this bike is turning out to be a giant headache.
the GT5A motor is crap. everything about it is crap. i've tried 2 of them so far, in various configurations.
first, stock, with an NT carb.
vibrations at 25-30, enough so you can't hold onto the bike. head gasket blew after 1 day, even after changing the head studs and hardware to some high quality **** with flange nuts instead of the acorns.
added another base gasket to decrease the compression. still vibrated, detonated, and just plain sucked.
rebuilt and reversed the motor, built the "side draft" manifold for the mikuni, trimmed the piston skirt, cleaned the ports, matched the exhaust and cut out the catalyst.
speeds about 35, then massive vibration again. head gasket blew in 20 minutes. sanded the head (warped), added another base gasket and another head gasket, no change, head gasket blew after an hour, vibrations broke my manifold.
next, used a GT4 case with a balanced crank, and the same GT5A jug and head, reversed style with a shorty intake and an NT carb.
vibrations lessened, but detonated like crazy, won't idle, and the jug and head have such lousy tolerances that the piston seems like it's just rocking around in there. blew another head gasket.
swapped the motor back to normal configuration, still using the GT4 case. added a custom made, awesome expansion chamber.
NT carb is in the way of the clutch cable. bike makes weird noises like the piston's not connected to the rod, or the bearings are falling out, or like someone's shaking a jar full of change.
still managed speeds about 35, vibration's still there, i'm starting to think it's the frame.
after a ride to the liquor store (10 blocks total) there's oil leaking from the head gasket.
took head off and threw it against the brick wall a few times because i couldn't find my BFHammer.
that didn't fix it either.
made a conclusion that the GT5A motor is the biggest piece of **** that ever came over from china. as long as i live, i will never put another one on a bike, work on anyone's bike that has one, and never comment on one again.
in other words, i wash my hands of it, and disavow any knowledge of it's existence. but not before putting a curse on anyone and everyone involved in it's development, manufacture, and assembly of it. i hope an earthquake destroys your factory.
moving on, i now have a GT5 in place. although it's from the same accursed factory, i had one in stock configuration on the Monark Raffle bike, and it reached 40mph with a 34t sprocket, with no mods other than an NT carb and match porting the intake and exhaust.
the GT5 has been reversed, piston skirt trimmed, ports cleaned, and i'm building a manifold for the Mikuni, using my newly acquired (and still learning) welding skills. enough of this alumiweld soldering crap. i'm also building an expansion chamber for it.
the first problem i've encountered is that the GT5 is almost 1/4" thinner than the GT4 and the other crap motor who's name i refuse to utter.
big deal, right? only a 1/4"...
now, my chain rubs on my super cool moped tire.
tomorrow, i will buy a KMC 415 chain to replace my Diamond 41. if it continues to rub, i will hone my welding skills and weld a slightly offset, adjustable plate for mounting the motor straight to the frame. it will need to be slotted, because if this motor doesn't provide me with the level of satisfaction i'm accustomed to (which is a very low level, considering the quality of engine's i'm working with) i will need to throw it away and put something else on. preferably, something that hasn't come out of the skyhawk factory (the one that will soon collapse in a localized earthquake. if the factory is built with the same craftmanship as their engines, a very small earthquake will do the trick. maybe even a good door-slam or a car backfire...)
as far as the tank goes, i haven't got to that point yet. i've only spent 3 weeks trying to get a motor to work, so i'm a little behind.
with any luck, this bike will be ready for the Bairdco Racing Association's first race of the year 2013
i've decided to name this bike the "Albatross."
