first time motorbiker

GoldenMotor.com

oogamiser

New Member
May 18, 2014
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mass
so after some decent shopping around and looking around in this forum, I decided to go with a flying horse 66cc slant fire motor...I bought a cheap mountain bike off of craigslist to throw it on

I got the motor on and running after taking the top end apart and lapping the upper cylinder and head and porting the cylinder just to get rid of any sharp edges and loose cast off...lubed everything up with 2 stroke oil and put it together...then threw it on the bike and checked the compression...it was at 90psi after a few turns...I rode it for a little while, didn't open it up all the way, I'm staying at or below 20mph until it's broken in...after about ten miles I reckecked the compression and it came out at 190psi...

I'm running on 93 octane...the plug seems to be getting a little hot...the engine ran beautifully tho, it has plenty of pull and I'm 250lbs...I'm thinking the compression is a tad high tho...I got a torque wrench specifically for the motor so I know I didn't over torque the top end...guess I'll have to get another gasket...

I also didn't lap the heads much at all, just enough to smooth them down...

so far, it's been tons of fun, just tinkering with the motor and setting it all up...albet it's also been kind of a pain in the butt...I'm glad I got the workbench in the basement...

I wouldn't mind getting an upgrade for the clutch pads...if any place sells clutch material that would be awesome...after the first start up and run, it wouldn't start again...I thought the cylinder had cracked or something because it didn't seem to be getting any compression so I took it apart and everything was hunky dory...then I tried adjusting the clutch, all that did was make it squeal like a pig...so I took the clutch plate off to expose the clutch pads and they were all blackened...and it was also wicked hot...I thought I would try filing down the clutch pads, getting them cleaned up and throw them back on, but that did nothing, so then I decided to just file down the clutch plate after realizing the plate wasn't grabbing all the pads evenly...it took me an hour to file it down until it was perfectly flat, but it was worth it, I threw it all back together and it ran perfectly...at first I thought something was wrong because it wouldn't start up again, but then I realized I had forgotten to put the wire back on the plug...

I want the motor to last me, I plan on using it as my main mode of transportation, I know the basics, start with a good oil and the right mixture, right now I'm just a little higher than 25 to 1 gas/oil mix...I know I'll need to either replace the head gasket or stack two of them to lower the compression...

what size ball bearing goes to the clutch throw out arm? my motor didn't come with one I think...it still works tho, but eventually, it'll wear down to nothing making it useless...


I plan on upgrading the spoke gear thinger there...simply because there's no way I'd be able to get it perfectly true and level...if there is an upgrade for the magneto and generator that would be awesome...I want the power to be able to install a full led lighting system, turn signals, bright head light and tail light, plus whatever else will help people from running me down...or perhaps just bright enough to blind people...I'd rather not have to rely on batteries unless it's for a back up system.

I'm thinking of naming her the Bxxch...simply because I expect her to be temperamental and a nuisance to my neighbors...but like all other things in life, there's a solution to everything...

this was a very long winded introduction hello and gday! btw, I am very mechanically inclined, the bike I got has seen better days, needs new tires, but the ones that it came with will suffice for now, rear tire wasn't very straight, but it's straighter now, and working on the motor is just easy...two strokes are awesome little things

the only real question I have right now about my build is the compression...wtf, seriously...I didn't expect it to be that high...has anyone else experienced this? should I wait until it's broken in to do something about it?

as far as the upgrades tho, is there any upgrade for the magneto generator? I wouldn't mind building a custom lighting system...I want to be seen and avoided
 

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2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Welcome to the forum. Sounds as if you're off to a good start. You must have done some reading here and benefited from it.

I'm not sure what you mean when you say your engine came without the ball bearing in the clutch actuating mechanism. If that bearing wasn't there you would not be able to disengage the clutch. Often the bearing is stuck in grease and doesn't come out easily. Are you certain it isn't in there? Whatever, it is 8mm, or 5/16" diameter. It, as well as the steel pin, the bucking bar, that goes in the sprocket/shaft bore needs to be well lubricated with a good grade of bearing grease. The cam in the cover also requires lubrication.

Someone will chime in with a link to a magneto/generator. There is at least one available on ebay but I do not have that link. Some that have used it say it works, some say don't waste your money. You'll have to decide.

Good luck, have fun and ride safe.

Tom
 

oogamiser

New Member
May 18, 2014
15
0
0
mass
yeah, my dumb mistake...the clutch arm was just really sloppy...making sure the cable is tight solves the problem tho...with all the led's on the market these days, there's a possibility to use the stock generator to power everything I want, but I want to look like a ufo on wheels...
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
yeah, my dumb mistake...the clutch arm was just really sloppy...making sure the cable is tight solves the problem tho...with all the led's on the market these days, there's a possibility to use the stock generator to power everything I want, but I want to look like a ufo on wheels...
If you're referring to the infamous 'white wire' on the magneto you should know that it produces something like 6 to 9 volts AC current and can only provide about 2.5 to 3 watts. That isn't much and you won't see a lot of light from it.

I'd seriously suggest you reconsider battery power if you want mega-lighing. The white wire won't provide it and over drawing from it will shut down the ignition system.

Tom
 
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oogamiser

New Member
May 18, 2014
15
0
0
mass
I keep hearing that about the white wire...I might just stick a tach on it and find another way to get lights...I saw a coil kit that installs inside the magneto case, but that only puts out ten watts...for an led system, that might work, but like I said, I want to see and be seen...if the battery option is all that I can come up with, it'll have to be self contained system with the bike recharging the battery...

is there any way to beef up the magneto?
 

F_Rod81

Dealer
Jan 1, 2011
1,031
2
0
Denver, CO
Welcome to the forum!

Like Tom said if you use the white wire it will work but only put out 3w max and puts lots of stress on the coil. You will get better lighting from a wal-mart shelf light. Here is an upgraded version that has been on eBay for some time now. Convert from 6V to 12V and do it right. I'm not a fan of the white wire so I just cut it and use a cree light.

here is the link

http://www.ebay.com/itm/12-VOLTS-MINI-GEN-MAX-For-Motorized-Bicycle-Lighting-/400108733087?pt=LH_DefaultDomain_0&hash=item5d2856c29f
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Thanks, Frank, for posting that link. I didn't have it.

Does anyone have any experience with that device? I have read good and bad about it. I typically don't do enough night riding to warrant the cost. I recharge my SLA batteries from a charger and they will usually provide me with good light for up to an hour. That's more than I ever ride after dark. Nevertheless it would be nice to recharge the batts from the engine. I might have to consider this.

Tom