1978 cb550 Newb needs help!!

S

socal_hustler

New Member
Ok so i just picked up a beautiful 78 cb550 that had a seized engine but was all there! I took the engine apart and freed up the piston. The pistons look to be fine but there was some rust in the sleeve. Ive read that i should rebore it, but what size? Please forgive me but this is my 1st bike and 1st project!! Do i need to buy new pisons and new rings? or just new rings? Any info would help!!! Thanks in advance DTT!!
 
How bad is the rust? You might be able to get away with just a hone and new rings.
 
Its not too bad....i'll try to take some pics tomorrow!! Ringo love your bike!! I read about your build....its a thing of beauty!! ok enough about that!! hahaha Thanks for the reply!
 
Hey thanks man. Hopefully all you need is a hone, but if you have to have it bored, look for some .25mm oversized pistons and rings. ebay ought to be full of them. Good luck.
 
Generally if you're just looking at surface rust because the valves were open as the engine sat its not a problem, just squirt some oil in the cylinder and crank it over with the starter enough to blow the oil back out. Get out of the way, it will be nasty. Then get the engine started. It will smoke like hell for a while but after that it may clean right out. Change the oil and filter before you do anything else and then once you get it running change them again.


I guess the real question is what was wrong with it in the first place? Did it have a broke piston or ring(s)? If its just surface rust that's one thing, but if there is other physical damage then you will have to see how extensive it is to know how much it will have to be bored. Used cylinders suitable for boring are plentiful.
 
Thanks KONG for the reply!! Not sure what was wrong with the bike...when i purchased it, there wasnt much history on it! One piston was stuck real good!! I was able to free it with a lot of 'seafoam" and some elbow grease! All the piston look to be in pretty good shape nothing broken from what i can see. Im going to try to put up some pics real soon...i need to replace my camera just lost it! All the gasket looked to be in tact, there was kind of clean oil in the motor...im thinking the bike was just sitting for a very long time! I purchased it from a "tow yard" so all they told me was that it needed "engine work" Once again thanks to everyone who is taking their time to read and post!! Im going to need all the help i can get!!!
 
Here is another question...what honing tool do you guys recommend i use? Where should i buy it? Sorry i dont have pics yet....still trying to replace my camera Thanks guys!
 
A machinist can hone your cylinders for you. The process is usually pretty cheap. I think I paid less than $30 for both cylinders on my bike.
 
Where in the bore was the piston stuck the top of the cylinder is a bigger deal than the botton i have one hole on my bike that had some ring pits i just ball honed all 4 jugs to deglaze them and replace the rings my 500 runs great bottom line its not the end of the world also ive bought big bore piston n ring kit for a 500 for 125 off ebay after after some measuring i discovered my 125 dollar big bore kit was the first over size for a 550 witch is hundreds cheaper than buying tge parts by them selves
 
bradj said:
Where in the bore was the piston stuck the top of the cylinder is a bigger deal than the botton i have one hole on my bike that had some ring pits i just ball honed all 4 jugs to deglaze them and replace the rings my 500 runs great bottom line its not the end of the world also ive bought big bore piston n ring kit for a 500 for 125 off ebay after after some measuring i discovered my 125 dollar big bore kit was the first over size for a 550 witch is hundreds cheaper than buying tge parts by them selves
Click to expand...
It was stuck a lil higher than mid way....Thanks for the info on the big bore kit for the 500 that should fit the 550!!
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light

    • Spread the Love

    Back
    Top Bottom