mods u can do for free!!!

hi all
im in the middle of doing my first range of modifications to my air cooled PB. I thought i'd share it with you guys as all the mods im doing wont cost a thing, and thats what we like, thats why we all have bikes that cost $500, we are tight asses!!!!! (kidding)

Pipe:
the stock pipe is not to bad, just needs a bit of adjusting...
cut the header just where it is welded to the expansion chamber and remove the 5cm of header pipe that extends into the chamber!!!! Dodgy chinese!! Then remove 3cm of header pipe.
Now add 5 or 6cm of pipe to the middle of the expansion chamber... i used 2.5in exhaust tubing i got for free from the local muffler shop. It was an off-cut. This is not ideal diameter, but its pretty close.
While your there cut where the chamber meets the stinger pipe and remove the stinger pipe that protrudes 3cm into the chamber!!!
Weld it all back together, try and put it on your bike and it wont fit!!!! you have to reposition the mount because the pipe is now longer.
Anyway, this is suppused to make quite a difference to your bikes power. At the moment my bike is in pieces, but when i get it all back together i'll tell u all how it goes. Should be a week or 2.

Note; Welding this metal is hard. need a mig welder and someone who knows how to drive it

Carb:
Run a 14mm drill bit down the middle. Then expand the intake (air filter) side to create a cone shape to it. Grind it out to the lip u will see that goes around the intake hole. about 17mm at the intake tapering down to 14mm diameter where the slide goes.
Create a small tapering out on the other side too. Then grind the hell out of the inlet manifold to make it flow to the reeds better.
Get yourself a few tiny drill bits from a hobby shop or something. Need about .70 to .80 mm diameter for drilling out the main jet to richen it up. Or use a tap so u are able use dellorto jets... but they are pricy.!

Reeds:
cut the middle supporting bar out of your reed block. Get some carbon fiber or fiber glass reeds from a morotcycle shop (they may have some old ones in the workshop - thats what u want) anyway, doesnt matter about the size. Bigger the better. U also want 0.35 or .5mm thinkness reeds.
Then use the stock ones to cut the right size reeds out of the big ones u have.
These reeds will flow heaps better and wont flutter so badly at high revs.

I'll be porting the head and matching the ports to the crank next weekend so i'll tell u all about that then, Ill also be able to test all these mods. So i'll tell you how the bike goes compaired to stock.

Note2: i got all this info from pocketbikeplanet.com forums. U should check it out, amazing amount of modification information.

beats spending modey on stuff u can do yourself, and its half the fun of owning a PB to!!

jamie


Anyone else got any mods that are cheap they want to share?

I just wanted to add my 10 cents on the free mods post

1. Cutting the bar out of the reed block and using carboin fibre reeds in place of fibreglass or stock without any other engine mods i'm sorry to say gives a zero improvement, compression on standard CAGS is quite low and restricting reed movement by using stiff reeds in conjunction with stock carby is quite pointless.

2. Once again drilling out the main jet in a stock carby will allow more fuel to flow and without more H.P. just flood your bike.

3. Porting the stock Head improves flow and bottom end i agree but nothing makes a 2 stroke sing than COMPRESSION.

4. Exhaust, really why go to all that trouble, a welder will charge $50/hr a performance pipe isn't really all that expensive and gives a huge improvement to a stock engine.

No Offence but there's no such thing as a FREE mod it always ends up costing you somewhere!!!

Carter Race Engines

thats a good point about the reeds, gotta have some more horse power to open the stiffer carbon fiber ones

and yes the main jet should only be drilled after the engine has been fixed up.

i meant all of these mods to be done together, otherwise there is no real point.


I guess im lucky, as i have all the tools that are needed and a good friend who knows how to weld, so these select mods have been FREE for me!


jamie

just go and buy performence parts

whats the fun in that?????
anyone can go and spend a sh!t load at some shop and make their bike fly, but there is satisfaction in knowing that u made a performance difference just with modifying the stock crap.

Mods u do yourself give self satisfaction, reality is at the track most serious guys are spending some dollars to get an edge, its looking like the stakes and level of competition is increasing every month, all in all its still a very much affordable sport, how serious or how much depends on your budget. The main aim i think is just HAVE FUN

there is also drilling holes into the black airbox cover.. like this .... i did this to my bike and it goes just as good as my mates bike and he has vstack and pod filter.
heres the link..
http://www.pocket-bike-racing.com.au...er=asc&start=0

junek, regarding the pipe and reeds. the mods you are doing to the pipe for the effort involved is not worth the time spent, for great results in moding the stock pipe i advise you and all to lengthen the header pipe by 30mm, lengthen the area between cones 80mm and lengthen the stinger 100mm, the stinger pipe will have to be long to start with as you need to bend it 180 degrees so your muffler will be faceing towards the front of the bike not way out the rear. yes as you mentioned you must remove the internal pipe sections that the chinese messes up.
as for the reeds, use fibre- glass noe carbon fibre on a relatively stock cag.

why bend it towards the front of the bike??

the extra length you have added to this pipe is about 200 mm, if the tail pipe does not stick out the rear to much you don,t need to bend 180.