Planet Minis

schofell84

how about you just get me a job where i can learn all that good stuff

as far as all that technical stuff, does anyone have any really good books they'd like to suggest? i've accumulated a few, but amazon isnt very helpful in deciding what to buy.



ooh oooh ooh! 3valve-er!! kurlon had some very interesting numbers on his website a while ago.

BlackBeard

Id like the previous post of destroked 88 machine, numbers of 88 kit bolt on VS. destroked modified engine, (see difference in tq curve) piston coating vs bare. optimum valve size resulting in highest flow. Gapless rings, and what Id really like to see if ceramic coating on the piston and head dome really retain the heat in the chamber better with less transfer down the slug.

schofell84

how about polishing the piston and combustion chamber? lets see if that helps the heat situation.

BlackBeard

yes, but what im reffering to is people "painting" their piston tops and heads with ceramic paint coating and proclaiming it retains heat much better

schofell84

totally understood, im also interested in the ceramic treatment options available. but, ive also read aluminum can be polished to 99% reflectivity, whether or not that all pertains to heat i have no clue but it sure would be cool to see some numbers.

thorwarrior915

Bone stock 49cc motor vs bone stock 49cc motor with extensive head mods. Increase valve size, investigate valve shrouding, flamefront propogation in the combustion chamber (modify plug orientation/style?), porting, decked head vs. non-decked, mod the cam sprocket for optimal timing, valve and valve spring/retainer material. The whole point would be to show just how much is to be gained with head mods vs. the common bore/stroke/carb setup. The only other mod would be modifying the stock-piston valve reliefs to compensate for bigger valves and or more aggressive lift and duration.

LongMooie

Most of you will have already seen this but i dont look at monkey bikes but just found this
and thought id post here to spark some interest
Honda Monkey 2009 Limited 6 on Flickr - Photo Sharing!
i must say i like the look of that motor, and with fuel injection there be no more threads on "JETTING"

PHATDAN420

the process of lighting a flywheel...im sure its easy to some ppl that seen it done before..but me never seen it and love to get some insight

z50 chopper

I'd like to see a tech article on how to porkchop a crank and then install it in an otherwise stock 50 then compare it to a fully stock 50 to see if there is any performance gains (hp and torque)
maybe then port the head and polish the combustion chamber.

Could do this for both OHV and OHC engines.

LongMooie

take it to a machine shop and have them spin down the top either side of the pick ups dont take too much off on the radius edge
im sure if you do a search youll be able to find how much in weight you can take off

LongMooie

i started a thread on porting not so long ago i showed before and after photos of my first attempt of porting, couldnt tell how it performs but it sounds alittle more revy

firepower354

We set one up on a mill and turntable, so there wasn't a band around the middle for the trigger. Just left a lump opposite it. An extra oz and a half or so, I think. Still heavier than a YX outer rotor...

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cyclerider57

Keep in mind right now I am merely asking what build you'd like to see. I'm not doing a research feasibility study and paper on different setup options. I will be going about the build and posting information as I go. For example, if I was to post a picture of a crankshaft and you noticed something about it that intrigued you then you could ask questions and we would get into the technical aspects of it. Each part would be broken down in those respects. I will still be deciding what happened within the build but I would be explaining my build with technical information.

For example, unless the piston I planned on using already had a ceramic coating (I have various ones here), I wouldn't add one. I have already gone through the work and research to find out if it would be feasible so I'm not going to do it again, especially when you are working with power increase increments that cannot be measured on a running engine of this size by standard means. There is a reason most mainstream motorsport engines DON'T use ceramic coatings on the dome of the piston (IE: F1, Le Mans, etc). Yes, friction coatings on the piston, WHEN INSTALLED CORRECTLY, will decrease friction. NO, you will not swap a piston out on a minibike and see a difference merely from the coating.

Again, this would be building an engine and breaking it down into smaller pieces and discussing the happenings of each. This would NOT be a feasibility study of various parts, processes, or tests back to back. Look at it like this, you have a build idea (IE: top end hp 50cc build), then I build it as I would if it were my own and going for whatever specific goal. Then I would "defend" my choices through technical discussion. We are basically looking for the "rules of the project", then I go off and do my own thing to build it and periodically post information and pictures to stimulate discussion of the technical aspects.

I would love to do continued studies of each of these tiny spots within the engine (skirt coating tests, ceramic coating tests, surface finish tests, etc) and write technical papers of each (this is what SAE technical papers are for) but I don't have the time or desire to do it on these engines. I am confident enough in my past tests and experience to judge each build for myself to determine if I would find these sort of things effective enough for the added cost.

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z50 chopper

That sounds good.
A build that has a balance of top end torque and horsepower that can be used for offroad trails, motard and street use.

Or a vegas rules engine build.

Maybe a Bonnevile build or a drag race build. (top speed)

Just some of my general build ideas, is this the kind of feed back you are looking for?

schofell84

shoot for a bonneville record?

LongMooie

cycleride, i think its good that your giving up your time to show the forum members some motor build tech stuff
ive thought about this and think that for the average minibiker that wants to get abit more envolved with there engine build you could do something like this
go over anything that envolves the cases as this is where your build would start
gearing options, i dont think install guide is needed as you can find this on the web!
crank mods and options
clutch options
piston options and mods
head porting maybe even how to install bigger valves

this would cover all engine builds and help everyone!

BlackBeard

If it were up too me I would love to see either a destroked 107cc mill or a built 106cc scut kit. I am really curious as to what one of these engines wopuld run like with a short stroke motor in em!

z50 chopper

After re-reading the whole thread I rethought my ideas why not revisit your previous builds.
Stock bore and stroke build (49cc) for all out power and speed using as many stock parts as possible or the 88bbk build up. And refine them from what you have learned since building them.

But considering many Federal and state/provincial laws about motorcycles and scooters as far as drivers licenses go, I'd go for the 49cc build since the same techniques can be used on almost any larger displacement engine of the horizontal design.

Then if you were to turn this into a bike build up go for a titled frame and build a street legal dual purpose bike, staying away from aftermarket as much as possible like useing an XR75 swing arm and crf70 forks etc...

Keep an average cost list so people can see how much it would take to build a simular engine.

schofell84

if you want guidelines to build a motor by, your best best is to stick to a popular class and then build from there. i think a 50cc rpm/hp biased motor would be cool, as it could be used for something like bonneville, "stock" (cheater), and displacement limited road racing classes. ... and you could stuff a five speed in there without blowing it up!

on a side note, i've never really seen any good information on how a piston crown effects flow properties ... stuff like that, information thats really hard to find would be the good stuff to cover. how about an article on lower end (crank, rod, flywheel) aerodynamics?

cyclerider57

With only 40 replies in 2 weeks it is pretty hard to justify taking my time to do a tech specific BUILD for the forum. Again, I had no intentions on writing "articles". It was going to be a discussion among members and myself as the build progressed and why I was doing what I was and NOT a lecture from my end. I have no desire to be a "teacher". Ask anyone that has spent time with me (on the phone, in person, through email or pm's, etc) asking questions, I prefer tossing tidbits of information and making people think for themselves. I don't directly hand over information blindly with no effort from the other side. Hate my "process" if you'd like but I've noticed the only way people really learn and obtain knowledge is through having to do some work to get it, even if it is as simple as asking a question. Those that sit in the shadows and merely read information thinking it will be useful down the road better keep a laptop handy because when it comes time to use that information they will realize they store it no longer.

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