High-altitude suggestions for stock KZ440 engine?
- Astrin
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The idle mixture is factory sealed. In principle, I could unseal it and adjust the mixture - but is that advised? I can live with how it is, it's just inconvenient to have to bump start it sometimes.
Sam Hokin - Santa Fe, NM
1991 BMW K75RT road | 1983 KZ440 cafe toy | 2006 SV-650 track
"BMWs are slugs, for gentleman riders who are also slugs." -- letter to Cycle World, 1984
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- redhawk4
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1978 KZ1000A2 Wiseco 1075 kit
1977 KZ650B1
1973 Triumph Tiger TR7V
1968 BSA Victor Special 441
2015 Triumph Thunderbird LT
1980 Suzuki SP400
Old enough to know better, still too young to care
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- Astrin
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Sam Hokin - Santa Fe, NM
1991 BMW K75RT road | 1983 KZ440 cafe toy | 2006 SV-650 track
"BMWs are slugs, for gentleman riders who are also slugs." -- letter to Cycle World, 1984
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- redhawk4
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I've found if the pilot jet is too rich for altitude the motor bogs in the lower mid range and then clears as the revs go higher, if it's running OK once warm and in normal riding, then you definitely want to focus on getting a good idle before doing any thing else, you don't want to compound problems by changing anything else at this stage.
+1 on using non ethanol fuel, I use that in all my bikes and any motor that isn't running pretty much every day. It may cost a bit more and not always be convenient, but it certainly eliminates a whole host of other issues that can occur with ethanol eating rubber components and the water separation issues. I still think you'll find even ethanol free fuel though is not quite the same stuff we had in the 1980's.
1978 KZ1000A2 Wiseco 1075 kit
1977 KZ650B1
1973 Triumph Tiger TR7V
1968 BSA Victor Special 441
2015 Triumph Thunderbird LT
1980 Suzuki SP400
Old enough to know better, still too young to care
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- SWest
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- 10 22 2014
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Steve
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- Astrin
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swest wrote: Where was the bike originally sold?
Steve
It, and I, are from Wisconsin. We just moved to Santa Fe a couple months ago. So I've got plenty of experience with the bike at near sea level. My BMW has the little plug/switch that tells the ECU to use high-altitude settings, so that starts up great, although it idles a bit low once warm, which is obviously easy to fix. The Kawi is mainly really hard to get started on the battery. And I enjoy futzing with it.
Sam Hokin - Santa Fe, NM
1991 BMW K75RT road | 1983 KZ440 cafe toy | 2006 SV-650 track
"BMWs are slugs, for gentleman riders who are also slugs." -- letter to Cycle World, 1984
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- Astrin
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redhawk4 wrote: I'd try adjusting the mixture screws and idle adjustment to get a good idle at the correct speed, and then go from there. The other thing on the idle circuit is to make sure your jets and passageways are meticulously clean, draw some copper wire through all the openings to make sure there is not a surface layer that's not being removed with just carb cleaner etc.
I've found if the pilot jet is too rich for altitude the motor bogs in the lower mid range and then clears as the revs go higher, if it's running OK once warm and in normal riding, then you definitely want to focus on getting a good idle before doing any thing else, you don't want to compound problems by changing anything else at this stage.
+1 on using non ethanol fuel, I use that in all my bikes and any motor that isn't running pretty much every day. It may cost a bit more and not always be convenient, but it certainly eliminates a whole host of other issues that can occur with ethanol eating rubber components and the water separation issues. I still think you'll find even ethanol free fuel though is not quite the same stuff we had in the 1980's.
Thanks, redhawk4! Great tips! I'll check into all that stuff!
Yeah, I'm so in need of E0 fuel for my BMW (rubber fuel line, etc.) that I created the website pure-gas.org which has done really well, and stations themselves are now posting up to it, which is cool. There's exactly one source of E0 in Santa Fe - a terminal by the airport with 90 octane (a bit low for the Beemer, but oh well). It's a long enough haul that yesterday I bought a 14-gallon "Flo'n'Go" gas can on wheels, with hose, from Pep Boys - now I can get almost three full BMW fills, or numerous Kawi fills in my garage!!
Sam Hokin - Santa Fe, NM
1991 BMW K75RT road | 1983 KZ440 cafe toy | 2006 SV-650 track
"BMWs are slugs, for gentleman riders who are also slugs." -- letter to Cycle World, 1984
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- SWest
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- 10 22 2014
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Steve
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- SWest
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- 10 22 2014
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Steve
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- Astrin
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swest wrote: I assume you have CV carbs....
Steve
Yup, stock Keihin CV carbs. I can happily say the bike does NOT run like a dog up here at 7,000 ft. It just starts like a ... mule. Although I haven't had it out on highway yet. But it seems fine once warm on the 40MPH boulevards and still seems to have that 3000 RPM sweet spot that is so terribly nice.
An interesting mistake I made was to leave the choke on a bit and head out. The bike had NO power. I was confused thinking that it just wasn't warm enough, firing on one cylinder, and finally pulled over and realized there was a bit of choke on. Pulled it off and VROOOM. Was an interesting discovery. So it must be running on the verge of too-rich even with the choke off in the current state. I'll report back when I get the carbs tuned to perfection.
Sam Hokin - Santa Fe, NM
1991 BMW K75RT road | 1983 KZ440 cafe toy | 2006 SV-650 track
"BMWs are slugs, for gentleman riders who are also slugs." -- letter to Cycle World, 1984
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- bluej58
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- The chrome don't get you home
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These old Kaws are meant to run on 87, when I went to Colorado and rode in high elevations I went with the 85 octane because it was available and the bike ran great!
Higher octane doesn't mean better gas, it is added to retard pre ignition in high compression / performance engines, " knock "
Around here elevation aprox. 650 feet I run 87 octane in my stock 78 1000 unless it gets above 90 deg. then I start to hear a little knocking and may go with an 89 octane.
I don't think that the alcohol has as much to do with your hard starting and loss of power as does the octane level.
If you ride the bike a lot I don't think that you have to worry about gas separating, what it does to the modern rubber bits? I don't know but I usually change gas line hoses around every other year, around 18.000 miles because they are hard and replaced the carb and petcock O- rings around 30,000 miles.
Petcock rubber like the one that has all the holes in it for the shut off valve usually start leaking around 12,000 miles but is cheap and easy to replace
What Octane are you running? is 85 available to you? at 7000 bet I bet it is .
Give it a try even if it has a little alcohol in it I think it will help.
www.nicoclub.com/archives/gasoline-octane-myths.html
JD
78 KZ1000 A2A
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- SWest
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- 10 22 2014
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Steve
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