Whasta matter here?

Zippster

New Member
Oct 8, 2008
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Austin Texas
Last week I installed my generic "80" cc Chinese engine, and its been running great until yesterday. As of yet I've been unable to get it to start and keep going. It turns, it sparks, it fires, and as long as I keep pedalin' it runs but dies the moment is lose momentum. It sounds how it used to sound when I killed it with the choke back 2 days ago. Once I got it to start, but to keep it going without moving I had to constantly rev the throttle. I figured it may be overly rich because I could smell the gas, and it began to start easier with the choke all the way off, so I brought the e-clilp one notch up taking it to the top and now my throttle seems to not work (that's probably my fault in reinstalling the slide, I'll try again on Sunday). I stopped trying to start it when I kept getting sudden lurches from the engines at irregular intervals, thinking them to be detonations (although I may be way off).

:-||

On a side note, when it was running, I could never idle it forward without the dang thing jerking all over the place. Whether the fault lies in the chain, the engine, or the clutch, I dont know, but I've already tightened the star nut on the clutch - but that was after the thing died on me.

Thanks in advance for the patience - I have a strange tendency to scare people off after the second post...

EDIT: I guess the problem also might be the electronics - the plug is stock and the connections are iffy, and I tried to install a radio shack switch to kill but it doesn't work...
 
Last edited:

brisbane_boy

New Member
Oct 26, 2008
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Australia Brisbane
hey zipp. sounds like u need to check ur spark plug for oil build up. also check its getting fuel?
When you say it idled but jerked forward sounds like ur clutch arm isnt in far enough wen ur clutch is in the lock position!!

Hope this helps
 

Zippster

New Member
Oct 8, 2008
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Austin Texas
When I took the plug out it had some nice oily crap on the electrode, but that wiped off easily. I really don't think the clutch is the problem any more, because this problem started elsewhere. When I was riding home one day, it just started to bog down horribly as I went, and by the time I made it back it just plain died on me.

gotta go, cya
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
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up north now
Yes, I would replace the plug at least.

The lurching could be anything from running it too slow, to uh, running problems.

The idle problem could be a lot of things too. Does it run O.K. if you are going with the throttle on?

I would put the "C" clip back where you had it if it ran good that wy, since the mixture won't just change on you.....more like the plug is bad.

More details!
 

Zippster

New Member
Oct 8, 2008
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Austin Texas
Heya

The other day I pulled the plug, and noticed something I missed before that makes me now feel like an idiot.

The spark gap was almost nonexistent.

D'oh!

A screwdriver temporarily fixed that up and now she actually runs - woohoo!

Before actually riding the thing I immediately reset the mixture to where it was before, and fixed a wild idle rpm problem by undoing all the throttle measures I took previously. Now it idles just as before, and the bike is ridable, yet overall the power is in the poorhouse. I attribute that to my haphazard screwdriver regapping job and hope to somewhat accurately regap the stock plug in the meantime before I pick up something of greater quality.

That being said, how does one go about regapping a plug without a regapper? Also, how much better will an accurately gapped / aftermarket plug be in terms of power?

Thanks all
 

brisbane_boy

New Member
Oct 26, 2008
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Australia Brisbane
hey zippy. Get urself a NGK sparkplug. I peronly just run the stock gap. Im sure others will hav there own way but.
Should work heaps better just with the better plug.
 

Zippster

New Member
Oct 8, 2008
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Austin Texas
I'm back

I got a flat front tire, so I haven't gotten much riding in yet, but last run I ran into some more interesting problems. The spark plug is still on the fritz, and I will replace it ASAP, but what bothers me is that it got bent out of position in the first place. How could that possibly happen? Did it just get so hot that it sagged down and bogged out? If so, why did it happen all of a sudden on a ride home? I don't want to burn through plugs all the time...

Secondly, is it normal for the gas in the line to bubble up a head half-way up? Last time I rode I heard a rather strange popping noise - am I screwed?

Thanks for all that - I'm off to Pep Boys on the morrow
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
Popping noise and "bubbling fuel line" sounds like the motor mount bolts are loose, or broken.

Check the gap again to see if it closed up...again. If it did the piston may be hitting it for various reasons. If it is, send it back for a replacement. (the whole engine)
 

Ghost0

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Mar 7, 2008
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Bellingham, WA
You may also have one of those "special" plugs that has the loose electrode. I would just spend the $3 and get a new plug. Might as well get a new plug wire while your at it.
 

Zippster

New Member
Oct 8, 2008
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Austin Texas
Okay

Last time I checked the motor mount bolts are fine - I got 'em nice and tightened up with some nylok nuts and they aren't going anywhere soon without my express permission. The pop could have been something totally benign, and I hope it was (what else could it be?). When I ran it last I pulled the plug again, and the electrode was right where I left it last, so whatever caused it to change in the first place is still biding its time. I regapped it to the credit card width and it ran largely the same as before, with little difference in performance. I've noticed that the thing is a real b**** to start, all too often dying just when I stop pedaling, but when I was able to rev it just once it sprang back to life as normal. I don't think I'll be able to make it to the auto store today, but if I do, what is the wire that I should replace, and how do I go about swapping it? Do I have to remove the magneto and the black plug-hookup box or w/e its called? Should I replace that too while I'm at it?

I've already cut the stock killswitch wires and experimented with a radio-shack switch spliced itno the spark-plug circuit to ground it to the frame when flipped, but nothing happens when I try it. It runs regardless of the switch position. That being said - is a switch even necessary in the frist place? Can't I just choke it off?

I'm learned a lot in the last week to say the least - I'm not giving up until she runs as she ran at first.
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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That being said, how does one go about regapping a plug without a regapper? Also, how much better will an accurately gapped / aftermarket plug be in terms of power?
You can very carefully gap a plug with a pair of needle nose pliers. But the little slotted tools are very inexpensive and come with gage wires. Your plug sounds like one of the chinese tofu cheesemeister plugs with the "adjustabra" electrodes. :-||

A good NGK plug makes all the difference in the world! Order a couple from us. Plugs are so inexpensive it's just not worth messing with a bad one at some point.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
Okay
I've noticed that the thing is a real b**** to start, all too often dying just when I stop pedaling, but when I was able to rev it just once it sprang back to life as normal.

Check your idle screw...

I don't think I'll be able to make it to the auto store today, but if I do, what is the wire that I should replace, and how do I go about swapping it? Just unscrew it from the CDI and get a 7mm plug wire.

I've already cut the stock killswitch wires and experimented with a radio-shack switch spliced itno the spark-plug circuit to ground it to the frame when flipped, but nothing happens when I try it. It runs regardless of the switch position. That being said - is a switch even necessary in the frist place? Can't I just choke it off?
Yes, either that, or let the clutch out to kill it...no harm there in either method.

I'm learned a lot in the last week to say the least - I'm not giving up until she runs as she ran at first.

Let us know how it goes.
 

Zippster

New Member
Oct 8, 2008
28
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Austin Texas
Back again

I got a new plug - all they had was an NGK B7HS so I gnabbed it - and a wire, but haven't installed them yet. For now I'm running stock plug, as I think I've found yet another problem.

I feel like an idiot for asking this, but if the gasket on the clutch cover is torn, am I screwed? I know I'll need a new gasket (which I'll have to find somewhere...) but could that explain what's going wrong? I just took a spin around the neighborhood, and the engine seemed in a bad mood: it took forever to start again, but once it was up it ran with most of its power back. However, I kept getting more strange sounds, and when idling at a sweet rpm, it would randomly die. Am I staring at an air leak here?

Also, how do I go about swapping the wires? I figured how to get the old one off, but the wire I got that fits my new NGK has the plug connectors on both sides and is of a very slighly larger diameter. Can I just cut it and try to screw it in, or do I need a new wire.

We're getting closer!
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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Clutch cover gasket has zero to do with how the engine runs. Mine is thrashed. I don't plan on replacing.

Fix the known bad **** first. Eliminate the bad first. Get the new plug in there.

The wire is easy . Whack it off and screw it in.