cb175 carb dumping gas

L-ski

L-ski

Active Member
alright so today I started my bike and it started pouring gas out of the lower tube on the left carburetor (overflow tube?)... I'm pretty new to bikes but not new to fixing broken stuff.... I'd like to fix this myself but I don't really know where to start so I figured I'd look for some suggestions on here. My buddy said I'd have to re-build the carb completely and that the float was messed up?

any input/suggestions would be great!
 
Needle and seat or float is bad. If u have not had the carbs apart or messed with them yet it pretty rare that the floats are just out of adjustment. Basically the float rises up with the gas filling the bowl which pushes the needle into the seat stopping the flow of incoming gas. If the gas flow doesn't shut off the bowl overfills and runs out of the overflow. Id check the needle/seat by taking the bowl off of the carb and hooking up a line to the fuel inlet and blow air in it with your mouth. Push up the float and see if you can't blow thru the line anymore. If so the needle and seat are sealing. Next remove the float and being careful not to bend any of the tabs and shake it. Is the fuel inside or does it feel heavy? If so replace it. Remember for comparison you can look at the other carb. All this can be done with carbs on the bike on most bikes and is fairly quick and easy. Hope this helps
 
Your bike is 30-40 years old. It NEEDS a good and proper cleaning, and a rebuild kit installed, as things are wearing out. The needle and seat are worn, and need to be changed. You can mess around all you want, maybe even get them to seal up again for a while, but it will happen again.
 
Hey thanks a lot for the detailed response! Im going to go out and see if i can look at it today and try that.
And as far as it being old enough to be my parent, I was thinking the same thing... It wouldn't hurt just to get the re-build kit just for the sake of doing it at this point haha.

are there any good websites that sell re-build kits, or would ebay suffice?

thanks again
 
Dont just throw money down the drain. Its more than possible that your carbs are completely fine, they just need to be cleaned. If youre bike has like 40k miles on it, its possible parts of the carbs have worn down to the point theyre useless. If not, its pretty unlikely. Take them off and clean them first, and then decide if you need to get a rebuild kit.

If i had to guess, id say just a peice of rust or sand or something is sitting on the tip of the needle, preventing it from closing. Either that or the float is stuck and no longer "floating".
 
Yeah, my bike only has 4300 miles... but Idk if the odometer is original. Can I use the spray can type carb cleaner on it after I take it appart? Sorry for all these basic questions.
 
Ya, the spray will do it. Just be sure to keep it away from rubber. Do you have an air compressor? The pressure will blast any gunk out the jets as well (just make sure you have a good grip on everything).
 
Unfortunately I don't have my compressor at my apt. Should I remove any gaskets then before I spray anything?
 
Yeah, keep the spray away from all rubber bits. If the insides are dirty, get some brass brushes and go to town. The jets can be cleaned well without a compressor, just takes some fine scrubbing. If they are really bad, leave them to soak in a glass jar with carb cleaner over night
 
yeah that's it, the spray shit will get you up and going simple as that. Dump a can of seafoam in the tank as well. That will make your bike run like new, and even add a few horsepower to boot ::)
 
They really should change the label from "carb cleaner" to "the spray shit that KillerDwarf doesn't recommend". What do you use then? Pixie dust and unicorn farts?

I thought for a "mechanic" you would have better advice than that.
 
Well it cant hurt to try cleaning them. Plus it will get me familliar with taking them apart. If cleaning them doesn't work, ill just pick up the rebuild kit and call it a day.
 
Well Big Rich, if you didn't catch the rollie eyed guy, let me tell you that my post was total sarcasm! ANY carb cleaner in a can shit is a total waste of time and money. You have no idea how many bikes and sleds I get in with the owners telling me "it isn't the carbs" 'cause I cleaned them 3 times already" Then I ask " how did you clean them? with that spray stuff?" It doesn't work!! I will then dissassemble the carbs, and sure as shit find a plugged pilot jet, Sometimes plugged so badly that they need replacing. Poking them with wires and drills will alter their size, and screw with your jetting. Also the needles, and seats test fine with the blowing method, but often seep just a little bit, as the rubber has become porous due to ethanol.Inspection under a good magnifying glass will reveal this. The jet needles should be replaced to deal with ethanol, as when these old bikes were built, ethanol was known as moonshine, and the only way it was found in a fuel tank, was to fool the cops. Bikes which have been sitting for quite some time are the worst for blocked passages. The proper way to clean carbs is to dissassemble them, put them in a cleaning solution, let them soak sometimes even for a couple of days, and then rinse, and then with compressed air, blow them clean and dry. Again, anything that you can buy off the shelf at your local car parts supermarket, labeled as carb cleaner is a waste of time and money. Even if the product is clearance priced at a buck, save your buck and go buy a coffee!
 
So what "cleaning solution" do you use and where do you obtain this since I can't buy anything from my local parts store?
Thanks for all the suggestions guys!
 
All solutions which I have used in the past now seem to have lost some of their potency. Even the expensive industrial carb cleaners don't work all that well anymore. I have found, through other forums however that Pine-Sol works. It does work fairly good. It needs to be the original formula, and needs to be full strength. Don't use it in the house. It stinks!!!!! On really dirty carbs you will probably need 2 days worth of soaking. Do not soak rubber parts in the Pine-Sol, as it will soften, and make them expand. A good cleaning, and inexpensive rebuild kit from Sirius will have your carbs working like new again.
I recently had a '76 Yamaha XS650 here. The bike had never ran right, and had been to a few mechanics who had all cleaned the carbs. The bike would run OK, and then back to running crappy according to the owner. Well, I cleaned the carbs, inspected everything by eye, got the bike running again, set the carbs, and it ran pretty good. Took it for a good long ride, and thought that I had 'er fixed. I left the fuel taps on, for a day, and noticed some seeping coming from the overflows. Not dripping, just some wetness. I pulled the carbs apart, and tested the needles and seats once again with the blow test. They were fine. I pullet the jet needles out, and thin time inspected them in bright sunlight with a strong magnifying lens. I noticed porosity. I went to Sirius, and got the kits from Chris. Installed them, and man did that bike wake up!!! It ran like brand new! It even ran noticebly smoother, as the first time I rode it, it vibrated quite a bit. This time it was smooth. I took it for a good 40 mile test ride through all types of situations. Hwy, countryside, and city. Bike worked flawlessly. People in town even commented on how nice this old bike ran. The owner was going to sell her bike, as it always gave her trouble. She is now keeping it, and loves how the bike has been running.
The choice is yours, follow my knowledgeable advice, and get your bike running great, or follow the directions on a spray can and maybe get your bike running OK. I do this shit for a living, not just after supper.
 
awesome man, well i already bought some carb cleaner/ parts soak in a can and currently have one carb off. I can tell that the idle jets (small holes?) look pretty bad, my question now is: When I take all the parts out of the carb, will I need to re-adjust the 2 fule/air screws on the outside? Or can I just leave them at the setting they are on and when I re-assemble the inner parts, they will maintain their setting?

Also just want to clarify... the needle is on the end of the throttle cable, correct?

And i guess if this stuff doesn't work ill pick up some pine-sol haha.
 
Turn the air screws in until lightly seated. Count the number of turns it took to seat them, Remember that number, as that's how many turns from fully seated you'll be re-installing those screws to. Now remove the air screws, and put them in the cleaner. I use a small kitchen strainer for all my small parts. Makes it much easier to retrieve the parts. The jet needle which I speak of is the fuel inlet needle located beneath the float tab. Make sure you remove and clean the pilot jet, as it is always the one that plugs. If you're not sure which one it is, or where it is use a manual, or an online parts fiche to locate it.
 
Well, I just reassembled everything and lo and behold, the bike started right up and didn't have any gas coming out of the overflow. I let it idle for 8-10 minutes and im about to go take it for a quick spin.

I found my "emergency" air compressor in the back of my car and used that to blow off some gunk that was stuck in the smaller places too.
Later this week or next weekend I'll take the right side carb off and do the same.

Thanks again for helping me get my bike up and running for the time being!

If anything, at least now I know how to disassemble and reassemble my carbs ;D
 
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