MOPED ARMY

dave:

i just read your past posts ... and i'm a bit worried that you might be damaging your ped. please bear w/ me, i mean no disrespect.

the hacking off the muffler, will lead you to trouble. so might the drilling out of the jet.

i think ree and ron and the others had it right to take the repair thing slower. here's my advice (mind you, i'm not an expert at all and i'm only familiar w/ a minarelli engine).

the best place to start a repair is w/ the carburator, as others suggested. take it off, and clean it. don't mess w/ drilling jets unless some told you to. everyone tells me it's such a bad idea. besides, you don't really need a bigger jet ... my ped runs faster w/ a 49 than w/ a 62.5. so go figure. most people in the moped army prefer 52 or thereabouts. i'm using a 55, but will switch to a 52 soon, since it'll give me more top speed (i'm pretty sure of that).

so clean the carburator thoroughly. check the float, it might not be a tight seal. also, check the petcock to be sure plenty of fuel is going in (also be sure your inline fuel filter is clean; put one on if you don't have one). doing those things takes me about 15-20 mins tops and usually solves the problem.

if that doesn't fix it, then you move on to tougher things. if the moped starts and all (as i think you imply), then it's not really an engine problem (please someone correct me if i'm wrong here). that means it's probably a fuel problem or something like that. check your idle and throttlw settings in general, that sometimes helps a bit.

if it ran well before ... and i think you mentioned that it did, then just a regular maintenance check should do it. do the simple things first, one at a time, then move on up to harder things. don't do anything drastic until you check w/ the gurus first. from everything i've been told (and warned about), the 2-stroke engine is completely different from anything else. so don't assume your experience (which is, no doubt, quite extensive) will translate easily into this.

my brother is an engineer and designs parts for cars (some of his stuff is on the road and in concept cars at this year's auto show). he knows his way around cars; he rebuilt a camaro when he was 15 for his first car and has been moving up since. he was baffled by my 2-stroke minarelli engine. in terms of general theories of propulstion and such, he can figure it out. but in terms of what to do to fix it ... he left that up to me completely. so, go figure, eh?

anyhow, that's all i can offer you. sorry i can't be of more help.

oh, wait, i do know of something you could've tried for the muffler. here in kalamazoo, we take them off (unsrew, not cut!) and set them on fire. it cleans the carbon out of them really nicely. then we put them back on. if you need a muffler, check on ebay or put in a request on the for sale forum. you might get lucky.

good luck w/ the repair work. don't give up on the moped! you can also try talking to it. my "lucia" seems to do better when i woo her in italian. ;-)

First of all... You should tell us which ped it is. What year?. Mileage?

(but as I remember it it is a Euro... so I am not an expert on them)

And I am glad you are a wrench for a living.

And I am almost surprised that you need help.

But..... here goes.

I have never seen a small engine that has to have a fully charged battery to run.

On most of them the battery really only has 3 functions...

1st... as a large voltage regulator (and that is whether it is alive or dead) to keep light bulbs from blowing at high revs.

2nd... to keep the lights from going too dim at idle speeds at night.

3rd... to spin the electric start (if it has one)

So I can say you can rule out the battery as a source of trouble (dead or alive).

You said the oil pump might be on the fritz... bad news.

Why do you say this?

Has the oil level stayed the same for months?...bad news.

But they don't drink a whole lot of oil either.

But if the oil system failed a month ago... no amount of oil will now "fix it".

You say you removed the head and scraped off carbon... OK....

But did you push the piston to BDC and look (with GOOD light) for scoring and scuffing down in the cylinder?

You could have ruined the ring seal by starving it for oil without getting an actual seizure.

If this is a ped with the exposed head and cylinder.... pull the cylinder right off (easy as can be) and take a close look at the piston skirt and look for heavy scuffing... and even aluminum from the piston smeared over the rings.

If that is the case you need an oversize piston and rings and a bore job.

And toss the oil pump and premix it.

Also... put the piston in the cylinder and stick a feeler guage in between them (the piston should be in the BDC position while you do this measurement)....What is the clearance?

Also... You said you cleaned the carb... That means you used 100 psi of compressed air thru all orifices many times?

While you have the cylinder off play with the rod and look for evidence that the rod bearing or crank bearings are gone.

Push it, pull it, spin it... you are looking for too much friction, stiff spots, funky noises, too much play.

You of course have the proper spark plug?

Thanks, Miguel.

The bike has been running poorly for the past few days, and all the steps I've been taking have been attempts to get it going again.

I've got 2 jets, one that I drilled out and one that is stock. I'm running the stock one right now. The carb is clean inside and out, and I'm running an inline fuel filter. The plug is what the book specifies, and gapped within spec. I check the condition of the plug every time I've tried making adjustments, just to make sure I'm not running too rich or too lean.

Cutting off the stock muffler was an act of desparation, as I could not think of another reason why my bike was running so poorly. A fellow 'pedder has a used Tomos biturbo I'll probably buy from him, so I can get rid of this noisy straight pipe...

I have a fixed CDI ignition, and I don't really want to mess with that until it is a last resort.

If my bike were just a toy, I could be a lot more patient with it, but it is my only transportation right now. My trip to work is 11 miles one way with lots of hills on a 6 lane with 50mph traffic. That's why I'm getting so frustrated...

I'm not trying to hotrod the thing, I'm just trying to get it to run as well as it did when I got it.

When I flip the ignition switch to "Start", the light doesn't light anymore, so the battery is obviously dead, and is running strictly from the magneto. That is the only thing that I've noticed that coincides with the way the bike is running, which is why it is suspect...

david

Hey David, was just thinking, allong with other ideas, mabe ? the flywheel key could of sheered? Just another thought...Doug D.

What is the spark plug color during all this?

David,

I go out for a beer and you fall apart!

I just finished reading this thread. It took a while!

I'm with You and Fred, I think you may have an ignition problem. You should try to find out if the battery has anything to do with the ignition before you beat yourself to death over that one. It could be a bad cdi unit if it does not require a battery.

Keep a couple of things in mind as you work:

The Mantra:

It's only an engine...

It's only an engine...

The problem:

Two cycle motors are so simple that when they do not run correctly, it is really difficult to find something to fix. Never assume anything is good, just because you just replaced, cleaned or repaired it. When you have a problem, try one thing at a time and immediately return it to the way it was, before moving on to the next potential solution (don't put the dirt back in the carb).

After you have tried everything and failed, the thing you did not try is the problem. In this case it sounds like the cdi or battery, but never overlook the spark plug, wire and cap.

Oh, and never give up. It's only an engine... It's only an engine..

Remember, in the words of the immortal Red Green, "We're all in this together"

Ron

Thanks, fellas. I'm glad I'm not all alone in this...

One of my co-workers, Wayne, took me to the cycle shop at lunchtime today, and I bought a battery and had them put it on a trickle charge overnight. Wayne admired one of the bikes there (a 650cc single cylinder Suzuki), and we wound up being held hostage by a couple of salesmen out front, where the bikes were. I love cycles myself, but I'd forgotten to bring my coat with me and damn was it cold and windy out there... (Yeah, I'll take some cheese with my whine)...

Anyway, I'll have a new battery tomorrow and hopefully that will fix it. Wayne gave me a coil he'd bought for his long gone Tomos, but I don't know if it would work with my ignition system. If I can just get it running half as well as it should, I'm considering a biturbo and maybe some new rings...

I'll keep y'all posted...

david

I MISSED IT, WHAT BIKE DO YOU HAVE? DOUG D.