect on duration #'s whether you use none or 10!
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Post by niz76 on Mar 25, 2017 19:45:53 GMT -5
Yes if your exhaust duration is higher than 180, then it would be approx. 198 (!) according to your pic....
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Post by 190mech on Mar 25, 2017 20:02:14 GMT -5
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Post by pinkflames420 on Mar 26, 2017 12:34:03 GMT -5
Head gasket will have absolutely no effect on duration #'s whether you use none or 10! Sorry Niz! I hate to make you repeat yourself lol, EDIT : I MEANT BASE GASKET EVERYONE!  I apologize for this mistake and to believe my durations were a lot lower than they actually are. That was ALOT of good info there and I hope it can still be of use to someone! This was still a better outcome for me, having durations not as low as we thought. Will take some more notes and check back 🙂 |
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Post by pinkflames420 on Mar 27, 2017 19:07:51 GMT -5
Okay I promise this is my last official take on my durations. Includes my cereal box BASE gasket. Mind you I'm gonna need to remove the gasket anyways due to the durations being a bit TOO HIGH. Then back on with the copper HEAD gasket, since I think my squish might be too low with 0 BASE gaskets due to the fact I ground down the cyl head.
So, (ps, I triple checked for good luck,these gotta be it)
Exhaust duration was @ 197 degrees
Transfer port durations @ 127 degrees
Now I know that my transfers are too low, or I suppose the exhaust durations are too high since my blowdown is 60.
My transfer durations look to be a in perfect spot for my kit, but How would I deal with the high exhausts durations? reading about blowdown is also throwing me off a bit because I found a chart stating ;
RPMs.------->Blowdown required for various rpm ranges.
10k - 32
9k - 28.5
8k - 25.5
7k - 22.5
6k - 19
My blowdown of 60 is twice that of the 28.5 stated in the chart 😕
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Post by 190mech on Mar 27, 2017 19:27:04 GMT -5
Transfer duration looks wonderful!Ex IS high for a streeter,but could be run as the CVT can be tuned to keep it on the pipe at all times..Will not have much low end torque though...Is the piston flush with the bottom of the transfers at BDC with this setup??
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Post by AtariGuy on Mar 27, 2017 20:52:58 GMT -5
Okay I promise this is my last official take on my durations. Includes my cereal box BASE gasket. Mind you I'm gonna need to remove the gasket anyways due to the durations being a bit TOO HIGH. Then back on with the copper HEAD gasket, since I think my squish might be too low with 0 BASE gaskets due to the fact I ground down the cyl head. So, (ps, I triple checked for good luck,these gotta be it) Exhaust duration was @ 197 degrees Transfer port durations @ 127 degrees Now I know that my transfers are too low, or I suppose the exhaust durations are too high since my blowdown is 60. My transfer durations look to be a in perfect spot for my kit, but How would I deal with the high exhausts durations? reading about blowdown is also throwing me off a bit because I found a chart stating ; RPMs.------->Blowdown required for various rpm ranges. 10k - 32 9k - 28.5 8k - 25.5 7k - 22.5 6k - 19 My blowdown of 60 is twice that of the 28.5 stated in the chart 😕 Your blowdown is actually 35 degrees. If your exhaust opens at 99 degrees before the piston reaches bottom dead center, then closes again at 99 degrees after the piston passes bottom dead center, it's open for a total of 198 degrees of crankshaft rotation. I'm rounding for easy numbers. Now if your transfer opens at 64 degrees before bdc, then closes again at 64 degrees after bdc, then it was also open for 128 degrees of crank rotation. We need the point it opens the exhaust to the point it opens the transfer. Exhaust at 99 BBDC minus transfer at 64 BBDC, thats 35 degrees of crank rotation that the exhaust can blow its pressure down below a rough 5psi... |
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Post by pinkflames420 on Mar 27, 2017 22:11:40 GMT -5
Transfer duration looks wonderful!Ex IS high for a streeter,but could be run as the CVT can be tuned to keep it on the pipe at all times..Will not have much low end torque though...Is the piston flush with the bottom of the transfers at BDC with this setup?? Ah the cvt tune will be fun. Yes sir, bottom of ex/tran ports align with top of piston at bdc.  |
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Post by pinkflames420 on Mar 27, 2017 22:19:35 GMT -5
Okay I promise this is my last official take on my durations. Includes my cereal box BASE gasket. Mind you I'm gonna need to remove the gasket anyways due to the durations being a bit TOO HIGH. Then back on with the copper HEAD gasket, since I think my squish might be too low with 0 BASE gaskets due to the fact I ground down the cyl head. So, (ps, I triple checked for good luck,these gotta be it) Exhaust duration was @ 197 degrees Transfer port durations @ 127 degrees Now I know that my transfers are too low, or I suppose the exhaust durations are too high since my blowdown is 60. My transfer durations look to be a in perfect spot for my kit, but How would I deal with the high exhausts durations? reading about blowdown is also throwing me off a bit because I found a chart stating ; RPMs.------->Blowdown required for various rpm ranges. 10k - 32 9k - 28.5 8k - 25.5 7k - 22.5 6k - 19 My blowdown of 60 is twice that of the 28.5 stated in the chart 😕 Your blowdown is actually 35 degrees. If your exhaust opens at 99 degrees before the piston reaches bottom dead center, then closes again at 99 degrees after the piston passes bottom dead center, it's open for a total of 198 degrees of crankshaft rotation. I'm rounding for easy numbers. Now if your transfer opens at 64 degrees before bdc, then closes again at 64 degrees after bdc, then it was also open for 128 degrees of crank rotation. We need the point it opens the exhaust to the point it opens the transfer. Exhaust at 99 BBDC minus transfer at 64 BBDC, thats 35 degrees of crank rotation that the exhaust can blow its pressure down below a rough 5psi... There we go. Thanks for sorting that out for me. Ex opens for 81.5 degrees minus transfers opening for 116.5, totaling 35 degrees for blowdown. I understood the blowdown equattion, but was confused by you mutiplying the number of open degrees by 2 instead of subtracting it from 180 then multiplying by 2?? edit: nvm I finally got it lol didn't wanna post the above till I thought forsure, sorry. Knew I shouldna doubted |
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I apologize for this mistake and to believe my durations were a lot lower than they actually are. That was ALOT of good info there and I hope it can still be of use to someone!