Jakebike top end power pack

I have no experience with them, but it looks like they sell a really nice expansion chamber.
http://shop.jakebike.com/High-Performance-Expansion-Chamber-48.htm

Not a bad price for a reed ported jug and HC head. But there are several cylinders for sale advertised as reed valve ported when in fact, they simply have a reed bolted on a regular cylinder. The transfer and boost ports have to be specifically designed to work with a reed or it's just a gimmick. If this cylinder is ported correctly to actually take advantage of the reed kit, it is not a bad price. I'd have to see better pics of the bottom of the jug to tell if its real or not.
Be aware of exactly what you are buying and ignore the advertising copy.

You would be better off talking to a customer who has bought the kit.
Owners and employee's tend to tell you whatever will make you happy rather than the truth. Just a fact of life. Punch it up on google and search for opinions from actual users.

Gasp said:

Wheelbender; yeah im torn between the Jake bike,SBP,and arrowbikes chambers. Im trying to figure out which one will help the most through all ranges.

maniac; i learned that lesson the hard way, first bought an entire kit, ran it and shortly decided to upgrade everything. So I've got almost a whole kit ill likely not use when I could have bought the engine alone. If I emailed Jake or one of his associates do you think they'd be willing to answer a few questions?

I appreciate your guys input, despite my extensive reading the fact remains that im new to this and dont know all the ins and outs yet. I may start posting pictures as I put it all together, I've got big dreams for this thing and if all goes well it should be a beautiful beast when im done so keep it coming! The more I know the better

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I sent Jake a PM several months ago asking about a fuel tank.

I am still waiting on the reply....

seems really pricey, he sells a 1 gallon chrome tank for $45, you can get the same one for $30 elsewhere. The Powerplenum looks and sounds like a gimmick, and from the looks of it it actually interferes with airflow (it sits just a bit higher than the intake path, and has a large empty chamber. There's no reeds listed so I doubt it's reed ported. just looks like it's got enlarged ports. Transfers look stock and thats where these motors are losing their power in porting. But its hard to tell because the pictures arent very good for those details. If you get a motor from dax, speeddemon or virtually any NON grubee-GT5, they're fairly well ported straight out of the box, better than stock anyway. If you want more power, 20 minutes with a dremel to WIDEN the port and raise it 2 mm will give you more revs (around 7500) and power. (no, I'm not a fan of pre-ported jugs). He sells em for $80, you can do it for free.

Power plenum? Just get a set of Arrow Reeds (RSE will do if you run a 48cc). Tried and race-tested. $85, $25 more than the Power Plenum.

Carb? Yeah, carb's good. Get a 19mm Mikuni or Dellort PHBG (racing carb). You can get em here for $75 CAD
http://www.mbe-motorsports.com/cata...rto&osCsid=mm7ogvvbuadm4u9kdp01c0bi60&x=0&y=0

The pipe looks like SBP's pipe welded together. If you can weld, you can make one yourself for $25 and get power exactly where you want or need it. If you cant, you could buy a voodoo pipe from BGF, gut your stock exhaust (works, but not as well as an aftermarket pipe), or get an Arrow Torquer 2 for $50. SBP charges the same (I'm pretty sure) for their pipe, and is adjustable.

The head? You could, or you could get a Puch 70cc hi hi head for $30 from www.treatland.tv and drill out the mounting holes, or if you have a lathe or time, you could have off 1 mm off the stock head, and save even $30.

So do I think it's worth $300? No, but I can do most of that myself. If you have no fabricating skills at all, then you could get it. If you dont have a dremel, you can buy a Rotary tool (dremel, just not the brand name) for $30.

Gasp said:

Incredibly helpful info mew, after reading your post, searching around a little bit, and really thinking about if i wanted someone else to do the work that will be important to my bike....im off to buy a couple new tools ;D

Ive found a few comprehensive threads on most of what i want to do too

Any tips on porting and polishing? it seems like kindof a delicate process...

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Not delicate, just that if you port too much you'll lose power where you wanted, if it ends up lopsided to one side too you could lose power because it wont be able to flow properly and evenly. Polishing doesnt really make much of a difference in these motors, at 8500 RPM (probably beyond what your average 66cc will do) the motor only sucks *roughly* 10CFM. To my knowledge, the things that make the biggest differences in power go in this order: (from most to least)

#0 Turbo: Never done on an HT before, but common nets 2-stroke motors 2-4x their current output. So a 25hp scooter may see 80hp, or a 5hp bicycle may see 15 or 20. Very, very expensive setup with these motors though, I'm looking at probably $1000-$1200 for the turbo and everything to run it, plus a rear wheel that wont explode under the immense power.

#1 Expansion pipe. If you want a ton of power in one go, get a new pipe. SBP's pipe has the best reviews but all the ones I've seen have high power bands, but give more power (better with a shift kit). IF you can weld, that Torque pipe will give you less power, but over a broader range (so you'll accelerate/climb hills better)

#2 Exhaust port: The bigger the better, but there are drawbacks, too big and the transfers will blow the fresh gas and air straight out (short circuiting), and the piston rings take extra wear (and if you dont chamfer/bevel the edges AND round the port, even snag and break a ring on the first revolution). Manufacturers make a small 'bridge' in the middle of the exhaust port to prevent ring snagging but this has drawbacks as well. Jenning's book states 62% of your bore (66cc this will be 47mm * 0.62, juuuust shy of 30mm) is a good upper-limit safety zone, though racers will often use 70% or even more, but their rings and even cylinders are expendable. Raising the port will introduce more power as well (keep it oval though!) but will also raise the timing, losing power at the low end but gaining it in heaps at the top end. Again, good for shift kits.

#3 Compression: There is a drawback to this, but shaving the head mating surface 1mm will net you roughly 125psi? depending on the motor's design. The drawback? Detonation, heat, etc, more power can be had from doing the below FIRST, then adding compression if you still feel you need more.

#4 Reeds: A properly chosen reed setup (between Arrow and RSE) can net you some good gains, especially in the top end, as well as better lubrication for your wrist pin bearing because the air/gas will flow by it to get into the boost port.

#5 Transfer angles: This, if done right, will net you better fuel economy (less short circuiting) and more power, thus... better efficiency. They will blow more of the exhaust gases out so they dont drain power. Combined with a reed port aiming upward into the cylinder, will net big power gains.

#6 Carb: The 16mm carbs are great for the stock motor and if tuned right you dont need to waste the extra $50 on a dellorto clone or whatever. But if you want real performance, especially high end, you want to match your carb with your target speed (this is true of the expansion pipe as well, aim these both for the same area and get ridiculous power boosts). Essentially with properly sized reeds you'll be looking at around a 19mm carb for 8500 RPM.

#7: Balance: Balancing the crank is kinda tedious to do, you'll need a drill press to drill the hardened steel and a manual impact driver to get the bolts out. But when done right, dramatically reduce vibrations, thus improving engine life AND performance.

#8: Proper porting: This makes more of a difference with the GT5 than the Dax F80 or other Type D motors (if you measure your piston, from the edge of the crown to the tip of the wrist pin hole, if it's 16mm it's a Type A, if its 21mm it's a Type D). The Type D already has decent porting, just cleaning them up and smoothing them out should be the most you do unless you're porting for a shift kit or racer. The GT-5 on the other hand the ports are too high.... about 2mm too high. Adding 2 base gaskets will correct this.

#9. Match gaskets: While assembling your motor you may have noticed your gaskets cover part of the port. Just cut that out to match using an exacto knife, its quick and easy for the intake and exhaust ports, but the base gaskets are the worst, disturbing airflow into the transfers massively impedes the engine's ability to scavenge, so if you have time, clean those up for sure.

#10 Jag CDI: Yeah yeah, people say its placebo effect but it's really not, it only nets you a couple mph more (say 2 or 3), but is fully adjustable so when you add power you can readjust the spark to compensate, and it really does smooth out the ride, you'll notice it after break-in one day, you'll get on it and say "wow, my motor's running really smooth today". This also saves your bearings from undue wear because the ever-advancing stock CDI does make more power, you can only advance it so much, most 2 strokes, especially street bikes, use a retarding ignition for reliability (when power isn't a priority, and you cant rebuild the motor every ride).

The stock clutch is good. Just make sure you fit the little friction pucks
so they can "float" in their holder. This allows for full contact on both friction discs. Do a search and there is a write-up with pictures. Big difference
and no $ needed. ( basic blue-printing really)