Author Topic: 1975 cb750 New project  (Read 1585 times)

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Offline kanpara

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1975 cb750 New project
« on: January 24, 2011, 05:53:27 AM »
 Hi everyone , at the beginning i apologize for my poor English . I am from Istanbul/Turkey and i had a cb750 for some time. I made some builds for this bike in the past. I changed the pistons and rings  , cylinders , valves and did some machine job for them.It runs good but i want to tear it down completely and build a no problem bike . ( i guess everybody want the samething here ).
 Firstly i found a spare bike for my project . I took the engine out and completely teared it down. Generally it seems okey for a junk bike and I dont know anything about my bikes bottom end so maybe i can use some parts of this engine. Yesterday i started to work on my bike . I took the engine out . First i want to clean it up then i will use paint remover . I want to make it ready for paint before tear down . Here is some photos of yesterday , 

Offline bluesmoke69

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Re: 1975 cb750 New project
« Reply #1 on: January 25, 2011, 08:24:35 PM »
Good luck with your project.

Offline kanpara

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Re: 1975 cb750 New project
« Reply #2 on: January 27, 2011, 05:49:00 AM »
 bluesmoke69  thank you very much ,

  I started on dismantle the motor. I placed the parts orderly on a white board page. Before 1000 mile i change the valves , bore the valve guides and use a MC 0.75 piston and ring set  ( in the picture below ) . Also a bore the cylinders to the 0.75 . You can see the head and cylinders pictures , they had only 1000 mile but they seem very very dirty . I think i ride the bike little rich or is these pictures are normal ? .
 
 When i inspect the camshaft there are some elliptical places in the top of it . I want to buy a new one :) . Rocker arms seems okay , but i want to ask you people , are these old rocker arms work good with my new camshaft ? . Cam bearings look good but i didn't buy a plastigauge yet so i don't know the condition yet and I must measure the bearings with new camshaft i guess.

 I have 2 question today :)

 are my 1000 mile pistons and valves are normal or am i used them rich ?
 are my old rocker arms can work with my new camshaft ?

 This is my first project so i don't have enough knowledge . If you want to offer anything i am really open for suggestions.
 Here are some of photos ,





Offline kanpara

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Re: 1975 cb750 New project
« Reply #3 on: January 27, 2011, 05:52:59 AM »
 some other photos :)

Offline bluesmoke69

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Re: 1975 cb750 New project
« Reply #4 on: January 27, 2011, 08:44:54 PM »
Looking good!!

Offline kanpara

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Re: 1975 cb750 New project
« Reply #5 on: February 03, 2011, 01:19:42 PM »
 Hello again , i was working on my engine today , i desambled the bottom end , you can see the oil pump and some bottom end parts . I found some particles in the cartel and top of the oil pump , is it a bad issue or normal for a engine which make nearlly 1000 mile after piston and valve rebuilt . I want to replace all the main and rod bearings but i am very double minded about replacing the transmission bearings . Anyway , i am very very open for coments and advises ,

cem

Offline kanpara

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Re: 1975 cb750 New project
« Reply #6 on: February 03, 2011, 01:27:22 PM »
 i forgot the talk about the primary chain and tensioner , i will replace the primary chain set but tensioner seems okay for me . Is the primary tensioner a must for a good rebuilt ? ,

  Cem ,