Love motorbikes ! - Chris Bush from Richmond NH


Apr 9, 2008
I will post a picture of my center mount "80cc" motor on an old schwinn phantom, my pics are at home. I love my bike ! Probably have about 200 miles on it already.

Some observations so far:

1. Had to adjust clutch every 50 miles or so during break in period. Broke in at 1:16 as recommended. Front bracket broke, I replaced it with a hand fashioned thing, made out of a gutter hanger strap. This metal is more flexible. Motor is solid now.

2. Have somewhat of an oil / fuel leak I think from lower gasket, but maybe from exhaust gasket ? I have tightened the head bolts a number of times, hoping not TOO many. I went out and got a cheap torque wrench, supposed to torque them to 21 ft/lbs, but they max out at about 18. One at about 15 - worried about this one. No more tightening, at least for awhile !

3. Started cutting out at full throttle. Forum most helpful, I removed blown gasket from carb mount, and replaced with a perma-tex like product - I got the "oil resistant" (black color) variety. Pretty sure that was the problem, but also screws that hold float bowl up on carb body were loose, fuel leaking out of carb. Tightened them too. Now that gasket has set, I will see if I have full throttle back.

4. Get an old schwinn if you can afford it. Mine has MASSIVE spokes, compared to today's ****, and the frame is almost solid - at least very thick tubes. Really doesn't vibrate much.

5. I tried to wire a light off the magento 6 volt supply, as it was claimed I could do so. Maybe would work with an old style flashlight battery of 1 candlepower or something, but sure won't work for a xenon lamp (still not enough light anyway). don't try it, it isn't worth it.

6. I used plastic wire conduit (black) to route wires (magneto, and I have rear turn signals) around bike, using black cable ties - bike is black. Gosh it looks cool.

7. I used pieces of innertube to rubber mount motor, tank, mirrors, pretty much everything. I highly recommend this, as it reduces vibration, and may save you from mounting clamp failure. The cheap mirrors I got are the wrong type (low rider) and vibrate too much, even with the rubber mounting. Pretty much useless, along with cheap turn signal I got off internet - batteries drain (and don't fit well !) even when the signal is off. If you do a search on EBAY for bicycle turn signal, you will see the one I mean - real cheap and it doesn't work.

8. This thing goes up pretty much any hill, and we have a lot of them. A few big ones, no way. I love it - but am wondering how long the motor is going to last me - reading the forum posts. Of course I got it cheap on EBAY, and I suspect the head bolts are going to be a problem.

Can anyone say with any certainty that there is a supplier out there that sells Chinese center mounts of good quality ? Everyone talks about DAX on this site, but some of the posts I have seen indicate similar problems with DAX motors, that I have had with my own. For instance, the clutch gear has to be greased, and the gaskets are obviously ****.

I am thinking of getting a spare 'back up' motor, but only if I can get one of REAL quality. I like the 2 cycles, because of the dry plate clutch. Anyone seen a 4 cycle WITHOUT a centrifugal clutch ? These clutches are ****, reminds me of my minibike days maybe 40 years ago...

Later for now. Would greatly appreciate any comments / information

Chris Bush


Active Member
Feb 14, 2008
Hi Chris. Welcome to MBc! Home of many answers, and awaiting your ideas.
Cant wait for some photos. Welcome to the world of Happy Time.

General request to all new members.
Please, before posting any questions, do a search. Then READ,READ,READ.
There is a ton of information here. Many of your engine and performance issues in the Garage & Tech/Mech Help have already been covered. Here at MBc we are the home of nearly all MoteredBike questions. If you search and are unable to find your answer, don't hesitate to post your question. Were here for each other! Enjoy! :D
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welcome to MBc, yes plz do posts some pics in the picture gallery...anything chinese is s**t...however we change em and fix em and they do run with lots of care in checking handlebars, chain, seat, side mirror, tail lites, spokes carry a spare clutch add front brakes and coaster brakes, they don't like sand as i live at the i have a ch80 now and for my next project it will be this: good luck with yours..also if you do run into a snag, if you start at the last page of a thread and work forward, i am sure it has been asked at least 50 times before...bye
ps thanks for your deltails...
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Well-Known Member
Mar 23, 2008
An excellent post. Thorough. So my head bolts should be torqued to 21 ft/lbs? I'll check that first thing. I'm getting a bit of oil leakage as well. seems to be from the spark plug hole of all things. But it'll be good to know that the head is fastened down properly. And if that doesn't clear up my oil seepage I won't be overly concerned; it's minimal.


Apr 9, 2008
Hi -

Thanks. Just be careful as: 1) Diff kit manufacturers (if there are more than one !) may quote different ft/lbs, and 2) as I think I stated, I didn't go all the way up to 21 ft/lbs - one of the bolts just kept turning and this made me nervous. They are currently at about 15-18 ft lbs.

Enjoy your bike. The weather is just starting to get nice around here...