some cheap mods i did

[ridingpistonbroke]

I removed the head gasket and put a paper thin one
on there,and did some flow porting on the inlet manifold
and exhaust.the only thing i bought was a dremel but
i needed that anyway so it doesn't count.

Anyway,after doing some reading on porting and port timing i thought
i better do the "porting" to the bits away from the cylinder. i have to ride
this thing every day and cant really afford to stuff it. a bit of grinding
for some flow shouldn't do any damage,the raised compression is a gamble
i have chosen to take. you can see in the first photo,the exhaust on the
left has a black oval shaped mark,and the inlet on the right with a light
oval area around the centre. this is obviously where the ports of the motor
are hitting.

I took the dremel with both a grinding and a sanding wheel and took as much
as i could on the exhaust, and really opened up the inlet.to the width of the pipe.
gave it a sand inside while i was at it. love the dremel. lol. all my gaskets i make now are from
leather i tore off an old sofa,works great. i have other gasket material but its
really for thermostat housings and smells like burning jb weld when its hot.
with a hole punch and some scissors you can go nuts with a foot of material.
i have run the leather on the inlet for 3 weeks riding evreyday to work,no dramas.

after there where cleaned up-

The head gasket itself that i made is an alum can,also cut with scissors and
hit with the hole punch.i didn't get a photo of the gasket before i put the head on,
but it was as simple as tracing out the old one and cutting it out. when i took it
out it started easily and runs noticeably smoother when it's cold,usually its a she-dog.
took a while to warm up as it does, but even when cold it definitely runs better.
when it warmed up it definatly felt stronger,top speed was the same though.
i only had a short ride, but i am taking it out again this afternoon,make sure
its good to take to work. i had to tighten the head bolts slightly more than
i did before but she should be right. i did the work this morning, in about two hours. cost $0.
hopefully i have gained some power and not made a grenade out of it.
next is a expansion chamber,maybe a pocket bike exhaust. my exhaust has been
slightly modified, but its pretty ordinary in every meaning of the word.

the hi-tech head gasket material-

will update after a proper ride. comments welcome good or bad.there are some
more photo's but im limited in one post.

[I DO NOT RECOMMEND DOING THIS, IF FOR SOME REASON YOU DO, AND THE
PISTON CLEARANCE ISN'T ENOUGH AND YOU HAVE PROBLEMS,THAT'S YOUR
OWN STUPID FAULT.I TAKE NO RESPONSIBILITY] just in case someone says "yeh bro you said it would work"

cheers.

 

[ridingpistonbroke]

took her out for a belt lastnight. awsome. i dont really have to help it take off,
asides from a complete stop just to get it going. climbs hills better too. it
felt like i might have got a couple of kmh on top speed but not much,accelerates
way better.i was keeping up with cars lastnight through the backstreets. seems relaible,
so far anyway. the motor sounds nice,i checked with a torch after the ride to
see if there was any leaks,none yet. bought a pocket bike exhaust as well so
that should be here next week,and i can get the most out of my china.booya.

seeing as i made this thread i thought i should share all the mods i have done to
this thing.being a tight ass, you can be rest assured the mods cost very little if
anything at all.

here are some of the photo's i couldn't put in yesterday, just the leather
and the gaskets i cut. i make them because the stock ones aren't the best,
and i cant be bothered waiting for ones i have to order.
-

i will update on some other things i have done to the motor,mainly
to quiten it down.most of the mods i got from here,some i just did.
now i have to take the beast to work.


thanks for looking.

 

[ridingpistonbroke]

The ride today, to and from work was great,bought a six pack on the way
home and couldnt even notice the weight. its definatly faster on the top end,
why-i dont know. some of the other mods i have done to it was make new
gaskets for all the alum covers.magneto/coil,clutch lever and the big clutch cover.
i got this idea from my neighbor to cut the sound down,and it does it great.
when my motor was new i traced out the stock gaskets and made new thicker ones.
you can use rubber,thermostat gasket material or leather.
for the clutch lever i used two hole punches,one bigger than the oether, and punched
out these little "washer" type gaskets (a whole punch set is like $10 bucks form a hardware shop
and a must have for making gaskets).

clutch cover gasket-

the other thing i did was put a good smear of silicone inside all the covers besides the clutch lever.
if you tap the covers they sound awful tinny,and even with my gaskets this
could be heard pretty badly. with the silicone it makes more of a thud sound when
you tap it and fixes the noise great.my neighbors and my bike are very quite,
the only noise is the chain idler and the exhaust. yesterday a made rubber bits
to go in between the fins.every little bit helps. if you do put silicone in were the
clutch gears are, dont over do it. the grease can break down the silicone, go
into the gears and make a mess.

inside clutch cover-

I replaced the bolts that mount everything also but i don't think we
need photos of that. i initially bought high tensile bolts,screwed them
into the motor and cut the heads off with a grinder.way over board.
i learned 6mm threaded rod can be bought for about $10 a metre and
you can go nuts with it,and apparently its plenty strong enough.

hopefully someone found this usefull.

if someone can give me a quick rundown on trimming the piston skirt
on the inlet side, that would be awesome. just interested in what it does
(something to the timing?) ,if its worth it and how to go about it.
im happy with performance,if this mod drastically reduces the motors
life i will leave it.

cheers.

 

[ridingpistonbroke]

contrary to what i thought i was going to do i trimmed the
skirt anyway.couldn't help myself. did a bit on sunday night and rode
it to and from work today,nice. powerful and smooth,but i didnt get
enough material off for my liking. today i reground it close as possible.
i didnt take enough pics,but at the start the skirt was blocking the intake
by about 4-5mm now theres a bout 1mm or less and the right shape.

when i took it out it bogged when it hit the the throttle,it was cold but i
do this just for a moment to see what it does. it bogged before i upped the compression
so iam not bothered,she gets babied until its warm anyway. it warmed up
and i just couldnt stop smiling over this thing.on w.o.t its a bit wild.
im afraid of what it will do when the exhaust comes.that brings me to the end of
my mods for now,if i go too far i will stuff it.

note:yesterday when i trimmed the skirt i didnt have my glasses.
the dremel gripped and nearly spun up the side of the piston, honestly
i think a bit of poo came out. be careful.
today i had them and took my time,quite proud of it actually.
only mods now might be lifting/lowering the c/clip,see what it does.
hopefully i dont blow this thing,i ride it sensibly. this forum is the best,do some research,get
your dremel out,get on your bike and ride it.

i only wanted this bike for transport,this forum has made me start saving for
another kit i want to put on a bmx or an old cruiser type bike with a saddle,
do some engine work on it and have it for weekends. the kits seem to have
gone up in price,strange. i only rode it this afternoon around the block,
as normal tomorrow it goes to work, that will give me a better idea of how
its going.

this is the piston after it had yesterdays work, and i marked it with
a texter today to show what i had to cut out.a bit hard to see.

this is after i took the material off it that i needed-

the motor at tdc,notice only a thin bit of piston at the top. -

and yes i know the intake gasket needs trimming.

 

[BarelyAWake]

I just wanted to mention I've been following your progress w/interest - thank you for taking the time to post such good pictures and descriptions of your Dremel adventures

I can but sympathize with the "brown alert" that happens with only the slightest inattention whilst wielding such a tool lol

...and I too have been known to sacrifice a work glove for the cause - leather gaskets can be quite effective (depending on location & type of leather ofc) and best yet - they don't degrade due to the ethanol content of modern fuels. It's defo "old school" - leather was a not uncommon gasket material for a great variety of items even as recent as the 1940's in case ya didn't know

 

[Prasinos]

Trimming the piston skirt is going to close the intake later, this allows more air to come into the engine as the intake duration is increased. At low rpms however, as the piston starts the downstroke, the compressed mixture inside the crankcase will "spit up" through the carburetor. So basically trimming the skirt improves high end but you sacrifice low end torque. Since these motors don't deliver much power past 7000rpm i wouldn't recommend taking any more material off the skirt. I can tell you that widening the intake port will keep all of the same timing but allow your engine to breath easier.

 

[ridingpistonbroke]

I appreciate the reply's, Barely,i think i got most of these ideas from you.lol.
ive found the leather isnt to good on the exhaust. im a bit old school with alot
of things, yesterday a felt a bit of Burt Munroe calling,i was even looking up
speed records for motorized bikes.before i got too far i had to remember i
was being an idiot.i forgot what these bike where all about. today that was restored.

well,i took the bike home from work today having some great fun. fly's up small hills
and holds speed up semi steep ones. right low down shes not as good,but there's definitely
more power there. there's a pretty good possibility im shortening its life too,
that i dont know. if someone does let us know.

no more mods for this girl,she's the daily driver i'm not doing any more work to
this except exhaust/tuning. next is a stingray or something with a saddle and one of these badboys,
with some proper port work on the cylinder when its new.i will take a video this
weekend of my bike for you to see,she's pretty quick. i would like balance
cranks but i fear its more than i want to do. i would like one though.

prasinos,thanks for taking the time to post.i wasnt sure on exactly how it worked,
cheers for explaining it.

anyone have any ideas of the gain from a pocket bike exhaust? im thinking of
getting the chamber welded on at about 10-12 inches back from the motor.
this is the one i am getting-
New Exhaust Pipe Muffler For Mini Pocket Dirt Bike - eBay, Scooter Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 15-Oct-10 12:40:26 AEDST)
i was suppose to get this, but today i got an envelope in the mail and a gasket
for what looks to be a intake gasket for some motor for something. i will have
to get onto that. im thinking the exhaust will just make it run better,harness
the power already there, and make it better,not necessarily more powerful.
any input is appreciated.
cheers.

love the shynagurl

 

[chainmaker]

Thanks for the posts. Never thought of using leather.

Cheers