2-stroke/single-speed...operation for topend performance?
- Thread starter augidog
- Start date
btw, i have your math figured out...it doesn't make this any less frustrating tho...i'm not interested in banging my head trying to make numbers match. if i can't focus on 2 readouts while riding, so be it. honestly, i appreciate your help, it's my eyes that aren't cooperating.
i know now i can pull the 16...it looks like i hit an under-load fuel "wall" of about 9k...time to go hunting for the proper intake so i can get my carburetor on there & try again.
i know now i can pull the 16...it looks like i hit an under-load fuel "wall" of about 9k...time to go hunting for the proper intake so i can get my carburetor on there & try again.
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duivendyk
Guest
The first collumn is what you get when you multiply engine rpm in thousands with the numbber of teeth on the primary ,i.e 13*9.37or 121.8 (rounded off to 122),this number is proprtional to the road speed.Now if you repeat this for the 14t test run,you get a different # also proportional to speed in the exactly same manner since nothing else has changed.If you take the ratio of these numbers that is for the 14t and 13t run, you get 1.058 this ought to be the same as the measured speed ratios 36.5/34.8 or (1.049).
In the 16t row I did the same thing and compared the 16t run with the 14 t run,there the ratios ,1.14 and 1.022 don't agree at all.I was trying to check on the integrity of your data.I trust your speed data (time measurement) more than your rpm readings ,which could well be on the flaky side.Is it clearer now?
In the 16t row I did the same thing and compared the 16t run with the 14 t run,there the ratios ,1.14 and 1.022 don't agree at all.I was trying to check on the integrity of your data.I trust your speed data (time measurement) more than your rpm readings ,which could well be on the flaky side.Is it clearer now?
yup! i sure do appreciate your interest and help. the tach display is a bit small for these old eyes...looks like a row of "8's" until i squint. squinting is NOT a good idea at 35mph...i think i need bi-focal goggles 
more soon
more soon
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duivendyk
Guest
Maybe I did not make my point clear enough:If you compute the rpm for your run with the 16t sprocket based on your measured speeds 36.5 and 37.3 mph, the relative sprocket sizes 14 and 16 t and the rpm for your 14t run,(9220), you get 8244rpm, instead of 9200 you measured, a substantial discrepancy (allmost 1000 rpm ).That's what had me concerned me about your test results.Possibly you misread the 8 for a 9,that would explain things,that mighe be it !!
oh, i do get it! so, assuming that i did get accurate enuff with my chart (with the correction)...
what do you think of my chances of a 16tooth/40mph run with the correct (15mm) intake?
anyone: should i try "stacking" my (stock) exhaust a bit now or prioritize intake? how would you do it?
what do you think of my chances of a 16tooth/40mph run with the correct (15mm) intake?
anyone: should i try "stacking" my (stock) exhaust a bit now or prioritize intake? how would you do it?
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duivendyk
Guest
If the engine speed actually dropped that much when you went from 14 to 16 t that is close to 13%,I'm wondering what 15t
(6.5%) would do if there is such an animal.I'm trying to figure out around rpm the max.power occurs,I think it's definitely below 9.3 k , my guess it's maybe around 8.5/8.8 k.What other sprocket sizes do you have at your disposal? You might have missed the sweet spot in between,that's just a guess on my part.The math is no help, not enough info.The other thing is that day to day comparisons might be misleading due to changes in wind conditions,which is frustrating.
(6.5%) would do if there is such an animal.I'm trying to figure out around rpm the max.power occurs,I think it's definitely below 9.3 k , my guess it's maybe around 8.5/8.8 k.What other sprocket sizes do you have at your disposal? You might have missed the sweet spot in between,that's just a guess on my part.The math is no help, not enough info.The other thing is that day to day comparisons might be misleading due to changes in wind conditions,which is frustrating.
yer supposed to say "heck yeah! it'll do it"
i think you may be right, that particular r-range is always pretty beefy. again, maybe more fuel will pull me a bit higher.
well! the paint-guy just came by...woohoo, he's so into helping that we're gonna get sparkly way under budget...
so, it'll be about 3 weeks, then i'll get to start over...but this time it'll be stripped down, long low and lean, similar to my avatar...with sidepanels on the back triangle for my number-plate...
meantime, the drivetrain will go on the diamondback with the whizzer front-end and sun-rim/drum, a VERY heavy bike...i'm gonna keep it geared low and chase some rpm's for a while...
stay tuned
ps-i'd still appreciate any knowledgable exhaust advice.
i think you may be right, that particular r-range is always pretty beefy. again, maybe more fuel will pull me a bit higher.
well! the paint-guy just came by...woohoo, he's so into helping that we're gonna get sparkly way under budget...
so, it'll be about 3 weeks, then i'll get to start over...but this time it'll be stripped down, long low and lean, similar to my avatar...with sidepanels on the back triangle for my number-plate...
meantime, the drivetrain will go on the diamondback with the whizzer front-end and sun-rim/drum, a VERY heavy bike...i'm gonna keep it geared low and chase some rpm's for a while...
stay tuned
ps-i'd still appreciate any knowledgable exhaust advice.
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sparky
Active Member
I've been curious about how to match up a carb, and to know what you need before you order it. You got any tips?shoot...got my HP carby (hi/lo 14mm) but the intake was the wrong one
What tach did you get?
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