Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: Charliecharlcomb on April 19, 2023, 05:53:40 PM

Title: Overflowing carbs
Post by: Charliecharlcomb on April 19, 2023, 05:53:40 PM
I've just wheel my bike out of storage for the winter for its first startup of the year. All good, especially after so much work of late. When I put it away in the late autumn I noticed 1 or 2 cards were overflowing, which I though I'd rectified by removing the float bowls and having a clean up.

Today all four were overflowing! I've had the carbs apart so many times over the last couple of years getting to the bottom of some irregular running and really thought they were fixed. It seems weird that all four are flooding now. I'm prepared to replace all four float needles and seats but wanted to check on here first to hear if anyone thinks something else may be the cause. The carbs are not high milage so they shouldn't be worn, however the bike has had patchy use over the 30 years I've owned it.

Any ideas?
Title: Re: Overflowing carbs
Post by: McCabe-Thiele (Ted) on April 19, 2023, 06:56:16 PM
Had you drained the carbs prior to winter storage?
Title: Re: Overflowing carbs
Post by: Charliecharlcomb on April 19, 2023, 08:01:46 PM
Had you drained the carbs prior to winter storage?

No, I fear you are going to tell me i should have!
Title: Re: Overflowing carbs
Post by: Sesman on April 19, 2023, 09:43:12 PM
Shit in the carbs….but be careful how you do it..🤔
Title: Re: Overflowing carbs
Post by: McCabe-Thiele (Ted) on April 19, 2023, 10:10:18 PM
As you are probably aware when petrol evaporates in the fuel system it leaves behind a residue not unlike a thin film of plastic/gunk that can block jets or make float valves stick.
Even when drained the floats can stick with a fully extended float needle causing initial flooding as the float can become temporarily trapped/stuck.

Sometimes if you switch off the fuel after the carbs have started to flood shaking the bike sideways or a gentle tap of the carb bowls can resolve the flooding so when you turn  the fuel back on all is well. The longer the bike has stood unused the less likely it is that the problem will fix itself as jets block up.

I use Wynns Dry fuel in the tank to avoid water separation over winter plus I use SUL fuel. I have successfully used Octane Reviver to use of old petrol in fuel injected cars - even injector cleaner might work to unstick a light gumming up of the needle valve.

Oddly enough my old Yamaha XJ900 never flooded after standing over the winter - I always used Wynns Dry Fuel after I had to replace the tank due to pin holing.
 
Title: Re: Overflowing carbs
Post by: Johnny4428 on April 19, 2023, 10:26:42 PM
Shit in the carbs….but be careful how you do it..🤔

🤣🤣🤣
Title: Re: Overflowing carbs
Post by: Oddjob on April 20, 2023, 12:05:45 AM
Always drain the carbs before storing the bike for the winter. I'd advise draining the tank as well and swilling it around with diesel to coat the inside of it.
Title: Re: Overflowing carbs
Post by: Charliecharlcomb on April 20, 2023, 10:56:52 PM
I've just wheel my bike out of storage for the winter for its first startup of the year. All good, especially after so much work of late. When I put it away in the late autumn I noticed 1 or 2 cards were overflowing, which I though I'd rectified by removing the float bowls and having a clean up.

Today all four were overflowing! I've had the carbs apart so many times over the last couple of years getting to the bottom of some irregular running and really thought they were fixed. It seems weird that all four are flooding now. I'm prepared to replace all four float needles and seats but wanted to check on here first to hear if anyone thinks something else may be the cause. The carbs are not high milage so they shouldn't be worn, however the bike has had patchy use over the 30 years I've owned it.

Any ideas?

A quick update. Took the carbs off today, cleaned out the float bowls and jets, reset a couple of float levels and it’s all good again.
Title: Re: Overflowing carbs
Post by: McCabe-Thiele (Ted) on April 20, 2023, 11:19:30 PM
Having to remove the carbs is as we know here not a quick & easy task not sure on your model - on the 400 its a wrestling match just getting the air intake chamber back in place.

Pleased to read you have a result & sorted the issue.
Title: Re: Overflowing carbs
Post by: Johnny4428 on April 21, 2023, 06:29:51 AM
When you’ve removed them a half dozen times 🥵🥵 you get reasonably competent with the procedure.😂😂
Title: Re: Overflowing carbs
Post by: Charliecharlcomb on April 21, 2023, 07:41:52 AM
I hear you!