Throttle/brake servo issues

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.

Tyson Adams

Member
Messages
17
Hi everyone, I'm running the savage x special edition and apart from 3 clutch bells and 2 one way bearings, the longest ive been able to drive it so far is about 6 tanks post run-in. I had a few trim issues and the wheels were spinning at idle, with the brake engaged I was trying to turn down the idle speed and smoke pissed out of the servo and fried it. Rookie mistake I know but like all rc problems, it seems you have to do it once to learn! I tried connecting a spare one to it and turned it on and it twitched and went both ways and carried on. The bloke at the rc shop was useless with advice and I've since discovered this forum! What is the issue here? is it the servo itself or will a different work or what? Do I have to reset the receiver or something?
 
what radio you using? and if you plug an analog servo in a digital system it will do just what you describe....
 
the standard TF-40 2.4ghz digital that came with it. This could be the problem as the servo I tried probly wasn't digital?
 
Possibly so, I checked but did not see specs listed, suppose it cant hurt to try and see....
 
just make sure it is centered and set the idles gap according to the manual, usually about 1mm open at idle...
 
So I've installed the new servo, its working great with no twitching, I'm now trying to set the adjustments so it doesn't burn out again. The throttle opens and closes nicely, however the brake closes but when you take your finger off, it opnes slightly and slowly closes again.It appears as tho the arm isn't sitting on the servo fully, so the rod is catching on the plastic guard that goes over the air filter, whats gong on here please? I must add sorry for the what may seam stupid questions guys but the manual doesn't go into great detail with this, and I live 2 hours from the rc shop, who are a bunch of stuck up wankers who expect users to know everything. His response was that he doesn't use hpi so I cant help you. Hence why ive turned to you guys. Thanks
 
Last edited:
Hi tyson, just couple of suggestions so hope they help.
If your carb opening, upon release of brake on the Tx, opens slightly and slowly closes? -
- Is your idle stop screw set so that when you brake it prevents the opening from closing up? It seems your idle stop screw may not be stopping the carb opening and when you apply brake, it moves inwards closing the gap, then when you release the brake, it slides out from the tension of the servo and then slides back in from the tension of the throttle return spring. Is the spring on there?
- If you have the spring, check if it's not binding on anything especially the rubber accordion cover over the LSN.
- Also check if it's not getting caught with the Spur gear slipper nut. A friend of mine had his spring catching that nut when throttle is open.
- Also make sure your servo arm is level and parallel with the travel of the rods and not binding up anywhere. If your using the stock throttle/brake system, make sure the spring on it isn't too high tensioned.
- Whats the specs of the servo your using? Does it have enough tourque?
- Also I found that if I adjust the LSN ball joint by releasing the little grub screw under it (it's just below the ball joint of the LSN), so it's as inline with the throttle return spring, the carb closes and when brake is applied, it doesn't twist. With the ball joint a little off level, I noticed when under braking, the return spring, which isn't sitting level anyways, twist the carb a little making the Gap close up slightly.

Hope that helps. Just tossing in my few cents from what I have come across through my trials.
 

Latest posts

Members online

No members online now.
Back
Top