Planet Minis

s_10onbagz

outer rotor is basically a scaled down stock stator & flywheel. the inner rotor kit has nothing inside the flywheel, just the pickup on the outside if I'm not mistaken.

arlindsay1992

Outer rotor: Rotor with magnets is outside the ignition coils.
Inner rotor: Rotor with magnets is inside the ignition coils.

Stock flywheel would be classified as an outer rotor.

cyclerider57

I don't plan on dumping the idea of doing a build as I've already got a bunch going that would work. The idea of creating it specifically for this forum would be dropped. I'd basically turn it into a build thread just showing pictures and information on the build. I just won't be going out of my way to stir up technical information. I'll still post about the build and answer questions about it.

I'd love to do a big bore de-stroke 88 but won't for a few reasons. I am already designing an engine with 57mm bore x 35.25mm stroke but it is a v4 so will be 360cc. The next reason is based on testing and analysis. A stock stroke 88 has such a short stroke already that I am not limited by piston speed when I try to increase rpm. The only major advantage going to a 57mm bore would have on one of these as an 88 would be potential for more valve area (there are of course many other advantages and disadvantages for each, IE: 57mm bore wouldn't shroud the backside of the valves as much). I wouldn't be able to utilize the flow area advantage without running my 4v head designed for 57mm bore considering I have a superhead +R that I worked over with 32mm/26mm valves (yes, for a 54mm bore crf50). Both a long and short stroke 88 would have similar performance because the normal limitations aren't there (within a few tenths of a hp since rpms would be similar on each and the others tend to even out). Even at 18,000 rpm (won't be going to that), I wouldn't be pushing the piston speed to high on the stock stroke. We will see what happens.

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50rider340

I understand where you were going with this thread as planetminis has lost a lot of its tech info. Well in depth info. Checking the site everyday usually the same questions always being asked ex. What knock off bike should i buy. YX kick start broke. you know where im going with that. I do remember back 2-3 years ago, you and a few others were always posting up there ideas and photos of builds. Not just out of the box. You were always changing the valves guides ports valve stem diameter etc. And probably so much more that you were leaving out. I miss those days of reading those. I think you posting photos and your ideas may stir up more interests that your looking for.

Just tossing this out there what is your thoughts about boosting these little motors? A waste of time? Done correctly could go somewhere? Obviously for street use. Ebay has those really tiny turbos that i always want to drop the coin on for hahas.

z50 chopper

I have seen those turbos too, though it is a fun thought I do not think it would be practical and I haven't seen one recomended for anything smaller than 200cc engines.
So you could get too much boost and end up damaging your engine, I'll let your imagination run with that.

cyclerider57

All I can say with absolute certainty is that I have never done it. Personally, I don't think it would be any benefit unless you designed a super/turbo specifically for one of these true minis. I think the parasitic loses would outweigh the benefits especially if you didn't create your own fuel injection system too. You would be creating more carburetion and charge quality problems then it would be worth. Without designing your own you probably wouldn't be able to create a 1+bar intake pressure consistently. Pressure is directly related to velocity and volume. These engines have virtually no volume so it would take a specific design to be able to capture and create any pressure to actually make more power past what the design absorbs to even turn.

__________________
The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

cyclerider57

Let it begin...

http://www.planetminis.com/f8/high-h...ml#post1392888

__________________
The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

way2fast4u7

don't know if you will see this as it is so far after when you posted the original post. But, I found a magazine out of europe, called "Racecar Engineering" and it shares a lot of different ideas in engine building. Moreso on the F1 front, but still a lot of info transfers over. A couple months ago they had an issue with exhaust building basically just to get a guy in the know. also had dynamic analysis of chain drive systems. just a thought

schofell84

excellent, i wonder what a subscription costs ... is it available in the states?

edit: 107 bucks a year. wowzers.

50rider340

That was my take on the turbo idea too. Because most people that have tried it have come up short with it actually being beneficial. The only thing I have seen work is the aisin AMR500 supercharger on a 50cc motor. There's a website with a guy reporting insane HP gain out of just 50cc's on a cafe bike. AMR500s are not cheap that's the only problem.

If I end up trying to do the turbo build I'll post it up. I wouldn't run a blow through set up. I would go with a draw through because running into issues with float bowl pressure would just be a huge headache, and fuel injection would be way out of the price range. I have seen draw through turbo set ups on a couple rotary motors that ran efficient so it is possible.

By volume your talkin about combustion chamber, or intake and exhaust ports?