Author Topic: cb550 questions (Read 2801 times)

FLseven50 · « **on:** October 04, 2010, 11:20:46 PM »

hey guys i just picked up a 1974 cb550 and i have a few questions as this is my first CB. (fairly new to carb'd bikes in general too).
A little info on it: odo reads over 67k miles and speedo cable is broken so its probably higher. starts first kick or push of the button. doesnt spit, stutter or miss over entire throttle range but just feels sluggish. for instance, i've read thru multiple carb tune/ mpg threads and some claim theirs will pull up thru 8000rpm in 5th gear on the top end. had mine on the highway tonight and it would barely make it over 5500rpm in 5th and i had to tuck in to the bike to get that. i couldnt have been doing over 70 mph (no speedo). the bike has a 4-1 header, and no muffling at all, pipes end at the collector. and currently no airbox either, just the plenum and the metal mesh screen (PO gave me a NOS airbox to put on) my question is could these 2 things be what is robbing my power so much? or am i just expecting too much out of my old 550?
Thanks in advance guys. I can tell this is one very helpful community here on sohc4. I have a cb750k1(?) that i recently dug out of my dads shed as well that needs some serious saving, so that will bring even more questions im sure.. hopefully i will be able to post some pictures up of both bikes soon so you can see what i'm working with.

Frostyboy · « **Reply #1 on:** October 04, 2010, 11:58:29 PM »

Welcome to the forum. Congrats on picking up a 550.
Certainly start by refitting the standard air box with a new filter, but don't ignore the basic tuning items either. Valve clearances, plugs, points & timing. Better check the advancer is swinging free as well.
These things need some back pressure in the exhaust system with standard carbs as I understand it. Maybe you'd want to consider slipping a muffler on that thing.
Good luck, I think that machine will be singing the right tune shortly.

dave500 · « **Reply #2 on:** October 05, 2010, 12:53:35 AM »

ill guess its running lean with open pipes and no airbox,even though it starts up ok,pull the plugs and look to see if they are whitish.P.Os can do funny things to bikes.

Flying J · « **Reply #3 on:** October 05, 2010, 01:59:51 AM »

Yeah, it seams that the further you get from the stock setup the worse the bikes run unless you take the time to jet and then re jet and make sure its right but even then it doesnt seem to run as good as stock. You should be able to hit 75-80mph easy with a good running bike.

FLseven50 · « **Reply #4 on:** October 05, 2010, 08:51:15 AM »

Thanks i'll definately start there. i looked closer and i guess it does have a bit of baffling in what i called the "collector." i guess its actually a baffle but it doesnt seem to help much, sounds nice tho. also i think the carbs might not even be opening fully as there is loads of slack in my throttle cables, and ive already adjusted them as far as i can. can they just stretch out over time or do you guys think something could be routed wrong? if i dont have to buy new cables i'd rather not. at least until i do a clubman setup. i've hopefully attached a couple pics of the 550 (one of my newly painted headers) and one of the 750. can anyone ID the body on the 750? looks similar to a tracey but i've never seen one quite like it. thanks!

Guess i cant attach the pics. i'll upload and link them later.

Flying J · « **Reply #5 on:** October 05, 2010, 09:08:22 AM »

no pictures. If you have sloop in your cable you need to adjust it at the throttle and at the carb. There shounld not be much slack. Even if the cable streched it cant strech longer then you can turn your throttle. They can strech but not spontaneousness lengthen. As for pictures the best way to do it is to get a photobucket account and post the pictures by copying and pasting the [img ] link. Does that make sense? Otherwise you use the additional options at the bottom and "choose file" but there are size restrictions.

Duanob · « **Reply #6 on:** October 05, 2010, 10:27:10 AM »

" if i dont have to buy new cables i'd rather not"

they're like $13 a piece. get the thing running right before trying to make it look "cool". No matter how cool a bike looks on the kickstand it looks pretty bad when it doesn't run right.

FLseven50 · « **Reply #7 on:** October 05, 2010, 03:39:26 PM »

"No matter how cool a bike looks on the kickstand it looks pretty bad when it doesn't run right."

Agreed. I have adjusted the cables in both places and am at the end of adjustment. at first i thought i went the wrong way so i went the other and it made them longer so i know i've got em as tight as they go in both places. i still have about 90 plus degrees of freeplay rotation in the throttle. i feel like it might actually be stopping me from opening the carbs all the way. is that possible or will the grip turn until to WOT regardless of this problem? that could be contributing to my sluggishness.

CB750

CB550

FLseven50 · « **Reply #8 on:** October 05, 2010, 06:43:03 PM »

i rerouted the cables to their proper location according to a diagram i found thru this site but it didnt help my freeplay problem. i guess i'll be ordering new cables this week if i cant figure this out soon, its very aggravating while riding. anyone know what that body is on my 750?

Flying J · « **Reply #9 on:** October 05, 2010, 08:03:52 PM »

looks like the tracy that is famous on this site.

CBGhia · « **Reply #10 on:** October 05, 2010, 10:36:19 PM »

You probably have the wrong cables on the bike. The PO may have used whatever was laying around.

Frostyboy · « **Reply #11 on:** October 05, 2010, 10:46:52 PM »

About the slack in your cables:
This is a long shot, however we never know what our POs have been up to do we?
I can't see how this could happen unless somebody has had a fiddle, but see what you can work out.
The wheels (for want of a better word) where the cables are on the shaft connecting to the carbs appears to be retained with pinch bolts & lock nuts.
Maybe, just maybe, it's out of sync with the rest of the linkage which could induce the slack in your cables.
Looking at it, I think you might have to disconnect the return spring (which is a pita) while you do it, but maybe you'll find you can loosen the pinch bolts & turn the 'wheels' back towards the carbs & thereby reduce some of the slack.
If that bits okay, you might be able to loosen the pinch bolts at either end of the shaft & accomplish some sort of similar adjustment there.
Let me know if you find something. Good luck, like I said, it's a long shot.

dave500 · « **Reply #12 on:** October 06, 2010, 01:14:02 AM »

long thin screw driver or similar with hacksaw slot for return spring removes the pain in the arse.

Frostyboy · « **Reply #13 on:** October 06, 2010, 02:13:18 AM »

Quote from: dave500 on October 06, 2010, 01:14:02 AM

long thin screw driver or similar with hacksaw slot for return spring removes the pain in the arse.

Very good Dave, can't beat experience!!!

dave500 · « **Reply #14 on:** October 06, 2010, 02:23:08 AM »

or fashion stout wire with hook and dangle and lift up when lower end connects.

Frostyboy · « **Reply #15 on:** October 06, 2010, 02:25:25 AM »

I just hooked mine up yesterday. Easy with the rack off.

dave500 · « **Reply #16 on:** October 06, 2010, 02:33:22 AM »

ive only done it on a bike to fit a slightly lighter spring.

FLseven50 · « **Reply #17 on:** October 06, 2010, 07:41:34 AM »

i'll give this a shot today hopefully. but i think if i rotate that back wont it take up slack in one cable and put even more in the "push" cable? seems like it would come back easy enough without that cable though, do you guys see problems with removing it?

dave500 · « **Reply #18 on:** October 06, 2010, 01:12:13 PM »

leave both cables,if the spring fails you wont be able to drop the revs,its a safety design,some guys remove them,beware.has the full throttle stop but altered?or the cable outer bracket?

Flying J · « **Reply #19 on:** October 06, 2010, 01:19:18 PM »

I ran a pull only. And he is right if the spring breaks you cant throttle down. Has anybody had the spring brake? Beats me. If my spring brakes and the throttle is stuck open, you have many options. Pull in the clutch, apply the brakes, hit the kill switch, turn the key off, turn the fuel off or like the people in the defective toyotas, do nothing and panic. If you dont run a push know the consequences and how you will deal with them.

dave500 · « **Reply #20 on:** October 06, 2010, 11:46:42 PM »

itll happen as you go through twisties after a full throttle blast,youve set up for your corner and started to lean in and back off but its still powering you,you crash.i had one of the cable outer locknuts come loose and foul up the action a little,the revs only held at about 2000,still not a nice feeling,ill always run two cables.,its only because the slides dont have a compression type spring internally that its dangerous.

Stev-o · « **Reply #21 on:** October 07, 2010, 06:18:37 AM »

Nice pair of bikes...

Duanob · « **Reply #22 on:** October 07, 2010, 09:38:40 AM »

I likey the 750 and I'm not even a cafe fan! I would black out a lot of stuff on that bike like wheels, fork ears, exhaust, fenders, etc. It will look too damn kewl.

pTc Performance · « **Reply #23 on:** October 07, 2010, 10:43:37 AM »

hi i was wondering if anyone knows if the 1974 fender on the cb550 was the same as the rear fender on the 75 im trying to restore my 75 550 but i need both front and rear fenders

Duanob · « **Reply #24 on:** October 07, 2010, 01:59:17 PM »

You might want to start a new thread. But yes I believe so. You can find part numbers on the many fiche websites.

http://www.servicehonda.com/look-up-parts/03

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Author Topic: cb550 questions (Read 2801 times)

pTc Performance