ATC500R "Build Thread"

[TecateDan]

went through a similar problem. Is the carb old? is the slide worn out. Chased a carb problem for a year and it was a worn out slide. 45 is to small for a pilot as well esp if your running a larger carb..

UPDATE! I had Rachael pull start me with the VForce last night! She fired right up! It idled high as heck and messing with the air screw didnt affect anything, it idles lower with the choke up so Im pretty sure its a lean pilot jet. I started with a 45 pilot and 170 main, per suggestions I am jumping to 175 and 55 pilot. Sounds amazing with this pipe! And the vibrations are nothing, i was suprised. overall I cant wait to work the bugs out with the cooling system and go get the kicker welded up, its coming together!

[RIDE-RED 250r]

I may have missed it earlier in this thread..


But did you do a leakdown test on the engine Jason??? If not, that's the first thing I would do if richening up the pilot doesn't take care of it. My 250r I just put together did the same exact thing..... So I finally broke down and made myself a leakdown tester....And sure enough I had an airleak... I addressed the leak and no more death rev on cold starts!

[JasonB]

Ya thanks guys! It's got a 39pwk that's only a year old and still fresh IMO. I pulled the carb on my lunch break and have a 175 main and could only find a 52 and 58 pilot so I will start with the 52 and see if it runs better. I didnt leak down test the motor like I wanted to, it's getting a full rebuild after TRIKEFEST but it looks fresh inside the cylinder and there are no cracks on the piston skirt (common problem with stock cast pistons). If I can't get her to idle right than its off to the plumbing supply store to buy items for the leak down tester. Thanks for checking out my progress guys!

[TecateDan]

How are u setting pilot... Warm up machine... Turn up idle and play with adjustment on air valve. Screwed all the way in is to small a jet all the way out to larger. You want max idle at 1.5 turns. Get the pilot right or you'll regrets it...


All u gonna see is

[JasonB]

It got hot alright ! Fired over and the idle was prob around 1500 rpms I would guess. Pulled the choke and it sounded like it dropped to about 1000. Maybe that's too high of a guess, it sounded too high though. Anyways I ran the air screw all the way in and popped the choke up the idle dropped a little but not much. Setting pilot you are supposed To run the idle up about 500 rpms above normal and run the air screw in all the way. Back it out 1/4 turn at a time give it 10-15 seconds between turns to catch up. But anything Between 0 and 1 screw turn out gives you the highest idle than the pilot is lean, anything over two turns out with the highest idle means the pilot is rich. That's my understanding at least! Anyways, judging by the high idle and no effect from the air screw tells me the pilot is too lean, because I know the idle circuit is clean as a whistle so there's no clogs

[JasonB]

All your going to see Dan

[JasonB]

I’m sure there are lots of opinions on this, but my limited experience has been 0 to 1 turn out on the air screw is too lean a pilot, 1 to 2.5 turns out is perfect and more than that is too rich. Once the pilot is close and it idles low I like to fine tune the air screw by snapping the throttle open from idle and going richer till any bogging is gone and it sings up cleanly. Sometimes you end up changing the pilot again because even though it starts and idles fine, the “snap” test shows a need to go one way or another with the pilot because the air screw goes out of the desired turn range, but it sounds like you are at really lean right now and at the RPM you’re idling at I doubt you’ll get any bog when you snap the throttle. I sure hope you don’t have a leak. Did you check the float height when you got the carb? That is step one when tuning a carb. Another thing, If you end up with the trike running best with the needle clip at one extreme or the other it’s a pretty sure sign that the pilot is off, so you are well served to have the needle clip in the middle now while you are tuning the idle and pilot circuit. I don’t bother with the main jet till everything else is close to perfect, just put something “fat” in it till you are ready to tune the main. I can just imagine what that thing is going to pull like when it’s all tuned up.

Thanks for the input! I know about 1.5 turns out is optimal and I planned on leaving the needle in the middle position and running around that. And the main was my last concern, really excited to get the pilot right first and then get to go for a spin around the block to see how she runs. The motor came out of a running 88 that Mr Clean bought specifically for this build before I bought it, so I'm not super worried about issues like crank seal leaks yet. We will see after it runs again tomorrow night though, so excited about this bike! Never been on or around a 500 2 stroke of any kind before

[TecateDan]

Your right that exactly what I will see. John is the jockey so ill also see him way out in front of jayson

[JasonB]

Crack kills!

Lol you know you like it

[JasonB]

Your right that exactly what I will see. John is the jockey so ill also see him way out in front of jayson

It's going to be a battle of epic proportions! The earth will rumble and the air will smell of sweet high octane and castor oil

[just ben]

and that brings up a great point, i wonder how many 500's will be out at TF,,,,,, we got Dan's and Fabio's love child , mine, Kevin and Corey had theirs last year, Xowner, sure im missing a few. Billy you should piece yours back together and make a Pheonix build just days before TF

Maybe I should put one together for TF

[RIDE-RED 250r]

Maybe I should put one together for TF

Good idea!!

[TecateDan]

DO it Man.. Just one more 1/2 liter KX that will be on the win podium!!! I'm thining a KX sweep would be sweet at the drags.

Maybe I should put one together for TF

[LastFoolerInVA]

all these 500's.. are yall running in the open or mod class???

[just ben]

all these 500's.. are yall running in the open or mod class???

They have to run in the open.