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Old 09-20-2009, 05:29 PM
  #121  
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is the one on the side the low speed
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Old 09-20-2009, 10:47 PM
  #122  
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Yes it is. It's made of brass and located on the end of the carb opposite the slide valve.
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Old 09-21-2009, 01:15 AM
  #123  
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Default New Engine RB Concept WS9

Hi Guys,

Have been running in an RB Con WS9. Started very gingerly last thursday running tanks through at idle then medium speed etc. Lots of blue smoke all seemed to be going well, very happy.

Then first race day. Starts off well. Tune is good but occasionaly on the main straight at full tilt the engine bogs down for a sec then gets going.

Over the course of the day this gets worse. Then Final round of qualifying (5 min heats) it slows down altogether. I bring it in and Temp it and its over 400degrees Farenhit.

Is the engine screwed after operating at that heat is my first question and what would have caused it to get that hot?? It was smokey all day which is a good sign apparently. Does the heat mean too rich or too lean??

Secondly I think i have an air leak. As coming off full throttle the revs dont come down like they should. It keeps open throttle for a second or 2. Is this the sign of an Air Leak as this is what I am told and then how do you go about finding it?? This is a brand new engine so I would hope it doesnt have a leak but maybe it does??

Sorry for the long blog this morning but these problems are frustrating and would love to get to the bottom of them and start embracing Nitro as I am a former Electric racer...

Many thanks

Brian.
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Old 09-21-2009, 02:17 AM
  #124  
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You fuel mixture is too lean. It's possibly the main needle, but don't run the engine again in this condition. It's not death to the engine, but it's certainly not helpful to run it this lean. Check my post a few back and use the procedure to set the low-speed needle. Once that's set, open the main needle a full turn. This should make the setting excessively rich, but that's OK for now. Gradually turn the needle clockwise in 1 hour increments, unless it's so grossly rich that it's not able to accelerate to full speed. Continue to lean the main needle until it starts running strong from top to bottom. As long as the engine keeps running better, keep going in small increments. Pay close attention and when the performance stops getting better (do NOT read "getting worse") stop leaning the main needle. Open it back up one hour and you should be ready to run. All of the aforementioned should be done with the engine at full temperature. Do not tune a cold engine - it's a waste of time. As a final step, recheck the low-speed needle setting and be sure it falls within the range specified. It may or may not need a final adjustment.
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Old 09-21-2009, 02:46 AM
  #125  
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If the pinch method doesn't work out for you, you can tune the LSN the way Ron Paris and many other does:

Most engine manufacturers recommend a specific setting for the idle-stop screw, and they’re usually well within the ballpark. For now, set the idlestop screw so that the engine will idle at a moderate rpm without stalling.
Bring the engine up to operating temperature by driving it for a few minutes. Now stop the car and listen to the engine’s idle speed. If the engine idles fast but then slows down in just a few seconds, the low-speed needle is probably set too rich. Lean the low-speed needle (by turning it clockwise in one-hour increments) until, after running a few more laps, the idle stays high for about twenty seconds or so when you stop the car. Once you’ve done this, use the idle-stop screw to make the final adjustment of the idle speed.


The 20 second idle is with approximate ½ full tank.

Cheers
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Old 09-21-2009, 04:03 AM
  #126  
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Hi All,

I will give a short feedback from my OS V-Spec. I have tuned the engine as recommended from M7H and Lille-Bror.

But...
It's really not easy - if the engine idles is 20sec in the higher idle after a fast run and I only give a short shot pull on the throttel it went back to the lower idle. - So I am not able to reduce the idle speed.
So I checked what happens if I lean the LSN more. The engine sounds after a high speed run like ah ah ah - it stutter. -> it seams for me that it is to lean but this is only after high speed block or if I pull full throttel three time on the starter box.

Next time I will check how long it takes to stop the engine after pinching the fuel line.

Br
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Old 09-21-2009, 04:20 AM
  #127  
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Originally Posted by racer_hh
Hi All,

I will give a short feedback from my OS V-Spec. I have tuned the engine as recommended from M7H and Lille-Bror.

But...
It's really not easy - if the engine idles is 20sec in the higher idle after a fast run and I only give a short shot pull on the throttel it went back to the lower idle. - So I am not able to reduce the idle speed.
So I checked what happens if I lean the LSN more. The engine sounds after a high speed run like ah ah ah - it stutter. -> it seams for me that it is to lean but this is only after high speed block or if I pull full throttel three time on the starter box.

Next time I will check how long it takes to stop the engine after pinching the fuel line.

Br
racer_hh
Sounds like you may have an air leak somewhere? Pull the back plate and carb out. Check the rear inside of the case for cracks (where the back plate slides in) This was a problem on some earlier V-Specs but still happens occasionally on the newer motors.
Now reassemble the motor and seal with RTV silicone or carbseal around the back plate, the carb O'ring and the carb pinch bolt.

Now go back to factory settings and start tuning again using the Ron Paris method
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Old 09-21-2009, 04:32 AM
  #128  
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Or try turn the HSN a little out and see what happens

Edit: And check your exhaust system for leaks.

Last edited by Lille-bror; 09-21-2009 at 05:08 AM.
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Old 09-21-2009, 12:06 PM
  #129  
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Originally Posted by racer_hh
But...
It's really not easy - if the engine idles is 20sec in the higher idle after a fast run and I only give a short shot pull on the throttel it went back to the lower idle. - So I am not able to reduce the idle speed.
So I checked what happens if I lean the LSN more. The engine sounds after a high speed run like ah ah ah - it stutter.
Your almost there!
Try to lower the idle a little bit, you will see it will work, if you give a short pull on the throttle, you will give the engine a bit extra fuel, which will lower the idle....
So, just lower the idle a little bit....
Only, it might be possible that the idle will be to low when your engine is not fully on operating temps after a warm start... (hard to explain, you will recocnize it when it happens)

Last edited by M7H; 09-21-2009 at 01:56 PM.
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Old 09-21-2009, 01:48 PM
  #130  
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Hey Lads,

I had a post a few back about how I was having trouble with my brand new RB WS9..

I just had the engine out of the car and was having a look over it. The compression seems almost gone. Its not easy to turn the flywheel but its certainly not hard. Someone said to me before if you hold it at a right angle it should stay up and not flop over..mine flops over!! Does this mean after the excessive heat it experienced is the engine ruined or is this kind of compression normal after run in??

Thanks again,

Brian.
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Old 09-21-2009, 01:56 PM
  #131  
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Originally Posted by RC8_Brian
Hey Lads,

I had a post a few back about how I was having trouble with my brand new RB WS9..

I just had the engine out of the car and was having a look over it. The compression seems almost gone. Its not easy to turn the flywheel but its certainly not hard. Someone said to me before if you hold it at a right angle it should stay up and not flop over..mine flops over!! Does this mean after the excessive heat it experienced is the engine ruined or is this kind of compression normal after run in??

Thanks again,

Brian.
is that the 400° ?

i would definitely say you did some serious damage runnin at that temperature


i would chock that up to user error , always error on the rich side if anything

it takes a while to learn about nitro 2 stroke engines and what makes them tick

happy motorin' ,
monty

i would doubt that you would be able to obtain a warranty on that one
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Old 09-21-2009, 02:13 PM
  #132  
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Originally Posted by RC8_Brian
Hey Lads,

I had a post a few back about how I was having trouble with my brand new RB WS9..

I just had the engine out of the car and was having a look over it. The compression seems almost gone. Its not easy to turn the flywheel but its certainly not hard. Someone said to me before if you hold it at a right angle it should stay up and not flop over..mine flops over!! Does this mean after the excessive heat it experienced is the engine ruined or is this kind of compression normal after run in??
Is the glow plug installed in the head while you perform this test?
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Old 09-22-2009, 01:51 AM
  #133  
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Originally Posted by M7H
Your almost there!
Try to lower the idle a little bit, you will see it will work, if you give a short pull on the throttle, you will give the engine a bit extra fuel, which will lower the idle....
So, just lower the idle a little bit....
Only, it might be possible that the idle will be to low when your engine is not fully on operating temps after a warm start... (hard to explain, you will recocnize it when it happens)
Damn, you are good, M7H. Respect
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Old 09-22-2009, 02:21 AM
  #134  
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Steve,

Yeah the Plug was in it and tight....sounds like I might have a problem.

Oh Dear.
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Old 09-22-2009, 11:08 AM
  #135  
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That's not good news but let's make sure you're doing the test properly. When you check to see if the engine can "fall over" on it's own, did you rotate the crank so it was no the compression stroke? The idea is to rotate the flywheel clockwise (looking from the front) until the resistance from compression rotates the engine block to level (parallel with the ground). If you did that, and the engine block still easily rotated through the compression stroke under its own weight, then there's damage to the piston and sleeve.
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