JCP Swinger 2 -air leaks and then fuel starvation

Hi all, thanks in advance for any input, first bike, trying to get it running the right way. Searched around the forum and have some ideas on how to fix my problems but want to run it by people who aren’t as green as I am.

Got a Swinger 2, was running rough when I bought it. Had a bunch of funky repairs done that I’ve been sorting out.

Main thing was an air leak - 10 mins after riding, would not respond to more than 1/4 throttle, anything more and engine would bog down. Air leak. Sprayed carb cleaner, found leaks at both ends of the intake elbow. Cut a new gasket for the bottom, jammed an o-ring between the intake elbow and the carb. Cleaned exhaust pipe and baffle for good measure. Sprayed again, no leaks. Sweet!

Fired up, idled, rode for 2 mins and then died. Not Sweet! No air leaks, seems fuel starved not electrical but who am I to say?I checked the fuel line and gas is flowing. Thinking it simply isn’t tuned right.

My laundry list of things to do is: take apart the carb(note: I’ve done this once before already to replace throttle cable and clean it), increase the fuel ratio on the little clip, check for clogs or any damaged parts, get the jet size if possible (I think it’s a bing 12 clone so jets may be blank) make sure float is sitting correctly, reassemble.

After that I don’t know which way to go, maybe check spark plug and points, or play with the idle screw more? Or should I be looking at the petcock and fuel flow more? It really feels fuel starved now that more air is coming through. Added some small pics of the bike in all its glory and the carb in all its misery.

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Re: JCP Swinger 2 -air leaks and then fuel starvation

2 things to check.

1 if it is fuel it could be the float needle is sticking and not letting fuel to flow as easily as it should. But when the bike is off fuel still trickles down and eventually fills the bowl.

2 if it is electrical, it sounds like a bad condenser. They will run fine when cold but after a couple minutes they warm up and fail.

Check the float out first as it is easiest to get into. For the condenser you will need to purchase a flywheel puller tool to get to the stator plate with the condenser.

Re: JCP Swinger 2 -air leaks and then fuel starvation

To add to the above, if it is fuel you can check to see if the mesh screen underneath the fuel inlet banjo bolt on the carb is clogged.

If it is still behaving like it has an air leak, it could be from the magneto side crank seal.

Re: JCP Swinger 2 -air leaks and then fuel starvation

^^^^^^ both good things to check.

Re: JCP Swinger 2 -air leaks and then fuel starvation

Mike and Jay, thank you both! I plan on checking out the carb-related things tonight and following up on the needle/ banjo screen.

I’ll check for more air leaks when I test it out after putting the carb back on. I really hope it’s not electrical...

Thanks again will post updates asap!

Re: JCP Swinger 2 -air leaks and then fuel starvation

Ѭ ɞŦЯʚOluv Ѫѫ /

Just plan on rebuilding all of it. Everything stock it comes with sucks except maybe the tank and frame.

Unless you just want a grocery getter it’s not going to be that fun.

Re: JCP Swinger 2 -air leaks and then fuel starvation

Yeah I’ve definitely noticed a lot of parts that will need to be replaced already. I’ll post the current petcock situation tonight and here’s the old kill switch I replaced.

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I’d like to get it running as a grocery getter first and then start frankensteining it more after that.

Re: JCP Swinger 2 -air leaks and then fuel starvation

Ok so I opened up the carb and a couple things stuck out:

Looked like grit inside where fuel comes in from the banjo, that little brass hole.

Float needle seemed a little bound so when I reassembled I cleaned it out and made sure it was moving freely.

the needle was at 2nd to the top so I moved it to the last rung on the bottom.

After that I cleaned it all up with carb cleaner and put it back together. Adjusted the idle screw out, and started up.

Idled fine, revved rough at first since it was a little cold still. Then was fine. Rode for 10-15 mins, hitting WOT when moving without any issues.

Might've been the gunk near the banjo inlet, maybe too lean after fixing air leak and also being at altitude (~5k feet).

One thing: it’ll bog at very low speed, about 0-5 mph, when giving it WOT. Will accelerate after warmed up with less throttle, but now seems like too much fuel when goosing it from slow speeds. I have the stock airbox but no filter (reason for the gunk) and was thinking of getting that MLM air filter from Treats for $28, thinking that’ll regulate the airflow better at low speeds and also keep the gunk out.

At any rate, here’s some pics of the adventure. Riding for a little longer now, no leaks, we’ll see what breaks next. Thanks for the help!

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Re: JCP Swinger 2 -air leaks and then fuel starvation

Play with the needle position, too rich and too lean can seem similar at idle and low speed

Re: JCP Swinger 2 -air leaks and then fuel starvation

Gotcha, I’ll keep fidgeting with the needle after more test rides and figure out the best place for it to be, maybe one notch from the bottom will be the happy place. Thanks!

Re: JCP Swinger 2 -air leaks and then fuel starvation

For the stock setup. I would put the needle clip in the middle position. You have it pretty rich with the clip in the lowest spot which can definitely make you bog on the low end.

I would definitely look at replacing that float needle. It might be good for a bit, but the rubber tip has softened and changed shape slightly which is what caused it to stick, but now it could possibly not seal and you end up with your carb over flowing everywhere.

Re: JCP Swinger 2 -air leaks and then fuel starvation

Will definitely have to play with the needle again then, bump it up one notch probably. I’ll get a new float needle ordered along with some other treats, then change the needle clip and swap the float needle at the same time. After that hopefully I can leave the damn carb alone for more than a week. adding more pics of the carb.

Everything else inside looked pretty good (although again, what do I know). Already ordered carb gaskets and I’ll probably swap out that gasket on the top of the carb where the throttle cable and choke go in, it’s still in one piece but the layers of the material are separating. After the intake gasket I found out cutting them isn’t as easy as I thought.

Thanks again for the follow-ups!

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Re: JCP Swinger 2 -air leaks and then fuel starvation

A dirty valve seat will cause stuck needles .

Polish the seat to a bright shine with q tips and a mild abrasive like Brasso or the like . Even some tooth pastes work .

Re: JCP Swinger 2 -air leaks and then fuel starvation

Ooh didn’t look too closely at where the needle sits. I did spray the hell outta everything with carb cleaner. When I go back in to get the gasket changed and the needle clip adjusted I’ll hit that area with something abrasive and shine it up, thank you!

Re: JCP Swinger 2 -air leaks and then fuel starvation

And , when you run out of that junk carb cleaner , buy brake cleaner instead .

Brake cleaner cleans better , leaves no residue , doesn't want to eat rubber type bits and is very useful for/on a lot of other things .

I haven't bought carb cleaner in about 30 years or more .

I buy the flammable type as it seems to do the best job and it works as starting fluid , if you're quick enough . ;)

Re: JCP Swinger 2 -air leaks and then fuel starvation

Oh dang I didn’t know carb cleaner wasn’t good for carb parts. I bought brake cleaner at the same time and still have a bunch left, I’ll use that from now on, thanks for the tip!

Re: JCP Swinger 2 -air leaks and then fuel starvation

> Mike Pavlik Wrote:

> -------------------------------------------------------

> Oh dang I didn’t know carb cleaner wasn’t good for carb parts. I bought

> brake cleaner at the same time and still have a bunch left, I’ll use

> that from now on, thanks for the tip!

Good choice .

Carb cleaner is a bit 'meh' for cleaning and it eats rubber and rubber type bits .

Brake cleaner definitely cleans better , quicker , leaves no residue and evaporates too quickly to harm those little hard to come by rubber type bits .

Re: JCP Swinger 2 -air leaks and then fuel starvation

> P D Wrote:

> -------------------------------------------------------

> > Mike Pavlik Wrote:

>

> > -------------------------------------------------------

>

> > Oh dang I didn’t know carb cleaner wasn’t good for carb parts. I

> bought

>

> > brake cleaner at the same time and still have a bunch left, I’ll use

>

> > that from now on, thanks for the tip!

>

> Good choice .

>

> Carb cleaner is a bit 'meh' for cleaning and it eats rubber and rubber

> type bits .

>

> Brake cleaner definitely cleans better , quicker , leaves no residue and

> evaporates too quickly to harm those little hard to come by rubber type

> bits .

Yeah I learned this a whole ago now. Dont understand why carb cleaner is a thing. Break parts cleaner is the best. And you can use it on your brakes if needed.

Re: JCP Swinger 2 -air leaks and then fuel starvation

> Jay Rivett Wrote:

> -------------------------------------------------------

> Break parts cleaner is the best.

> And you can use it on your brakes if needed.

Ha . Imagine that . ;)

Re: JCP Swinger 2 -air leaks and then fuel starvation

Works out for me, there was a 2 for 1 on the stuff when I bought it so it was cheaper than the carb cleaner anyway.

Re: JCP Swinger 2 -air leaks and then fuel starvation

> Mike Pavlik Wrote:

> -------------------------------------------------------

> Works out for me, there was a 2 for 1 on the stuff when I bought it so

> it was cheaper than the carb cleaner anyway.

I almost always find it for less than the cost of carb cleaner .

Re: JCP Swinger 2 -air leaks and then fuel starvation

Oh, well then it goes back to why does carb cleaner even exist? Probably for people like me who don’t know any better, higher margins/ unit, something like that.

Re: JCP Swinger 2 -air leaks and then fuel starvation

> Mike Pavlik Wrote:

> -------------------------------------------------------

> Oh, well then it goes back to why does carb cleaner even exist? Probably

> for people like me who don’t know any better, higher margins/ unit,

> something like that.

I wondered the same thing . Then I left home and the answer became very obvious . ;)

Re: JCP Swinger 2 -air leaks and then fuel starvation

> Mike Pavlik Wrote:

> -------------------------------------------------------

> Oh, well then it goes back to why does carb cleaner even exist? Probably

> for people like me who don’t know any better, higher margins/ unit,

> something like that.

For cars? OLD cars. ;)

Re: JCP Swinger 2 -air leaks and then fuel starvation

Update: Ran it again with the only change being adjusting the idle screw to idle higher. Warmed it up and was riding. Good at wot, no issues with engine dying.

One weird thing: giving it less throttle, maybe 1/4 or less, immediately after wot, would cause the engine to react sluggishly like it was bogging down. I would then go wot again and it would wind all the way out no problem. Tried it a couple times and every time the throttle response at 1/4 throttle or less would cause it to bog. Seems odd to me. I might adjust idle screw more, double check for leaks. Is this because of the clip being set too rich inside the carb? Thinking of putting it back to the 3rd notch. Going to check the spark plug now too, just because. After that will probably order some jets. Any idea what size I should be on a pretty much stock swinger 2 with a bing 12? I currently run with a filterless airbox but will eventually get the mlm air filter for it from treats. Also, I live in CO so would the 5-10k feet be a factor when rejetting?

Thanks all! Excited it’s running now but want to get it running better before doing any type of distance with it.

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