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Old 04-30-2008, 06:21 PM   #1
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Default help help losi 8ight servo eater

Guys, I need help. A really good friend of mine just purchased a brand new Lose 8ight ready to run buggy. Within the first 2 tanks of gas the stock 290 throttle servo went out. He replace both servos with the jr 650 m's. The 650m lasted 3 tanks before it went out, then he put the stock 590 in and it lasted 2 tanks before it quit. Now he has put another 650m in and it lasted 3 tanks. We have checked the linkage and everything is running smooth and not binding. Any advise would be greatly appreciated because he is ready to quit the sport and he is just getting started. Thanks
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Old 04-30-2008, 06:27 PM   #2
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make sure your endpoints are set correctly and there is no load on the servo when it is neutral. some servos make noise when in the neutral position but most dont and shouldnt. I am guessing your endpoints (EPA) are out of adjustment. When you open the throttle fully the servo should be set to stop as soon as the carb is fully open, not past. same goes with the brakes. Hope this helps.
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Old 04-30-2008, 06:42 PM   #3
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thanks for the info i will check it anymore info will be great thanks again
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Old 04-30-2008, 06:52 PM   #4
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Make sure the servo sits high enough off the chassis. Chassis flex can hit the servo and destroy it. I used more spacers on all my servos than it said in the manual and never had an issue. Also take off your air filter and open the throttle to 100% and then close it down to about 95% to alow for the chassis flex. After doing this you should be fine.
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Old 04-30-2008, 07:35 PM   #5
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You will get a lot of info from early postings in the Losi 8ight thread. The problem is the RTR chassis has too much flex unless you do a few things. The first is to spend the money on a good servo. I would recommend a Futaba 9451 or 9351. You can also try a radio try stiffner or get upgraded chassis stiffners or get a pro chassis on ebay for around $55. The first thing I did was spend the money on a strong/fast servo and have had the same one in there for over 1 year racing on a weekly basis.
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Old 04-30-2008, 07:58 PM   #6
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Thanks for the info on the pro chassis i will tell him and check out his end points. he is new to this and is thinking of tossing it in the lake and getting a kyosho 777 so we can use each others spare parts.
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Old 04-30-2008, 08:14 PM   #7
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Losi don't eat servos. Setting them up, and your radio adjustments improperly does...............

I'm still on the original two servos, and my 8IGHT is 2 years old with countless races on it. Going to another buggy is not going to change anything with an improper setup.
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Old 04-30-2008, 08:27 PM   #8
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Some things to check on the servo:

-are the proper spacers used to keep the servo up & off the chassis?

-Are the rubber servo grommets installed? Make sure they aren't overtightened.

-What about the EPA? Is it set correctly?

-Does the servo make a buzzing sound when in neutral? If yes, inspect the spring on the throttle arm linkage as it may have too much tension.

-Do you have O-rings under the servo tray posts? These help to dampen some vibration.

Also, there's something else I did on mine when I got the kit. I noticed that the post that connects the servo tray is located such that it binds the wire of the throttle servo. I tool a sharp knife and removed some material from that particular mounting post and also cut down the guide plate that sheilds the wire from touching the spur like this.



This way, when you install your throttle servo, the wire has a little bit more breathing room as shown in this next pic:



Lots of servos were toasting when the car first came out and lots of people were thinking it was a flex issue, but that doesn't seem to be the case. Some of these toasted servos were autopsied, and no burnt motors or stripped gears to be found, but on many of them (cheap and expensive alike) the wiring had become unsoldered/broken at the point where it meets the circuit board... Almost as if the car's vibration was transfered directly to the post pinching the wire and caused it to come undone.

Anyway, I did that mod on my car over a year and a half ago when I first got the 8ight and I still have the same Airtronics throttle servo.
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Old 05-01-2008, 03:21 PM   #9
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Funny thing is Nobody mentioned the carb....

two things to worry about:
End Points
Carb setting

make sure to check your end points and linkage with the air filter off. and who the hell sets their throttle servo at 100%... (mine is at 45-55 tops... breaking at 30-35) and always set the carb AS STRAIGHT AS POSSIBLE... in some cases (depending on the engine) you may have to get the dermal out and shave alittle off the upper center diff brace... the more liner the travel the less resistance the servo needs to over come. and get some high quality servos, 200oz. or higher. your running 1/8 Nitro cars not a 1/10 electric.
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Old 05-02-2008, 05:39 AM   #10
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Thumbs up Hey Captain......

I think a small rodent has been chewing your radio tray.....
Nice post! This is one I haven't heard or seen.
Good stuff.
Thanks,
TEX
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Old 05-02-2008, 06:18 PM   #11
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Hi Tex.

I guess it's a bit of a fluke because the 8ight was my first nitro r/c, but I guess when you come into something new with no preconceived notions, you tend to notice and question odd little things. In all honesty, I think that the toasting servos are the result of a design flaw in the car: had they relocated that radio tray post 5 or 6mm more inboard, these problems might not have occured.

At any rate, if any good could come from this, it's that it highlighted the importance of setting up your electronics properly whereas it might otherwise have been just another neglected detail.
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Old 05-03-2008, 10:54 PM   #12
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Wow! With all that dialing just to make the throttle servo reliable, you would think Losi might actually re-design the tray! Buy lots of servos, nothing you do will solve the problem completely, why do you think so many racers are switching to the new Xray XB808's. The Losi also has diff case issues, but I'm sure you will soon find that out.

Xray = Same balance, Better quality, Lighter, Stronger, Doesn't eat servos, precision quality parts that last longer. Your choice, stock 5 servos or stock a few Xray parts in your bag.

Drop the Losi...

Peace!
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Old 05-03-2008, 11:12 PM   #13
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I think a redesign of the tray would have been at the top of my priorities if I had any decisive pull at Losi, but sadly I don't so...

In all honesty, it's really not such a bad car. I've had no diff problems at all with mine, but then, there seem to be quite a few grumblings lately about leaky gas tanks and different plastics being used to cut costs. None of which I can verify, but it wouldn't surprise me either. Aside from the exploding servo issue, all of the other "problems" on the car are relatively minor and cheap to address, and if anything, the 8ight IS a tank <--take it from a fool who drove it into everything from sidewalks to chainlink fences to ditches and lamp posts.

As for the Xray, I have one of those on the way, but the car is still far too new to draw any conclusions about reliability, eating servos,etc. Do notice that the 808's driveshafts are both set at quite an accute angle, so there may be some wear/vibration issues with that over time. Like every other car out there, it will have its strengths and faults.
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