Topic: Desperately need help with a 1975 cb550!

[qcksilver127]

Hey everyone, I'll try and make this detailed but short. I have a 75 cb550. The motor has had a fresh top end rebuild from a local repair shop. Compression is good on all four cylinders. The carbs have all been rebuilt, synced , set up properly. Rejetted to work with pod filters and 4 into 1 exhaust. The bike still will not rev with the choke off. With the choke on it will rev to 3-4k then starts to spit and sputter and shoot flames from header. Same shop said it needed new coils and voltage regulator to fix. I purchased new coils and voltage regulator myself and installed. No better. There are no vacuum leaks, carbs are good, engine is good and still runs like poop. I'm about to give up on this thing and set it on fire! Someone please tell me something I haven't tried! I cannot sink any more money into just taking it back to the shop. Any and all help will be greatly appreciated. Thank you!

[qcksilver127]

I'll try and post a few more pictures when the rain stops. Kens Cycle of Johnson City TN rebuilt the carbs. I'm pressure sure needle is in the 4th position. 45 lows 100 high jets. (I have 105's to install) I cannot return the parts I bought they came from eBay. I suppose I could, but it's not worth the hassle. However I am sure the are all in working order. I've purchased parts from this guy before and he has never let me down. Coils came off of a wrecked bike that ran fine. Regulator shows good constant voltage. I can get the bike to idle without choke. Idle is set correctly. It just will not rev unless choked. Everyone says stock air box yada yada. I know that's the best but it cannot be replaced due to modifications. I've seen a video of my bike doing a hellacious burnout so I know at one time it ran fine with current setup. I'm just stumped now.

[DH]

How did it run before you did any work to it? Why was work done? Do you have a fully charged battery to start with and is it being recharged by the charging system??

[harisuluv]

First you need to resign yourself to the fact that it's very likely something was not set up properly.  You can't eliminate spark, compression and carb or else we have nothing to help you with. 

The carb settings are odd.  Usually the mains remain at 40 even with pods.  100 is STOCK for that bike.  The needle, who knows what it currently is at, i know you're "pretty sure" but maybe you can find out at some point.  Basically those carbs aren't set up for pods at all, you were taken.  Who knows what he did to them, or if he just dunked them, might not have even taken them all the way apart.  What did he charge you, if you don't mind?

Probably not what you want to hear, but if you're over budget as it is you are probably going to have to learn about carbs now.

[Bailgang]

Dumb question but I have to ask. Are you sure you sure your choke is off when trying to rev it? I don't know how new this bike is to you but you'd be surprised at how many new owners get the choke position backwards on the 550 carbs.

[Hot500]

Have you tried running the motor without the pods? Does this make a difference?

Sounds like the carbs are flooding big time. I would rip those carbs off and check those float levels. Stock should be 22mm.

[qcksilver127]

Alright so I just pulled the carbs and installed 105 jets in place of the 100s. First time I've ever been able to get the bike to redline but now there is a new problem. The bike has turned into a flamethrower. It backfires and shoots flames the entire way up. It did not do that before. All I did was turn the carbs upside down, replace jets and reinstall. I've taken a video. Tried uploading it up here and to YouTube with no luck. If anyone would like to see and add there two cents I can text it to you. My number is 423 612 6687. I'll text the video in return. I know that's a bit of an odd request but like I said I want this thing fixed. Thanks.

[qcksilver127]

What?

[qcksilver127]

Ok here goes nothing lol

[qcksilver127]

It won't let me upload the video. I give up.

[riverfever]

Where are you trying to host the video?