electric start "silver bullet train" engine

[jatgm1]

wow, never new they changed their mind so much on what a hardrock was supposed to look like lol. well, it looks like the 1999 version except the top tube and front down tube have more space between eachother where it mounts to the from where the handlebars go through. anyway, i actually found a guide on making a 79cc bike from scratch where this dude actually mentions a hardrock frame and it looks just like mine

http://www.instructables.com/id/79cc-Motorized-Bicycle-From-Scratch/

and have you ever seen a 79cc engine put stress cracks in a steel frame bicycle? just out of curiousity. i know a guy that welds motorcycles, so ive been debating trying to take everything off the frame and see if he has any ideas about how to reinforce it. to better handle an engine.

 

[Frankenstein]

More to come but will be fun, I'm a size 10...

 

[KCvale]

Well, I finally got my replacement parts, the same s**t that it came with not the improved pull starter and it has already failed.

Looks like they just used the cheapest CDI internals they could find and shoved them in into a new plastic box so it could be mounted inside the already obnoxious bigger electronics box and has failed as well.

As for the new electric start parts, who the hell knows!?
The starter motor is trying to draw like 15A to turn over the engine, s**t, you are talking a full sized car battery to handle that, and even THEN the figg'n thing won't start!

All I know is I still have an expensive pile of useless s**t we can't start, and if we can't make it go tomorrow it will end up a viral U-tube explosion to get rid of it.

But hey, best of luck with your new BT-80, just hope you don't get one from the first batch.

 

[Frankenstein]

Interesting, like how they combined the pull and electric start nicely.

Tasty looking exhaust port, big.

Transfer ports without walls in them, not like the normal happy time.. I think I heard someone mentioning they wouldn't work well without the transfer walls, but I've seen it before and so this is not all that unusual, especially for a one piece jug/head.

Small head bolts, using allen wrenches for them, but no head gasket leaks, which is nice.

 

[Frankenstein]

Well, I finally got my replacement parts, the same sh*t that it came with not the improved pull starter and it has already failed.

Looks like they just used the cheapest CDI internals they could find and shoved them in into a new plastic box so it could be mounted inside the already obnoxious bigger electronics box and has failed as well.

As for the new electric start parts, who the hell knows!?
The starter motor is trying to draw like 15A to turn over the engine, sh*t, you are talking a full sized car battery to handle that, and even THEN the figg'n thing won't start!

All I know is I still have an expensive pile of useless sh*t we can't start, and if we can't make it go tomorrow it will end up a viral U-tube explosion to get rid of it.

But hey, best of luck with your new BT-80, just hope you don't get one from the first batch.

It's not mine but I intend on having my hands on its curves anyways.

Perhaps Steve has some background in explosives he can share with you. Or at the very least some old grenades left over from his adventures in the military.

 

[Frankenstein]

Could you also describe why it's not an improved pull start? It seems at least partially designed better, it is part plastic but the pull start is disengaged from the engine while it's not in use, not even the throw back when stopping it can it engage, unlike the version we see on our bikes now.

It's got this weird plastic ratchet like bump that protrudes as you begin to pull the start rope, and when you let it go it retracts from the area that would catch one of the 4 catch points on the engine.

Its not the worst or the best pull start, but it's still not the worse, and I'm happy they did that, it feels very smooth as I pull the rope start and the engine turns over a few times.

15 amps is... Not much... Since I see numbers like 300 or 500 cold cranking amps on batteries, which would be needed since they easily are rated low hundreds to 2 hundred even as much as 350 amps on a bigger motor.

15 is pretty much expected on a small motor, and when I was pondering down the motorcycle battery lane of some store recently I remember the 70 and 100cca batteries for small motorcycles with small starters, some having larger capacity and other smaller, but definitely having heafty cold amps since that's what a starter needs, a bunch of power quickly, not a bunch of power over the span of a long time (you may have been thinking about simple capacity, not the max draw, which on a car battery is large compared to its storing capabilities)

 

[Frankenstein]

Wow and funny enough... A while back I was experimenting with from different electric motors from various tools and figured it takes about a 1/4 horsepower (on full draw) or stronger electric motor to start one of the standard motors, a bit more for a higher compression head if starting one of them.

Turns out your measured current of 15 amps at 12 volts, which is equal to 180 watts. Converted over to British horsepower 180watts is .241 horsepower...

How funny a coincidence. Looks like 1/4hp motor is the basic requirement for these sized motors, for starting purposes that is. You even mentioned it wasn't even able to start it most the time. They probably are using the absolute cheapest for these things, which is a problem that should be foreseeable.

1/4hp was just able to start a 66, 70cc is the rating on these, so it's just getting harder for that small motor to handle. Perhaps an out of the box upgrade would be to find a bigger wattage starter that fits that assembly, so that starting would be less of an issue.

 

[jatgm1]

well the motor isn't much different from pit bike motors, maybe you can find something similar by googling that.

 

[KCvale]

I have a nice 12V 9A SLA battery that should be more than enough power, it wasn't.
I jumped it with my battery charger and trying to start it again it pegged my charger at 15A, + the batteries 9A is 24A and it STILL wouldn't turn it over but a couple of turns.

The battery shipping with the bikeberry kits is only 7.4A and even that should be enough.
It's not a lack of battery power, it a consistent lack of quality parts.
I was told the pull starter was redesigned with metal opposed to plastic where it broke on me the first time.
That is not what I received, nor did you I suspect.

 

[KCvale]

well the motor isn't much different from pit bike motors, maybe you can find something similar by googling that.

Huh?
And what do you consider a 'pit bike' to be?