Zuma rear wheel locked after overhaul

[sc00ter]

If you ground the spark plug to check for spark, watch out if there is still gas/vapors in the cylinder-it will turn into a flame thrower! Get a cheap spark tester from a auto parts store.

Another thing, did you point the arrow on the piston toward the exhaust port?

Cracked reed pedal will also prevent it from starting. The reeds don't like being ran with an exhaust leak.

After you verify your'e getting spark, you could always use a dash of starter fluid to help bump it over. If it still won't start you'll need to do a compression test.

I wish I knew someone 2-stroke savvy in the L.A. area. Know a bunch of lowrider car guys and a few bands, but no moped/scooter guys out that way to send help. I kinda regret tossing that low miles stock top end in the recycle bin now. There is Myrons Mopeds in Fullerton. Shaun is a good dude and knows his 2 strokes.

[KDS4444]

Your offer to put me in touch with a person out here who could help me is very generous. There is nothing like a personal network connection to actually get things done! As it is, though, it seems like I am on my own for now.
I tested the spark plug, and had some surprises:
The plug tested out just fine as far as resistance goes, so I grounded it and cranked the kickstarter. It sparked! A bright blue-white spark came shooting right across the gap, just as it should! I was pleased, and put it back in the engine. This time, there was something like turnover happening. The engine didn't exactly catch and start turning over on its own, at least not at first, but I tried cranking it again a few more times and one of those times the engine actually ran for a second or two on its own!
But it didn't sound right. It's hard to put my finger on it, or describe the sound itself, but it didn't sound the way I know it should. It also wouldn't take off like that a second time for me. But it shows me that I am getting ignition. So my guess now (and probably yours as well) is compression. If I have a leak anywhere around the cylinder base, head, or spark plug itself, this is the kind of response I might get from the engine. "Yay, fuel! Spark! Ignition! Move that piston! Oh, wait, not enough compression.... Sorry! Goin' down!" I've had a compression issue once in the past, and it sounded like a giant dragon fly was inside my engine— it was the sound of compressed air escaping around the cylinder (oh and yes, quickly, I am sure the piston is facing the correct way, I was VERY careful about that! The arrow on the head of it points towards my exhaust port!). This didn't sound quite like that, but it could certainly still be the problem here.
Or, as you said, it might be the damn reed valve. That's one part I have not taken out and had a look at yet, esp. because it isn't terribly accessible. But as you said a cracked reed would also prevent me from getting proper compression in the cylinder. Are there tests I can do to see if my cylinder is leaking somewhere first? I can also try tightening my cylinder nuts down just a bit tighter and see if that helps at all. But I feel good knowing that at least I don't have an electrical problem and that my spark plug is working as it should.
Thank you for continuing to engage me here. I really appreciate the willingness to keep with me and help me try to solve this problem. That means a lot.
....
Later that evening...
....
Okay, I went down and tightened up the spark plug and cylinder nuts again, and gave the kickstart a go. The engine caught! I was amazed! It still didn't sound right, but it was running! I let it run for 3 or 4 seconds, and pondered taking it off the kick stand and driving it around the block. But then things suddenly changed: the speed of the piston in the cylinder picked up, and the sound coming from the engine became much more raspy and loud. I shut down the engine immediately. The sound was unlike anything I have ever heard before coming from the scooter.
It seems that I am finally getting compression, at least briefly, inside the cylinder. But the rasping noise? Would a cracked reed valve petal make a noise like that??
One more thing: I noticed when I put my air filter box back on that there were some cracks in the elbow joint where it attaches to the carburetor. I assume I will now need a new air filter box. The cracks mean that some unfiltered air is now able to get past the filter and go straight into the carburetor. Would this be causing the sounds I heard?

[sc00ter]

A cracked/broken air box is a death wish to ANY motor, but its extra bad for a 2-stroke because they are so sensitive to everything being correct. Pattern replacement air boxes are the way to go. Scootertuning.ca and sometimes Scooter Swap Shop have them for good prices. Or get a OEM one for a bit more. Don't be tempted to get one of those pod style air filters, they require jetting changes. Stick with stock or pattern replacement. If its just the elbow that looks cracked, that's normal. The rubber coating on the elbow flakes from age/heat and makes it looked cracked.

Be careful when tightening down the head screws. I forgot the torque vale but it needs to be done at the correct torque/evenly so the head doesn't warp.

It you had a broken reed it wouldn't even start. So your'e fine on the reeds. Plus, the reed cage is a PITA to seal when re-installing. So any reason not to remove it is good.

That sound you hear is a new one to me. Never had a noise like that.

My Zuma is still in a million pieces. But typing to you has kinda motivated me to get it sorted and put back together.

Again, good luck on figuring it out. Asked around to the lowrider guys and they don't know anyone who messes with "mopeds". Worth a shot though.

[KDS4444]

I went ahead and checked the reed valve: it was fine, some of the petals were a little loose, so I gently curved these into a flatter position, made a new gasket for the valve, and re-sealed it against the engine block. The trick right now is how to re-attach the valve to the carburetor: apparently it has to go down quite a ways! I didn't realize how far when I took it off. Wasn't able to do it using just my hands, am considering wrapping it up with a ratchet strap and seeing if I can force it back together that way. The rubber of the join here has to stretch a LOT go get back on that carburetor!

Anyhow, I think the reed valve is not the problem. What I really aught to do is get a torque wrench and use it to tighten down the cylinder nuts to spec, it's just more cash that I don't want to spend (I ordered a replacement elbow joint for that air box, another $15 for a piece of rubber I won't have for another two weeks) and I've managed to tighten them down once before without said wrench and got compression. Of course, the risk of over-tightening the nuts is pretty horrendous (stripped cylinder posts, I know), but it looks like the only possible remaining problem here is the seal around my cylinder, yes? And if I can get that to seal, I should be golden....?


It seems like every time I turn around, I find another part that is slightly damaged or out of alignment or needs partial replacement. I guess that is part of owning such an old machine. Sure is a pain in the ass though. I am not sure how much cash I will have spent with this repair that began as an attempt to lean out my fuel supply and inflate my rear tire (!) but I think it's on the order of a couple hundred bucks so far. To say nothing of all the labor and the time, both yours and mine! I am learning something as I go, which I guess is worth something somehow. This damn bike better last for another 10 years problem free! (I suppose that is too much to begin to hope for... considering that it still isn't even running normally yet).

[sc00ter]

I had a Stage 1 modded Zuma (exhaust and transmission) and that scooter had 30,000 miles on it when I finally sold it. It was a 2005 year.

My friend sold his Stage 1 modded Zuma with 45,000 miles not long ago.

Wear and tear were drive belts every 10,000 miles-did the rollers at the same time, tires, air filters every 10,000, reduction box oil every 10,000, front brake pads when needed and other small parts that need random attention.

You can "rent" a torque wrench for free from any major auto-parts store. And again, I wouldn't have touched the reed cage. The "sloppiness" is normal for the reeds.

Does your electric start work? Why are you kick starting it every time? I ask because are you sure nothing is acting strange in the transmission, causing the weird noise you hear. Wal-Mart sells the battery for the Zuma (Everstart) for a great price.

Nothing else is popping in my head right now. We've see all sorts of stuff fail from doing wheelies, DON'T do burnouts, nose wheelies/rolling endo's mess up shock seals and other abuse related issues-so we have a pretty good knowledge base.

My wife was suppose to go to Oakland, CA but the pandemic stopped that. She was gonna drop thru the L.A. area when returning (Driving cross-country with her sister). She knows Zuma's VERY well! She's been helping with everything from tires changes to full engine builds. Rescued us on rides and helped fix stuff on the side of the road. I bet she would have figured it out quick! She started on a Stage 1 modded Hyosung Sense (great little scooter!), upgraded to a Buddy 125, Cam-Am Spyder (P.O.S.) and now has a Honda Silverwing scooter.

Again, best of luck figuring it out.

[KDS4444]

Once again, covid-19 stands in the way of my possible future success! If your wife ever decides to travel again and makes that same trip, and if my scooter is in any condition other than perfect (which is most of the time) I'd be thrilled to have her take a look at it! (How can I entice her? Food? What can I bake for her??).


Regarding the kickstarter— yeah, fair question. The very first thing to go on the scooter was the push start button. The machine was even still under warranty, but I didn't want the hassle of bringing it back to the dealership for something I could work around so easily.


And then some time later I had a little accident with the bike, and broke off one of the rear blinkers, so I made custom ones to replace them (they're pretty neat!) using high-power LEDs. But in the course of adding wiring for those LEDs, I did something that caused my battery to slowly drain down to nothing in about an hour of non-use, and I could not find where the short was, so I took the battery out and replaced it with a thing called a "battpack". It's basically a very large capacitor that sits clamped to my frame, and it works (has worked) perfectly. Only drawback is that I only have power while the engine is running, and I have to keep using the kick start to turn the engine over. But no internal battery at all! It's been like this for over a decade. I had no idea batteries were so superfluous, but it turns out they are. (technically this modification is illegal, I forget why, please don't tell the sheriff!)


If you have any suggestions on how I might shove the carburetor back into the rubber joint of the reed valve, I am all ears. And again, ask your wife what I can bake for her if she ever comes this way! It would be a treat to show my bike to someone (anyone, really) who gives a damn about Zumas!

[sc00ter]

I put a tad of grease around the carb lip to help it slide in. They (intake/reed assembly) tends to get a bit hard with age. But it can be done relatively easy. I also hate the air filter box back onto the carb. You have to make 100% sure its seated or it sucks in raw air. One of the WORSE air filter assemblies to put back on is a OEM PUCH moped air filter. Worse vehicle, 80's era Toyota Vanwagon.

I think she ditched the cross country trip as of now. One of her sisters lives in Oakland, and a friend in a band lives across the bridge. It's funny, I'm in my late 40's and she's in her mid-60's and we know so many grindcore and hardcore/pink band members. Those are the fun, interactive concerts! This Covid needs to leave so we can resume going to fun shows again!

Quick thing to point out. Sometimes the kickstarter gear will stick a bit when coming back up. It will start with a tingling sound and get worse as its ignored. Next time you kick it, pull the kick starter up with your foot. I don't think thats even remotely your issue but you never know.....

[KDS4444]

I've discovered this about air filter boxes: if you blast the rubber elbow joint with a hairdryer on its hottest setting for like 30 seconds, you will soften it up nicely and it will slip over the port on the carb oh so easily! Someone borrowed mine which is the only reason I haven't tried this with the reed valve joint yet. The dude is supposed to be bringing it back tomorrow. It makes a HUGE difference, and everyone working with scooters or motorcycles of cars should practice this tip! Heat that bugger up first! (er, but don't use flame to do it, for what might be obvious reasons).

[KDS4444]

Hm. I opened up the crank case (yet again) and it turns out my variator nut was coming loose. I could have sworn I put threadlocker on it, but apparently not. I have put threadlocker on it now, however, and tightened it down well. Am just waiting for it to cure before I try starting it up again. I have put some sealant around the cracks in the air filter box which I think will hold it until the replacement elbow joint arrives in a week or so. I still haven't gotten my torque wrench, but I have tightened up all of the nuts around the cylinder head as well as the bolts around the reed valve as tight as I dare. Stripping any of these would be a disaster.


My mother has suggested I get an electric scooter and ditch this project altogether before it gets more expensive and still doesn't work. If I had a charging port ready to go for my parking space, I wouldn't hesitate. I do intend to make the switch to electric at some point, but I am so close to finishing up with the Zuma that I can almost taste it. I think!


... Less than 20 minutes later...


Well, it runs. I wasn't sure it ever would, but it does. It's making large plumes of noxious low-lying smoke as it does, so there is still some adjusting to be done somewhere, but the damn thing runs again. How about that??

[sc00ter]

If I would consider an electric scooter, it would be a NIU GT series. But, I got into electric bicycles (Pedego) instead. Get by with a bicycle helmet, can slip onto a sidewalk and I have a extra charger at my work. Removable battery is the best.

I want a AddMotor MOTAN M-66 R7. Step-thru, 25mph and mag wheels. And cool options! I'm just not sold on the product support right now. So I'm still waiting for my dream electric bike......

Take it (Zuma) out for a ride and see if the "smoke" burns off. There's a chance you flooded the exhaust and whatever is in there will/should burn off. The variator nut should be 45Nm. A impact wrench will work, but I personally don't recommend it. Your'e lucky the nut didn't come off and knacker the end of the crank shaft! I bought a Zuma that had that happen. Somehow I tapped the end of the crankshaft and it worked like new! It was TRASHED! I got lucky!

If you knew someone that was trustworthy I would pay them to go thru everything instead of replacing the Zuma. Hopefully, all is good and it will serve you for many more years.

Again, good luck and hope all is well!

[KDS4444]

I figure I must have created a leak in the cylinder when I messed around with the piston and O-rings. Have gone ahead and ordered replacement parts for the cylinder head, body, piston, and rings, and replacement gaskets (to replace the new ones I JUST put on two days ago). Will try taking off the whole shebang and putting on these new parts and see if I can make magic happen.


In the mean time, I am toying very actively with a possible electric alternative: there is a "Zoom Scooter" dealer here in L.A. that has one model still left: it goes 35 mph, carries 60miles per charge, and costs $1400 ($500 less that it costs to purchase one new from the manufacturer and have it delivered to me). Only hitch is, well, $1400, plus the City of Industry is a trek from my place (3 hours by bus to get there, 1.25 hours back if I drive a scooter back).

[sc00ter]

Please do your research on this potential electric scooter, if you go that route. I know in ebike land, some companies push out straight junk and them drag their feet till the warranty expires. Not all mind you do dirty things like that, but just avoid the companies that have bad reviews/ratings.

Just outta curiosity, what is the miles on your Zuma? A friend just hit 25,000 on a stock engine. It sat for about 2 years but he cleaned all the old fluids out and put it back on the road. He hit me up outta the blue to see if I still messed with them and to see if I had some weird small parts on hand.

Good luck on whatever option you choose!

[KDS4444]

Oooooo... My odometer cable slipped out of my front wheel well years and years ago. I have no idea how many miles it has taken. The odometer reads 5,000 odd miles, but I must have tripled that by now!