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Ultrasonically Cleaning Carbs

1304 Views 6 Replies 5 Participants Last post by  CXPHREAK
Well, a tank liner that is coming loose (at least some tank liner had...) prompted me to pull my tank and carbs this weekend. It's a '78 CX500. I pulled the float bowls and found sediment and gunk in both. The left carb had fuel and more sediment than the right carb which had NO fuel and was bone dry. The sediment in the right carb was powdery and a slight bit less than the left. Actually, quite a bit less. There were black pieces in the left carb and it looked nasty.

When I pulled the top of the carb off I could see through both the jet where the needle goes and another hole to the right of that. The needle was able to move around side to side, is that normal?

How far disassembled should carbs be before ultrasonically cleaning them? I don't want to break anything but I want to disassemble them far enough to allow the cleaner and ultrasonic cleaner to do its job. I planned on using a 4-1 mix of simple green and water.

How long do you clean them? I have the 2.5 liter ultrasonic cleaner from Harbor Freight but haven't used it yet. The cleaner can run a cycle for a maximum of 480 seconds. Not more than 3 cycles in 15 minutes. But then it says the automatic safety shutoff will be activated after 45 minutes of continuous use. (480 seconds is 8 minutes so, 2 cycles takes you past 15 minutes...)

So the instructions are a little could run more than 3 cycles using one of the shorter cycles on the machine. The cycle time can be set to 90s, 180s, 280s, 380s, or 480s per cycle.

So, how long should it take to clean really dirty carbs?

Just presuming mine are bad for worst case scenario...

Thanks for any advice and information you can share!
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i dont split the carbs apart.but remove this lot in the picture.


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Get Larry's carb book...

If you're going so far as to bust out an ultra sonic, I'd tear them down to absolutely nothing, and I believe all of the parts are safe to go in the simple green solution, but I'm not sure off hand. If you don't have Larry's carb book, then I STRONGLY suggest it, it's the best $20 or whatever I've spent for my bike... You will have to re-sync the carbs, but it sounds like you already should, and odds are someone in your area has a vacuum gauge and can help you with that process, I still have to sync mine, but I'm having a friend from the forum come over soonish to help, and he's picking up some parts too while he's here...
If you're leaving them im in the U/S for extended periods of times, try to get a cleaner that is safe for aluminum. Home Depot sells a purple version of Simple Green (Pro HD, I believe) that is safe. It is sold exclusively by Home Depot, and it is a Simple Green product.
Strip the ACVs and the accel. pump also.

The covers for these are a different type of alloy and can dissolve in the ultrasonic and also in some cleaning chemicals.
Thank you gentlemen!

I had a couple questions into Larry as well and his answers and yours + a copy of his carb book on the way should go a long way into solving the issues.

Thanks again!
It's pretty hard to go wrong with Larry's carb book.

Just done cleaning a set of carbs for a VF 750 based on the tecniques in the book. Wish I had the indepth specific info Larry supplies for the CX carbs though.

Have a friends CX 650 in the shed at the moment for the carbs and other things to be attended to and eventually I'll get to he carbs on my daily rider for the "Larry treatment".
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