Wow frameteam2003 - that's one of those bikes that's extremely deceptive, looking at just the finished ride ya'd be hard pressed to realize just how much thought & effort went into it - a truly unique build that's so clean it looks factory! Glad ya posted the build pics or I'da been fooled too lol
Where'd ya dig up the springer? I don't think I've seen one quite like that before...
:shock: ZOMG Trash - posting PMs! I feel so exposed lolz
/covers self
Upper Class White Trash said:
as far as the port and polish this winter i will be doing that but i was looking for was what parts/price gave you the best gains for your money spent aside from the free gains from porting and polishing
but you haven't any base for me to go on before you did you mods. i can only see money spent for your mods/parts not the HP or speed gains from stock engine...
Well, TBH there's a coupla difficulties with providing such specific & precise data as you're requesting - the first and most relevant is due to the Chinese *cough* ..."quality control" there's a
huge amount of variance from engine to engine, let alone factory to factory. Stock, out-of-the-box ppl will usually get anywhere from 20-30mph with identical bikes & what looks to be identical motors so it's extremely hard to have a basis for comparison, particularly as almost no one has a dyno beyond the "seat of the pants" guessing. A minimum of a 30% difference between identical engines
before any modification means ya might get lucky, have a particularly good engine & see little gain from such mods - or exactly the opposite.
The second "problem" is as I've been a motorhead for years I've not run one of these engines "stock" - when I got my first one I hadta crack it open just to see what kinda engine I got for so little money... & I'm
very glad I did lol, I now like to say that it's not so much a "
Motorized Bicycle Engine Kit" but a "Motorized Bicycle
Engine Kit" in that the engine itself is a "kit" with the finishing stages skipped to cut costs & only loosely assembled as to not loose the parts in transit. The thread I linked ya to in the other forum's PM:
The Basics, Port & Polish and Port Matching pretty graphically illustrates not only how sloppy they are, but how simple & easy it is to fix/finish. As I've not run my motors out-of-the-box... I can only say that mine drastically outperforms some others locally, but even that's unfair as there's so many variables.
Upper Class White Trash said:
...i'm happy with mine as it sets but i know that a carb with a air/fuel mix screw would able to fine tune not necessarily for big gains in the top speed but will do a better job lubing engine and fuel delivery/MPG.
this is why i asked the cost to gain ratio you got from your mods then could share with others best price to power when it comes time for them to spend their money..
Well... again the specifics are wildly variable but I will say that a proper expansion chamber is without a doubt the absolute most beneficial purchase for the money. A critical component of a two stroke engine, an
Expansion Chamber acts sort of like the exhaust valves on a four stroke motor. The kit supplied "muffler" is not only unduly restrictive, simply drilling it out or removing the endcap only provides the most marginal of gains and may even lead to engine damage (lean condition) as the point of an expansion chamber is to provide a small amount of timed &
tuned back pressure to help prevent the fuel/air charge from passing right through the combustion chamber, keeping it in the engine long enough to be ignited. It can also be one of the least expensive "modifications" (I like to think of it as replacing a missing component lol) - while for
maximum gain you should seek an expansion chamber with the correct shape/volume for your exact engine displacement & tune the headpipe length to suit your powerband needs, you can ofc use one that's "pretty close" - which means you can use any number of the commonplace & cheap 50cc "pocket bike" expansion chambers available all over the 'net for as little as $20, sometimes even less. I will also say that even that wont provide nearly as much as is potentially available unless the engine is properly port matched first (free & easy).
The pesky carby... heh, well again - it all depends on application. If ya spend all of your time at wide open throttle there's no benefit
at all with a more complex carburetor as your utilizing it's main jet exclusively and it's fuel/air adjustment can be easily altered to suit with just the needle clip settings. While it's true a proper air/fuel set screw makes it easier to fine tune to your exact elevation/atmospheric density & oil/fuel ratio (less oil in mix = more fuel & thus slightly richer air/fuel ratio) the same can be accomplished with simply rejetting the stock carb. As I ride all year 'round (cold air = denser, leans mix), have a shift kit (thus run at lower RPM/throttle) and run an extremely lean oil/fuel ratio* I found the more complex carb to be
slightly beneficial... but by no means a requirement. Where you might see a pronounced
power gain with an aftermarket carb is if you've gotten one with a larger venturi (larger passage allows more air, thus more fuel = greater available CFM)... but remember, regardless of the carby's size - you're still limited by the intake manifold's inner diameter, the intake port's size and ofc your engine's displacement.
So... while I'll not say that a more complex carb is a waste of money, I will say it's about the lowest priority insofar as performance upgrades with the least beneficial "price to power" ratio. A minor point but still a factor is the old truism that the more adjustment something provides, the more adjustment it requires - if ya don't like fiddling about all the time trying to get the most out of something, stick w/the bone-simple stock carby
* "run an extremely lean oil/fuel ratio"
Disclaimer: There's much controversy regarding "exotic" synthetics at such extreme ratios as 100:1... While I do it myself, I don't particularly recommend it as there's little gain beyond simply having to buy less oil (there's less buildup, but that's minor) and ofc there's hazards involved. Generally it's best to run w/e the
oil manufacturer recommends for their product, not the Chinese engine manual. A good all around mix is 32:1 with a standard, non-synthetic two stroke oil (not marine two stroke oil as that's for liquid cooled engines, thus a lower average operating temperature).
