Post by sime66 on Aug 15, 2016 7:29:16 GMT
Speed/revs/gear tables/GPS:
1) I’m really not hung up about speed in the slightest. The reason I continued with my speed tests was it serves as an indication of optimum carburation. My top speeds were already plenty enough for me before I did the tweak that caused the seize; I’ll be happy at that pre-seize point again, or even a little safer. Top speed doesn’t interest me; I don’t even enjoy over 70mph on my scooter, I’m just hanging on. I like it nippy, and torquey on the hills – I already had that and it was great. But if we're looking at speed, we could agree some points to make our comparisons more worthwhile.
2) You asked about why I thought (Scooterhelp) gear tables were less reliable than GPS, and I explained my thinking, but you didn’t comment;
I’d really like to know if you agree that speed calculated from revs is always higher than actual road speed, (given that our best - not exact** - measure of actual speed is GPS, but that isn’t the point I’m making), and why that difference is, I’ve made that point about rpm vs speed before, but it never gets much response, or comment on my attempted explanation; maybe it’s too obvious to comment on? Or maybe it’s something we actually don’t know? If we don’t know, I’ll stop assuming my explanation is correct due to it not being contradicted.
I agree it isn’t important, but I still think that a 73mph GPS and an 83mph from speedo or 83mph from gear tables are not directly comparable; I believe they are considerably less than 10mph different. I think that first film from Friday shows revs and speed don’t even agree on the same speedo; I think the speedo is high, and I think the actual revs are pretty accurate and useful, but don’t correlate true road speed either; if translated to speed that result would also be high - but different again.
**Science doesn’t measure anything exactly anyway; it just continues to improve the accuracy of the method of measuring the basic units – I’m pretty sure none of us has any caesium-133 to precisely check a second, or krypton-86 to precisely check a metre, which are the bases for speed! Precision wasn’t really my point, which was more to do with consistency of measurement if we want to compare.
I think we can compare GPS speeds
I think we can compare revs
I don’t think we can compare speedo speeds
I don’t think we can compare speed calculated from revs.
This all stemmed from your question about my post; I wasn't even particularly making a point initially; just explaining my thinking because you asked me:
"I think 63mph indicated, and 61mph from gear tables would both be higher than actual – for reasons previously discussed - and GPS would be lower than both of those….."
and
"Why you think the scooterhelp gear speeds are no good? They seem close enough to me."
and
"I don’t think Scooterhelp gear speeds are 'no good'.....I do think that speed, obtained from rpm using any of these gear tables/calculators, will be a theoretical speed that will be higher than actual achieved (due to losses like clutch and road-to-tyre*)"
3) Yes, I’ll have a look at Özant Emil video later and see what I can suss out; I have just said why I don’t think revs gives a true speed, but in this case it might shed some light on that lairy speedo of his.
To my scooter:
4) I don’t quite yet follow what you say there about extended inlet timing making it run richer; it’s the same mix for longer - I’ll need some time to think about that to understand it. I do think my Pilot is rich at the moment; I do suspect that it was lean before, because I kept going leaner to try to get Progression temps up, and temps are now suspect; that’s why I intend to start between the two points and see how the 45/160 feels; get my jetting done right, slowly, without reference to temp. I can say sod the neighbours and do one noisy session in the lane and get my Pilot sorted like I did before when I did it properly, rather than the tweaking I was doing after I’d started on the MJ, which was mainly by temp.
5) How far over is my CHT? – I have not WOTted it since CHT and scoot were broken, and then fixed but CHT still playing up, so I can’t be precise (but we know where precision gets us anyway); all I can do is compare some lower rev runs – The short answer is 15-20/25ºC, but maybe even more at WOT:
On my early morning weekend run to the shops I’m easing off when it’s showing over 130ºC, when it would have been about 110ºC before = 20ºC
Between villages I’m easing right off when I get to 150ºC on a fast gentle run, when I’d be happy to see 125ºC on a that very short WOT run = 25ºC
Even up the lane, where a couple of up-and-downs would have got my engine warm enough to play with my Pilot, say 110-115ºC, I’m getting 130ºC = 15ºC
All I can say is the error increases with speed or temperature and is between 15ºC and 25ºC in the range I’ve tested it, but I haven’t tested it at full revs because it is getting too high before then.
I should also reiterate that the plug still looks rich, and it performs well but rich, which my plug confirms. I very much suspect the CHT sensor or gauge, but I’ll be happier to proceed when I’m certain, or the cause is found if there is actually one. I will proceed anyway; it’s my foot and MOT that’s been holding me up, not the gauge, but in the meantime I’ve been chewing the temp thing over – that’s all, not a biggy; we’d already agreed the CHT must be wrong; I’m just trying to convince myself of it.
1) I’m really not hung up about speed in the slightest. The reason I continued with my speed tests was it serves as an indication of optimum carburation. My top speeds were already plenty enough for me before I did the tweak that caused the seize; I’ll be happy at that pre-seize point again, or even a little safer. Top speed doesn’t interest me; I don’t even enjoy over 70mph on my scooter, I’m just hanging on. I like it nippy, and torquey on the hills – I already had that and it was great. But if we're looking at speed, we could agree some points to make our comparisons more worthwhile.
2) You asked about why I thought (Scooterhelp) gear tables were less reliable than GPS, and I explained my thinking, but you didn’t comment;
I’d really like to know if you agree that speed calculated from revs is always higher than actual road speed, (given that our best - not exact** - measure of actual speed is GPS, but that isn’t the point I’m making), and why that difference is, I’ve made that point about rpm vs speed before, but it never gets much response, or comment on my attempted explanation; maybe it’s too obvious to comment on? Or maybe it’s something we actually don’t know? If we don’t know, I’ll stop assuming my explanation is correct due to it not being contradicted.
I agree it isn’t important, but I still think that a 73mph GPS and an 83mph from speedo or 83mph from gear tables are not directly comparable; I believe they are considerably less than 10mph different. I think that first film from Friday shows revs and speed don’t even agree on the same speedo; I think the speedo is high, and I think the actual revs are pretty accurate and useful, but don’t correlate true road speed either; if translated to speed that result would also be high - but different again.
**Science doesn’t measure anything exactly anyway; it just continues to improve the accuracy of the method of measuring the basic units – I’m pretty sure none of us has any caesium-133 to precisely check a second, or krypton-86 to precisely check a metre, which are the bases for speed! Precision wasn’t really my point, which was more to do with consistency of measurement if we want to compare.
I think we can compare GPS speeds
I think we can compare revs
I don’t think we can compare speedo speeds
I don’t think we can compare speed calculated from revs.
This all stemmed from your question about my post; I wasn't even particularly making a point initially; just explaining my thinking because you asked me:
"I think 63mph indicated, and 61mph from gear tables would both be higher than actual – for reasons previously discussed - and GPS would be lower than both of those….."
and
"Why you think the scooterhelp gear speeds are no good? They seem close enough to me."
and
"I don’t think Scooterhelp gear speeds are 'no good'.....I do think that speed, obtained from rpm using any of these gear tables/calculators, will be a theoretical speed that will be higher than actual achieved (due to losses like clutch and road-to-tyre*)"
3) Yes, I’ll have a look at Özant Emil video later and see what I can suss out; I have just said why I don’t think revs gives a true speed, but in this case it might shed some light on that lairy speedo of his.
To my scooter:
4) I don’t quite yet follow what you say there about extended inlet timing making it run richer; it’s the same mix for longer - I’ll need some time to think about that to understand it. I do think my Pilot is rich at the moment; I do suspect that it was lean before, because I kept going leaner to try to get Progression temps up, and temps are now suspect; that’s why I intend to start between the two points and see how the 45/160 feels; get my jetting done right, slowly, without reference to temp. I can say sod the neighbours and do one noisy session in the lane and get my Pilot sorted like I did before when I did it properly, rather than the tweaking I was doing after I’d started on the MJ, which was mainly by temp.
5) How far over is my CHT? – I have not WOTted it since CHT and scoot were broken, and then fixed but CHT still playing up, so I can’t be precise (but we know where precision gets us anyway); all I can do is compare some lower rev runs – The short answer is 15-20/25ºC, but maybe even more at WOT:
On my early morning weekend run to the shops I’m easing off when it’s showing over 130ºC, when it would have been about 110ºC before = 20ºC
Between villages I’m easing right off when I get to 150ºC on a fast gentle run, when I’d be happy to see 125ºC on a that very short WOT run = 25ºC
Even up the lane, where a couple of up-and-downs would have got my engine warm enough to play with my Pilot, say 110-115ºC, I’m getting 130ºC = 15ºC
All I can say is the error increases with speed or temperature and is between 15ºC and 25ºC in the range I’ve tested it, but I haven’t tested it at full revs because it is getting too high before then.
I should also reiterate that the plug still looks rich, and it performs well but rich, which my plug confirms. I very much suspect the CHT sensor or gauge, but I’ll be happier to proceed when I’m certain, or the cause is found if there is actually one. I will proceed anyway; it’s my foot and MOT that’s been holding me up, not the gauge, but in the meantime I’ve been chewing the temp thing over – that’s all, not a biggy; we’d already agreed the CHT must be wrong; I’m just trying to convince myself of it.