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Old 08-01-2009, 09:09 AM   #1
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Default RB B9 from hell

Dear fellow racers,

I have recently purchased an RB B9 which is giving me headaches. Before putting this piece of hardware on the shelf I hope some might have experienced similar problems with their engines. Here's the deal.

Break in done according to RB's manual. Approximately one gallon of fuel has been used so far.

When I run the engine with a brand new RB #6 glowplug (CP2) it runs fine for about a tank or two (sometimes only half a tank). Then it starts to flameout when applying WOT (or at least 3/4 WOT). No matter what I attempt in adjustment this behaviour continues. There is no obvious damage to the glowplug (coil's not broken etc.) and it glows upon testing. If I install a brand new RB #6 glowplug I am able to WOT again but only for a short while (roughly a tank or two again) and problem reoccurs. Something must have happened to the glowplug though? However if I keep power on the glowplug I am able to WOT though! Engine is running slightly on the rich side but nothing that makes it four stroke.

Has anyone had similar behaviour on their engine? (especially RB B9). Any input is appreciated!

Thanks.

/Tom
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Old 08-01-2009, 09:18 AM   #2
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just wondering if motor has been dissassembled and sealed up with permatex.?.......if your fuel lines and tank check out ok this may be the route to take...take your fuel tank and plug the vent.......put a length of fuel on the fuel outlet and put the tank in a container of water.....blow into fuel line and see if any bubbles escape from tank........is bottom end WAY rich or WAY lean????..........
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Old 08-01-2009, 09:31 AM   #3
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agree with above start looking for air leaks. around carb base and back-plate are most common.
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Old 08-01-2009, 09:31 AM   #4
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Sounds rich. When in doubt lean it out
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Old 08-01-2009, 09:32 AM   #5
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Also, find a Sirio 5 plug. Does wonders for Nova based motors.
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Old 08-01-2009, 10:08 AM   #6
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odonnell 77
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Old 08-01-2009, 11:15 AM   #7
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looks like quality of RB race engines is not what it used to be couple years ago. quite a few people around have issues with RB C6 and now B9 engines. They run very strong for couple races and then they start to dies after refuelling, are impossible to tune. Even factory broken in engines.
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Old 08-01-2009, 11:48 AM   #8
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Tank, fuellines etc. has been checked for leaks. As for the engine - no, I haven't sealed it up. But this behaviour doesn't really bear resemblance or characteristics of an airleak?

It might very well be that the bottom is overly rich. I am going to try lean it out and see if it makes a difference.

As for other brands of glowplugs. Am I naive when assuming an RB plug probably would be the best choice for an RB engine?

Keep 'em coming! - especially anyone who has experienced glow plugs being worn out this fast without showing obvious signs of damage (and frankly still working when the glow power is left on) and knows the most likely cause of this.

Thanks.

/Tom
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Old 08-01-2009, 12:22 PM   #9
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Make sure the idle gap is not too wide, this will make you run the lsn overly rich. I agree, a Odonnell 97 ot 77 plug would be better.

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Old 08-01-2009, 12:27 PM   #10
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ok

After speaking to the RB techs at the euros. The problem with flamouts when pitting our just coming out is cold fuel getting on the pipe, savoya runs a splash guard attached to shell that fits between the tank and the pipe.
Your engine sounds to be too rich on the bottom!
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Old 08-01-2009, 12:55 PM   #11
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I have owned 3 RB C6's and ran the #5 and #6 plugs only. Never had any trouble with any of them. I know this doesn't help you situation, but I just wanted to let you know this is NOT a common problem.

I would go back to factory settings, LSN Turns out and HSN 3.5. One common mistake with these motors is they like to be a Lil' rich on the bottom. Most tuning problems with the RB's is the LSN, read the "Tuning Bible" on this site and see what happens.

RB's are the best mills I have ever ran. So I am sure there is a solution. I ran the 192mm header and 2045 pipe. The problem you are having is tuning or air leak, (most likely tank or lines), I NEVER had to seal an RB carb.

By any chance, is this in a MBX6???
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Old 08-01-2009, 01:13 PM   #12
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The motors are still good, but Novas (maker of rb) plugs aren't what they used to be.
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Old 08-01-2009, 01:26 PM   #13
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Quote:
Originally Posted by SPEEDSKI View Post
I ran the 192mm header and 2045 pipe. The problem you are having is tuning or air leak, (most likely tank or lines), I NEVER had to seal an RB carb.

By any chance, is this in a MBX6???
I've run the engine in both my MP9 and ST-RR (truggy) with same outcome. I use the 2045 aswell and a 7mm venturi (orange). What makes you think this is an airleak? (wouldn't temperature be all over the place, power loss etc. in case of an airleak?).
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Old 08-01-2009, 01:45 PM   #14
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Quote:
Originally Posted by wingracer View Post
The motors are still good, but Novas (maker of rb) plugs aren't what they used to be.

we did try Odonnell, Orion plugs and they did not help. and OD97T works great in my ninja. I had couple RB engines taken apart, cleaned and sealed. Tuned it and it worked great for about 30 minutes (almost the same power as my PTM Ninja), then outside temp went up and engine lost its tune. After about 15 minutes of trying I gave up. Put back my ninja that works the same no matter the weather is, no matter what plug i use (OD97T and P5). Did not have to touch it for 7 racing weekends. I am not an engine tuning expert (still lot to learn) but I was able to tune my old WS7 and VSPEC quite well and now my and my friends ninja. But C6/B9 are pain to tune.
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Old 08-01-2009, 03:38 PM   #15
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a gallon? lean her out, sounds like the bottom is rich and the top. i have best results when tuning the bottom from lean (very small gap with long idle) and top from rich (takes over 100ft to clear out), then you only have to touch the bottom again if you change fuels, maybe. i think you may be over protecting the motor by rinning it "slightly" rich but it seems folks who try that end up with front bearing leaks too often. if the motor is slightly rich or too rich it acts almost the same. its an rb, it can take a few lean runs once in a while.
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