Carb Slide Assembly - Dumb Noob Question

[Lenny5160]

I have my stock 1985 carb all torn apart for a cleaning. When checking the needle clip position, I just pushed the needle up through the slide (not knowing how this all comes apart) and a M-shaped metal clip came popping out through the spring. So I don't know where that thing belongs and how to get it in there.

I have the carb almost completely disassembled. I left the petcock assembly on the bowl and the main body still has the idle speed screw and choke assembly intact. Everything else is out. I was planning to blow carb cleaner through all holes and put it back together. Anything else I should do while it is apart?

Also, I read somewhere about an o-ring on the idle mixture screw. I don't remember seeing one but will check when I get home. Should that be there on all models?

Thanks!

[hh_899]

the m shaped clip just goes down in to hold the needle in place make sure that the float shut off has no dirt in it because the have a bad habit of fuel leaking thru them and out overflow tube

[Lenny5160]

So the needle goes all the way to the bottom with the M-shaped clip pressed down on top of it, correct?

The clip is in the default middle position. Is there a more ideal position for a bone-stock engine?

[FlyingW]

The stock 70 carbs are lean. Move your clip all the way down (richer mix). Be sure to measure your float height.

[Lenny5160]

OK, so I tear the carb apart, clean everything, and get it back together. Put in a fresh plug and give it a pull - and it comes to life on the first pull. But whoa, holy RPM! It is stuck WFO.

I have had the slide on and off enough times to make my fingers sore, but each time I have a limp throttle as it is stuck open. When I take off the slide assembly, the throttle movement seems perfect. When I put the slide in I rotate it a little until it drops (black cylinder is probably 1/8" below the top of the carb itself) but when I tighten it up, I have no travel like something is bound up.

Help please!

...but when it fires up, it goes straight up to full RPM with no bog!

[FlyingW]

make sure your idle adj screw is backed out. Do you have full travel on the thumb throttle lever when the slide is installed? Disregard the second ?

[FlyingW]

it sounds as if the needle isn't going in to the hole when you put the slide in to the carb.

[Lenny5160]

If the needle isn't going into the hole, I think 1 of 2 things would happen. Either the black cylinder wouldn't go down into the carb or the needle would come popping up through the center. Does my description of the cylinder dropping about 1/8" past the top of the carb sound correct?

I think when I screw the top onto the carb and everything compresses, the throttle cable is being pressed down out of the slide somewhat. But I guess if that were the case I would more likely be stuck at idle if all else were correct.

My idle adjustment screw has never been touched in the rebuild process. Will backing it out allow the needle to go "home" more easily?

I put everything back together as it was, but I did put the clip in the bottom position on the needle.

Thanks for the replies so far. I'll get this figured out yet! I can't just put mechanical injection on this like I did with the car when I got tired of messing with the carb.

[hh_899]

It dosent sound like you have it seated properly flip the choke open look at the slide and the needle it should close off the area completly

[FlyingW]

That's what it sounds like to me too.

[Lenny5160]

Me too now that I really think about it. Didn't know that the slide was supposed to "block off" the main body. It is staying up in the top, i.e. the slide only dropping 1/8" below the top of the carb.

Does it need to be turned to a particular position, or is the needle just not finding the hole in the main jet?

I appreciate the responses. I knew it had to be simple but just plain didn't know how it is supposed to be.

[blue27]

the shorter fat slot goes against the idle screw. sounds like you need to spin int 180 degrees

[FlyingW]

Like blue said, the small notch goes on the left side of the carb and the slot that runs the whole length of the slide goes on the right. The slide acts as a air regulator. As the slide goes up, it pulls the tapered needle up thus opening the hole that goes to the bowl. As the slide goes up, air is pulled through the carb venturi. This causes a vacuum which pulls fuel from the bowl. The farther up the slide is the more air and fuel is drawn in to the intake. Just be sure to turn the slide until it drops all the way down. Long groove on the right side.

[Lenny5160]

That slot information is exactly what I was looking for! Even after knowing that, I had to play around with it a little bit. It almost felt like I had a bur on the slide, but couldn't find anything like that. But once I got it past that point it fell right in and I am in business! Thank you, blue!

Between the carb cleaning and new plug, I now have a much better trike. Still not great, but is at least driveable. With 210# of my son and I on it, I need to kind of ease into it to get us going but I was able to get to the top of 2nd gear with a little downhill help. On level ground it still wants to bog down and pop when I shift from 1-2 but it can recover and doesn't want to instantly die like it used to. And I had no need whatsoever for the choke.

I will probably still put a 88cc big bore kit on it sometime but until then we can have a little fun the way it is.

[FlyingW]

Glad to hear it Lenny. The popping is because its still lean. Pull the slide out again and move the clip all the way to the bottom of the needle. Make sure your pilot screw is at 1 1/8 turns out from the bottom. Pull your air filter if it has one and clean the foam element real good. I found my Tonka Trike actually runs best with no filter at all.

Rather than a 88 kit, you might consider putting in an aftermarket motor. Many 70 owners are going to the aftermarket motors becaus you can get an entire brand new motor with the carb and electrics for less than 300.00. The 88 kit will cost you more than that. The benefit is you can get a larger motor (more power) either electric start or kick start with a CDI ignition (no points to mess with). I've got a 110 electric start in my Spontanious Combustion trike and I love it. It does take a little work to get it in and all hooked up but the motor itself bolts right in. Tres sell motors that are genuine Lifan motors but he does a pull start conversion on them so you don't have to modify the chassis (rear fender) for a kicker or try to stuff a battery up in the frame as I did. Despite the challenges, it is a great upgrade to the 70. The motors can come clutched or semi-auto clutch. Electric start or kick start. Think it over.

[blue27]

good to hear you are on the track!!!!! Keep it up 70's are addictive.

[Lenny5160]

I do have the clip in the bottom position already since it was suggested in this thread. Perhaps that is what helped it run much better. Also could be the plug since the existing one was pretty black.

I have the pilot at 1 3/4 and didn't mess with that at all tonight.

I am not planning on doing the complete 88cc kit; just the bore-up kit which is $100 or so. I will also do the points and condenser, and someone also recommended a timing chain. But I am pretty much doing it to restore compression to like-new rather than chasing power. I have young kids and a relatively small yard (0.4 acres), so I want them to be able to putt around cleanly but safely.

If I want to go fast my dad, brother, and I have 2 drag cars to satisfy my cravings!