Thursday, January 10, 2013

Bing Overhaul

As I mentioned in my last post, the Bing carburators were taken to a friends home for overhaul. I should've taken a before photo showing the caked on dirt and grease from the last 30 years. Here is the left carburator after cleaning off the external grime and disassembly. The only part I didn't see a need to remove was the throttle plate and shaft as there was no signs of wear. The diaphragms were still in good shape though the slide and jets were pretty grungy.

Here is the "enrichener" assembly after it was removed from the side of the carb. One of the other reasons I had to clean the carbs is last October, the "enrichener", the circuit used to add additional fuel for cold starts, stuck and I had to manually move the lever as the spring force was insufficient. At this point the entire body was cleaned in the solvent tank focusing on all of the passages and ports. New "O" rings, gaskets and diaphragm were fitted after blowing compressed air through all of the passages. One shim was dropped and disappeared on the floor somewhere so a replacement was ordered from the U.S. distributor of Bing in KS. Isn't it nice that small, tiny parts from a 30 year old carburator are still readily available.


Here are the two freshly cleaned Bings almost ready to be re-installed. This is the air intake side and you can see the cylindrical slide and can just see the tapered brass needle attached to the bottom which regulates the fuel. The dome on the top houses the rubber diaphragm that moves the slide up and down and the fuel bowl is on the bottom of the photo. The floats looked good and still floated and the adjustment was right on. The only left over parts were four new "O" rings that are used to seal the throttle shafts.

This is the engine side and when I started, the throttle blades and other areas with airflow were caked with hard, black deposits and are now all clean and shiny. The capped off vacuum port below the throttle opening used to drive the pulse air system that I had removed a couple of years ago (LINK). To install the small shim, I just need to drop the bowl and remove the main jet. Thirty seconds max. I'm headed out of town this weekend (south rather than north) so there's no real rush. Total time 2 hours 40 minutes including searching for the dropped shim.

The next task is the transmission input shaft spline lube as well as greasing and adjusting the rear swing arm bushings. I'll need to remove the sidecar to get reasonable access to the right side of the bike as well as remove the rear wheel so maybe I'll get started with that this evening. I need to remove the rear wheel anyway to replace the tire.

11 comments:

Erik R said...

I've never tore in to a motorcycle carb before. I've cleaned and rebuilt a few small engine carbs though. Good job!!

Coop a.k.a. Coopdway said...

Lots of carbs opened but no CV's at this point. Yours look new Richard!

redlegsrides said...

Those carbs are looking good Richard!

RichardM said...

I've never tore into a constant velocity (CV) carb before and I think I figured out how they work. But, hopefully, these will work fine. Once they are installed, they still need to be adjusted and balanced.

RichardM said...

Hopefully they work as good as they look but I won't know for a couple of weeks. My friend. Bob K, has both a Hg manometer and an electronic version for balancing the carbs.

RichardM said...

This was my first venture into a CV carb. Now the slide moves very smoothly. The slide and the needle it controls were pretty filthy though the diaphragms were still in good shape though the new ones felt like it was made of thicker rubber.

Trobairitz said...

I don't know much about carburetors, but wanted to say I really like the new blog header picture.

RichardM said...

I wasn't sure it was worth blogging about a carburetor overhaul but here it is. Kind of an odd topic.

I thought the picture indicated a problem with most point and shoot cameras. She would press the shutter when I entered the frame but the camera wouldn't capture the image until I was about to drive out of the frame. But I like the way it came out. Nice midday sun...

Conchscooter said...

carburettors are brilliant. dull but clever.and durable. i am still reluctant to enter the world of fuel injection because i neither park the bike for every long nor do have to deal with very cold starts. pumps inevitably fail and i wonder if a fuel injector pump will last thirty years never mind all the air sensor gubbins.

RichardM said...

Can't agree with you more. I like my old airhead as it is air cooled, carbureted, gravity flow fuel and no computer anywhere. I suspect your Bonneville has similar virtues. EFI has many benefits but I'm not sure I want to have to depend on a dealer for repairs....

BeemerGirl said...

I would have loved to see a before picture because those after ones are just too clean! You did a great job cleaning and fixing them up. I'm catching up on posts, and with winter you probaby won't know, but I'm looking forward to what happens to your fuel mileage now.