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[HELP] Chasing tune on RB engine.
03-06-2016, 03:32 PM
#1
[HELP] Chasing tune on RB engine.
So here's the deal:
Symptoms:
On THE Car I was using a Team Orion 3Ports last October or so at the track and started to have a wandering idle. I have some backup engines and fancied the RB CS Sport I rebuilt, sealed up and went to the track 3 times, got it tuned on the starter box and on the track it would die after letting up the throttle. Chased tune up and down, removed venturi, added a copper shim none of it helped. I can get the idle crazy high and it will not die right away but a couple of blasts on the ground and dies.
List of changes:
-New tested fuel lines, no improvement;
-New exhaust seals, no improvement;
-New tank, no improvement;
-On the XB9, no improvement;
Further info:
-Once I lift the rear the engine goes fat and dies, both buggies;
-No fuel leaking anywhere, no bubbles on the fuel lines but I saw some fuel on the pressure line possibly from being too rich;
-Still didn't got the carb seal for the Team Orion, have another two backup engines that I know have a very good tune just need to mount one of them on the XB9;
-Started with the least amount of idle gap the engine could run, clears good on the box but once it touches ground or is tilted it's over;
-Same plug it was running before, the plug is good.
I would like to fix this engine as I like it.
Symptoms:
On THE Car I was using a Team Orion 3Ports last October or so at the track and started to have a wandering idle. I have some backup engines and fancied the RB CS Sport I rebuilt, sealed up and went to the track 3 times, got it tuned on the starter box and on the track it would die after letting up the throttle. Chased tune up and down, removed venturi, added a copper shim none of it helped. I can get the idle crazy high and it will not die right away but a couple of blasts on the ground and dies.
List of changes:
-New tested fuel lines, no improvement;
-New exhaust seals, no improvement;
-New tank, no improvement;
-On the XB9, no improvement;
Further info:
-Once I lift the rear the engine goes fat and dies, both buggies;
-No fuel leaking anywhere, no bubbles on the fuel lines but I saw some fuel on the pressure line possibly from being too rich;
-Still didn't got the carb seal for the Team Orion, have another two backup engines that I know have a very good tune just need to mount one of them on the XB9;
-Started with the least amount of idle gap the engine could run, clears good on the box but once it touches ground or is tilted it's over;
-Same plug it was running before, the plug is good.
I would like to fix this engine as I like it.
03-06-2016, 04:42 PM
#2
How's the glow plug look?
03-07-2016, 04:25 AM
#3
Wire is grey and plug bottom is wet. See attached image.
No oil dripping around the outer bearing/flywheel area.
Switched to an older RB/NR carb, the stock CS Sport carb. It's a composite carb without provisions for running replaceable venturis and a bit shorter side to side. Also it's a double o-ring neck instead of single like the previous carb. Used the same boot as the RB S5 carb sealed up everything with engine sealant and fired up the engine, after a quick tune it doesn't bog down and dies. As the tank is low on fuel, the engine doesn't change tune much even tilting the buggy or when I see air bubbles passing through. Didn't bother to use the air filter, which came a bit wet from the other carb... LSN was set like the S5 carb and had to lean out 2 turns or so. Top is flush like the S5 carb. Will do a autopsy on the S5 carb right away.
No oil dripping around the outer bearing/flywheel area.
Switched to an older RB/NR carb, the stock CS Sport carb. It's a composite carb without provisions for running replaceable venturis and a bit shorter side to side. Also it's a double o-ring neck instead of single like the previous carb. Used the same boot as the RB S5 carb sealed up everything with engine sealant and fired up the engine, after a quick tune it doesn't bog down and dies. As the tank is low on fuel, the engine doesn't change tune much even tilting the buggy or when I see air bubbles passing through. Didn't bother to use the air filter, which came a bit wet from the other carb... LSN was set like the S5 carb and had to lean out 2 turns or so. Top is flush like the S5 carb. Will do a autopsy on the S5 carb right away.
Last edited by 30Tooth; 03-07-2016 at 11:19 AM.
03-07-2016, 12:44 PM
#4
Wire is grey and plug bottom is wet. See attached image.
No oil dripping around the outer bearing/flywheel area.
Switched to an older RB/NR carb, the stock CS Sport carb. It's a composite carb without provisions for running replaceable venturis and a bit shorter side to side. Also it's a double o-ring neck instead of single like the previous carb. Used the same boot as the RB S5 carb sealed up everything with engine sealant and fired up the engine, after a quick tune it doesn't bog down and dies. As the tank is low on fuel, the engine doesn't change tune much even tilting the buggy or when I see air bubbles passing through. Didn't bother to use the air filter, which came a bit wet from the other carb... LSN was set like the S5 carb and had to lean out 2 turns or so. Top is flush like the S5 carb. Will do a autopsy on the S5 carb right away.
No oil dripping around the outer bearing/flywheel area.
Switched to an older RB/NR carb, the stock CS Sport carb. It's a composite carb without provisions for running replaceable venturis and a bit shorter side to side. Also it's a double o-ring neck instead of single like the previous carb. Used the same boot as the RB S5 carb sealed up everything with engine sealant and fired up the engine, after a quick tune it doesn't bog down and dies. As the tank is low on fuel, the engine doesn't change tune much even tilting the buggy or when I see air bubbles passing through. Didn't bother to use the air filter, which came a bit wet from the other carb... LSN was set like the S5 carb and had to lean out 2 turns or so. Top is flush like the S5 carb. Will do a autopsy on the S5 carb right away.
03-08-2016, 05:10 AM
#5
I had the same issue, it turned out to be front bearing issue. Front bearing had no oil or fuel residue so I thought it was fine, but still turned out to be the front bearing. On other engines, the issue was front bearing and very tiny nick on top of the piston which made it impossible to tune.
03-08-2016, 06:58 AM
#6
That plug is garbage.
03-08-2016, 01:56 PM
#8
It's just dark but the coil was perfect. It sat for 10 or so years.
It has a Rossi R3 now, I've had luck with those. Will see tomorrow or the day after. It's a RB 6 standard plug on the photo, anything close to it?
Today I just had one issue, it didn't like the outer filter and had a wandering idle. I recall an engine I helped tune which had similar issue which was rectified with a new plug.
It has a Rossi R3 now, I've had luck with those. Will see tomorrow or the day after. It's a RB 6 standard plug on the photo, anything close to it?
Today I just had one issue, it didn't like the outer filter and had a wandering idle. I recall an engine I helped tune which had similar issue which was rectified with a new plug.
03-17-2016, 12:41 PM
#9
Well no luck with the new plug. Still the same wandering idle after setting it and after picking the rear end up.
Checked for loose screws and were good, while I was blipping the throttle I saw the carb flexing. Going to check what's going on because I can't have two broken carb necks. I am pushing the carb down when tightening.
Checked for loose screws and were good, while I was blipping the throttle I saw the carb flexing. Going to check what's going on because I can't have two broken carb necks. I am pushing the carb down when tightening.
03-22-2016, 04:06 PM
#12
Tested RB S5 carb that had the carb boot frozen solid from being old on the Team Orion engine, it's all good now, changed carb boot obviously (Kyosho GX21 carb boot I had laying around). Power with the 6mm venturi is a light switch though! Going to put the RB engine on the side and once I have more time see what's going on with the carb flexing.
Thanks all.
Thanks all.
10-29-2016, 06:33 AM
#14
a quick fix ive tried is a tiny bit of the teflon tape under the needle orings, than a bit of oil or grease to screw them back in so they tighten up and seal again.. i use the smallest amount of gasket sealer on the crush washers that go in-between the fuel inlet banjo fitting... dont forget a zip tie around the slide boot... if it ok, than you know to get new rings and boot
ive had an engine come back to normal trying this after thinking i needed a front bearing..
10-29-2016, 02:42 PM
#15
Thanks Wrench appreciate it!
The carb is working great on the Team Orion 3ports... The problem is only on the RB, I got a set of new bearings which I intend to replace because sometimes I heard a strange zing when the bump starting the engine. Like it was way too lean but still spiting fuel from the carb. No strange wet spots on the engine so I don't suspect a leak in the case.
Tomorrow or so will update this situation.
The carb is working great on the Team Orion 3ports... The problem is only on the RB, I got a set of new bearings which I intend to replace because sometimes I heard a strange zing when the bump starting the engine. Like it was way too lean but still spiting fuel from the carb. No strange wet spots on the engine so I don't suspect a leak in the case.
Tomorrow or so will update this situation.