Weird Hobbit Problem

So I have a strange problem with my moped, a 1983 Honda Hobbit (PA50-II). It starts perfectly fine while cold, and it rides fine for as far as you want to ride it. But then, if you turn it off and try to start it warm, it's a no-go. If it was an especially short ride, it will start , but you really need to crank it. Very bizarre.

I've been consulting with a local moped expert (also member on this site) who has been super helpful, but this issue has us stumped, and by us, I mean it has him stumped, because I'm a novice and stumped by eeeeverything anyway. Anyone have suggestions? What could let a moped start fine cold, but then stop it from starting when warm? Keeping in mind, there's no noticeable problems with performance when running.

I'd appreciate any idea (even crazy far shots) about what might be the cause. I work part time and just bought a bunch of new tools. I'm ready to get in there and get dirty, but I've had my fill of walking home from places that I've ridden to...

Re: Weird Hobbit Problem

Have you tried a brand new sparkplug. Also consider new main seals on the crank. The case leak might manifest when all warmed up. The engine runs with the case leak when warm but won't restart because the case pressure is too low. Those are my two guesses. Which means if it were my bike I would probably do those two steps first. Both are relatively easy and could be done without pulling the engine.

What are your engine temps at failed restart.

Re: Weird Hobbit Problem

David Lewis /

Replaced the spark plug. Did not replace the crankcase seal. Looks like it's $10 or less, shipped, so there's no reason not to try. Thanks for the tip.

A couple questions:

- Engine temps? How do I check that? (Sorry if there's an obvious answer.)

- Would this issue leave the bike running relatively normally after start? When it does start, I don't notice anything weird. I haven't been riding too long, though. If the effects are subtle, it's possible that I would miss them. But, if the bike screeches and howls and explodes (or something), I would probably (maybe) notice.

Either way, I've got the seal plug in my TreatLand shopping basket. Waiting to see if I need to put anything else in there so I can save on shipping. Thanks again for the advice (and thanks in advance if you're able to answer those questions)!

Re: Weird Hobbit Problem

I agree with changing the seals just for good measure but you will run into trouble doing that when you get to the ignition side seal. You will have to devise some competent method for pulling your cam follower off the crank. That takes some skill and special tools to do with out damaging the follower or the delicate coils.

Question are you turning off your fuel after these rides?

Re: Weird Hobbit Problem

David Lewis /

I'm willing to buy special tools, since I'd like to keep the Hobbit around, if possible. Wouldn't hurt to have the specific tools that fix it up. Hopefully I can muddle through the seals with tutorials and advice from moped bros I know in the area. Thanks for the heads up!

As for fuel, I don't usually turn it off between rides, but I do turn it off any time I put it in my van. I have been putting it in the van a lot lately, between taking it long distances or picking it up any time I can't get it started. It's at least possible that I've turned it off at some point between each (or most) rides lately. Could that lead to problems, or help troubleshoot which problem it could be?

Re: Weird Hobbit Problem

Just for the troubleshooting sake test ride again and immediately turn off the gas when stopping. Wait a bit likke you normally wood to have the problem occur then open the cock and try to start.

Re: Weird Hobbit Problem

check for spark when it will not start. bet its not there.

Re: Weird Hobbit Problem

Downhill Harvey (OFMC) /

I would have said it's the condenser (typical condenser symptoms), but your bike has a CDI, right? So no condenser to deal with. Have there been any modifications to the bike?

Re: Weird Hobbit Problem

David Lewis /

First off, I think everyone should buy a moped just to experience all the support you can get from the moped community.

Second off, ugh, moped won't start cold now! I went out to do the fuel troubleshooting that cheetahchrome suggested and look for a spark like pat splat suggested, but no dice on initial start. (Also, to Downhill Harvey, yeah, it's CDI. No modifications that I'm aware of. Stock as they come.)

New situation: With the decomp lever down, the choke on, and giving it gas, it will start up for a second and immediately die. Think I'm going to change those seals and go from there. I'll report back if it's still not working right. Feel free to offer any suggestions in the meantime!

Re: Weird Hobbit Problem

David Lewis /

Wait...I took the ignition coil off to take a look at that a couple days ago, and come to think of it...I can't remember if I hooked it back up. Would that make it sound like it's starting but not actually start? If so, opps! I'm out-and-about now, will answer questions tonight. Still gonna change those seals, since everyone seems to think that it either is the seals or isn't the seals, but it wouldn't hurt to change them either way.

Re: Weird Hobbit Problem

If you have the choke on don't give it gas, it will release the choke right away. I never use the de-comp on mine, but I doubt that is your issue....would have said condenser too, but being cdi you don't have that. I had bad seals when I got mine and it would not idle at all, so interested to see what this turn out to be. Uh, yeah, if you didn't hook the coil up you are not going anywhere, check that before getting into the seals. (edited)

Re: Weird Hobbit Problem

Inductive strobe timing light at your local auto parts store for $35

Re: Weird Hobbit Problem

David Lewis /

Morning! I read a lot of "How Do I Fix This" threads on the Internet that don't have any conclusion. There's all these good ideas, but the OP never comes back to say, "This is the one that seemed to work." In the interest of future generations that may have a problem similar to mine: I replaced the variator side crank seal and the problem is gone! So either (A) That seal was bad, or (B) I accidentally fixed whatever it was in the process of tinkering around in that area. Possibly (C) the moped just loves this new cold weather because it was a snowmobile in a past life, but I'm thinking (A) or (B).

Before the seal, I also cleaned the carb, replaced the spark plug, and changed the muffler (though that was unrelated, not necessarily expected to fix anything). The no-warm-start problem persisted beyond those. After I replaced the variator side crank seal, everything seemed to work fine. I still need to replace the other seal, but since it's all working, I'm holding off until I can get into my friend's heated garage either this weekend or the next. So, if you have warm-start problems, consider the crank seal, I guess.

Thanks everyone that made suggestions!

Re: Weird Hobbit Problem

Bad Cadillac™ /

What parts have you replaced on the bike so far?

If the answer is just a spark plug, then you can't expect a 40 year old moped to be reliable without going through the bike and replacing gaskets, hoses and seals for example.

Re: Weird Hobbit Problem

Thanks for the 'conclusion' . :)

Re: Weird Hobbit Problem

If it's working fine and the temps are ok don't bother with the other side. Always a chance if using a deck screw to capture the old seal that u can score the crank.

Re: Weird Hobbit Problem

> cheetahchrome . Wrote:

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

> Just for the troubleshooting sake test ride again and immediately turn

> off the gas when stopping. Wait a bit likke you normally wood to have

> the problem occur then open the cock and try to start.

Same thought here.

Float needle is worn/damaged allowing carb to flood when not running.

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