Topic: new donor bike inquiry

[pinnacle]

ok i just picked up another donor bike to fix up my 78 cb550k  that i blew the head on but this one is a 74 cb550.are there any differences that will keep the motors from being a direct bolt on?i noticed the carbs are different and some electrics.how can you tell if it is a f model and what diff will that make on the motor?

[pinnacle]

ok so here are some pixcs of it anybody want to chime in?

[fmctm1sw]

Not sure but is there some kind of high handlebar fetish up there in Canada?

[Tnutz]

make sure you use the rocker box from your 78.

[pinnacle]

what is the rocker box do you mean the valve cover assembly and why? just curious will my carbs and intakes from my 78 fit the 74 motor until i am able to fully clean the other carbs? and are there in other parts from 78 that i should transfer over that would make it better such as stator,the mac 4 into 1 or the 4 into 2  that this one has.here is a pic of what it is going into.

[dave500]

the carbs will be ok,the donor has the series 1 carbs,your PD ones will be ok although youll have to use the intake runners aswell,whats blew the head?damaged valves ?

[pinnacle]

yep i replaced a bent intake valve on #3 piston put everything back together as the manual instructed had it running for about 45 min and then heart break exhaust valve on a #1 piston made contact with piston and put a hole right through it.thats how she goes .anyways two tired advised grabbing a new 550 motor as i could not be sure how much damage was done with impact and how much debris was floating around the motor.

[dave500]

sounds odd,has it high compression pistons or a high lift cam or something?,cam timed correctly?

[pinnacle]

i don't think so ultimately i think i screwed up somewhere along the way or like tt said possible that there was another bent valve that went unnoticed and broke off at the stem after it started to run.but here i am with a new  motor ready to go  and we will see if i learned my lesson.

[OldSchool_IsCool]

Not sure but is there some kind of high handlebar fetish up there in Canada?

As for why, the early 550 rocker covers did not bolt down the rocker pivot shafts.  As they turned and shook, they wore unevenly in their bearings. 

http://forums.sohc4.net/index.php?topic=20408.msg212239#msg212239