Cams and cranks

[whiteknight]

ok been a while since i posted a question.

i have a race CDI, as far as i know this has changed the way the bike revs plus a diffrent power curve compared to standard, obviously the usual stuff that you do when you derestrict the scoot has been done, but i was wondering how much cop are cams and cranks. im going on the basis that if you go for parts that are made for the job then you wont be caning the balls off of the OEM parts which in all fairness dont really like being blitzed to hell. so on that note if cranks and cams are a good idea or if anyone who might be able to give sum pointers on what would be "good" choices or just point out pro's con's ect. ect.
i guess if i did get a diffrent cam that can be matched up to the CDI then i would make better use of the power curve and with a new crank it would be able to take the strain of high revs (this is just theory)

cheers guys

[zombie]

You are right in the "power curve" matching. It's really the Ign. timing curve. If you can get (from supplier/Manuf.) the actuall advance curve used you can shop for a cam with matching "charter" or timing. Some cams are better at top end, and some at low. Same for timing curves.
In the real world there are dozens of cams at unstated/known specs. so a good match is about 25:1. I'd like to try a few to see. The only down side (besides all that) is the idle may be difficult, and same for cold starts. If it is a Good cam. A sh**ty cam will have no real effect on idle, and maybe less on top end.
The only time you need a crank is to stroke, or replace OEM. There is no benefit in an oem spec. $400.00 crank.

[whiteknight]

Cheers zombie, i was hoping you would reply to this one... im gonna do abit more homework then have a look at sum parts on offer, but i do want summit that can utilise my steep power curve.

[zombie]

You could mark your flywheel and run a timing light to see what the curve is. Run it up on the center stand, and get the degrees with the light at varying rpm's. You would then have to visit more GY6 type forums to see if anyone has duration/power ranges for after market cams. There may also be a dyno shop that specializes in GY6 cams.

[whiteknight]

cool nice one zombie, looks like im gonna be on a quest. heres hoping other forums are as nice as this one. thanks for the advice.

[baddi]

Crankshafts:

This is a key komponent, which translates the force down from the work-stroke into circulare power. From physics, we know that higher speed means alot more than weight when talking about kinetic energy, and that lower  weight can easier be accellerated. This means that a lower weight camshaft will get more energy from the work-stroke of the engine and have more power netto than a heavier crankshaft.

BTW, the formula for kinetic energy, which is what we are interested in are 1/2*speed + mass^2 

So even though a lighter crankshaft will be more important on a 2-stroke, it will have positive effect on any engine. Just look at Formula One cars, where they try to achieve as low weights as possible

[whiteknight]

bloody hell where did that come from?? Nice one man wasnt expecting a lesson on kinetic energy  that was my initial thought about the cranks.. obviously it all comes down to the less weight it has to push the more efficiently the engine can work, that coupled with a new cam to make use of the race CDI and increasing the flow in and out of the engine including upjetting the engine (in theory) should go like a preverbial stabbed rat.

zombie i have joined 49ccScoot.com  they seem to have a mountain of engine related wizardry and teccy knowhow, they seem quite.......serious and...serious  hopefully i can do sum swatting up on there.

[zombie]

After you beat the bushes, let us know what you find.
The White Knight is leaving the Realm on a quest for wisdom. Lets say a group prayer he does not get brow beaten to death.
Safe crusade White Boy! God speed. (jack every thread)

[thebatman]

IMHO, i would think a cam is mandatory... Word and i have had this convo before..
When you build a car, a cam is normally the 1st thing that's swapped out..

Yeah, hardly any cam sellers have any info.. they just list as A1,A2...H1,H2-12..

There is a gy6 forum but most of those guys are in to the 150's+ on builds.. i;m signed there as well.
It's chinesescooter.com
For reading.. scootdawg forum has good info. Alot of the same ppl there and at 49cc(mostly mina guys there)

[baddi]

IMHO, i would think a cam is mandatory... Word and i have had this convo before..
When you build a car, a cam is normally the 1st thing that's swapped out..

Yeah, hardly any cam sellers have any info.. they just list as A1,A2...H1,H2-12..

There is a gy6 forum but most of those guys are in to the 150's+ on builds.. i;m signed there as well.
It's chinesescooter.com
For reading.. scootdawg forum has good info. Alot of the same ppl there and at 49cc(mostly mina guys there)

Hardly any info? :S The market you've got must be really hard to navigate in.

Here in Denmark, i often buy at the biggest (not that big) tuning store we've got, which is called Speedline. These guys only sell quality (expensive) brands and have done so you can just put in which scooter you've got, and it will show only the parts that fit. Also, they've written some info on many of their parts.

Unfortunately they aren't that much into the physics, but you could be able to use the site to see which parts fit the agility. http://www.speedline.dk/da/scooter/kymco-agility-cylinder/ I know that it is in danish, but it will take seconds to find out how to navigate the site. The categories are in the left side of the screen.

[zombie]

Thank You Baddi! I'll search thru it tonight.

[wordslinger]

..josh bought a dyno....


             

[whiteknight]

ok an update on my "Quest"  i have joined 49ccscoot.com and they have a whole load of technical info on 2 and 4 stroke engines, im talking bores and stroke info, engine info, brakes, suspension and frame the works. been quite interesting looking through the pages and pages of info. but i will look on others aswell but this has been the most fruitfull.

[wordslinger]

        "http://scooterinvasion.net"


..there's some crazy sh** goin on here too!!!

[whiteknight]

        "http://scooterinvasion.net"


..there's some crazy sh** goin on here too!!!

trust me take a gander at this, its a treasure trove man.... truly.

http://49ccscoot.proboards.com/index.cgi?board=archive