Truenotch Posted November 18, 2012 Share Posted November 18, 2012 So this thing started as a Healing Minimax 16" BMX that I decided to chop up. Probably shouldn't have ruined it, but it was cheap and I don't really care for nostalgic kids bikes. So this was the original plan: I had no idea about what the engine or driveline was going to do, all I cared about was that the bike is small and potentially scary. Fast forward 6 months and not much had happened, but I did acquire a blackout generator. It's 2.5kva and the motor is 7hp according to their website, bonus! http://www.blackoutp...&products_id=23 I moved cities and the two halves of my bike came too, along with some 50x25mm thinwall box section that I'd used for a job on my AE86. Thanks to 10-5 and Yowzer's garage, I was able to play chop/weld one afternoon and ended up with this: mexi style: Then put my motor in (backwards, hah) for a test fit - it's tight! ... It's quite wide compared to my frame! Quote Link to comment Share on other sites More sharing options...
kicker Posted November 18, 2012 Share Posted November 18, 2012 Awesome! Looking forward to seeing this come together. The engine size to rest of bike proportions are perfect Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 18, 2012 Author Share Posted November 18, 2012 Cheers man, it's very small! So today I spend a bit more time chopping and test-fitting with a driveline in mind. The first thing to figure out was a seat and also how to add enough width for an extra rim for the drive: And a couple of test fits with short bars and long bars: I'd changed my mind on the powerplant and was thinking about going small-capacity for this bike... But I sat the motor in there, and it really looks the part!! Should I stick with it? I also decided that it needed less rake after seeing Seedy's bike in action at Dromageddon... I also needed more space for the engine (sparkplug was fouling on the frame), so I chopped out the seat post and gave it a tweak up. Then I made a piece for the front to replace the factory tube I'd bent... It's starting to look more like a motorbike. Oh yeah, I owe you a set of front forks for a girls bike Yowzer . Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted November 18, 2012 Share Posted November 18, 2012 holy box tube bat man Yeah use that motor, it does look lush Its a shame you cut out the bot braket though for the factory crank, that would ahve worked nicly as a lay shaft Also get round to cutting off the cover round drive side of the engine, will give you a better idea of how wide the motor is. unles you plan on using that as a leg gaurd maybe not a bad idea haha, My innder leg is soooooo fucken bruised) Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted November 18, 2012 Share Posted November 18, 2012 but fuck it looks cool! Quote Link to comment Share on other sites More sharing options...
mark105 Posted November 18, 2012 Share Posted November 18, 2012 there was talk of using it as a leg guard, chop a section out and put a plate on front spec. Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted November 18, 2012 Share Posted November 18, 2012 pussys Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 18, 2012 Author Share Posted November 18, 2012 It still has the bottom bracket / pedal mounts there but the bearings are fucked from when I welded the bottom tube to it, so it's become an ornament . I'm planning to run a narrow lay shaft part way up the vertical tube at the rear - then the belt will be inside the rear forks and I'll be able to remove it without cutting the frame in half. Any idea what sort of reduction I should aim for Allan? My motor will be pretty similar to yours. Quote Link to comment Share on other sites More sharing options...
sentra Posted November 18, 2012 Share Posted November 18, 2012 in auckland we call layshafts "lameshafts", fyi. Quote Link to comment Share on other sites More sharing options...
DodgySam Posted November 18, 2012 Share Posted November 18, 2012 your Lame Dave. Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted November 18, 2012 Share Posted November 18, 2012 Yeah thats why you have a Signiture Money/ hunny badger Bike I will measure up my pullys tomorrow for you mate Just remember you will be running a smaller rare wheel, so you can go bigger if you want, Guess it depends on what speed you want haha We all know mine does 80. Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 18, 2012 Author Share Posted November 18, 2012 Sweet, cheers for that. I think 10-5 is running about 4:1 reduction to his rear wheel (which would be similar diameter to mine) but I'll have more RPM to use, so I'd be guessing somewhere around 8:1 might be right? It's bound to be wrong at first anyway . Reckon a sneaky layshaft underneath the cylinder is a good idea? Space is pretty limited and I want to move the drive inwards as soon as possible to save my shoelaces. Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted November 18, 2012 Share Posted November 18, 2012 that is exactly where mine is. depends on what you plan on doing for a clutch type thing I have no room for a tensioner on mine as it is. the belt is to close to each pully and if i push them together they would touch if the belt was longer Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 18, 2012 Author Share Posted November 18, 2012 What RPM do these GX copies normally do? 6500? Quote Link to comment Share on other sites More sharing options...
UTERUS Posted November 18, 2012 Share Posted November 18, 2012 Valves start floating around 5ish, but will rev to 7k with grunty springs. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted November 18, 2012 Share Posted November 18, 2012 They'll valvebounce before 5K, but with stiffer valve springs and advanced timing they'll crank to 6 happily. The flywheel is a bit risky though Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 18, 2012 Author Share Posted November 18, 2012 Hah, ok. Going by those calks I'll only need around 5:1 reduction for 80kph, which should be pretty easy. That means 1:1 to the lay shaft and a 60mm pulley to drive the rim (should be 305mm to the inside of the rim, but haven't measured). Quote Link to comment Share on other sites More sharing options...
Ned Posted November 18, 2012 Share Posted November 18, 2012 Yeah thats why you have a Signiture Money/ hunny badger Bike I will measure up my pullys tomorrow for you mate Just remember you will be running a smaller rare wheel, so you can go bigger if you want, Guess it depends on what speed you want haha We all know mine does 80. Just in case others read this and buy the wrong size shit, this statement is incorrect. Rear wheel size will make no significant change to front pulley size due to it all being close enough to 1:1 from drive rim to tire rim so any size rear wheel will give you more or less the same reduction ratios. Quote Link to comment Share on other sites More sharing options...
KIRK Posted November 18, 2012 Share Posted November 18, 2012 goto motorized bikes.com and download the gear ratio calculator. its real sweet. Can I have the grips, the front tyre, the rims, the bb , cranks n pedals, the bars, the stem, and the headset off the minimax? edit: and the seat, and seat post Quote Link to comment Share on other sites More sharing options...
Seedy Al Posted November 18, 2012 Share Posted November 18, 2012 Ned so your saying if he ran all the same sized pullies to me he would be running at the same speed as me, with his 16 inch wheels? Quote Link to comment Share on other sites More sharing options...
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