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Post by pinkflames420 on Feb 12, 2017 14:41:00 GMT -5
Are you using those pipes? I like the blue one  |
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Post by oldgeek on Feb 12, 2017 19:11:50 GMT -5
Are you using those pipes? I like the blue one Sorry, the blue one is on my Vino and the big one is for this build. |
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Post by oldgeek on Feb 12, 2017 19:47:18 GMT -5
The weather here was great for riding today, lots of bikes and scooters about. However I did get the time to check the setup of the 54mm kit and the 52mm kit using the 45mm stroke orange plastic stuffer crank. The 54mm kit is 77.20mm from the deck to the base. Using one average base gasket the durations were exhaust 183, transfer 132. and it looked like this. TDC  BDC  The 52mm kit is 78.5mm from deck to the base. Using no base gasket at all the durations were exhaust 176, transfer 125 and it looked like this. TDC  BDC  The piston in the 54mm kit fits very loose in the cylinder, matter of fact I now remember it fit loosely on the short case build. It also taps the crank at BDC just a bit. I will get some numbers, but I likely need a piston for it? The 52mm kit is brand new, I dont have a head for it but that is not a big deal. I guess the durations could be tweaked on it to make it better. So considering the pipe I am using what kind of durations should I shoot for using either kit? |
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Post by 190mech on Feb 12, 2017 20:55:21 GMT -5
Piston backwards in the 52mm kit pics...The 54mm "B" transfers look a good bit wider than the 52 pic,thats a good thing!Gotta watch that the aux ex ports dont get uncovered by the flat sided piston skirt(hate flat sided pistons,but the bean counters made the call to save a few grams of aluminum) and back flowing into the transfers(short circuit) like this unhappy day with me on an offbeat build..  |
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Post by oldgeek on Feb 12, 2017 21:44:24 GMT -5
Piston backwards in the 52mm kit pics...The 54mm "B" transfers look a good bit wider than the 52 pic,thats a good thing! LoL! Yeah I was in a rush to get the numbers so I could go ride! I check durations with the exhaust pointing up and the motor on my lift up above my head.  With the pipe I want to use, do you think I can put the exhaust duration up in the mid to upper 180's? I am looking at the info at the very bottom of this PAGE |
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Post by 190mech on Feb 13, 2017 4:36:50 GMT -5
Upper 180's should be fine..
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Post by Lucass2T on Feb 13, 2017 5:12:45 GMT -5
Upper 180's and that tecnigas wil probably yield peak power at around 9-10k rpm.
Pretty good!
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Post by nelson on Feb 13, 2017 17:47:20 GMT -5
I have a 45mm stroke crank with the orange plastic inserts I would like to use on this build. I put the crank on the V blocks to give it a look, and found it to be a little caddywoumpass, so I will try my hand at crank truing now I guess. My cylinder choices are a 54mm standard height with the 2 small extra exhaust ports (used from the shortcase build) or a 52mm tall cylinder with a single exhaust port. I would love to give one of the autotech aluminium 54mm cylinders a whirl, but my scooter parts budget is zip at the moment. The exhaust will be a tecnigas RSII that 190mech has said should make a good 90+ pipe. I run the rs2 on my 90. See about 10k rpm, I have hoca 54tall and 43.5 stroke. Thing is pretty bullet proof haven't had any issues with it really in 2 years iirc duration is 187 don't remember exhaust. I have a nice 52mm head you can have. It has been shaved for a nice squish vs the donut style head they come with. Free, you pay shipping! Will get pic if you want. I found the 54 to make way more power than the 52 but I didn't do any work to either..just checked em and bolted them on |
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Post by niz76 on Feb 13, 2017 21:00:48 GMT -5
I found my stock 90 (52mm) to be pretty lame until I got the huge squish gap down and compression up. That woke it up! The Hoca 54 even more so! I also found manually advancing the timing made a HUGE difference in my scoot. Of course gotta keep an eye on temps when messing with timing- but who'm I telling? U know all this! |
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Post by 190mech on Feb 13, 2017 21:15:23 GMT -5
Its a fine line when boosting compression and iggy timing,but another scorched piston on the mantle makes for exciting "there I was" stories..A CHT gauge is needed when going this route,keep a close eye on it,doesnt take long for a meltdown...
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Post by nelson on Feb 13, 2017 22:06:20 GMT -5
I found my stock 90 (52mm) to be pretty lame until I got the huge squish gap down and compression up. That woke it up! The Hoca 54 even more so! I also found manually advancing the timing made a HUGE difference in my scoot. Of course gotta keep an eye on temps when messing with timing- but who'm I telling? U know all this! Yes, the hoca 54 with aux ports around .85mm on the squish. |
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Post by nelson on Feb 13, 2017 22:12:09 GMT -5
Its a fine line when boosting compression and iggy timing,but another scorched piston on the mantle makes for exciting "there I was" stories..A CHT gauge is needed when going this route,keep a close eye on it,doesnt take long for a meltdown... Yes, I destroyed a 12 pin bearing. Bought new piston and good to go. That was about 7-8k miles. |
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Post by oldgeek on Feb 13, 2017 23:05:40 GMT -5
Thanks for the offer nelson, if I end up going 52mm I will take you up on it. I spent a lot of time tonight looking at and thinking about the 2 stroke ports and the way they work/interact. Not so much the exhaust and pipe, but the way the transfers and the boost port work with the piston. I feel like I know even less now than when I started! Lol. There is a whole lotta stuff going on at both sides of the piston in a 2T engine! I also tried my hand at crank truing, it seems to be as mysterious as the 2 stroke cycle. It aint easy, I give props to those that can do it. I got the stuffer crank trued measurably better, but not buy much. I can see the runout on the flywheel side when the crank is turned by hand so I know it will have to be better than that. When I started working on it, the dial indicator was swinging over 4 marks, I have it down to 3 marks now. Each mark is a thousandth? |
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Post by Lucass2T on Feb 14, 2017 0:24:27 GMT -5
A hundred i think. You gotta get the crank's runout within one hundred's.
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Post by 190mech on Feb 14, 2017 7:06:16 GMT -5
.1mm = .003937",depends on the dial indicator measurement system..
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