Author Topic: '75 CB550F Engine Misfiring? (videos) (Read 4294 times)

TravisB · « **Reply #25 on:** September 13, 2012, 08:26:22 PM »

I found this older post by you (TwoTired), and this is more or less exactly whats going on, unbelievable!

Quote

The air plenum just behind the carbs has a drain fitting. This hose is a reduced diameter hose that routes behind the engine and in front if the swing arm. The end is open but rather small to allow any gas that might over flow into the chamber to drain. If would be very bad for that chamber were to fill with gas. And back fire could ignite it and ingesting raw liquid into the engine cylinder can bend/break a piston rod.

The fitting at the top of the engine goes to the side of the filter box (NEVER the air plenum chamber).

TravisB · « **Reply #26 on:** September 14, 2012, 09:00:59 PM »

I correctly rerouted all hoses and the bike seems to be running much better. I had other projects planned for the evening that required pulling the fuel tank so I haven't had the chance to run her and get a complete diagnosis. Thanks for all the help so far!

I found a new issue this evening, the tail lights arent running so I pulled the fuse box side cover and sure enough the bottom terminal for the "Tail" fuse is gone!

TravisB · « **Reply #27 on:** September 16, 2012, 05:59:21 PM »

Well I put new spark plugs in her and rerouted the hoses and she seems to be running well now. Also I replaced my right hand controls so I don't have to kick her every time! Check out the video and let me know how she sounds (I had just put the fuel tank back on so I had to get some gas through her revving ).

1975 CB550F Super Sport

seanbarney41 · « **Reply #28 on:** September 16, 2012, 08:49:24 PM »

Cool...that's a really nice bike Travis...great to hear it running good, keep taking good care of it

TravisB · « **Reply #29 on:** September 17, 2012, 01:15:50 PM »

Thanks Sean!

Finksies · « **Reply #30 on:** September 20, 2012, 02:20:01 AM »

My bikes doing the same thing 1977 cb750 super sport. I had it out yesterday and it was running mint, then its started running like crap all of a sudden and doing the spit back occasionally at idle. Im going to try replacing plugs and wires. Thanks for the post.

LesterPiglet · « **Reply #31 on:** September 20, 2012, 02:37:40 AM »

Rear left indicator is pointing at the deck.

TravisB · « **Reply #32 on:** September 20, 2012, 03:39:09 AM »

Quote

My bikes doing the same thing 1977 cb750 super sport. I had it out yesterday and it was running mint, then its started running like crap all of a sudden and doing the spit back occasionally at idle. Im going to try replacing plugs and wires. Thanks for the post.

Finksies, check your engine breather/airbox hoses are routed correctly. As TwoTired pointed out, look at chapter 8 of the Honda Shop Manual.

Quote

Rear left indicator is pointing at the deck.

I suppose you're right. I'll have to adjust that today. Good eye!

Tews19 · « **Reply #33 on:** September 20, 2012, 03:59:15 PM »

Sweet looking bike, hard to find them in that condition. It shouldn't have to be revv'd that long to stay running. I would clean the tank and the carbs if you have done the most of the 3k tune up already.... After cleaning, sync the carbs. Good thing for you those carbs are super easy to clean.......

Wait till TwoTired comments. The man is a genious and knows pretty much everything with the 550. He helped me get mine running like a beast. Sad that I sold it less then 2 weeks ago.. Best bike I have had yet.

Finksies · « **Reply #34 on:** September 20, 2012, 04:48:59 PM »

Took my plugs out today. All three brown, except for cylinder #3 which was pretty black. While I was checking for spark in the cylinders I also got zapped by cylinder #3. Pretty sure the wire is junk, and probably not giving the plug enough spark. New wires tomorrow

LesterPiglet · « **Reply #35 on:** September 20, 2012, 04:52:12 PM »

You do know you will have to splice the wires as they are sealed to the coil? Easy job tho.
Oh, can I have your front guard, tank and seat please?

TravisB · « **Reply #36 on:** September 20, 2012, 06:40:02 PM »

Cleaning the carbs is on the list of thing to do. How long did it take you start to finish Tews? And did you use rebuilt kits?

TravisB · « **Reply #37 on:** September 20, 2012, 06:46:10 PM »

Also, Lester, shipping is going to crush you from DC to Ireland!

Tews19 · « **Reply #38 on:** September 20, 2012, 07:18:02 PM »

I saw this video.... It wasn't that bad.. Two guys who really had no idea about the carbs that are on your bike... I watched it and then jumped into it the very next day....

http://forums.sohc4.net/index.php?topic=107467.msg1203048#msg1203048

I had the carbs rebuilt by a shop the previous summer. I used everything that was in the carbs already..... Rebuilt kits were from Z1 enterprises... Honestly take the time to watch the entire video.. Not tat bad. I didnt dumb the carb bodies into carb cleaner though.... I used an air compressor to get to the hard to reach areas... I did it all in a day.. But I am sure I could have been done faster but I have 4 kids in the house and a wife....

Tews19 · « **Reply #39 on:** September 20, 2012, 07:20:08 PM »

Here was an thread on syncing the carbs as well......... God I miss this bike....

http://forums.sohc4.net/index.php?topic=107533.msg1203813#msg1203813

TravisB · « **Reply #40 on:** September 20, 2012, 07:23:10 PM »

Thanks for the info, I've got a dog so I'll plan for a long weekend, heh.

TravisB · « **Reply #41 on:** September 21, 2012, 10:44:21 AM »

Now that the engine is running great (over 1500rpm) I'm trying to figure out my idling issue. The idle is set correctly as sometimes it will hold at around 1500rpm and idle okay for about 30 seconds before sputtering and stalling. I took a short video to show whats happening. The idle doesn't race up on its own it usually hits 1500 and then quickly drops below 1000 and stalls. Is this likely a carb issue, fuel delivery (dirty petcock), or other?

http://youtu.be/cQtQr0jKjGY?hd=1

TwoTired · « **Reply #42 on:** September 21, 2012, 11:50:23 AM »

Have you done the 3000 mile tune up yet?

Vacuum balance?

Checked the carb bowls for crud?

TravisB · « **Reply #43 on:** September 21, 2012, 12:00:12 PM »

I'll have access to an air compressor in two weeks. I plan on pulling the carbs then. I am just wondering if there is anything else I should look for before then.

LesterPiglet · « **Reply #44 on:** September 21, 2012, 03:44:10 PM »

Turn your idle screw up until it settles. Tell us what the revs are then.

seanbarney41 · « **Reply #45 on:** September 21, 2012, 04:53:55 PM »

I would confirm that your ignition advancer is not sticking, clean, and well lubed.

skamagedon · « **Reply #46 on:** September 23, 2012, 11:59:29 AM »

+1

Quote from: seanbarney41 on September 12, 2012, 10:20:57 PM

Replace points and condenser, set point gap, set timing...should cost less than $50 depending on quality of components purchased. My guess is one condenser went bad and burned up one set of points...time to replace that stuff. Pay attention to tune up/service intervals in the future

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Author Topic: '75 CB550F Engine Misfiring? (videos) (Read 4294 times)