project learning?

[blaze15301]

from what i understand. the aluminum fly wheel takes weight away from the whole thing. so in turn it puts less stress of the parts and give a small performance boost. but its mostly a weight reduction technique

[msmrx57]

An aluminum flywheel will improve throttle response due to reduced rotating mass. On an engine like this it won't be a huge difference.

[altec]

If it was mine, I'd rig up a ghetto balancing setup (Like a home tire balancer) and start drilling speed holes.

If it works, cool. If not, then it would have been fun.

[CorsePerVita]

An aluminum flywheel will improve throttle response due to reduced rotating mass. On an engine like this it won't be a huge difference.

Absolutely correct. You are using less rotational mass, therefore less energy is needed to raise the RPMS since the engine isn't using all that energy towards that rotating mass. Nice when you are trying to shift quickly, or trying to increase response. Not saying it's a bad thing, not by any means.

Only time i've really ever seen anyone bother is if they're decreasing laptimes at the track or if they're absolutely wanting quick shifts. On something as small as a minibike, meh. But it's your dough, if you want to, by all means! Mod it up!

from what i understand. the aluminum fly wheel takes weight away from the whole thing. so in turn it puts less stress of the parts and give a small performance boost. but its mostly a weight reduction technique

It takes weight away from the flywheel.

Let me use an analogy. Let's say you have a wooden dowel. Pretend it's a crankshaft. You are the engine. You put a huge weight on the end, say a 10lb weight, and you try to spin it. You can eventually turn and turn and get it up to say 4000rpm... but it takes a while, it's heavy!

Obviously, if the engine had more power, and the weight was about the same, it'd rev a lot faster than you can spin it, but imagine why it would take a while.

Now, pretend you're holding the dowel again, but this time, the weight (flywheel) is now 5 lbs less. You no doubt would be able to spin it MUCH FASTER.

Some benefits of this are raising the RPM takes less time, so depending on how shifting is setup, can actuall decrease your shifting time slightly. The other benefit is that there is less stress the engine puts out so you do gain a slight amount of power (depending on how heavy the flywheel is).

So all in all it's not so bad. But here is a few bad things....

Aluminum does not wear as well as harder metals, so depending on the surface of the flywheel (some are aluminum with inserts, most bike flywheels are just aluminum for the lightweight ones) it may actually wear a lot faster.

The other problem is that in an application where the rpms can change very quickly, matching rpms can be somewhat difficult as you are essentially just "blipping" the throttle and dumping the clutch in some instances, totally depends. This can make it a real pain in the butt to shift. Again, depends on the weight of it and how fast the thing revvs up in the first place. Application, etc...

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........ that said...

A few things you could do to get some more kick out of this bad boy.

Sprocket combination... If you change the sprocket combination on the little bugger you could actually end up making your final drive "shorter" and get some more oomph out of it. You'd lower the top speed but it would accelerate faster. This is a very cheap and EASY WAY to grab the acceleration out of a bike just by changing the front srocket down a tooth or two.

For instance you have a bike with a 14T sprocket and say a 42 in rear, depending on chain length let's say at 70mph in 6th gear you're at 8500rpms. If you changed it to 14T you may drop it to say 8000rpm, and increase your top speed a little, but it'd take longer to get there. If you went to a 13T sprocket, your top speed would decrease, but make it a shorter final drive, and therefore get there more quickly.

Hope that makes sense?

Anyway, nuff of my rambling. I should stop talking bikes or I'll be going on all night.

Less talk, more progress!

[blaze15301]

update

well folks. i did it....... i tore the whole thing down all the way to just the block. i figured id mess around today and i went out to the shop to turn it and see if it was still ok. i herd a clicking noise and i had no idea what it was. so naturally i went a tinkering i took the entire thing apart. i did not like what i found. no more clicking tho the governor is remove. it was grinding. some advice on how to clean all this and get the piston back in would be much obliqued. thank you.

ewww look at that dirty piston. its horrific.

now that is a bit better wouldn't you say. i still could use some help on how to get the other stuff off.

the head gasket. im still not entirely sure how to clean this either. can i use a wire dremal bit?

the cylinder after i cleaned it up.

now for the govener removal.

that little knob had to be cut off.

look at that evil vial thing!

look how roomy it is in there.

how can i get the rust off the cam shaft?

now for my long over due cleaned carb. she almost looks new.

and last my new throttle.
honda = 46.79
ebay= 9.95
me=

[d_stilgar]

Nice work. I'm going to be working on my Aprilia RS50 this summer. I want to do a few mods to it and it should be fun. What did you do to clean everything?

[CorsePerVita]

Do you have a replacement gasket for the head? You can probably clean some of it up with a VERY SOFT dremel wire brush, do not use anything abrasive on it. Your best bet is to have a local cycle shop machine it for you so it's nice and flat, take all the pitting out. They'd hardly have to take anything off of it. Getting it machined at a local shop that knows their stuff wouldn't cost much for such a small bit, too.

As to the rust on the camshaft be careful. You do not want to do anything that would scratch/dent/cause abrasion on the camshaft. The issue here is the part where the camshaft rides within the case still needs to have precise tolerances. Scratching/scoring or any accidental dents can cause you some headache down the road. If you're worried about the rust then TAPE OFF anything that rides on another surface and use some scotchbrite or something along those lines. You could also wire wheel. But don't touch any surfaces that meet other surfaces. Think of it like a head gasket on a car, or camshaft on a car, contaminants/pitting/scratches/flatspots are the devil for it.

The OTHER option is to just have someone hot tank it, you'd be amazed what a nice hot tank bath can do. Some shops use acid bath (which will pretty much strip anything off of anything) while others use a citrus bath. Either way, make sure whichever route they go will be fine for it and not harm it, but you'll be amazed how nicely it'll clean up. Same for any other potentially rusty/contaminated parts.

My other concern would be all the rust up there on the head were the combustion chamber is (valves). With all that pitting if it's made it's way up to the valves and they have pitting on the edges near the valves and where the valves actually sit it may not seal right.

We're talking a small little teeny motorcycle not punching out much power, so this may not be of big concern, nor would it be a huge ginormous difference. But if you're going full resto and going back to original state to make sure it's all rebuilt and good to go running tip top i'd at least make sure that looks good, those areas can definitely be soft wire brushed. Just use something softer than the metal it's made out of to clean up the rust and surface areas.

Once it's running, hot gasses and oil will take care of the rest.

[blaze15301]

Nice work. I'm going to be working on my Aprilia RS50 this summer. I want to do a few mods to it and it should be fun. What did you do to clean everything?

i used a wire brush some qtips water/gas to clean up the out side and the inside i just wiped it all down with a rag.

thank you for your input corse. the gasket for the head is aluminum so im not going to replace it, if i can. thanks for letting me know what to wire brush and what not to. that could have been bad.

[blaze15301]

just a little update for you guys. i got the block back together. the carb is on im working on the throttle assembly now. i have to buy all new rocker plates springs and studs. the studs are stripped out and the plate cracked. the valve springs have to be upgraded to 18lb springs due to the Governor being gone. also the jack shaft rod is bent int the back. i may try to smack it with a hammer and bend it back. its not to far off. im hoping to have the engine running bye the end of the month.

[CorsePerVita]

Keep up the good word! Looking forward to seeing it finished!