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Old 09-09-2008, 08:15 AM   #1
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Default fadding engine power

So here is the deal. The guy I race with and myself are both having the same problem and we are stumped. Both of our truggys for the first four to five laps are real fast, but seem to fade a bit through the middle to end of our tanks. We have a double double section in the track that is a real easy for us to tripple single at the begining of the race, but as it goes on I can't got it. What would cause this for both of us?
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Old 09-09-2008, 08:19 AM   #2
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Sounds like you are too lean. The motor should be running a bit rich until it gets good and warmed up. Try to richen it up just a hair and try again.

Also, too lean on the LSN can cause a fade due to overheating as well.

Or, clutch may be going soft when it gets hot and killing your bottom end torque.
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Old 09-09-2008, 10:02 AM   #3
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+1 being too lean

in your warmup laps the engine should feel rich till it gets up to operating temp
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Old 09-09-2008, 05:32 PM   #4
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I guess that might be the case as to being lean. What is strange is that on my nova 821b that I run, I have always been around the 200 degree mark and it has excellent power. I did lean it out a bit this last time, and got it to the 230 degree mark, which I am sure was still real safe, but maybe this engine does not like to get that hot.
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Old 09-10-2008, 12:18 PM   #5
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Don't trust your temp gun. It COULD be off 20 or more degrees easily. Just tune it so it runs nice with good smoke then temp it. Use that number as a ball park.
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Old 09-10-2008, 12:38 PM   #6
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I would first have to ask how many gallons of fuel have you run through your engine?
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Old 09-10-2008, 01:20 PM   #7
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Your motor is shot- lost compression- thats why it only runs when its cold- buy another one and start FRESH or get it pinched and continue to suffer
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Old 09-10-2008, 09:35 PM   #8
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Quote:
Originally Posted by notch johnson View Post
Your motor is shot- lost compression- thats why it only runs when its cold- buy another one and start FRESH or get it pinched and continue to suffer
Not the case. How could you even say that with the little amount of info I gave. My engine has just over one gallon of fuel through it. I ended up richen it about 5 hours on the high needle, and 3 hours on the low and it ran great today. It was strange, all I did was seal the carb and slime the needles o rings, but something to do with that had a real effect on the jetting.
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Old 09-10-2008, 09:55 PM   #9
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Check your front bearing. If you have any oil on the front of the engine it is leaking. This is usually over looked it seems. I had one leaking on an RB S7. I could not get the carb tuned when the engine was warmed up. Your problem sounds a little like what I had. i replaced the $9 bearing and it runs perfect now. I had 2 gallons on the bearing when I replaced it.
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Old 09-11-2008, 08:13 AM   #10
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my front bearing is leaking pretty bad. I got the engine running real well last night. I think I should replace both bearings at once, I just hate to open her up when I got it running well.
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Old 09-11-2008, 10:17 AM   #11
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Quote:
Originally Posted by hobdog View Post
my front bearing is leaking pretty bad. I got the engine running real well last night. I think I should replace both bearings at once, I just hate to open her up when I got it running well.
That front bearing is your problem. I would replace the bearing. You do not need to replace the rear unless you really want to. I would also adjust all your carb settings to the base starting points. Since all of your adjustments are with a leaking bearing.



Here is a how to on RB's site. This will work for most other engines. As for the heating I used my in laws stove top with a glass surface. Worked great.

http://www.rbproducts.com/mainEn.php...ncept%20engine
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Old 09-11-2008, 10:20 AM   #12
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what clutch are you using on it ? some clutches will start to fade out if they get warm, causing amotor to lose its bottom end snap ...
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Old 09-11-2008, 12:06 PM   #13
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I am going to replace the front bearing. Do these engines come with a low budget front bearing? It seems strange for it to go bad that quickly. I am using the mugen stock clutch bell with mugen stock shoes, 1.0 mugen springs and avid revolution bearings. Are the tko's the best front bearings?
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Old 09-11-2008, 02:04 PM   #14
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TKOs, IMO, are the best bearings to get Just FYI
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Old 09-11-2008, 02:29 PM   #15
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Quote:
Originally Posted by slaytanic View Post
Don't trust your temp gun. It COULD be off 20 or more degrees easily. Just tune it so it runs nice with good smoke then temp it. Use that number as a ball park.
I doubt that the temp gun would be out by 20 degrees I use a fluke gun, most of the better guns should be within 2% accuracy. The problem is the person using the gun and where and how readings are taken, the gun is useful for the safety factor.
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