naynay12

On my homemade rc car,anyone that has built one before,how do you connect it to the servo so that the throttle opens the all way.So im wondering how you guys connect your servo to make the throttle open all the way ..does it have something to do with servo positioning i was thinking?

Edit:If you dont understand what i mean...Well when i pull the trigger on the radio for the throttle all the way,the carb only opens about 3/4.I need to somehow make the carb open all the way.

da mad maori

not sure i understand the question but you'll have to utilize springs or "sliders" so when the servo slides on the cable when going the opposite direction


the further out the horn you put the cable.... the more the throttle will open??????

please explain more

Lars from Norway

There is too much flex in the throttle cable,half of the servo travel is waisted in tighten up the cable

naynay12

So what could you recomend lars?
da mad doari what i mean is when i pull the trigger on the radio all the way ,the carb only opens about 3/4 of the way,i need to somehow make the carb open all the way...

da mad maori

ah i see now

lars is right the cable needs a enclosure...(the pipe thing the cable runs in) you can get one off a bike.....

clamp them at each end so the cable runs inside the pipe and doesnt flex.......

make sense ?

Lars from Norway

Thats right da mad maori!
Looks like it have the mounts for bowden cable at the carb,but you have to make one by the carb.

naynay12

Ok ill give it a go.I might just try some plastic flexible pipe thing first and see how that goes.

bsrman14

Proper cable guide stops are needed to make the throttle open corectly. I told you this before. Remember?

cyclops1970

My Feedback: (5)

you could also turn your plastic blue throttle ofna thing so it faces outside give it more throw and also stop the line from flexing if that helps

drewcrew6

naynay: My servo sits directly below the carb and I have airplane linkage with a clevis but the plate on the throttle runs up and down so it makes it simple.

Drewcrew6

Vinman02

Use a longer servo horn and you'll get more travel.

Vince

splcrazy

i dont think its ment to open all the way so that the flap is completely horizontal , its ment to stay slightly on anlge , thats what ive been told many times by the experts in these engines

naynay12

Whwn i take the airfilter off though you need to move the carb slider thing all the way for the carb to open all the way...also their is a stopper on the carb slidder.
Yeh thats a good idea about the longer servo thing,i was busy today so tomorrow ill try with some enclusoure,then maybe try another longer servo horn though facing the oposite side since the tranny would be in the way...

bsrman14

A longer servo arm may be part of the problem? but you have to fix the other problem first with the cable guide stop mounts. Longer servo arms require more power to move. You need to try and keep the servo arm as short as possible to keep all the power. You need to move the linkage application with less power. Longer arms are a last resolution. This all depends on the selected servo for the application. For a throttle servo I recommend 150 oz or more. A 1/4 scale servo is the best.

naynay12

Bsrman the servo is metal geared 190oz.
What do you mean by cable mount STOP mount(the stop part).Also does the bike cable have to go one end to another since as you can see in the pics i have used black tube but it is to flexible might have to use real bike cable.The tube did not make much difference maybe 1/5 or so [probably because im not doing it properly).Also would it help to mount the servo side way maybe.

bsrman14

The pivot point of the throttle to the linkage conect toto the cable should all be at 90 degrees in nutral position or full throttle. The blue thing on the throttle servo get rid of it. I bet when you move the throttle servo the blue thing stays parall with the cabe to long. get different connectors. You can use screw lock push rod conector.( a wheel collars optional.) I use the wheel collar for extra security. It allows the cable to slide back and forth not binding the servo.

Lars from Norway

You have to make some mounts like i have done here,and put it in front of the servo.Or else the tube will be no good.The tube seems too flexible,so get one from a bike or similar

naynay12

Well i did a few things,i did what you said bsr man except i tightened the blue sliders down so they stay 90 degree for the whole time.I made amount for the throttle cable and now none of the servoes throw is waited trying to tigeten the cable.Now their is about 1/6 of the throttle not fully opening.In the vid the black carb slider is suppose to hit the stopper for the carb to fully open though it does not.Also it could have to fo since they are $20 servoes,metal geared and 190 oz though they might not rotate as much as normal servoes?
So im opened to any idea,i am thinking of either putting the servo side way and maybe that will give it more throw.Or moving the servo forward to where their is alot of room and fabricating a larger servo horn to give it more throw.That all i can think of i want to see if you guys have any eaiser options.Any ideas?
Heres the video... http://s160.photobucket.com/albums/t...t=IMGP1829.flv

da mad maori

hehe these homemade rc cars kick ass!!!

bsrman14

I would disconnet the throttle linkage and start over. Mark the cable with a marker where it exits the cable mount. Pull the cable manually and measure the travel. Put the linkage I told you to use earlier on the servo that distance measured from pull on the cable from the center of the servo and mount the linkage. When mounting the servo, mount the servo linkage parallel to the cable and use that ? measurement mount the servo that distance away from the cable mount. if done correctly everything should be 90 degrees and square. Don't use that blue part!!! Make sure you have cable guide stops at both ends of the cable guide!!!