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Calling John Aylor, aka Mad Moo
Posted: Tue Nov 13, 2012 12:52 pm
by Wolfie
John, I know you are a sage on your triples, Also I believe you live at altitude or have regular access to it..
I just wondered what sort of difference you have in your carb settings to cope.. is it just a small matter of needle clip shifting or a larger change meaning different jets?
Next year we'll be spending several days above 1000m and peaking at just over 2400m at times.
I know the bikes will misbehave and in the past I have simply shifted clip position which has helped... so, I suppose I just want to know if you think this is sufficient?
.. or if there is a 'rule of thumb' about per 1000ft or something?
Posted: Tue Nov 13, 2012 5:58 pm
by simonh
i rode johns h2 up 'his mountain' and it was bizarre having less and less power the higher up the mountain we got
But even in the desert it was at an elevation, so when hes racing there he has to jet for it
Posted: Tue Nov 13, 2012 6:06 pm
by kas750
simonh wrote:i rode johns h2 up 'his mountain'
Is that code?
Posted: Tue Nov 13, 2012 6:07 pm
by Wolfie
Bizarre isn't quite how I'd describe it, no matter how much I told myself it was the altitude.. I just couldn't get that nagging doubt outa my head.
And something serious could be wrong and I was just believing it was the lack of air.
nag, nag, nag, nag, hour after hour.. nag, nag.
the year I fiddled the needles was good though.. passing all the cars, two up loaded with kit, but it was simply that, no judgement, no looking at the plug colours.
Still had to decoke by the time we got back to sea level, well maybe not 'had to' but did it just as a matter of course. only takes half an hour.
Posted: Tue Nov 13, 2012 9:05 pm
by simonh
Posted: Sun Nov 18, 2012 3:32 pm
by Wolfie
Posted: Sun Nov 18, 2012 3:38 pm
by husson73
not a code the translation is too easy as demonstrates Simon
Posted: Mon Nov 19, 2012 7:56 am
by JA - Moo
Hey Wolfie,
Sorry, been busy, and haven't been by. As was posted, there are charts. I live at 5500 ft. (1676 meters) For that range of altitude, a needle adjustment, and air screw adjustment will usually do you. If you are heavy on the throttle, then reducing the main one or two sizes will be necessary. It's really tough to jet for varying altitude, so I set mine at the for the lowest altitude. that way you won't be lean when you are at your lowest altitude.
And altitude sucks, even when jetted right, you just lose power. At 5500 ft. 22% of the power you have at sea level is lost. At your 2400 meters you are probably close to losing a full cylinder of power. (33%)
A funny RB story, is he came here years ago for the Balloon fiesta, and he took my 750 up "my mountain". We got to the turn around area and I asked him what he thought of my bike. He said "honestly, it just feels like a strong 500." I then said, "well, we are at almost 10,000 ft." He kinda looked at me strange and said "that makes a difference?" I said "yeah there is no air up here" And he said, "well, how should I know, there are no mountains in England"........
Years Later Simon took it all the way up the mountain with the 500 engine in it, and felt the power loss for himself.
Here is "my mountain"
Posted: Mon Nov 19, 2012 10:10 am
by Wolfie
Cheers John, I wondered where you had got to...
According to the carb manual I found overleaf, for normal running about 2 clips should be fine but for the day going over the top at Port d' Envalira it would require 2 jet sizes.
Seeing as we'll only be up there for half an hour or so I think the clip adjust will be sufficient.
It was good to find an actual table to look at though since we won't have time to be faffing around with plug chops and things.
.. but that modern steed in the pic will have engine management surely? or is it normally aspirated?
Posted: Mon Nov 19, 2012 11:34 am
by Hal
Plus, it is hardly the Bonneville Salt Flats up there, so just how much running would you be doing WFO? I think you could be overworrying about the main jet.
Posted: Mon Nov 19, 2012 12:36 pm
by Wolfie
The needle looks to be mainly in command around the half throttle position, just about what we will be on the climbs or even more on any steep bits.
I don't expect to get things exact, just trying to avoid a painful slog around, and an engine full of soot by the time we reach sea level again.
It really is like having the choke stuck on for days..
Posted: Mon Nov 19, 2012 4:12 pm
by JA - Moo
Wolfie wrote:Cheers John, I wondered where you had got to...
Going through a home remodel, the GF said we either fix up the place, or she was going to have it bulldozed..........LOL I actually liked my shop/house........
Seeing as we'll only be up there for half an hour or so I think the clip adjust will be sufficient.
If your jetting is close, I don't think you will have any problem.
.. but that modern steed in the pic will have engine management surely? or is it normally aspirated?
The American version of the baby Ninja has carbs. It's gutless at any altitude.........