Carbs worn out???!

adriannarnold

adriannarnold

Coast to Coast
Hello Gentleman,

Been working on my CB175 for a bit now. I had it running fine, but the idling was a little off. I have been super busy lately so I decided to drop it off at a local shop and have them do a basic tune up. (valve clearances, timing, and carb sync)

Prior to this I had gone through the carbs twice, so I know they were clean etc. Running stock carbs, pod filters, and shorty mufflers.

When I went to pick up my bike the guy said they messed with it for quite a bit, but basically it runs exactly the same as when I dropped it off. He said my carbs are worn out. The slides and carb body are worn he said and leaking air. I think the bike only has about 8000 miles on it. I have never heard this before, but I am not a carb wizard by any means. What are your thoughts?
 
hmm dont mean to judge but is he any good , ie have you used him before for stuff like that?
seems like an excuse to me.
carbs do wear like anything mechanical but with only 8k on the clock i would be very worried if they were toast already..... :-\
 
Sounds like bullshit to me. Sounds like he didn't want to play with the jetting for the intake and exhaust setup you're running. If you are running stock jets with pod filters your idle is going to be off due to increased air flow then your exhaust is modded so you are more than likely running lean.
 
It happens quite often actually. Especially on bikes that have been run w/ out filters sometime in there life. Is it actually a cb? Or is it/was it a cl or sl originally? The only reason I ask is those bike tend to have seen dirt before which makes worn slides much more common...
 
Just thought I might add that it's pretty common to have carb bodies sleeved... But usually reserved for units that are a little harder to come by.. Old Amal's etc.
 
Thanks for the input guys. My buddy has used him in the past and he did a killer job with his carbs. I think the guy knows a good amount of what he is doing, but I think it may be a little of all three of your suggestions.

If I'm not mistaken the problem being purely with idling shouldnt have much do with jetting, but more with the idle mixture and speed screws. Correct?

Swapmeet, that's a great point, but this bike is an actual CB. I'll double check my speedo when I get home (which is no longer on the bike) but I am pretty sure milage was in the 8xxx range.

I may just sell these stock carbs and grab some mikuni vm18's

This wouldn't be so frustrating if he didnt charge me an arm and a leg for basically the same results I had.
 
A warn slide will only be enough of a leak to effect idle. If it sorta surges up and down irregularly at idle I would say it's the slides or a leak at the boot. Mikuni's are nice, But not really required in order to have a smooth running machine. Especially if your motor internals are stock.
 
Just as a reminder: if you do decide to go with VM carbs, check the intake mounts. I had vm20's on my 175 and had to make new mounts.
 
It's pretty easy to see wear on slides, particularly the early Honda's as they are chrome plated.
The carb body wears faster than slide but the slide will show signs of wear, especially if it was held at fixed throttle position for extended periods, usually around half throttle or less.
Above half throttle, the slide is well supported
You will see brass around center of slide on engine side if it's worn.
Bottom of slide shouldn't show any 'brass' (or very little at 'sides')
Bottom of carb won't be worn as there isn't anything to wear it
If shop knew what they were doing, they should have said slide was worn and needed replacing
 
Thanks again guys. Looks like I'll pull out my slides and take a look when I can. So if my slides are worn, I may be able to find replacements, if the carb bodies are worn, I am kind of screwed and will probably have to buy some mikunis. They seem to be cheaper than stock carbs.

Big Rich, you are right about the intake mounts. I would have to make new ones some how. How did you do yours? Not sure where to start.
 
adriannarnold said:
Big Rich, you are right about the intake mounts. I would have to make new ones some how. How did you do yours? Not sure where to start.
Click to expand...

I work in a machine shop, so I was able to make them in my "spare time". But pm Swagger - he has made a couple for some other folks.
 
Alright... So today I took my carbs apart and the left slide looks perfect, the right slide has a lot of dings and nicks on the bottom of the slide. (not even sure how they could get there).

Now it looks like I need either new carb slides, new carbs, or just make the switch to some new mikunis and figure out how to get them to mount up. Anyone know a good place to purchase carb slides for these little guys. I am pretty sure they are 18mm. None of this would be as frustrating except the fact that the shop charged me a retarded amount of money for monkeying around on my bike and not accomplishing anything, except losing one of my idle speed screws, which Ill have to go and try and claim.

Also my gas tank is leaking up near one the front mounts. Hoping its a small enough pin hole leak that I can cover if I line the inside of the tank. Losing out on excellent riding weather right now and this january I will be out of the country for a while so I really wanted to get some riding in before then. Back to work

Thanks again for your input guys.
 
Adrian, can you take some close up pics of the carbs you have and pm them to me? I have what I "think" are 175 carbs in my garage that are just sitting around.
 
If they are the same, I'll sell them cheap.

If those dings are on the bottom -ish surface of the slide, most likely the slide were stuck and some goofball used a screwdriver or something to pry them up. I'm ashamed I know that........
 
Now that you mention that. That is exactly what it looks like. I was pretty puzzled how the slide could get so dinged up like that. I'll get those pics to you tomorrow hopefully and I would love to take your old carbs off your hands. Thanks again
 
Okay, I got some pictures of the carbs today. As well as the mangled slide.
1-4.jpg

1_9.jpg

2.jpg

3.jpg

4.jpg

5.jpg


Let me know what you think Big Rich...Thanks
 
I just got into work for the night - but i'll check out the carbs in the am. And don't hesitate to remind me in case I forget. 12 hour shifts can do bad things to my memory......
 
Sounds goods. Ill be up early so Ill try and remember to shoot you a pm in the morning. I hear you on the 12hr shifts. I've done my share of 12-24hr+ shifts. Zombie state is a good description. Thanks again and have a good night.
 
After seeing your slides,ya, there not perfect. But I think your problem is else where. Could still be carbs... but I dont think it's the slides Mr.
 
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