pitbike gbox trouble. plz help

[shea man]

Hey guys, first time post.

had a play with my mates 125cc 4 stroke pit bike on the weekend, its got a few stickers on the rear swing arm but apart from that im not actually sure what it is.

complete motor was purchased brand new from the 3 amigos in SA. i beleive they have gone out of buisness now?

whilst in neutral it will freewheel then suddenly lock, and have traced it down to something broken / loose in the gbox.

first up drained the oil which came up clean as, no metal shavings.

stripped the motor back to as far as i can go without a manual. whats the go in regards to the timing chain / marks/ settings on these bad boys? obviously i cant pull the box apart without taking off the top end.

ive done a quick search but couldnt find any gbox guide/ walkthoughs.

does anyone have a pitbike manual or some info? will need to know all torque settings etc for reassemble.

much appreciated
Shea

 

[DvDRip]

3 amigos were THE dodgiest bastards in aus, they went out of buisness for that. what brand engine is it?

 

[shea man]

hey, not sure what the motor is, only markings i can find on it are a serial number and a symbol that looks like pacman.

heres some pics if this will shed any light....

 

[bulldog93]

i think its a ducar because thats the only motor i've seen painted black, unless hes done a paint job, well if the gears are stuffed in it you might as well get a new motor.

 

[headsmess]

u7sual timing marks are...cam sprocket at 9 oclock, theres a dot, and a notch on the head that should line up, and on the flywheel, the line marked T will line up with an arrow at the top of the case... or 12 oclock....

only need that for reassembly anyway.

stripping a box and reassembly is not really a huge job, but hard to show how to do, so theres no tutes around for it and theres no manuals either for chinka bikes, so...

just take it slow and easy and take notes if necessary... and reassembly is just the opposite of disassembly just fiddly

you might want to invest in a flywheel puller and a clutch nut socket...or just a new engine

 

[shea man]

thanks for the prompt reply guys, i'll pull it down anyway and go from there. almost guaranteed to be spacejunk but ah well we'll see
cheers
Shea

 

[Cactus Jack]

A Honda SL70 workshop manual is the closest you'll get since Ducar and Loncin motors are near identical in appearance ... Take step by step photos of disassembly then reassemble in reverse ... Don't just pull parts off willy nilly and put them all over the place ... lay them out next to each other in the order of removal ... It helps to rinse the oil off the inside of the motor before tear down by draining the crank case of oil then partially filling it with petrol or kero ... then swish it around and drain it out ... saves a lot of oily mess ...

 

[foolsp33d]

cactus, I was told diesel is a good ''oil'' to clean with!?? Iv got to drain the gearbox and xfer case on the 4wd, and want to flush them out, do u think its safe to use!?? (i KNOW there is Plastic in the gearbox of the 4wd as the shifter bush is kaput)

 

[headsmess]

ill agree with the kero and petrol, even lighter fluid if youre made of money, but diesel might be getting a tad too...heavy?

still, it will work, but petrols IS cheaper

and remember that diesel mechanics suffer the most from dermatitis due to the nature of diesel... and it stinks...and doesnt light up too easily either... safer? meh, whatevers handy and convenient i guess...

i remember cactus mentioning the old detergent and boiling water for cleaning... works a treat, just make sure it is boiling, else youll get rusty bits... best to do it just before reassembling and spray everything with some wd-40...

 

[foolsp33d]

um diesel is FREE.. (drive a truck and have a fuel card lol) i figured diesel would be a viable option as as A: its easily available and free(to me), B: being near impossible to light as such, it should be safer than using petrol or kero.. C:considering there is oil in the gearbox already, my aim is to flush any bits of plastic, hence being able to fill totally and drain, flsuhing any gunk out..
Its a car gearbox man, im not doing a rebuild, im changing oils lol, the old cheese would be somewhat P.O'ed with a 5spd and xfer case in the dishwasher if I was rebuilding it im sure. it HAS to be a day job, no longer. I need the veichle for work, so the less removing of parts I can do.. The better!

 

[Cactus Jack]

Yeah diesel , kero , petrol ... they're all good for flushing ... For a car gearbox the diesel will be OK since they don't get exposed to petroleum or acid contamination like car and motorcycle engines do ... just let it drain right out ... Headsmess is right about diesel and dermatitis ... bacteria grows in it ... Diesel tanks at servos have to be checked for temperature to prevent bacterial growth ...

Bacteria in diesel - ¡Cure Diesel Contamination, kill bacteria, fungus and yeasts in diesel

I religiously flushed my XR engines out with kero everytime I did an oil change ... and they never ever had any problems ... Fitters , engine shops etc all use kero to wash parts ... engine blocks , heads and cranks are jet blasted with hot water and detergent after being hot tanked to remove loosened up caked on crap , grit etc ... It's the ONLY way to get all the crap out of oil galleries ...

I always wash my motorcycle and car engine parts with degreaser , then scrub and agitate them in hot water and detergent then thoroughly dry them before reassembly ... As headsmess says ... you can also spray them with WD-40 after drying them ... For motorcycle heads , cranks and engine cases I run them under super hot tap water so that it evaporates quickly then use a hairdryer ... The key to reliability is to be surgically clean when it comes to engine building ...