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Old 11-15-2004, 12:29 PM
  #4051  
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Default Here we go again

I started up my R40 again today and so far things went really well. Lots of smoke from the MT12, revving happy, but all of a sudden when I hit the brake, the engine revved at a speed higher that idle and constant. I pressed the throttle and it didn't do anything after the 2nd press. Could it have to do with the clutch? Thats the only thing I'm thinking because it wouldn't be the needle settings or air leak. Maybe I need to use different spacers in the clutch than the one showed in the manual. Threadlock was used on the clutch nut. I'm running outta ideas. This is really ruining the fun.
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Old 11-15-2004, 12:39 PM
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1st thing to check is to make sure that the brake cam didn't over rotate and jamb. Make sure the car rolls freely. Try and isolate the problem. Is there binding in the drivetrain? Is it the 2 speed? or is it the clutch?
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Old 11-15-2004, 02:45 PM
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Default Re: Here we go again

Originally posted by HarKonnenD
I started up my R40 again today and so far things went really well. Lots of smoke from the MT12, revving happy, but all of a sudden when I hit the brake, the engine revved at a speed higher that idle and constant. I pressed the throttle and it didn't do anything after the 2nd press. Could it have to do with the clutch? Thats the only thing I'm thinking because it wouldn't be the needle settings or air leak. Maybe I need to use different spacers in the clutch than the one showed in the manual. Threadlock was used on the clutch nut. I'm running outta ideas. This is really ruining the fun.
Next time it revs - use your finger and force the slide carb closed. If engine idle decreases, you might have some linkage binding problems?
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Old 11-15-2004, 04:13 PM
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Originally posted by AMGRacer
I depends on how many corners you have and how fast you go through them. If you have lots of sharp little corners use pistons with more holes and lighter oils. If you have more sweeping corners use pistons with less holes and thicker oils. Thats putting it somewhat crudely.
http://www.fullthrottlespeedway.com
here one of the tracks they are fast sweeping tracks
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Old 11-15-2004, 04:59 PM
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Originally posted by 20 SMOKE
http://www.fullthrottlespeedway.com
here one of the tracks they are fast sweeping tracks
Alright. Let me explain the way i tune it like this. The springs control how far the chassis will lean into a corner given a constant turning force. The springs for a given cornering speed wont let you lean further than this, and therefore controls how much weight transfer occurs. Pretty basic tuning stuff.

Now what the pistons and oils do is controls how fast this occurs. On a fast high speed track when you change direction the chassis moves more violently and with very light pistons/oils will hit the "spring limit" very soon after you corner making the car handle very twitchy and ragged, but you will have the full grip of the weight transfer very soon after cornering. On a sweeping track you are cornering for a longer time and if you get the full grip kicking in early it makes it very tough to corner smoothly and you end up "squaring up" the corner. Also when you unwind some steering the chassis snaps back faster with light oil again making the car unstable.

My general "rules" I use for myself are:

Light oil makes heaps of grip but is unstable
Heavy oil, less grip more stable.
Light oil on slower tracks with short corners
Heavier oil on faster tracks with longer corners.
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Old 11-15-2004, 08:02 PM
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I guessing its the clutch. There is no problem with the linkage. It works fine. The car will rev at a constant speed higher than idle. While pressing the trigger back and forth, I get no response. The last time it happened I had to shut the engine off because it didn't respond. Throttle trims didn't do a thing. It's not the brake either. I'm thinking its the clutch, but don't know where to start. The car ran fine for a while, but then this happend. My friend said it has to be an air leak and I noticed on the fuel filter the rubber O ring was pushed out more than on the other side. Fuel spurted from it on my 8th scale, but caused no problem in running so I doubt its the fuel filter.
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Old 11-15-2004, 08:09 PM
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Originally posted by HarKonnenD
I guessing its the clutch. There is no problem with the linkage. It works fine. The car will rev at a constant speed higher than idle. While pressing the trigger back and forth, I get no response. The last time it happened I had to shut the engine off because it didn't respond. Throttle trims didn't do a thing. It's not the brake either. I'm thinking its the clutch, but don't know where to start. The car ran fine for a while, but then this happend. My friend said it has to be an air leak and I noticed on the fuel filter the rubber O ring was pushed out more than on the other side. Fuel spurted from it on my 8th scale, but caused no problem in running so I doubt its the fuel filter.
Your posts are a little confusing. You say you push the trigger back and forth? Does the linkage move when you do this? Does the engines RPM change when you do this?
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Old 11-15-2004, 08:33 PM
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Sorry. The engine will rev at a constant speed. RPM doesn't change. Same speed revving while the car goes no where. The servo does move, but the engine just revs and shows no response. I even had the air filter off to see in the carb. No improper movement...just the engine revving its ass off here and not responding.
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Old 11-15-2004, 08:39 PM
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Originally posted by HarKonnenD
Sorry. The engine will rev at a constant speed. RPM doesn't change. Same speed revving while the car goes no where. The servo does move, but the engine just revs and shows no response. I even had the air filter off to see in the carb. No improper movement...just the engine revving its ass off here and not responding.
OK If I understand you rightly here the engine is carrying fairly high RPM and any movement of the carb slide does not affect the RPM? This is absolutely impossible in normal circumstances. The only way this is possible is if you have an air leak in the motor after the carb. The motor is effectively an air pump regulated by a slide valve. If working correctly it is not possible for the slide to not regulate the RPM. It has to be an air leak.

The second problem you have may be clutch related. If your motor is revving very high and the car is not moving then your clutch needs to be looked at.
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Old 11-16-2004, 01:44 PM
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My general "rules" I use for myself are:

Light oil makes heaps of grip but is unstable
Heavy oil, less grip more stable.
Light oil on slower tracks with short corners
Heavier oil on faster tracks with longer corners. [/B][/QUOTE]

sound good to me
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Old 11-16-2004, 02:43 PM
  #4061  
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Originally posted by HarKonnenD
Sorry. The engine will rev at a constant speed. RPM doesn't change. Same speed revving while the car goes no where. The servo does move, but the engine just revs and shows no response. I even had the air filter off to see in the carb. No improper movement...just the engine revving its ass off here and not responding.
Har.....Don't worry about.....winters coming anyway....put afterrun in the motor,put it on the shelf....first warm tues in April,bring the car to Nanuet NY where we race.......I'll set the whole thing up for you,fix the clutch,the whole nine yards......

Plus you can try one of my r40's while you wait
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Old 11-16-2004, 02:47 PM
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Originally posted by fastharry
Har.....Don't worry about.....winters coming anyway....put afterrun in the motor,put it on the shelf....first warm tues in April,bring the car to Nanuet NY where we race.......I'll set the whole thing up for you,fix the clutch,the whole nine yards......

Plus you can try one of my r40's while you wait
Hey harry how do those HPI EVO 3s handle? Seems like you have some experience with them..........
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Old 11-16-2004, 05:59 PM
  #4063  
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Fastharry- Sounds like a plan. Hopefully I'll have a real car by then to do some traveling. I'd still like to run the R40 before it snows. We are gonna get temps that are going upto the 60s soon. I'll be snaggin a Savage in a couple weeks.

AMG- I wonder if its the fuel filter. When I primed the car by plugging the pipe and cranking on the box, fuel sprayed from one of the areas where the O rings are because it was partially out. I think that may be it, however, on my 8th scale buggy this never happened. I did notice fuel spilled, but no problems in running of any sort.
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Old 11-16-2004, 11:18 PM
  #4064  
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anybody here tried a solid front spool in r40? how is it compared to the front one way?
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Old 11-17-2004, 01:38 PM
  #4065  
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Well I fixed that problem. After some clutch work and all, that problem seemed to have gone down. Now I just have to work on the tuning. Right now I'm running the MT12 with an RB #6 plug and Odonnell 20 % fuel. I never really touched the low end since break in and just tuned the high speed needle. I'll be heading out now to go run it and see how it does. Will post if I have another issue. Thnx guys.
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