Author Topic: Fuel system cleaner  (Read 666 times)

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Offline TBarr

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Fuel system cleaner
« on: January 15, 2024, 04:24:21 PM »
My CB550 sat again with fuel in it despite my best intentions of not letting this happen...

I got it started up after draining the old fuel out and adding some fresh gas. I bought some fuel system cleaner that I found at the gas station by STP called 'complete fuel system cleaner' and put that in as well.

Bike is starting easily now but running rough, especially not idling well. I don't want to pull the carbs off again to clean them, does anyone have recommendations for a fuel additive I could use to try to help clean out any gunk in the carbs? My brother is a mechanic and recommends 44k for cars but I don't know about what to use for these old carbureted bikes. Is the stuff I put in already any good?

https://www.walmart.com/ip/STP-Complete-Fuel-System-Cleaner-5-25-FL-OZ-Bottle/16641228?wmlspartner=wlpa&selectedSellerId=0&wl13=3650&adid=2222222227716641228_117755028669_12420145346&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=c&wl3=501107745824&wl4=aud-2225087348627:pla-306310554666&wl5=9031613&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=local&wl12=16641228&wl13=3650&veh=sem_LIA&gclsrc=aw.ds&&adid=2222222223716641228_117755028669_12420145346&wl0=&wl1=g&wl2=c&wl3=501107745824&wl4=aud-2225087348627:pla-306310554666&wl5=9031613&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=local&wl12=16641228&veh=sem&gad_source=1&gclid=CjwKCAiAzJOtBhALEiwAtwj8tjTfAic5ccB1v7DhXE_JicGhZczWFSEu1XaOMnv6J_rKP1RmzF4_VhoC8jEQAvD_BwE 

( )

'71 CB 500 Frame with '74 Cb550k engine
Stock airbox

Offline Tracksnblades1

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Re: Fuel system cleaner
« Reply #1 on: January 15, 2024, 05:18:30 PM »
I don’t recommend any cures in a can..
But if you’re going there,  look for the cure that has the most  PEA and PIBA detergents in them..
PEA being the most aggressive of the two…

Not telling you to, but when using Cummins diesel injector flush kit, you run them on straight injector solvent , no dilution..
Kit comes with 2.5 gallons of injector solvent and a set of recirculating fuel lines. You run it at an idle until empty and you see it suck air up the clear fuel line..

Only miracle in a can I’ve ever seen do as it was advertised. 

Age Quod Agis

Offline BenelliSEI

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Re: Fuel system cleaner
« Reply #2 on: January 15, 2024, 05:59:11 PM »
What year is the 550? If the float bowls are just held on with a clip, drop them and pull the jets out for a cleaning. It’s tight but doable. If the idle jets are plugged up nothing in a can will help.

Offline TBarr

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Re: Fuel system cleaner
« Reply #3 on: January 15, 2024, 09:32:35 PM »
What year is the 550? If the float bowls are just held on with a clip, drop them and pull the jets out for a cleaning. It’s tight but doable. If the idle jets are plugged up nothing in a can will help.

It's a '74. Float bowls each have 4 screws. Kind of a pain to remove the middle two carbs, but 1 and 4 are easier. Still, I'm hoping for something I can just pour in to help. I pulled the bowls and 1 and 4 already and the jets didn't seem that bad, but the floats and float needles were sticky for sure.

'71 CB 500 Frame with '74 Cb550k engine
Stock airbox

Offline Deltarider

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Re: Fuel system cleaner
« Reply #4 on: January 16, 2024, 12:20:28 AM »
As long as there is still some passage no matter how minor, a fuel system cleaner can do a miracle. Can. Personally I wouldn't buy from slavedrivers like Amazon and Walmart.
If yours has the oldstyle carbs like 022A, 087A or 069A, you could try this:
1. Make a note what position the airscrews are in now.
2. Remove them
3. Poor some fuel system cleaner in the holes. Normally it will find its way into the float chambers.
No guarantee though.
Just for the records, for how long has your engine been inactive?
CB500K2-ED Excel black
"There is enough for everyone's need but not enough for anybody's greed."

Offline newday777

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Re: Fuel system cleaner
« Reply #5 on: January 16, 2024, 12:51:11 AM »
What year is the 550? If the float bowls are just held on with a clip, drop them and pull the jets out for a cleaning. It’s tight but doable. If the idle jets are plugged up nothing in a can will help.

It's a '74. Float bowls each have 4 screws. Kind of a pain to remove the middle two carbs, but 1 and 4 are easier. Still, I'm hoping for something I can just pour in to help. I pulled the bowls and 1 and 4 already and the jets didn't seem that bad, but the floats and float needles were sticky for sure.

What did the bowls look like when you pulled 1 and 4 off? Still liquid gas or gummy brown or green?

I haven't tried the STP cleaner,  just Seafoam and only in Goldwings.

How long did the bike set with the old gas?
Did you empty the tank of the old gas and shine a good bright flash light in the tank to look for rust? Even light surface rust can clog carbs causing bad running.

How long did you ride the bike after you put the STP cleaner in, and how long has it been since you put it in?
Did you put the full bottle of cleaner in the tank or how much?

Depending upon how long the bike sat with the old gas in the carbs will determine if a cleaner might work or not, and how long it will take for the cleaner to work.
The gas we get these days starts to go bad in just a few weeks of setting in the carbs, and can start clogging the emulsion tubes in the idle circuits in 6 months to a year. It could take 24 hrs setting in the carbs idle circuits for the cleaner to do it's job. Then after 24 hrs you need to ride the bike to burn out the gas in the tank in 1 ride then refill with fresh gas.
If it's been setting in them for years, you will have to pull the carbs out to properly clean the emulsion tubes.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline tommygunxs

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Re: Fuel system cleaner
« Reply #6 on: January 16, 2024, 09:59:35 AM »
I have (mayby) the same problem, I have been looking on the internet and found something called seafoam which seams to clean carburetors whitout removing them. I havent try this, in sweden we dont have seafoam so I have to order it from the US, but I gues i have to try this

Offline rocket johnny

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Re: Fuel system cleaner
« Reply #7 on: January 16, 2024, 10:48:50 AM »
i have used 44k for years .  it is a fuel injector cleaner .  not cheap but it works .  once a year i split a can between my k-6 and my acura
  it will take time and some miles to get it to work

Offline Deltarider

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Re: Fuel system cleaner
« Reply #8 on: January 16, 2024, 11:34:20 AM »
I have (mayby) the same problem, I have been looking on the internet and found something called seafoam which seams to clean carburetors whitout removing them. I havent try this, in sweden we dont have seafoam so I have to order it from the US, but I gues i have to try this [...]
No need to order from US*. In Europe we have a variety of additives that do the same. Where I live, we have Tunap, Forté and others. Actually your best adviser will be yachting mechanics that work a lot with outboard motors. These motors suffer the most as they usually hibernate for months. They seem to like Startron Fuel Enzyme Treatment.
* You can make it yourself actually: 4 parts of kerosine, 2 parts of naphtha (and 1 part of alcool). The only thing these products do better than your own brew, is that they will disperse perfectly even in the fuel.
« Last Edit: January 16, 2024, 11:43:42 AM by Deltarider »
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"There is enough for everyone's need but not enough for anybody's greed."

Offline BallAquatics

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Re: Fuel system cleaner
« Reply #9 on: January 16, 2024, 11:35:45 AM »
...  it will take time and some miles to get it to work  ...

Yep, that's what I was thinking too!  Or, a few hours to clean the carbs correctly.  Lol  Best of luck which ever route you choose!
Dennis...  74 CB550  79 CBX  82 Seca Turbo  2011 CBR  2012 NC700X

You will regret the bikes you DIDN'T buy much more than the ones you DID!!!  It's never too late to start a new adventure!

Offline TBarr

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Re: Fuel system cleaner
« Reply #10 on: January 16, 2024, 02:39:43 PM »
What year is the 550? If the float bowls are just held on with a clip, drop them and pull the jets out for a cleaning. It’s tight but doable. If the idle jets are plugged up nothing in a can will help.

It's a '74. Float bowls each have 4 screws. Kind of a pain to remove the middle two carbs, but 1 and 4 are easier. Still, I'm hoping for something I can just pour in to help. I pulled the bowls and 1 and 4 already and the jets didn't seem that bad, but the floats and float needles were sticky for sure.

What did the bowls look like when you pulled 1 and 4 off? Still liquid gas or gummy brown or green?

I haven't tried the STP cleaner,  just Seafoam and only in Goldwings.

How long did the bike set with the old gas?
Did you empty the tank of the old gas and shine a good bright flash light in the tank to look for rust? Even light surface rust can clog carbs causing bad running.

How long did you ride the bike after you put the STP cleaner in, and how long has it been since you put it in?
Did you put the full bottle of cleaner in the tank or how much?

Depending upon how long the bike sat with the old gas in the carbs will determine if a cleaner might work or not, and how long it will take for the cleaner to work.
The gas we get these days starts to go bad in just a few weeks of setting in the carbs, and can start clogging the emulsion tubes in the idle circuits in 6 months to a year. It could take 24 hrs setting in the carbs idle circuits for the cleaner to do it's job. Then after 24 hrs you need to ride the bike to burn out the gas in the tank in 1 ride then refill with fresh gas.
If it's been setting in them for years, you will have to pull the carbs out to properly clean the emulsion tubes.

The bowls still had liquid gas in them. I cannot remember the last time I had ridden the bike. I want to say 6 months but more likely q
'71 CB 500 Frame with '74 Cb550k engine
Stock airbox

Offline TBarr

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Re: Fuel system cleaner
« Reply #11 on: January 16, 2024, 02:45:17 PM »
What year is the 550? If the float bowls are just held on with a clip, drop them and pull the jets out for a cleaning. It’s tight but doable. If the idle jets are plugged up nothing in a can will help.

It's a '74. Float bowls each have 4 screws. Kind of a pain to remove the middle two carbs, but 1 and 4 are easier. Still, I'm hoping for something I can just pour in to help. I pulled the bowls and 1 and 4 already and the jets didn't seem that bad, but the floats and float needles were sticky for sure.

What did the bowls look like when you pulled 1 and 4 off? Still liquid gas or gummy brown or green?

I haven't tried the STP cleaner,  just Seafoam and only in Goldwings.

How long did the bike set with the old gas?
Did you empty the tank of the old gas and shine a good bright flash light in the tank to look for rust? Even light surface rust can clog carbs causing bad running.

How long did you ride the bike after you put the STP cleaner in, and how long has it been since you put it in?
Did you put the full bottle of cleaner in the tank or how much?

Depending upon how long the bike sat with the old gas in the carbs will determine if a cleaner might work or not, and how long it will take for the cleaner to work.
The gas we get these days starts to go bad in just a few weeks of setting in the carbs, and can start clogging the emulsion tubes in the idle circuits in 6 months to a year. It could take 24 hrs setting in the carbs idle circuits for the cleaner to do it's job. Then after 24 hrs you need to ride the bike to burn out the gas in the tank in 1 ride then refill with fresh gas.
If it's been setting in them for years, you will have to pull the carbs out to properly clean the emulsion tubes.

The bowls still had liquid gas in them. I cannot remember the last time I had ridden the bike. I want to say 6 months but more likely a year possibly more...

The carbs didn't look horrible when I pulled the bowls off. I put startron in the tank before I let it sit this time at least learned something from the last time this happened. The brass wasn't obviously green or gummy, but the floats and float needles weren't operating smoothly. We put about 1/2 of the bottle of STP into the tank with a fresh tank of gas.

The tank has some light rust in it but it's been like that for years, it didn't look any different than before.

The cleaner has been sitting now for about a day in the carbs, I was planning to ride it some more and see if it helps.

Just trying to get an idea if anyone thinks this cleaner may work or if not is there another one I should try?
'71 CB 500 Frame with '74 Cb550k engine
Stock airbox

Offline newday777

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Re: Fuel system cleaner
« Reply #12 on: January 16, 2024, 04:16:25 PM »
If it doesn't, pop the bowls off, drain them and fill the bowl with Seafoam. Seafoam also makes a spray called Deep Creep to spray off the upper bowl area of the carbs to loosen the floats.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline TBarr

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Re: Fuel system cleaner
« Reply #13 on: January 17, 2024, 05:35:31 PM »
If it doesn't, pop the bowls off, drain them and fill the bowl with Seafoam. Seafoam also makes a spray called Deep Creep to spray off the upper bowl area of the carbs to loosen the floats.

Ok, thanks for the advice. Do you like to use seafoam as a fuel additive as well?
'71 CB 500 Frame with '74 Cb550k engine
Stock airbox

Offline newday777

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Re: Fuel system cleaner
« Reply #14 on: January 17, 2024, 06:21:20 PM »
If it doesn't, pop the bowls off, drain them and fill the bowl with Seafoam. Seafoam also makes a spray called Deep Creep to spray off the upper bowl area of the carbs to loosen the floats.

Ok, thanks for the advice. Do you like to use seafoam as a fuel additive as well?
My bikes don't need an additive
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline scottly

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Re: Fuel system cleaner
« Reply #15 on: January 17, 2024, 06:59:17 PM »

I got it started up after draining the old fuel out and adding some fresh gas. I bought some fuel system cleaner that I found at the gas station by STP called 'complete fuel system cleaner' and put that in as well.

How much is "some" gas, and how much "cleaner" did you add to it? The cleaner doesn't burn very well if you added too much to a small amount of gas.
Don't fix it if it ain't broke!
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Offline CB750R

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Re: Fuel system cleaner
« Reply #16 on: January 17, 2024, 09:04:43 PM »
I have had good luck with Seafoam as well over the years, and also Motul fuel system cleaner.

I suggest fresh gas as well. If you had enough moisture collect in fuel with ethanol in it, it can phase separate (the alchohol and water mix dropping out of suspension) this can cause lots of poor running issues.

You might get lucky buy draining fuel tank and float bowls of the old gas, starting fresh with new gas with a fuel additive and getting it running,  i find running several tanks of additive enhanced fuel in the spring helps with any ill effects of my bikes being layed up over winter.

Offline PeWe

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Re: Fuel system cleaner
« Reply #17 on: January 17, 2024, 10:16:27 PM »
A long ride in legal speeds might be enough to clear the carbs pilot circuit. ;)
Add something like this in the fuel before might help.
- Red Line  SI-1.
- Tri-pak  (Made in Sweden)
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967