Buggy won't stay running

[godale03]

Hey guys,

Playing with the buggy yesterday and the thing would not stay running. As soon as I applied the brake it would cut out on me. If I let it idle down without applying the breaks it would die. It would not start unless I feathered the trigger on the transmitter. It is an OS RG X. It seemed to be pretty peppy and responsive when running, I just couldn't keep it that way. I was getting temps around 210 most of the time. These temps were with the body off. Any ideas guys? Thanks

Tom

 

[Plaidfish]

set your radio trim adjustments to zero......set your idle screw (maybe go in a 1/4 to 1/2 turn and let it idle high for a lil bit just so it stays running)......let it get up to temp...I've taken to raising the idle on mine from the radio and letting it warm up to about 160 before I start revving it up.......then it hits temp quick......and just go back to the basics.....If it's still not idleing well after you set the Idle screw then lean your LSN a hair and run it for at least 20 seconds to let the adjustent set in.....then see what it does when you stop......mine was giving me a hard time after I got it pinched and then magically the temps dropped and it would stay on......now I can let it flip over and just walk casually across th etrack to flip it...it stays on for a good while....and I hold the brake the whole time I'm walking instead of blipping the throttle...
remember when you set the idle screw or LSN to pull th ethrottle a little so you aren't screwing against something in the carb.....LSN needle heads mushroom easy......Not that I know from PERSONAL experience or anything

 

[godale03]

Ok, sounds like a good starting point. I just couldn't figure it out. I didn't want to just start turning needles just for the hell of it. Ok so what I am thinking based on your very well done explination by the way... that the opening on my carb is not open far enough, hence the opening of the idle screw... right? it seemed to run ok, once it did run I just had to keep the throttle up. I want to get it to run so that when I brake or flip it over it does not cut out. If it does during a race I am done... It was a little on the frustrating side yesterday.... it seems for every one good day I have three bad ones...

Tom

 

[Plaidfish]

1:3 is better than I was having last 2 months...I'm definately having better luck lately I got 3rd in the B main last race....there was a C main too so I wasn't the Ultimate Suck.....yeah I'd open up the carb a little more..just don't over do it...I try an dget it to where it might be a little higher rev but not move when it's on the ground......if it does move back it down a little and a hair less than it takes to stop moving the tires.....otherwise you drag the clutch shoes on the bell.......it took me a good 3 months of getting really frustrated w/ tuning before it started to click....and that was 3 months of going out almost everyday after work to see if it was right......I'm a slow learner I guess....the last month or so I've had pretty good luck w/ tuning issues being non-existent.....just remember let car get up to temp before turning screws and turn ONE needle at a time and then run it for a few seconds and see how it was affected....temp and performance wise.....I see guys start turning screws and just going crazy cause they don't wait to se the results of each change before turning it more....

 

[kx250ryder]

Beside what plaid mentioned above, another possibility is a throttle linkage issue. If you have the spring tension/position on the throttle linkage rod adjusted wrong, it will not close the carb all the way to the idle stop screw when you release the trigger. Make sure your linkage is allowing not only for the throttle to close all the way, but also for the throttle to open all the way too. It seems like an obvious thing that you wouldn't forget, but I have done it a couple times, especially when changing to a different engine than the one you first adjusted the linkage for.

Take a look, pop off your air filter (while engine is NOT running) and hit the brakes, see if the carb closes more than when the trigger was at netural.

 

[godale03]

Beside what plaid mentioned above, another possibility is a throttle linkage issue. If you have the spring tension/position on the throttle linkage rod adjusted wrong, it will not close the carb all the way to the idle stop screw when you release the trigger. Make sure your linkage is allowing not only for the throttle to close all the way, but also for the throttle to open all the way too. It seems like an obvious thing that you wouldn't forget, but I have done it a couple times, especially when changing to a different engine than the one you first adjusted the linkage for.

Take a look, pop off your air filter (while engine is NOT running) and hit the brakes, see if the carb closes more than when the trigger was at netural.

Cool will do. Makes sense when you think about it. I am getting better at this tuning thing but it is a slow process. I had to take the linkage apart a few weeks ago to make an adjustment. It is very possible I did not install it correctly. Thanks guys.

Tom

 

[Plaidfish]

you want the linkage to pull the slide as straight as you can get it.....if it means modding the servo horn then do it...when you pull it at a slight angle you are wearing out the carb slide and creating potential for air leaks and/or carb binding up whil e you run it.....not cool if it sticks at WOT....

 

[rbmaxxbasher]

try replacing the body

 

[godale03]

you want the linkage to pull the slide as straight as you can get it.....if it means modding the servo horn then do it...when you pull it at a slight angle you are wearing out the carb slide and creating potential for air leaks and/or carb binding up whil e you run it.....not cool if it sticks at WOT....

Hey Plaid.... does the RG X have a slide or rotary carb, you know I am not sure. If I had it here I could look at it. I think it is slide. How do you know if it is binding or not? It looks as if it is straight on. Anywho thanks for the information man.... as always you have saved my ass again..... I think I am up to owing you a case of cold ones by now....

Tom

 

[Plaidfish]

it's slide......and just watch the linkage from the top and see if it goes at an angle at any part of the range of motion.....if ti does you might need to get a larger servo horn....if you haven't yet get an aluminum one and SET YOUR ENDPOINT STOPS!!!!!.....I had to learn that one the hard way......and the OFNA linkage set is a nice littel upgrade if your's don't have the adjustment barrels on them.......I check for the binding by feel...when it looks straight I run the linkage through its range via the Tx and lay my finger on the slide and feel for any "rough" spots.....you usually have to start rotating the ball on the slide to fix that minor binding.....the smoother your linkages are the less problems you have.....