fixing a hobbit (long)

Travis Hill /

Hi folks,

First time poster here.

Okay, here's the deal. I have a hobbit that my gf's parents gave me. They said it has been sitting longer than I have been alive (I'm 23). Looking through some of the pictures here, it looks like it is a '78. There doesn't seem to be any rust on it at all. But it is really dirty (been sitting in their dirt floor basement). Anyway, I decided I would start by cleaning the carb really well. By the time I was done, I had the whole motor off because it seemed there was no other way to get to the carb. I got the carb off and opened up the float bowl and it looked like the inside of a cave! There is about a 1/8th inch layer of varnished gas covering everything inside the carb. I let it soak in carb cleaner and degreaser overnight and then let it sit in ATF for about 5 hours. I went back to it and a lot of the varnished gas had loosened up and I was able to clean a good bit of it. So then, I went and tried to get the main jet out. That was a PITA all by itself, but I finally got it out. I was using a sewing needle and a hammer trying to get all of the crud out but to no avail. I finally sprayed some gasket remover on it and let it set for a few minutes and eventually got through it with the needle. I think I also got most of the gunk out of the float bowl and the rest of the path that the main jet takes.

Is there anything that I am missing? I am warry about taking out any of the screws (idle, air mixure) because I'm afraid I'll never get it running right if I do.

Next I am going to go through the rest of the fuel system. It looks like someone took the fuel valve off and ran the fuel line straight to the carb with no valve. I am going to try to take the valve off my peugeot and put it on the hobbit. Think it will work? Also, one of the pedals is missing. I was going to take the pedal crank off and put one of the peugeot's on but I couldn't get it off. I might end up cutting it off.

I hoping to at least see if I can get this thing running with in a couple of weeks.

I am open to any suggestions and will probably be coming here a lot looking for help. I'm really excited about getting this thing running! Talk to ya soon! Travis

Re: fixing a hobbit (long)

i have a spare hobbit carb that looks exactly like that.. thick hard varnish everywhere.. havent gotten around to cleaning it yet.

The adjustment for the carb is simple. Start off with the air screw turned out one turn. The idle screw is out about two turns. Thats close enough to get it running. Adjust the idle on the _hot_ engine whenever it's on the road.

You must remove that air screw. Clean _every_ passage.

Also remove the little screw below the air and speed screws that doesn't "do" anything. Inside that hole is the tiny idle fuel jet itself, which i guarantee you is clogged.

Also remove the brass emuslion tube inside where the main jet was. That tube is sorta stuck in there. Strong air pressure in one of the little holes in the air-horn may blow it out. Or, stick a piece of wood into the venturi and push on the tube's end (the tube's end protrudes slightly into the venturi )

Clean every single part of that carb.. twice.

Re: fixing a hobbit (long)

Travis Hill /

Thanks for the reply!

I tried getting the "brass emuslion tube inside where the main jet was" out but it wouldn't budge. I even tried smacking it with a hammer and punch, but I'll try again. I did take the screw out that looks like it does nothing and cleaning in there. How much air should I feel coming out of this jet? I blew 95 psi through it but only felt a little bit of air coming through it.

Re: fixing a hobbit (long)

you smacked it with a hammer? The only way to smack it is from the bottom. That will not only bend the thin brass tube, it will jam it in, opposite to the way to removing it.

Re: fixing a hobbit (long)

Travis Hill /

Okay now I'm confused. I looked in the manual and it looked like it came out the same was as the main jet. So I flipped it over and put a punch in the other side and smacked it (after removing the screw that looks like it does nothing). So how am I supposed to get it out?

Re: fixing a hobbit (long)

hmm.. this is a stock 1978 Hobbit? You have a 11.5 mm Keihin carb? This carb has a butterfly valve choke and a butterfly valve throttle and no slide?

1978 will be stamped on the frame's head tube ID plate.. (steering tube with bearings)

Re: fixing a hobbit (long)

crap.. You hit the jet under the "screw that does nothing?"

That is not your main jet. That is (was) your idle jet.

the main jet is in the float bowl. the emulsion tube is above that main jet. The emulsion tube extends from the main jet up into the venturi.

i think that idle jet is toast.. It has a practically microscopic bore in it (before being hit with a punch)

Re: fixing a hobbit (long)

Travis Hill /

Yep it has the two butterflies and no slide. I'm not positive about the date (I'm at work and can't check it). The carb looks just like the one in the 83 manual on this site. Maybe I'm looking at it wrong?

Re: fixing a hobbit (long)

ok.. the idle jet (under the do-nothing-screw) is not intended to be removed. It was installed through a passage that was permanantly plugged at the factory. I don't have a carb in front of me but that passage's plug may be seen in the float bowl..

man.. i dunno if that idle jet was destroyed or if it can be salvaged.. it may be possible to drill it if a genuine jet micro-drill of the right size could be found.

Re: fixing a hobbit (long)

Travis Hill /

I can feel air coming out of it when I blow through the tube that housed the main jet though? It's not much but I can definatly feel it.

Re: fixing a hobbit (long)

the idle jet passes fuel.. it's passages join up with the idle-air screw passages.

I don't want to discourage you but you may have air flow through that area and still have a crushed idle-fuel jet.

It may be OK. Finish cleaning it and mount it and see what happens.

btw, you did what i did the first time i had to work on the carb.. removed the engine.. But it's not necessary.

The engine/swingarm hangs from the frame only by a single large bolt.

If you first remove the cables, wires, and fuel line and similar things attached to the engine or routed through the frame, and then remove that bolt and retract the center stand, (watch out!) the engine falls to the ground, resting on the muffler.

At that point you can unscrew the four reed valve housing screws and remove the carb/intake manifold as an assembly.

Re: fixing a hobbit (long)

Travis Hill /

Yeah I'm just going to keep at it and hope for the best. If I have good airflow through the tube that houses the main jet, do you think I should still try to remove it? You're saying if I removed the main jet the tube inside should basically fall out?

Re: fixing a hobbit (long)

Once the main jet is removed, the emuslion tube is held in there only by friction.

The main jet, when you reinstall it, pushes the tube up into the housing and seats it in position. There's no need to crank down on the main jet.. just a firm twist with a screwdriver does it.

That emulsion tube mixes air with fuel. To do this it has very small holes drilled up and down the tube. It is something that must be clean and free of rust particles or other junk. There's a good chance that the tube or the surrounding area is clogged with varnish and it should be removed and cleaned.

So, like i said previously, reach into the venturi with a piece of wood and push down on the tip of the tube. Once it starts to come down, it should practically fall out the rest of the way. But since it may be varnished in there, a good long soak in solvent may be required first.

Re: fixing a hobbit (long)

Travis Hill /

Gotcha. Thanks so much for you help.

Re: fixing a hobbit (long)

anytime.. see ya later, hopefully with good news.

Re: fixing a hobbit (long)

Travis Hill /

Following my buddy's advice I went to advance and picked up a can of "carb/parts cleaner." It is the size of a paint can and has 3 quarts of the cleaner in it with a basket so you can put your parts in the basket and lower it in the cleaner. Man this stuff works great. You're supposed to put the parts in for 20 minutes and then they should be clean. It says for stuff that's really dirty it could take longer. I put my float bowl and the rest of the carb in there for 20 minutes and it actually got almost all of the varnish off! I let it sit over night so when I go to look at it this evening hopefully it will be clean as a whistle!

Looking at where my fuel valve is supposed to be, there isn't one there. The previeous owner must have taken it off and ran a piece of hose from where it should be straight to the carb. Do you think there is anywhere locally where I could be able to get a replacement? I noticed there are bolts on the bottom of the gas tank on both sides. If I remove these can I take the tank completely off? I'm thinking I'll take the whole tank to a lawn mower shop or something and see if I can find a fuel valve that will work.

I was also able to cut off the old pedal crank that I couldn't get off and put the pedal crank from my peugeot on it. I think I'll do the same to the other side just so they match. Tonight I'm planning on finishing up the cleaning of the carb (hopefully) and switching out the other pedal. Then I'm going to start working on some of the cosmetics since I almost have a bare frame anyway.

Re: fixing a hobbit (long)

yeah. Remove the two bolts on the tank and then pull the tank down hard towards the engine. There is a big rubber thing that is a snug fit in a large hook shaped thing on the frame tube near the steering head.

As far as a new petcock for the tank, i have had a couple different bikes (puch, kreidler and honda) and the things seem to be made with same size threads and construction. It had a coupling that has a left-hand thread on one end and a right hand thread on the other. This allows you to tighten both ends without having to turn the petcock. So, if you find one from any moped tank, i think it might fit.

Re: fixing a hobbit (long)

Travis Hill /

I pulled the fuel valve off my peugeot and it has a female connector (fuel valve must be male) whereas the honda is the other way around. But, then again, there is no one here locally that sells anything for the peugeot so maybe the honda is more "the norm" that the peugeot which would be good.

Re: fixing a hobbit (long)

There are times when i cant find what i need nor can i make it ( like my lathe doesnt have the gears to cut metric threads )

But there's always a way around everything. One way might be to epoxy an available, suitable connector to the tank's outlet. This might allow substituting a whole range of valves or petcocks that would otherwise not fit.

Hobbit tanks seem difficult to find. I've had no luck, maybe because they are prone to rust out and are in demand.

I'd keep looking for a stock Honda petcock since it has the long skinny internal tank screen as well as a second, external screen-type filter on the bottom. It's almost as if they predicted the rust problem and so built two filters into the valve.

Re: fixing a hobbit (long)

Travis Hill /

The fuel valve on my peugeot has an internal screen like the one you are describing. I'm not too worried about that though. I plan on putting an inline filter after the fuel valve. The tank on mine does look pretty rusty, but I don't think it leaks. I'll make sure and check later on down the road though.

Re: fixing a hobbit (long)

I got some great advice from Fred about petcocks:

Here is what I did ... I removed the stock petcock entirely ... went to the hardware store and bought a brass 'hose-barb' pipe fitting ... (has female pipe threads on one end .. and the 'hose-barb' for slipping the fuel line onto on the other end ...

... then I epoxied the pipe fitting onto the gas tank pipe that the stock petcock threads onto .. (with JB weld) .... then ... you can run the fuel line straight to the carburetor.

My JB Weld fix has never leaked a drop. (like 3 years now?)

If you want an ON/OFF valve for the gas ... go to a lawnmower store and buy a universal INLINE fuel valve .. they are plastic and have O-rings inside ... they work great ... you just cut the gas line and insert the valve in the fuel lines.

Re: fixing a hobbit (long)

Travis Hill /

That sounds like it would work great. Don't you have to have a on/off fuel valve though? If not, wouldn't all the gas leak out of the tank through the carb?

Thanks for the idea!

Re: fixing a hobbit (long)

Travis Hill /

Went to my shop last night and pulled my carb parts out of the cleaner and whoa! All the parts looked brand new! I couldn't believe it. I changed my other pedal over last night so they match, and cleaned the moped up some. It shined up pretty nice for being 26 years old. I also go the gas tank off and started looking at it more closely. I noticed it sounded like something big was in it rattling and I peered into the gas cap area. I saw the tube and was like "wtf is that?" So I flipped her over and started shaking and the tube came out. It was about a 6 inch long tube from an old gas can that the previous owner I guess had broke off in there! The tank is in pretty bad shape with lots of rust inside so I'll try to clean all of that out tonight. I'm also going to put the carb back together tonight and hopefully be able to try and start the ped.

Question: I found the airfilter, it is down in the "airbox" that the tube with the three holes connects to. I can't see it but if I stick my finger in there I can feel it. Should the thing that the tube connects to come out? It kind of looks like it should but it won't budge. How else can I get the filter out? I think if I try to pull it from where it is now it will rip.

I'm really getting excited about this thing now. I'm still taking my time though because I don't want to have to go back and re do anything because I rushed through it.

Re: fixing a hobbit (long)

Travis Hill /

One more thing:

Do you know how to hot wire this thing? I don't have a key. I took the lock cylinder out and it looks like I should just be able to turn the thing that the lock cylinder would turn to put it to the "on" position but i'm not so sure. thanks

Re: fixing a hobbit (long)

The filter is removed from the left side, right above the pedal crankshaft. There is a small rectangular plastic thing, held in by a wire spring.

Move that spring down and then pull the long plastic filter holder straight out.. be careful you dont break it.

hey.. download the manual! :)

A manual for the 1983 PA50 Hobbit is here.. Good info that applies to the 1978 but the electrical diagrams don’t match up ..

http://www.mopedriders.org/article_cat.php?fldAuto=2&sid=5a2cab5705ffec7757b4538cafc5ba61

Heres a proper electrical diagram..

https://www.mopedarmy.com/forums/discuss/download.php?f=6&file=1082480832_honda_pa50_1978_wiring_diagram.jpg

Re: fixing a hobbit (long)

remove the front key-part of the ignition switch and turn the inner thing on the back part with a screwdriver.

Re: fixing a hobbit (long)

Travis Hill /

I got the manual awhile back. My airfilter doesn't look like the one in the manual though. Mine has this triangle tube thing with three holes in it that go into an airbox that is welded to the frame. The filter is in this airbox and the only way I can feel it is to stick my finger down the hole that the carb goes in.

So it sounds like I did right with the ignition then.

Re: fixing a hobbit (long)

no.. that rubber thing is not the filter. That is the air intake tube. You can yank that straight out if you want.

the filter is where i said it is.

Re: fixing a hobbit (long)

Travis Hill /

OKay maybe I just didn't look good enough. As always thanks for your help.

Re: fixing a hobbit (long)

now you got me worried.. _Is there_ a small, one-inch square of black plastic right above the left pedal crank or not?

If not, i'd like to see a pic of that area..

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