CB350 rebuild at home

[yasirsa]

[QUOTE=msabbasi;4098629]Yaser Jee,

We will not let you abandon this project .....

liked your words. and thanks for pushing me towards my project .i hardly trust mechanics they have to be professional but they are just available for money .

your car is a big asset and she deserve to be in good hand you shouldn't let her go she is beauty no doubt i saw your video the way she get half self start its just awesome she got push start button in unique style i loved it really

[yasirsa]

today i have roughly assembled crankcase side covers and took them for buff machine . then went to my machinist and he told me my work hasn't been done yet because previously mechanic has filled the camshaft( bushed camshaft) didn't inserted bush in side cover that's because side cover were worn out towards down and covers can not be adjusted centrally in lath machine he has to make flange ( adda ) for adding bush for left side cover . insh Allah will assemble on sunday hopfully

[yasirsa]

xulfi bhai

          hamara to awway ka awaa hi bigra howa hay these are private institutions they shouldn't have compromise on quality at least i wasn't expected this from Honda

i tested this sillicon and its quit good i did experiment on my daily runner 70

threebond 1207 is the stuff I also posted a picture of - its the same thing sold by Honda, Yamaha, Toyota, Mercedes Benz etc. as form in place gasket (FIPG). The problem with sub chalta hai is that it does not "chal" when it matters the most.

If the 650F gray stuff remains pliable and super sticky then it will work too. However the case halves should be flat.

btw - please proceed to shoot the shop foreman who says they use silicone to seal the casing halves. That is a sure recipe for an irritated customer. If you cannot shoot then give this fellow a british leyland engine and make him stop all oil leaks with the silicone

[msabbasi]

btw - please proceed to shoot the shop foreman who says they use silicone to seal the casing halves. That is a sure recipe for an irritated customer. If you cannot shoot then give this fellow a british leyland engine and make him stop all oil leaks with the silicone

Zulfiqar Sb.,

Nicely said!! How come the Brits could never master making oil tight components? Compare to the Brit marques of similar vintage to the 60's Toyota, Mazda, Datsun....

[msabbasi]

Yes your are right sir
I forget to mention Mr. Zulfiqar

Now again salute to Mr. A & Mr. Z

[msabbasi]

today i have roughly assembled crankcase side covers and took them for buff machine . then went to my machinist and he told me my work hasn't been done yet because previously mechanic has filled the camshaft( bushed camshaft) didn't inserted bush in side cover that's because side cover were worn out towards down and covers can not be adjusted centrally in lath machine he has to make flange ( adda ) for adding bush for left side cover . insh Allah will assemble on sunday hopfully

Without seeing what your machinist is planning to do, I can only say that the most important thing is to have the bushes “line bored”. That means the centreline of the two new bushes must be the same. Otherwise the camshaft will not be level in the head and lead to overheating in the bushes area plus short bush life. In my opinion the best way to do this is to assemble the side covers on the head and then do the final finishing of the bushes in one shot. If the side covers have dowels, make sure they are fitted at the time of machining.

I am sure your machinist will have a fixture for line boring. Don't let him talk you into completing one bush and then turn the head around to do the other bush. THAT IS NOT LINE BORING

[yasirsa]

thanks you i just noted about assebling the cam for final finish this is good point ok just sharing few photos of my fav speed meter which i searched on google

[yasirsa]

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[msabbasi]

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I see you decided not to go for the line boring option.

[Xulfiqar]

I used to see this in Karachi and laugh all the way home.

[yasirsa]

line bore machin isnt available here

[yasirsa]

a machenic was there and when these bushes were done he told me you shouldnt go for bronze bushes simply you need to add silver bush and he gave me a example of crank main began they are made of sliver becuz they will harm there self not your camshaft or crankshaft.and i was like good point . but its already done so i may leave it as is and next time i will do it in this way

[yasirsa]

I used to see this in Karachi and laugh all the way home.

you havnt told me before :S

[msabbasi]

line bore machin isnt available here

OK if line boring is not available there, a smart machinist will make a jig where the head/cover assembly is fixed where the tool goes called the "tool post". The tool is then fixed in a long "thick" steel bar called a "boring bar" and tightened in the part of the machine which spins called the "chuck". In this way the head/cover assembly called "the job" is manipulated while the tool spins. To avoid unwanted vibration of the tool since it is on a long bar, usually the boring bar is supported at the other end by using a "spinning centre" fitted to the "tail post" of the lath machine. In this way a normal lath machine is converted to a line boring machine. See the picture below to get an idea

Anyway it is too late now. But just consider this as information that can be used next time.

Cheers

[faisalayub]

OK if line boring is not available there, a smart machinist will make a jig where the head/cover assembly is fixed where the tool goes called the "tool post". The tool is then fixed in a long "thick" steel bar called a "boring bar" and tightened in the part of the machine which spins called the "chuck". In this way the head/cover assembly called "the job" is manipulated while the tool spins. To avoid unwanted vibration of the tool since it is on a long bar, usually the boring bar is supported at the other end by using a "spinning centre" fitted to the "tail post" of the lath machine. In this way a normal lath machine is converted to a line boring machine. See the picture below to get an idea

Anyway it is too late now. But just consider this as information that can be used next time.

Cheers

No doubt a best conversion from Simple Lathe Machine to Main Line Boring Machine. Being in a business of Lathe work, I know that more than 85% to 95% didn't know about that. Most of the people haven't go to Main line boring because its not cheap they prefer to change the Engine block (Chinese one or kabli), whose life is less than the Block they take out from their vehicle...

[msabbasi]

a machenic was there and when these bushes were done he told me you shouldnt go for bronze bushes simply you need to add silver bush and he gave me a example of crank main began they are made of sliver becuz they will harm there self not your camshaft or crankshaft.and i was like good point . but its already done so i may leave it as is and next time i will do it in this way

The mechanic who spoke to you was a FOOL. Please do yourself a favour and don't listen to fools. Crank main and big end (not bigen) bearings are called "thin shell bearings". These are basically white Babbitt metal on a thin steel backing. In the old days this metal was melted and poured into casts and hand lapped to the crank size. Nowadays we just throw the old bearings and fit in new ones. One of the reasons to use white metal is its low melting point (about 120-150 degrees C if memory serves) and being very soft. White metal (Babbitt) is an alloy containing lead, tin, antimony and copper. There is no silver in it at all. By the way what you call silver is actually Aluminium. Silver is a precious metal used for making jewellery etc.

Bronze IS THE METAL OF CHOICE for bushes and don't let anyone tell you anything different.

[yasirsa]

thank you i was just worrying about that

The mechanic who spoke to you was a FOOL. Please do yourself a favour and don't listen to fools. Crank main and big end (not bigen) bearing are called "thin shell bearings". These are basically white Babbitt metal on a thin steel backing. In the old days this metal was melted and poured into casts and hand lapped to the crank size. Nowadays we just throw the old bearings and fit in new ones. One of the reasons to use white metal is its low melting point (about 120-150 degrees C if memory serves) and being very soft. White metal (Babbitt) is an alloy containing lead, tin, antimony and copper. There is no silver in it at all. By the way what you call silver is actually Aluminium. Silver is a precious metal used for making jewellery etc.

Bronze IS THE METAL OF CHOICE for bushes and don't let anyone tell you anything different.

[faisalayub]

Agreed with Abbasi sb, bronze bush are best choice. Even we use bronze bush in connecting rod where the pin is attached with piston. Dont hear to them. Do as suggested to you by Abbasi sb..

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[Xulfiqar]

Its not entirely difficult to line bore such a small head. for starters you can check the line bore with an engineers flat as your base. My experience is of Karachi only so I'll tell you that in Karachi I knew about 8 or 10 machine shops that had this facility easily. Ask the people working on car engines this question "mehran/fx/bolan ke cam bush ki boring kaise karte ho" or "sheraad ke cam bush ki setting kaise karte ho"

both above engines require that.

[Xulfiqar]

The mechanic who spoke to you was a FOOL. Please do yourself a favour and don't listen to fools. Crank main and big end (not bigen) bearings are called "thin shell bearings". These are basically white Babbitt metal on a thin steel backing. In the old days this metal was melted and poured into casts and hand lapped to the crank size. Nowadays we just throw the old bearings and fit in new ones. One of the reasons to use white metal is its low melting point (about 120-150 degrees C if memory serves) and being very soft. White metal (Babbitt) is an alloy containing lead, tin, antimony and copper. There is no silver in it at all. By the way what you call silver is actually Aluminium. Silver is a precious metal used for making jewellery etc.

Bronze IS THE METAL OF CHOICE for bushes and don't let anyone tell you anything different.

You can tell the mechanics level of expertise by choosing his words - silver for aluminium, according to them aluminium is silver and chandi has no word in english lol..

these sort of mechanics make a rabbits hole for repairs - not wanting to learn by themselves. These same guys use bathroom grade RTV silicone to seal engine cases together, curil to stick gaskets, use worn tools and their elbow and wrists as torque ratchets and then say "bhai - assal me ye kharaab samaan milta hai market mein, poora engine assembly le lo scrap se"... To which they should be smacked because laziness and incompetance is not a valid reason for failure.

silver bush - lol, they think their local blacksmith who is melting and smelting blocks of scrap aluminium with oxy acetylene torches is correct metal.