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Old 10-03-2009, 08:10 AM   #46
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I was briefly at the track yesterday and shot a couple of video sequences. Here are my needle settings:

HSN: approximately 2,75
LSN: approximately 4,25

I did richen LSN slightly to 4,5 - but the only result is it drops from high idle to low (and eventually really low) a lot faster.

Anyway, I hope someone might give me futher clues to why the initial idle is so high when watching these videos (I apologize it's kinda shaky - holding a 4PK + camera and hitting the throttle at the same time isn't my specialty ):

Video 1 and 2 (HSN: 2,75, LSN: 4,25):

youtube.com/watch?v=Ov8gYmO8Kgc
youtube.com/watch?v=r7XFYIcTkMA


Video 3 + 4 (HSN: 2,75, LSN: 4,5):

youtube.com/watch?v=fVrbwNJQpuw

youtube.com/watch?v=tNiNHSRiL9U

Note: bear in mind the increase in RPM on video 4 @ 00:07 is me increasing throttle to prevent the engine from stalling.


Any input welcome - thanks!

/Tom
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Old 10-03-2009, 09:13 AM   #47
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how much gap do you have at idle? just a guess, but i bet it's too much and you're having to keep it rich to keep the rpm down (and not working properly). i know it seems the oppisite, but check the idle gap.
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Old 10-03-2009, 05:21 PM   #48
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I also think the gap is not set right. In the videos you hear the idle drop twice, it shouldn't do that. It doesn't appear to be rich because it is not loading up when you accelerate. I would recommend following these links here and retuning your engine. Re-set your gap, tune your low-end and the top will follow.

http://www.rbproducts.com/mainEn.php...0.21%20engines

http://www.rbproducts.com/mainEn.php...e%20carburetor

Many think that RB engines are harder to tune then other engines, I don't find that to be the case. My tune stays pretty consistant week to week.
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Old 10-03-2009, 06:33 PM   #49
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change your plugs. i had the same problems and it angered me to no end.
i now run Sirio Buggy 7's or O'Donnell 99T's and its been problem solved

also give it more time and fuel. 2 of me 3 rb's tookup to 3-4 Gallons to start performing
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Old 10-03-2009, 07:19 PM   #50
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Use OD #77 plug seal everything up set your low end flush then lean one full turn. Run your high end at three turns out.If this thing doesn't run after doing this then throw your tank away get a new one and replace fuel lines.
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Old 10-04-2009, 04:34 AM   #51
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I run the 7mm venturi (orange) and in order to even see the idle gap I needed to pull out the venturi. I attempted to shoot som macro photos of the idle gap (proportionally bear in mind this is macro). To me (the untrained eye ) it seems to be in the area of roughly 0.5mm - 1mm.

See pictures here:

frcc.dk/pics/rb_b9

Thanks.

/Tom
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Old 10-04-2009, 04:47 AM   #52
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idle gap of about 1mm is fine...0.5mm is slightly on the small side.
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Old 10-04-2009, 05:25 AM   #53
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After making these adjustments just set idle so it idles without dying or running away from you.Just try If I were you I would be trying anything right now.
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Old 10-04-2009, 05:29 AM   #54
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Check your complete exhaust system for leaks.

Cheers
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Old 10-04-2009, 09:20 AM   #55
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My needles are always within the previously noted settings. If you are having this much trouble I would:

1. Check the Rod, if it was broken in to rich for to long, it may be have to much wear. RB's like to be broken in hard, never easy and bloody rich.

2. Check for Clutch, Do not worry about what springs everyone else is running, I run two heavy and one medium springs so I can get the bottom set the way I like it and so the needles work the way I want.

3. Tank fuel lines, Clutch LOL

My B9 is running like a Raped Ape. Just like all my C6's...it is just an awesome motor.

OD 77T is my plug of choice.
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