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Old 01-05-2009, 09:35 AM   #1
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Default need help with my rbs5 L2g!!!

please can anyone help me. does anyone have experience with this engine. i'm not new to nitro and had a rb in the past. i have a dynamite high speed(086? i can't remember) and i've been using my ofna glow plug in it. its been running fine and towards the end of the seaon i ran it one more time and its completely out of tune! it can sit there and ilde all day. at normal operating temp when i run it at 3/4 throttle to wot it boogs/stutters really bad. i thought it was a rich boog so i leaned it out but that didnt do anything so i richened it and for the first few laps it ran awesome then the problem came back! do rb's have a certain setting they like to be? certain type of pipe and glow plug? please help!!! thx.
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Old 01-05-2009, 03:37 PM   #2
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I'd richen it up some more. If leaning didn't help and richening helped some I richen it up some more. Check for bubbles in the fuel lines to. And air leaks on the engine.

When my Rb stutters its a lean bog. If its too rich it just bogs down makes no power and dumps smoke everywhere. (I like smoke) Rich bogs are deeper, gurgly sounding. Lean sounds like its cutting off or missing kinda.


When I'm stuck I just go way rich to start over then slowly lean the car out.
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Old 01-05-2009, 03:44 PM   #3
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I'd richen it up some more. If leaning didn't help and richening helped some I richen it up some more. Check for bubbles in the fuel lines to. And air leaks on the engine.

When my Rb stutters its a lean bog. If its too rich it just bogs down makes no power and dumps smoke everywhere. (I like smoke) Rich bogs are deeper, gurgly sounding. Lean sounds like its cutting off or missing kinda.


When I'm stuck I just go way rich to start over then slowly lean the car out.
Assuming you have no mechanical issues and no air leaks in the motor....:

RB's like the bottom needle just a bit rich (1-2 hrs), then set idle to keep it running. The top should be slightly lean 1-hr or so is good. The rule of thumb is to set your carb rich and slowly lean it back into tune. Also the best plug for an RB is a Odonnell medium plug, or RB 5-6.
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Old 01-05-2009, 05:16 PM   #4
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please can anyone help me. does anyone have experience with this engine. i'm not new to nitro and had a rb in the past. i have a dynamite high speed(086? i can't remember) and i've been using my ofna glow plug in it. its been running fine and towards the end of the seaon i ran it one more time and its completely out of tune! it can sit there and ilde all day. at normal operating temp when i run it at 3/4 throttle to wot it boogs/stutters really bad. i thought it was a rich boog so i leaned it out but that didnt do anything so i richened it and for the first few laps it ran awesome then the problem came back! do rb's have a certain setting they like to be? certain type of pipe and glow plug? please help!!! thx.
Richen it up even more. the reason it helped for the first couple laps is because the tank was full at that point(meaning it was the richest at that point). When the tank starts to empty the motor starts to lean out. Your motor leaned out to the point of being too lean because of this. Let me guess it's colder outside than it last was when you ran it??? just a guess but the colder the outside temp the richer it needs to be because of the abundance of oxygen in the denser air. thus you need to add more fuel to the fuel/air combination.
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Old 01-05-2009, 05:47 PM   #5
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please can anyone help me. does anyone have experience with this engine. i'm not new to nitro and had a rb in the past. i have a dynamite high speed(086? i can't remember) and i've been using my ofna glow plug in it. its been running fine and towards the end of the seaon i ran it one more time and its completely out of tune! it can sit there and ilde all day. at normal operating temp when i run it at 3/4 throttle to wot it boogs/stutters really bad. i thought it was a rich boog so i leaned it out but that didnt do anything so i richened it and for the first few laps it ran awesome then the problem came back! do rb's have a certain setting they like to be? certain type of pipe and glow plug? please help!!! thx.
I run an s5 l2g in buggy as well with an 086 with turbo plug. its 1 of 3 rbs i have. iv got 2 gallons on the s5 right now and running it once a week now indoors up in michigan which is a bit cold indoors it seems to need 1 or 2 hours on the bottom end richened or leaned differently every week to run good. just curious, when you ran your s5 last few times did it hold a tune good from one week to the next?
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Old 01-05-2009, 06:10 PM   #6
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how do you run a turbo plug? i have the non l2g s5. the l2g isnt turbo is it?
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Old 01-05-2009, 09:17 PM   #7
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how do you run a turbo plug? i have the non l2g s5. the l2g isnt turbo is it?
A turbo head button from another RB would no doubt fit it. The l2g uses a seperate head button. The original style(anything before the l2g) uses a 1 piece head. You could use a turbo button on yours but you would also need a seperate cooling head. Anything designed for RB/Novarossi will fit it.
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Old 01-05-2009, 10:27 PM   #8
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well i just got the motor towards at the end of the season so i only broke it in. ran it one weekend at the track. ran great and never died and never had to adjust anything. after that it sat for maybe a couple weeks. i tried it out again and it completely was out of whack. it almost seemed like i had a bad plug or a massive air leak. changed out the plugs, replaced all the lines and still the same problem.
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Old 01-05-2009, 10:36 PM   #9
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ok i'll definitely going to try the different plugs out. thanks for the advice!!!
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Old 01-05-2009, 11:15 PM   #10
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Richen it up even more. the reason it helped for the first couple laps is because the tank was full at that point(meaning it was the richest at that point). When the tank starts to empty the motor starts to lean out. Your motor leaned out to the point of being too lean because of this. Let me guess it's colder outside than it last was when you ran it??? just a guess but the colder the outside temp the richer it needs to be because of the abundance of oxygen in the denser air. thus you need to add more fuel to the fuel/air combination.

Jammin, Dude, im gonna have to call you out on this one. Everything you state here is right except, there is no way in hell that the thing goes lean as the tank level drops. That is just not right at all. If there is fuel above the pick up, it gets the same amount of fuel to the carb at full or not. That wold be like your car,lawnmower,boat, weed whacker, or go cart goin lean at a lower tank level. As long as it aint empty, it aint goin lean. The motor might go lean as it heats up, and if its set lean at cold start its going to go leaner at opperating temp. Thats why you dont tune a COLD motor. You get it up to opp temp and then tune from there.

However, there is one thing that might could be checked. It sounds like there could possibly be a leak in the pressure line, or on the tank lid. If exhaust pressure is not sealed into the tank its losing pressure and not being able to force it up to the carb.
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Old 01-07-2009, 03:08 PM   #11
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how do you run a turbo plug? i have the non l2g s5. the l2g isnt turbo is it?
ebay jennysrcsports i think..they are like $23+shipping and it comes w.shims&turba plug..amain has the turbo head button for about $40 then you pay about $10 for the rb turbo plug. shims are about $5 so altogether ebays a very good deal. iv ran 2 gallons through it now on the same plug. kind of sucks changing over to all turbo plug engines..i have 10+ reg plugs and just bought a handful of odonell 97t turbo plugs.
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Old 01-07-2009, 04:11 PM   #12
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Jammin, Dude, im gonna have to call you out on this one. Everything you state here is right except, there is no way in hell that the thing goes lean as the tank level drops. That is just not right at all. If there is fuel above the pick up, it gets the same amount of fuel to the carb at full or not. That wold be like your car,lawnmower,boat, weed whacker, or go cart goin lean at a lower tank level. As long as it aint empty, it aint goin lean. The motor might go lean as it heats up, and if its set lean at cold start its going to go leaner at opperating temp. Thats why you dont tune a COLD motor. You get it up to opp temp and then tune from there.

However, there is one thing that might could be checked. It sounds like there could possibly be a leak in the pressure line, or on the tank lid. If exhaust pressure is not sealed into the tank its losing pressure and not being able to force it up to the carb.



Uh, my car leans out very slightly as the tank drains. Thats why we are allways told to tune at half a tank.

If you take a model airplane with a 2 stroke glow engine and hold it while its running at half throttle, then tilt it a little nose up the engine will lean a little and pick up speed a little. (mine allways did anyway)

These silly little engines r very sensitive to fuel level, tank height, etc. Sometimes we get lucky though.


Then again maybe his car leaned out only because it warmed up from running....
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Old 01-07-2009, 07:47 PM   #13
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Jammin, Dude, im gonna have to call you out on this one. Everything you state here is right except, there is no way in hell that the thing goes lean as the tank level drops. That is just not right at all. If there is fuel above the pick up, it gets the same amount of fuel to the carb at full or not. That wold be like your car,lawnmower,boat, weed whacker, or go cart goin lean at a lower tank level. As long as it aint empty, it aint goin lean. The motor might go lean as it heats up, and if its set lean at cold start its going to go leaner at opperating temp. Thats why you dont tune a COLD motor. You get it up to opp temp and then tune from there.

However, there is one thing that might could be checked. It sounds like there could possibly be a leak in the pressure line, or on the tank lid. If exhaust pressure is not sealed into the tank its losing pressure and not being able to force it up to the carb.
actually they do lean out as the tank starts to empty. not much but slightly. and with these little engines that is enough to throw it out of whack. like zerodefect said thats why it is reccomended to tune your engine at 1/2 tank.
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Old 01-08-2009, 04:03 AM   #14
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actually they do lean out as the tank starts to empty. not much but slightly. and with these little engines that is enough to throw it out of whack. like zerodefect said thats why it is reccomended to tune your engine at 1/2 tank.
He's right man. As the fuel level drops the space in the tank is displaced with a larger volume of air. This causes the pressure to drop slightly which pushes slightly less fuel out of the tank and into the carb. Cars and lawnmowers get their fuel a different way by either gravity or a fuel pump.
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