Carburetor misbehaving

[Guest]

Yesterday, my bike was running pretty well. https://vimeo.com/390630074
Today, it's bogging once I get above 3,000RPM at idle. What's up with that?

Also, I had a local shop try to remove the mixture screws (the deal was, if they couldn't do it, I didn't have to pay them). They tried for 2 days with penetrating oil and heat, yet couldn't loosen them. I think these screws are well and truly borked.

 

[hampshirehog]

Sounds like you need to strip your carbs and give them a real cleaning. You'll have to get those screws out - I've not seen screws yet that can't be removed (loads of tips on here about how to get the blighters out). If the shop used heat to shift them they may have buggered the o rings for starters.

 

[Guest]

Wally's right - they need a proper strip and clean. I've worked at mixture screws every day for a fortnight to get them out. They will come - eventually! Once you get the first hint of them loosening, continue with the heat/oil cycle, and turn them back in as well as trying to turn them out. This will help break up the corrosion. You'll need a screwdriver that fits correctly - grind one down if necessary.

It can be a long process, but there's not really an alternative. Use the time to order some fresh O-rings.

 

[Guest]

Wally's right - they need a proper strip and clean. I've worked at mixture screws every day for a fortnight to get them out. They will come - eventually! Once you get the first hint of them loosening, continue with the heat/oil cycle, and turn them back in as well as trying to turn them out. This will help break up the corrosion. You'll need a screwdriver that fits correctly - grind one down if necessary.

It can be a long process, but there's not really an alternative. Use the time to order some fresh O-rings.

Did you try anything besides heat and oil? Boiling in Pine-Sol? Diesel fuel?
What size o-rings should I order?

 

[Big T]

You still haven't read the BS carb tutorial?

 

[Guest]

Guide here: http://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

O-rings here: http://www.cycleorings.com/

I don't actually know what Pine-Sol is, as it's not available over here. I wouldn't recommend boiling anything in diesel. I've heard that a mixture of thinners and ATF can work well for freeing up stubborn parts.

I'll stress again patience is key - if you mess up the heads of the screws, you'll probably be looking for new carbs. Which actually means second-hand carbs, which may be just as bad as the ones you have now.

 

[Big T]

Guide here: http://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

O-rings here: http://www.cycleorings.com/

I don't actually know what Pine-Sol is, as it's not available over here. I wouldn't recommend boiling anything in diesel. I've heard that a mixture of thinners and ATF can work well for freeing up stubborn parts.

I'll stress again patience is key - if you mess up the heads of the screws, you'll probably be looking for new carbs. Which actually means second-hand carbs, which may be just as bad as the ones you have now.

Steve,

I do believe he's been sent links to that and the Top 10 Newbie mistakes at least once. OR three times.

He's just not believing what we say

 

[Guest]

Steve,

I do believe he's been sent links to that and the Top 10 Newbie mistakes at least once. OR three times.

He's just not believing what we say

I have the guide downloaded onto my desktop, read it, and followed it. I do believe what you say.
I've taken the carbs apart enough times to be able to do it in my sleep.
I'm on a limited income and don't possess that many tools, especially not a belt sander. I have a rotary tool with a few grinding wheels that slide over a rubber attachment. That's all I have for filing a screwdriver.
However, neither I, nor two different mechanics have been able to get the mixture screws loose. I don't even have enough money to pay Steve (the GS Whisperer) to look at my carbs right now. Any money I get may have to go to help fix my fiancee's vehicle, which is our sole means of transportation.

I did not join this forum to have assumptions made about my character or intelligence. I am doing all I can by myself, as I have done for the past 7 months. I have never owned, nor worked on a motorcycle before (scarcely even touched one). Everything has been new, and a learning experience for me. I don't have the funds to pay a mechanic to fix all the problems for me. I don't have a job, and none of the 30 applications I put in have resulted in a job (thought I did have an interview today). I was barred from donating plasma because of a mental condition I never asked for. I literally have no income aside from my disability checks, which come once a month. I even made a post asking if anyone needed me to go break up ice by the curb with a hammer and metal pole I found... no takers.

I've been doing what I can, a little bit at a time. It took me 2 months just to have enough to spare for a Dyna S ignition. I couldn't just buy everything I needed. That's why it's been taking so long. I have to wait until I have enough money for parts before I can make progress, and even then, I find something else wrong. I don't know anyone who can come by to help me fix it, or simply supervise. It's been just me, alone.

 

[Big T]

I understand your frustrations with the bike, we've all been there.

However, you can't expect satisfaction by doing 90 percent of the work. Fixing up an old bike is a long series of frustrations and problem solving.

Taking the carbs apart multiple times is not solving the issue. Removing the mixture screws is necessary for leaning the idle mixture passage to be clean and the new O ring under the screw to provide a good mixture.

So, take a few deep breaths and tackle one issue at a time until it's solved. We'll get you to the end.

I was puzzled by your O ring question. Did you get anO ring kit from Cycleorings.com?

 

[Guest]

I understand your frustrations with the bike, we've all been there.

However, you can't expect satisfaction by doing 90 percent of the work. Fixing up an old bike is a long series of frustrations and problem solving.

Taking the carbs apart multiple times is not solving the issue. Removing the mixture screws is necessary for leaning the idle mixture passage to be clean and the new O ring under the screw to provide a good mixture.

So, take a few deep breaths and tackle one issue at a time until it's solved. We'll get you to the end.

I was puzzled by your O ring question. Did you get anO ring kit from Cycleorings.com?

I have not ordered o-rings yet. I'm still working on getting the mixture screws loose. I'm in the process of reassembling the carburetor, but I stopped halfway for now. I'll put it back together completely tomorrow. I sprayed some Seafoam Deep Creep on the mixture screws, going to let that set overnight.

 

[LAB3]

I have not ordered o-rings yet. I'm still working on getting the mixture screws loose. I'm in the process of reassembling the carburetor, but I stopped halfway for now. I'll put it back together completely tomorrow. I sprayed some Seafoam Deep Creep on the mixture screws, going to let that set overnight.

I've been following your posts since you first showed up here, my nephew also lives with autism and I've spent a few years working in the CMH system.

Big T makes a good point, work on one thing at a time. You know you need to get those pilot screws removed and also replace the orings at some point. It makes little sense to try getting the bike running until this is completed.

From what I've read about removing pilot screws that are stuck, you will need to get a rotary tool and grind a slot into the screws to give a screw driver a deep enough groove to grab into. This will probably require that you also grind into the body of the carburator in order to get the tool deep enough to reach the screws.

You can probably rent a rotary tool for less money than buying one. Call a tool rental company and ask what it costs to rent one.

You can also look in the tools for sale section on Craigslist and Facebook Marketplace to see if someone has one for sale.

The tips of the pilot screws are pointed, once you remove them make sure the points are not damaged. They are made of brass and tarnish over time, recent damage will look like a bright gold color.

Once you are sure that you have good pilot screws, order the orings. When you are waiting for the orings to arrive, dip the carburators in a solvent to make sure everything is clean, you need to do this with the pilot screws removed to be sure that everything is properly cleaned.

Remember, do one thing at a time. Until the carburators are completely cleaned up properly you won't be able to ride the bike anyway. There are some things you can do in the mean time that won't cost any money such as cleaning the bike. Focus one getting one thing at a time, you will have it done sooner if you do.

Get a rotary tool to use, try to rent one. If you cannot rent one then you can try to buy a used one.

After you remove the pilot screws make sure they are good.

Order the orings and clean the carbs with the pilot screws removed.

Don't do any other work on the bike that requires you to spend money until the carburators are properly finished.

 

[Rich82GS750TZ]

Don't do any other work on the bike that requires you to spend money until the carburetors are properly finished.

This should be a sticky on the top of the forum page in big, bold letters. The best advice, IMHO, that any member on this forum has ever written.:clap::clap::clap::clap::clap::clap::clap:

 

[Guest]

I've been following your posts since you first showed up here, my nephew also lives with autism and I've spent a few years working in the CMH system.

Big T makes a good point, work on one thing at a time. You know you need to get those pilot screws removed and also replace the orings at some point. It makes little sense to try getting the bike running until this is completed.

From what I've read about removing pilot screws that are stuck, you will need to get a rotary tool and grind a slot into the screws to give a screw driver a deep enough groove to grab into. This will probably require that you also grind into the body of the carburator in order to get the tool deep enough to reach the screws.

You can probably rent a rotary tool for less money than buying one. Call a tool rental company and ask what it costs to rent one.

You can also look in the tools for sale section on Craigslist and Facebook Marketplace to see if someone has one for sale.

The tips of the pilot screws are pointed, once you remove them make sure the points are not damaged. They are made of brass and tarnish over time, recent damage will look like a bright gold color.

Once you are sure that you have good pilot screws, order the orings. When you are waiting for the orings to arrive, dip the carburators in a solvent to make sure everything is clean, you need to do this with the pilot screws removed to be sure that everything is properly cleaned.

Remember, do one thing at a time. Until the carburators are completely cleaned up properly you won't be able to ride the bike anyway. There are some things you can do in the mean time that won't cost any money such as cleaning the bike. Focus one getting one thing at a time, you will have it done sooner if you do.

Get a rotary tool to use, try to rent one. If you cannot rent one then you can try to buy a used one.

After you remove the pilot screws make sure they are good.

Order the orings and clean the carbs with the pilot screws removed.

Don't do any other work on the bike that requires you to spend money until the carburators are properly finished.

Thanks for the advice. I mentioned a couple of posts ago that I do have my own rotary tool. However, I am worried about cutting too deep and ruining the channel. I don't know exactly how much space I have to work with.

 

[Wingsconsin]

Progress can be slow -- but keep trying - progress is doing.

Progress can be slow -- but keep trying - progress is doing.


I truly wish you luck on getting this bike running

However -- 1 thing many don't understand is Munks Maxim "There is no such thing as a cheap motorcycle"

You can buy in at a low cost to entrance - but the many years of deferred maintenance is costly to catch up with.

 

[Grimly]

Munks Maxim "There is no such thing as a cheap motorcycle"

Huh; ain't that the truth.
My own bike, so no cost of entry.
Laid up for ten years, it cost the best part of a thousand quid to get it right again.

 

[Guest]

Here's a link to my blog where I had the same issue on my GS550E. Cutting into the carb was the only way to release it and worked a treat. https://biketech7.blogspot.com/2016/02/mikuni-cv-carbs-great-tip-for-seized.html

 

[steve murdoch]

Some good info in there, Chanco.
Thanks for posting.