Restoring Yamaha 100cc (YB100, model:1980)

[hidalgo]

aslam-o-alaikum hidalgo

wa alikum salam

helo hidalgo

hi

i am new on this thread

welcome

kharadias do not use vernier caliper for cylinder bore. they ask the customer to bring the piston and according to that piston they bore the cylinder. after they bored cylinder they put piston into cylinder they polish it and after polishing they recheck. if the piston is so tight they polish it again to get accurate clearance. our kharadias have no facilities to do work according to the Japanese workshop manual.

2stroke pistons are not chrome polished as 4stroke , not in same diameter from all sides ,kharadia calculates by using vernier and bores as much required for certain areas.hope it clears,he just measures it by vernier i have seen boring n polishing.

fahir is restoring yb100 1980 model. but the genuine spare parts are not available now. even yb100 latest model's genuine parts are very rare now. if any shopkeeper have, they charge more according to his will.

you areright but 1 can get org parts from bilal gunj n reputed stores having yb stuff

[Xulfiqar]

no pistons are ever polished, they are never straight either, they are conical and narrow from the top.

[Xulfiqar]

kharadias do not use vernier caliper for cylinder bore. they ask the customer to bring the piston and according to that piston they bore the cylinder. after they bored cylinder they put piston into cylinder they polish it and after polishing they recheck. if the piston is so tight they polish it again to get accurate clearance. our kharadias have no facilities to do work according to the Japanese workshop manual.

because they are cheapies, it wont cost them a fortune to measure with correct tools. Then out lovely mechanics also forget the soap and hot water when washing a newly bored and honed cylinder, you will be amazed at the amount of grit that is hidden in those little scratches and jammed in the port edges (on a 2 stroke)

Resultant = bad overhaul - then they add more oil to the petrol mix and lean it out, causing overheat, they try to compensate with only the idle mixture. (I usually laughed at this approach). Its a vicous circle. However with only a bit more attention you can eliminate all these factors.

btw if a machinist were using a vernier to measure the bore of any of my equipment I would remove all items immediately, the correct way is to use bore gauge (or even internal engineer calipers) with a large micrometer screw gauge to measure.

[nfssaad]

da fuq? kick the butt of the guy who polishes a pistons... what an ***.

i have worked for the past two years in a piston manufacturing company.. we have inspection equipment well in excess of 50laks plus to measure the final dimensions of the pistons.

multiple cnc machines create both ovality and taper profile of the pistons...

these a hole kharadias rape the piston before assembling it.

[nfssaad]

there are bore micrometers to measure bores...

verniers cannot be used for bore measurement.

[hidalgo]

because they are cheapies, it wont cost them a fortune to measure with correct tools. Then out lovely mechanics also forget the soap and hot water when washing a newly bored and honed cylinder, you will be amazed at the amount of grit that is hidden in those little scratches and jammed in the port edges (on a 2 stroke)

Resultant = bad overhaul - then they add more oil to the petrol mix and lean it out, causing overheat, they try to compensate with only the idle mixture. (I usually laughed at this approach). Its a vicous circle. However with only a bit more attention you can eliminate all these factors.

btw if a machinist were using a vernier to measure the bore of any of my equipment I would remove all items immediately, the correct way is to use bore gauge (or even internal engineer calipers) with a large micrometer screw gauge to measure.

so true,mechanic usually cut autolube n ask to mix oil in tank ,how to clean ports i saw lots of gunj in them which can t be removed by scraping (m talking about ports inside cylinder) not exhaust port.

[hidalgo]

because they are cheapies, it wont cost them a fortune to measure with correct tools. Then out lovely mechanics also forget the soap and hot water when washing a newly bored and honed cylinder, you will be amazed at the amount of grit that is hidden in those little scratches and jammed in the port edges (on a 2 stroke)

Resultant = bad overhaul - then they add more oil to the petrol mix and lean it out, causing overheat, they try to compensate with only the idle mixture. (I usually laughed at this approach). Its a vicous circle. However with only a bit more attention you can eliminate all these factors.

btw if a machinist were using a vernier to measure the bore of any of my equipment I would remove all items immediately, the correct way is to use bore gauge (or even internal engineer calipers) with a large micrometer screw gauge to measure.

also tell about setting just right fuel mixture.

[hidalgo]

da fuq? kick the butt of the guy who polishes a pistons... what an ***.

i have worked for the past two years in a piston manufacturing company.. we have inspection equipment well in excess of 50laks plus to measure the final dimensions of the pistons.

multiple cnc machines create both ovality and taper profile of the pistons...

these a hole kharadias rape the piston before assembling it.

i guessop mixed it by polishing i ment cylinder's polish

[Xulfiqar]

da fuq? kick the butt of the guy who polishes a pistons... what an ***.

i have worked for the past two years in a piston manufacturing company.. we have inspection equipment well in excess of 50laks plus to measure the final dimensions of the pistons.

multiple cnc machines create both ovality and taper profile of the pistons...

these a hole kharadias rape the piston before assembling it.

some chinese POS pistons crystal structure is so bad that the piston warps shape under normal use - I have even come across a chinese origin piston that had its skirt finished so rough that it caught my finger nail (O_o)

anyway - you might even find some special people boiling the piston in water assuming it work hardens it (lol - as if hot water is the same as a petrol fire). What really amazed me is that the machinists leave the 2 stroke ports sharp as blades, and if someone got their cylinder resleeved, OH MY GOD - the ports are horrible, all cut in the same plane, no angle aim, no attention to fit etc. No wonder the engines perform like a dogs breakfast.

[nfssaad]

some chinese POS pistons crystal structure is so bad that the piston warps shape under normal use - I have even come across a chinese origin piston that had its skirt finished so rough that it caught my finger nail (O_o)

that would probably mean that the skirt was either not machined properly, or the final diamond tool cut was missed, or the tool tip had worn out. and the piston escaped final inspection.

this is a common issue. production mindset is to just produce as much as possible. quality gai tail lainay.

i was pretty much wholly responsible for the qa dept of my company... and frequently faced this problem... production walon say sar mar mar kay dimagh khali hojata tha...

also recieved complaints from ahl after which i refined the inspection methods to ensure nothing escaped..

production had a bad habit of mixing rejections with ok production... bar bar sorting karwa karwa kay dimagh ki lassi ban jati thi..

[nfssaad]

zulfiqar bhai i have now left atlas engineering.. will be joining tapal energy as am maintenance tomorrow. they have 10+ MW wartsila diesel engines.

can i have your email, or fb id or any contact method other than pakwheels for correspondence?

[Xulfiqar]

that would probably mean that the skirt was either not machined properly, or the final diamond tool cut was missed, or the tool tip had worn out. and the piston escaped final inspection.

this is a common issue. production mindset is to just produce as much as possible. quality gai tail lainay.

i was pretty much wholly responsible for the qa dept of my company... and frequently faced this problem... production walon say sar mar mar kay dimagh khali hojata tha...

also recieved complaints from ahl after which i refined the inspection methods to ensure nothing escaped..

production had a bad habit of mixing rejections with ok production... bar bar sorting karwa karwa kay dimagh ki lassi ban jati thi..

Been there done that - everyone starts from somewhere, and you cannot begin to imagine what I had to face once.

let me give you an example.

I hand a diagram to a freshie (green eng) to make me 13 cables (dont ask what cables)

5 hours later I ask and find that he hasnt made any, I locate the person to ask and his answer was that he couldnt find solder

fast forward to next day, I tell him I need them by 1500, at 10 o clock I ask him how its going - his reply he cannot locate the clamp tool and solder station was malfunctioning.

AAARRRGGGG.

So I proceed to provide him with

solder
work the station
diagram
supplies (cable lengths and connectors)
clamp tool
chair
desk
tea
assistant

tell him that he has two hands and all the supplies ready to use - This time if I dont see cables Im going to go Nazi on him.

[Arifjaveed]

aslam-0-alaikum hidalo. please tell me how much cost for yahama yb100 2006 model clutch box from bilal gunj with primary drive gear

[fakhir]

This week's updates (5-May-2013)

Hi guys, hope all of you are doing great. This weekend I spent a couple of hours on the bike (3-4 hrs max). Succeeded in detaching the engine from frame. Attached pictures show the progress. Enjoy !!!

[fakhir]

Continuing from previous week, still disassembling the bike.

Finally got the exhaust pipe out, was pretty tough job. In this case C-spanner was not effective at all. Too much rust and gunk, the sleeve nut was totally jammed. I then used pipe wrench which did the job:

It seems that the drive sprocket washer had witnessed mechanic abuse (molestation or rape might be appropriate words). I had to use hammer and a minus head screwdriver to chisel my way into the washer. This made enough clearance for the socket spanner to comfortably sit on the nut:

Closeup view:

[fakhir]

Getting the drive sprocket off the frame. Attempt 1:

Since the bike was in neutral and I was unable to put it in a gear (maybe broken gears, who knows). I tried to jam the wheels with the help of wooden hammer shaft. Bad idea, i know. This method can potentially damage the rims. Another mistake I made that I removed the rear shocks way earlier. Rear wheel assembly proved pretty hard to control.

Attempt 2: The correct one. Press the breaks real hard . Furthermore use a long pipe for leverage and the sprocket nut will come off quite easily:

[fakhir]

Opening up flywheel nut:

Detaching the head. The outside appears to be covered in fungus:

Cylinder assembly:

Another view:

[fakhir]

Another look at the head:

Zooming in:

Further zoom. The surface appears to be covered with salt, fungus and other gunky stuff.

[fakhir]

Removing cylinder:

Cylinder closeup. We will take a look at it in great detail in near future.

Moving on to detach the engine from the frame. Before loosening up the main engine assembly bolts, it is a good idea to provide some support from underneath:

Cool, air filter assembly is off:

[fakhir]

Detached rear wheel assembly. It didn't go off without a fight:

Finally detached the engine. To my surprise engine was not that heavy as I thought it would be:

Closer look:

View from the other side:

Zooming in on the rotor wheel:

Drive shaft closeup: