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Old 04-21-2015, 11:54 AM   #1
NSA OP
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Dellorto Carb Settings (R90S)

Does anyone have a "starting" setting for the Dellorto Accelerator pumps? IE, 2.5 turns out from seated or something like that? The carbs were not in a condition for me to check prior to dis-assembly, and I'm looking for a baseline that should allow the bike to start, run, and ride, so I can tune from there...

Also, does anyone have a specification for float drop? I have the seated height measured, but haven't seen anything anywhere for drop. I've asked in other locations (FB) and been told it doesn't matter, but I've never seen a carb that didn't have a spec for drop available somewhere.

Thanks!
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Old 04-21-2015, 01:07 PM   #2
craydds
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Does anyone have a "starting" setting for the Dellorto Accelerator pumps?

Also, does anyone have a specification for float drop?
Not at home now so can't check my carbs, and can't tell you from memory. This might help - http://www.ducatimeccanica.com/dello...ellorto_1.html , or this - http://bmwmotorcycletech.info/dell.htm .
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Old 04-21-2015, 02:00 PM   #3
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Thanks! The first link is a great read for anyone who likes playing with carbs. Didn't have many specifics though. The second, Snowbum's, has a bit more specific info. Didn't address float drop though. I suspect I'm probably OK in that department. He did list a rather complicated way of measuring fuel output for the accelerator pump to adjust. I can usually adjust carbs by "feel" though, and he doesn't list an initial setting.
I guess I could follow his instructions until I found an initial setting if need be. If I do that, I'll then screw my pumps down and back out, and post the "screw out turns from bottoming" setting for those that need it in the future.
Or, if anyone runs across that setting, if you could post it for me, that would be great!

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Not at home now so can't check my carbs, and can't tell you from memory. This might help - http://www.ducatimeccanica.com/dello...ellorto_1.html , or this - http://bmwmotorcycletech.info/dell.htm .
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Old 04-21-2015, 02:17 PM   #4
KhaoSanMan
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I'm a ways off from tuning up my carbs, (bike is getting painted) so I for one would love to hear the results of your tuning and the settings you end up with!
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Old 04-21-2015, 02:18 PM   #5
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Don't know how to do a "rough" or rule of thumb setting but this is the right way to do and not very hard. It works and just takes a little patience.

http://r90sclub.dudley.nu/Newsletters/2006-09.pdf

page 10

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Old 04-22-2015, 07:06 AM   #6
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Thanks! I'm going to follow this procedure over the weekend and see what I can come up with

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Don't know how to do a "rough" or rule of thumb setting but this is the right way to do and not very hard. It works and just takes a little patience.

http://r90sclub.dudley.nu/Newsletters/2006-09.pdf

page 10

Slim
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Old 04-22-2015, 07:10 AM   #7
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I'll update the post as soon as I have them tuned properly. Played with it some last night and found I had to go richer than the base settings of 1.5 turns out on the idle mixture (more like 2.5 turns out), and had to go a full turn in on the idle screws... but, my timing is outta whack right now. I can't get it to retard far enough. So, after timing is set, I may well end up back at the base settings. Just for assembly, I set the pumps to just past the point where the pump lever would bind. I'll explain that better when I find the real position for the pump screw.

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I'm a ways off from tuning up my carbs, (bike is getting painted) so I for one would love to hear the results of your tuning and the settings you end up with!
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Old 04-23-2015, 10:29 AM   #8
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Quote:
Originally Posted by mslim View Post
Don't know how to do a "rough" or rule of thumb setting but this is the right way to do and not very hard. It works and just takes a little patience.

http://r90sclub.dudley.nu/Newsletters/2006-09.pdf

page 10

Slim
Slim, I like that tech article. Going to double check my Dell's by his method.
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Old 04-23-2015, 10:50 AM   #9
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Slim, I like that tech article. Going to double check my Dell's by his method.
Glad to be of some help. It worked for me. All I had to buy was the two lab graduates and a roll of silver foil tape from the Home Depot. The cool thing is that the test gas is still clean so you can dump it back into the tank after each test.

I haven't done a vacuum carb sync yet but I do have a "rough" carb procedure.

Take two sharpened pencils and insert the points just under the cut in the slides.

Open the throttle slowly. One pencil will drop before the other.

Adjust the idle stop screws so that both pencils drop at the same throttle opening.

It's very "hillbilly" so use at your discretion. I'm sure I read it somewhere but can't remember where. It worked well on my bike but I will get it vacuum synced when a fellow Airhead can help me.


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Old 04-23-2015, 12:53 PM   #10
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Just curious... what happened to that group? I check the website listed in the PDF, and it leads nowhere...

Quote:
Originally Posted by mslim View Post
Don't know how to do a "rough" or rule of thumb setting but this is the right way to do and not very hard. It works and just takes a little patience.

http://r90sclub.dudley.nu/Newsletters/2006-09.pdf

page 10

Slim
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Old 04-23-2015, 01:37 PM   #11
Big Bamboo
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Works for me: http://r90sclub.dudley.nu/
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Old 04-23-2015, 02:05 PM   #12
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That does work... there was another in there that was bmwr90sownersclub.org and it doesn't work. Maybe it went extinct?

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Old 04-24-2015, 08:37 PM   #13
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mine is set at not quite 3 turns out ... idles good with excellent response

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Old 04-24-2015, 09:36 PM   #14
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Do you have an exhaust nut wrench? I need to snug mine down. Now I can ride it :)


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mine is set at not quite 3 turns out ... idles good with excellent response

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