Rebuilding bottom end crank

i needed some milk, i forgot my wallet when i went to work this morn.

so i chanced it, because, y'know, this (stock standard) 48cc thing of mine is always breaking down, to ride to the shops and get some milk.

so yes, its nighttime. its mostly a video of black :) it wasnt for me, riding, but this camera...well... so much for Hewlett Packard :giggle:




mind you, i rode to work this morning, now i have a new rear tyre and tube. so thats 50km plus this 5km so far today.

and in about half an hour, part two, the ride home will upload. making 60km today. which is about the norm for a daily ride.

im loving this new exhaust bracket :)

and yes, rearviews are quite important. they are mandatory on real motorcycles for good reasons ;) shame noone passed me today :(

good thing i posted that last video. made me make one or two NECESSARY modifications. unlike "crowded needle bearings".

a spring mount for the exhaust, so it wont vibrate and break its mount again!

a heavy duty 700c tyre and tube!

a mirror!

oh, the joys of being a chronic procrastinator :) seriously kids, dont. it bites you on the derriere! get up and do it! NOW!!!!


so fabian... as the old TAB ad said...put ya money where ya mouth is...waiting for YOUR video still?
 
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oooh, the congestion cleared up and it suddenly went turbo mode!

the next 5km... took the back route home, the way with that evil pothole :giggle: even darker! so a boring video, it is! more audio than anything.



yes, my "quick run" to the corner shop is 5km. and when i go do grocery runs, its about 12km... or approx 8 miles.

im over this. time to get back onto some serious projects :giggle:

like that dyno that still hasnt gotten a bench yet!


(its nothing personal, i just dont like seeing...well, not BAD advice. just advice that suits one particular style of riding. once again, i feel no need to drag dead horses or other heavy items up steep bush tracks. nor do i feel that a twostroke should be run UNDER 5000 rpm unless idling. i havent had to buy any engine parts in about two years. at least, not for this particular motor. go figure. stop telling people that your way, and ONLY your way is correct. it isnt. neither is mine, truth be told.)



sorry OP :) i hijacked :) i simply dont want to see people being misled. a common practise on forum boards. constant :poop:
 
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stop telling people that your way, and ONLY your way is correct. it isnt.

Long term reliability under arduous conditions isn't going to happen revving your engine well over 5,000 rpm.
Sure, if you just want to make a complete nuisance of yourself in the neighbourhood revving the rings out of your engine for a 400 yard dash to the corner store, you don't need the engine or the bike to be reliable.
 
I think there is a "sweet spot" for rpm range for engine reliability, not too low and not too high. Higher rpm spreads the load out more per cycle but raises the inertia forces causing stress to the metals. Low rpm has more load per engine cycle but less inertia forces.
 
two strokes have no bottom end, well documented. theres a reason MOST are rated for around 7000 rpm +

I never said anything about 2 strokes. something like a predator 79cc, which is rated at 3 hp at 3600 rpm would be perfect. a 2 stroke is normally built to be revved to the moon
 
two strokes have no bottom end, well documented. there's a reason MOST are rated for around 7000 rpm +

That statement is a complete load of rubbish as a generalisation.
The port shape and port timing of a 2-stroke engine determine where maximum torque and maximum power will be generated.

A 2-stroke engine can be designed to give truck loads of torque at low rpm if so desired.
 
hmmm, this is the same engine, when it was all new and shiny...well, at least the head nuts were!

http://www.motoredbikes.com/showthread.php?40617-at-it-again-a-real-pipe-this-time&p=361755#post361755

whats the date? bit over a year ago now... new since i made that pipe...

though i have forgotten a few things...it spat the pinion gear bolt out through the clutch cover. so i had to replace the cover.
i guess a CR machined head would have prevented that from happening!

finally got around to checking the clutch last night. so, thats another 15 parts. pads worn down to the slotted disc.

of course, thats because it only ever gets ridden less than 2 miles...actually, make that 400 yards to the shops.

5km IS 400 yards, right? im still sorting out basic arithmetic, though you definitely have a firm grasp on it :)

there was the crank seal, that stopped it dead... well, stopped it from starting again. thats because its a highly unreliable engine :) only took over a year to show up how unreliable it really was. a shift kit would have obviated that problem instantly, of course. as would reed valves and a walbro carb.

17 parts in a year. oh, what an unreliable POS it really is! and yet i ride it...wait...PUSH it to work and back home again almost every day because its always breaking down, and i just love pushing my motorised bicycle upwards of 50km every day. it saves on fuel this way, not actually starting the engine, just in case.

maybe you are right after all :giggle:


:rolleyes:
 
5km IS 400 yards, right? im still sorting out basic arithmetic, though you definitely have a firm grasp on it :)

I love your humor. It hits my funny bone every time.
If only we lived somewhere near each other, we could organise a ride together to see who hauls the other persons bike home, or drags it home on it's side, should the wheels or tyres or pinion gear eject themselves from the frame, and by the sound of it, i'll be hauling your backside home, if you even make it anywhere near the destination:

it spat the pinion gear bolt out through the clutch cover. so i had to replace the cover.
 
I love your humor. It hits my funny bone every time.
If only we lived somewhere near each other, we could organise a ride together to see who hauls the other persons bike home, or drags it home on it's side, should the wheels or tyres or pinion gear eject themselves from the frame, and by the sound of it, i'll be hauling your backside home, if you even make it anywhere near the destination:

no no no! not the GEAR!

the retaining bolt :) it does pay to at least have a look and make sure things under covers have been tightened before operating these things, i will admit that! it was just sitting there idling at home, making a nasty grinding noise then pop! out it came. i was surprised, to say the least :giggle:

http://www.motoredbikes.com/showthread.php?40832-the-HEADSMESS-thread-o&p=363473#post363473

(only a month old!)



i reckon i would make it to melbourne but ive stated my theory on travelling south before. they get narky down there. and this is a racer, not a semi trailer... pffft, fancy putting a lambo up against a...well, another lambo... :giggle:

lamborghini-tractor2-1024x693.jpg


oh. someone beat me to it... :wacko:
 

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