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My Eternal Project, or the Scooter That Refuses to Live. Any Ideas?

4318 Views 59 Replies 11 Participants Last post by  Unkle Krusty
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And the scooter is dead for a third time now...I’m running out of things to replace.

If you’ve not been following my CF Moto saga, here’s a recap:

First Revival



Acquired in November from a fellow Gambler 500 team member. I replaced the battery, the carburetor, and learned the starter solenoid was installed backwards by a previous owner. It sat for roughly two years without running and I made a gamble that I can make the old fuel burn again. While I was successful in that, I made two critical errors:

1. I didn’t replace the fuel filter.

2. I rode it every day for a month, not really ever allowing it to get to running temperatures.

Despite that, the scooter was good for 75mph, impressive acceleration, and it all around it ran absolutely perfectly. I felt I had myself a good score and with actual fresh fuel I’d probably even break 80mph. I proceeded to daily it for a month, taking it everywhere.

Fixing my Original Mistake

I made sure I ran all the bad fuel out of the tank and made sure the tank wasn’t rusty. Then I filled it with good fuel.

I then replaced all the fuel lines, the fuel filter, and the carburetor. I then installed a pod filter. I also closed off the crankcase vent to the airbox. Instead, the crank vents out into the outside. The original problem with not being able to start after getting hot remained, but at least I was no longer fouling my air filter and carb with particulate matter (air filter material) and oil. Top speed was about 40. Figured I would get more speed from restricting the pod filter, but first I really wanted to address the problem with not being able to restart with a warm engine.

Take Three



I decided to replace basically everything else I didn’t touch. I took the panels off and replaced the air filter so I can ditch the pod filter and go back to the factory setup (I still have the crank venting to the outside, though) and not have to jet the carb. Then I replaced any old vacuum lines that remained. All this work resulted in no change. It does cold starts well, but introduce any heat and it’s dead. The engine tries to fire, but it just won’t.

You can get it to start on starting fluid, and then it will go on to run like it’s misfiring and it’ll die as soon as you stop moving...then fail to start again.

Only thing I haven’t replaced is the spark plug (because the bloody thing has a spark plug that requires a bigger socket than the one I have for my smarts), but I fear it’ll be a waste of time.

Is there anything else I’m missing or do you think the spark plug will be my magic bullet?

This was supposed to be an easy project, but it certainly has taught me a lot about motorcycle/scooter repair! If the spark plug doesn’t fix it I’ll probably get rid of it. I’m just not sure how much I would be able to trust it at that point..And I'd hate to do that because when this thing was running well it was an awesome way to get around. 75mph top speed and everything.

For a TL;DR - here’s everything I replaced:

- Battery
- Fuel Lines
- Vacuum Lines
- Carburetor (built in electric choke)(2 times)
- Air Filter
- Fuel Filter
- Oil
- Fuel

Only thing I can think to replace now is little sparky..
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More good news! I found out how to adjust the valves, it's actually pretty easy and I'm excited to do it!

Meanwhile, I found my replacement for the Chinese Ruckus clone.

This is a 2012 Sym Symba. Back in the day, Sym used to build the Cub for Honda. Then when Honda and Sym split, Sym continued to build the Cub under license for markets outside of Japan. Sym brought these motorbikes to the US about a decade ago. They were essentially the same bikes they've been building for decades, but with some technical upgrades. This example has 11k daily ridden miles and is ready for a new home. The owner collects bikes like me and actually offered to let me ride his Harleys after finding out I've never ridden one. :)

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Lots of respect for the Cub - I think it's the world's most produced motorcycle. Good for you!
IIRC, the Honda Cub (not counting license built versions like the Sym) is the best selling vehicle of all time. :)

Quick glossing through Sym forums seems to squash any quality doubts. These are super simple so there's not much to go wrong. To be specific, these are Super Cubs but with 101cc Honda dirt bike engines.
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It is very cute, but still doesn't relieve you of the responsibility of getting that Chinese POS up and running. So did you take him up on his offer?
I will on Monday when I go to pick the Sym up! :)

I feel I'm getting super close on the CF Moto, so next week I'm going to do what's basically a "hail mary pass" and see if I can squash the problem once and for all!
Well once again you get another super find. You are beginning to irk me you know. (just kidding):grin: And good for you on your new attack plan on the Chinese Ruckus clone. Hope it finally gets that puppy working.
Well if yo [u were my kid you wouldn't be able to ride the new one until you fixed the old one. ;)
Fear not, I'm actually taking off work tomorrow and making it a big motorcycle day. New CDI, plug, and coil arrived in the mail today.

Tomorrow I replace those parts then adjust the valves. If none of the above works that's where I'm going to draw the line and call it quits.

If the day goes the way I want, I'll have the scooter finally fixed (and it now being used for the Gambler 500), that cute Sym as my around town toy, and the Chinese Ruckus on the marketplace looking for a new home.
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I did it!!! :D

Not only did I get the CF Moto running again, but I cleared a new GPS top speed!



Here’s what happened:

First thing first, I started the scooter to get a baseline. It took a LOT of starting fluid and when it did get going it puffed out enough white smoke to compete with a steam locomotive.

I decided to change the oil since the oil it had already was pretty thin. This scooter has the easiest oil change ever!

After getting the engine warm, I changed the spark coil. I also found out that the spark plug was gapped way too close.

This resolved the issue where it wouldn’t start hot. Now it starts hot... barely. It still ran like garbage, so I considered the coil to be a factor, not the cause.

Next, I located the CDI. It was ahead of the battery tray and on top of the fuel tank. Unfortunately the CDI I bought was the wrong plug configuration even though I ordered the correct one... thanks, Amazon! I crossed my fingers that the CDI was good and moved on.

Next up, I found the valve adjusters.



Since the clone's engine is basically the same thing as Honda's engine, I decided to follow Honda’s instructions for mechanics..



Unfortunately, I couldn’t get the scooter to start and stay running without the engine making horrifying tapping noises. Meanwhile, the scooter still spat out white smoke. Whenever I adjusted the valves to a position without the tappet noises, the scooter would die and not start without a lot of cursing in Mandarin and starting fluid.

I was just about to throw in the towel when I decided to go for broke. I took the carb from my first resurrection of this scooter and gave it a thorough cleaning. Considering the carb it currently has was brand spanking new without even a mile on it, I figured I was wasting my time.

I installed the carb from the first resurrection and gave it a go. It started without starting fluid this time and when I adjusted the valves properly? It ran even better. Within a minute the white smoke cleared up as well.

I reluctantly took it on a test ride, but the little thing blew me away. It seems to perform even better now than the first time I resurrected it. I hit a GPS verified top speed of 80 mph. Not bad considering I’m not at all lightweight.

Uh...well... unfortunately this means that I want to keep it. This adventure has taught me so much about this scooter that I’d feel bad giving up on it after this victory. It also doesn’t help that even running I won’t be able to make my money back on it. So screw it!

To make it more “mine”, I got rid of the top box. The latch broke a few weeks ago anyway, so nothing of value was lost.



I was going to celebrate by bringing home that Sym...but looks like someone beat me to it and that Honda Elite. Darn. Oh well, at least I have this thing going again!
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After I get something running I always worry about it the next. Will the darn thing start and run like it did? Good luck!!!

So did I get that correct, you are not out any money on the Sym? That's really too bad. That was a great deal there.

BTW, looking at that picture of the engine, there is a hose right on top that has a heck of a kink in it. Probably a vacuum line which means something may not work correctly or change if it is un-kinked.
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Good eye! I replaced that line when trying to get the first carburetor working. Not sure how it got kinked.

The Sym was sold before I could get out to the seller today. The Elite 125 was sold yesterday. Oh well, it probably won't take me long to find another deal! :)
Sounds like your clone will do what you want until you find something, so good luck on both.:thumbsup:
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Victory! Congratulations!

The valve adjustment is interesting. Older CB450 twins can be adjusted the same way due to the torsion spring system they use. I wonder if your scooter is similar.
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Sweet I know you could do it. 80 MPH you are braver than I am. I was going to tell you to sell it now, but hell you have it's number now.
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I didnt see that you tried a compression check.
It probably would have steered you towards valves sooner.

A lot of car engines and a few bikes use an automatic choke.
I had a car with a problem and I solved it by putting a switch on the heating element in the choke!

My magic 3 is fuel, spark, compression.
It really helps me focus in the right direction.

Glad you are up and running.
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I think in this case the valves were definitely too tight. The "running poorly" part of this included a lot of clattering from the thumper and that should have pointed me at the valves.

I don't mind that I've replaced a lot of parts to get to this place. It's basically been given a reconditioning and in theory, should be good to go for a while. Oh, and the oil didn't have any shavings and didn't have that metallic shine, so it appears no horrible damage has occurred to the engine. It's definitely upped my wrenching knowledge and abilities so much that I actually started tearing into that GSX1100G project! I've long been afraid of taking apart carbs, but now I kinda look forward to doing it on the Suzie!

As of right now, I plan on adding some offroad lights and strapping an extra fuel tank to this scooter. I'll then run it on the Gambler 500 in May.

As for a new commuter bike, another Super Cub type of motorbike appeared on the local (to me) Craigslist.



This is a Yamaha U7E. The running gear was professionally restored in 2014 but it hasn't run much since then. $500 with a title, service manual, and boxes of extra parts! With a 70cc two stroke on board (yay! I love twos) it's good for the same top speed as the Sym was...or way more than I need to get around a city. :)
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Glad to see you didn't give up on it!
If it were me, I'd run it a while and see what it has to offer, if it proves reliable, considering you have so much into it, you might was well keep it and get your money's worth from it.
Now that all of this has given you a basic knowledge of that thing, any problems that may arise won't be such a big deal down the road.

You must be in a good area for scooters, they're a rare sight here.
All you see around here are people on those cheap electric scooters that can't be registered due to lack of paperwork when you buy them and various dmv rules.
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Oh yeah, I'm hanging onto it for a while. I've gotten an attachment to the silly thing now so it's hard for me to want to get rid of it. That and I'll never make back the money anyway, so I might as well enjoy it! The Yamaha I'll be looking at in a few hours will replace it as the work commuter. This scooter will then be my offroad steed for the Gambler 500 rallies or I'll do some other project with it. I'm just happy to have resolved the issue!
Congratulations, I knew you'd figure it out!
It's always fun to get to the bottom of something that had me stumped!
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Back in the day, Honda had smaller / tighter valve clearance than the others. We can assume they had better control of expansion due to heat.
I would not trust a China clone with the same clearances.
Once upon a time nearly all engines would tick, from the valves. And that is always preferable, or better than no sound.
Also used to be the rocker would get dished, so instead of 6 thou we would set at 5. As long as we could hear a tick we felt safe.

Fast forward with shims. Same story. The Suzuki shop tells the same story with my SV1000. " they usually tighten a bit, yours is good with a bit of noise "

Maybe one day I will write about valve timing, the final frontier. And why lining up the dots is not accurate enuf for a decent engine.

UK Does enuf have 2 f's
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