Topic: My CB650 is runnig great honda's just amaze me in every way

[speedy gonzalais]

Hi all and thanks for any help in advance

I recently brought a CB650Z (1979) well 2 actually but the other one is in boxes and not complete any way the one I'm working on was sitting in a kitchen for 15 years so is in OK condition just needs a bit of TLC well that's what i thought but was wrong. So i got it home took off the carbs and give them a good clean as the fuel inside was more like jelly.
I put them back on the bike flushed the engine changed the oil filter and filled with new oil i also replaced the plugs and fitted a new battery. I hit the starter switch and it fired up on 2 almost strait away but wouldn't run on all four there was backfiring and a lot of smoke upon further inspection of the cam i noticed a sticky valve, so i stripped the cam and removed the head and checked the other valves for leakage and as suspected nearly all valves were leaking so i removed them give them a clean then ground them in.
Now after a long story the engine is back together but will not start it fires and at one point fired up for a few seconds went up to 4000 rpm then died since then it just splutters and backfires but wont run now Ive gone over the cam timing several times and its spot on so it cant be that also Ive checked the spark and that's very strong i was quite supprised about that for a bike of its age and i checked the ignition timing it was out by a fraction but wen put right the bike just wont fire at all, theres plenty of fuel getting thru so it cant be starvation the only thing i can really think of being the problem is the ht leads may have been changed about by the previous owner but there is no mention of the correct order or even the firing order in the Haynes manual I'm just left sitting here scratching my head I'm open for suggestions any one please thanks again

[scunny]

left hand coil fires 1&4, right hand coil 2&3

[speedy gonzalais]

thanks for the reply i sorta know the left hand coil powers the left hand bank and vice versa but what i really need to know is whats the sueqance of the cylinders from left to right im thinkin it might be 360 out but until i now the order i cant be to sure

[scunny]

                                                   front
                                                 
                                                 1 2 3 4

                                                   rear

firing order  1 2 4 3   

[speedy gonzalais]

ok thanks i will try that first thing in the morning

[MJL]

thanks for the reply i sorta know the left hand coil powers the left hand bank and vice versa but what i really need to know is whats the sueqance of the cylinders from left to right im thinkin it might be 360 out but until i now the order i cant be to sure

One coil goes to 1 and 4, the other goes to 2 and 3. As long as those cylinders are paired on the same coil it is right. (It doesn't matter which wire goes to 1 and which goes to 4)

[mystic_1]

i sorta know the left hand coil powers the left hand bank and vice versa

That's incorrect.  On coil runs the outer cylinders, the other runs the inner cylinders.


mystic_1

[speedy gonzalais]

yea thanks for the help guys ive finally got it right today i was told the coils power the two cylinders below them but that was not right. she fired into life today but wont fire on number 3 under 4000rpm im thinkin there may be some gunk in that carb still but thats a tomorow job now thanks again

[mystic_1]

Congrats!  Bet that put a big smile on your face

I think you're right about the carb if it fires above 4000 rpm but now below.  Probably the idle circuit is gummed up.

mystic_1

[speedy gonzalais]

i havnt smiled as much since the birth of my son just cant wait to get it on the road now and cruise

[speedy gonzalais]

have taken the carbs off today totally stripped and cleaned with a high pressure jet and now she runs like a dream ive heard stories about cam chain noise and tappets on these bikes but i really cant seem to hear any thing like that.
theres a bit of clutch rattle on idle but im unsure if thats a problem. The engine has only done 11k so is the rattle some thing i should be worried about

[WFO]

Great news hopefully you found a gem a carb sync might be in order and adjust your cam chain and check your lifter gaps you might as well check everything

[kslrr]

Congrats on a smooth running cb650, I am green with envy (have been working on my '81/'79 cb650c for over a year).  A slight rattle at idle is normal but might clear up after a proper carb synch like mentioned by WFO.

[speedy gonzalais]

Congrats on a smooth running cb650, I am green with envy (have been working on my '81/'79 cb650c for over a year).  A slight rattle at idle is normal but might clear up after a proper carb synch like mentioned by WFO.

yea i pretty much went over the whole engine theres no cam chain noise or tappet noise theres the slight rattle from the clutch on idle but when i pull the clutch it goes away. Im gonna put the new chain on when the rain stops and take her for a cruise

[speedy gonzalais]

Congrats on a smooth running cb650, I am green with envy (have been working on my '81/'79 cb650c for over a year).  A slight rattle at idle is normal but might clear up after a proper carb synch like mentioned by WFO.

yea i pretty much went over the whole engine theres no cam chain noise or tappet noise theres the slight rattle from the clutch on idle but when i pull the clutch it goes away. Im gonna put the new chain on when the rain stops and take her for a cruise

and that was ment for wfo dont know what happened there ?

[tonycb650]

I think most (all?) 650s have some clutch rattle. it will probably quiet down some after a sync. But no, its not a poblem.

[Buber]

Eeee, not really. That's just the character..  But a very good one!