Carb Question

[Bob_Roller]

Doing a complete rebuild of my '82 LS carbs, bike just didn't feel like it was running quite right since I've had it .

I parked the bike in June, when both carbs started overflowing when I turned the fuel on

I just cleaned everything up in the carbs when I first got the bike, didn't disassemble anything in any significant way .

I've only gotten part way through the left carb and have found problems .

The idle jet is clogged soaking it right now to see if I can get it cleared out .

All of the o-rings on the jets and the like were shredded and hardened .

I'm sure I already know the answer to this question, but I want to make sure .

The small brass pickup tube that goes into the small reservoir in the carb bowl, it's not supposed to have a hole in it about half way up correct ?

Well mine does !!!!!!

I think I can fabricate a repair, using small diameter brass tubing from a hobby shop and some fuel resistant sealant .

Diaphragm was installed incorrectly, the small tabs were not in the grooves where they were supposed to be and tore easily when I was removing it, needle was set to the wrong position, it was on groove #4 instead of #3 .

Throttle shaft o-ring is the next job .

[Barry]

The idle jet is clogged soaking it right now to see if I can get it cleared out .

All of the o-rings on the jets and the like were shredded and hardened .

I'm sure I already know the answer to this question, but I want to make sure .

The small brass pickup tube that goes into the small reservoir in the carb bowl, it's not supposed to have a hole in it about half way up correct ?

Never had the pilot jet clog up. The holes are not particularly small.

My pilot jets seem to shred O rings every time I remove them. If the O rings are even slightly too big I think that tends to shred them.

Can't say for certain without looking but I believe that hole in the brass tube should be there.

Edit:  Yes I'm sure that hole should be there. It's function will be to limit the length of time maximum enrichment is provided after starting. With the small jet in the bottom of the bowl restricting the fuel flow into the corner tube, once the fuel level drops below the level of  that hole enrichment will be reduced.

[Bob_Roller]

It's the first time I've noticed it, when I sprayed carb cleaner into the tube, it came out the side, I'll know when I get the other carb apart tomorrow .

This carb definitely needed a thorough cleaning and rebuild .

The throttle shaft o-ring was as hard as a rock and had shrunken a bit, there was no drag on the throttle shaft when it was moved .

I've gotten about as far as I can today, forgot to bring my automatic center punch home before I went on vacation, that's what I use to 'peen ' the throttle plate screws .

[Mike V]

Bob,

I use a single strand of copper wire stripped from a ±12 gauge insulated electrical wire to clear any small orifices, works quite well and is flexible enough to guide in hard to reach places. Especially the small feeder ports inside the venturi near the butterfly.

I also don't peen the throttle shaft screws, I use a small bit of locktite and a squeeze on the exposed threads with needle-nosed pliers after butterfly alignment and screw assembly.

Another thing I spend some time on while doing a complete rebuild is check the slop of the float pin and float tab.  If I find a lot of adjacent movement (twisting direction) I very carefully close the tab opening a bit with small needle nose pliers around the float pin making sure the final movement is free, but no slop.  Careful here, doesn't take much of a squeeze.

Also, check any wear in your needle and needle jet.  Probably best to replace both if it's been a while since the carbs have been serviced.  Normal vibration causes wear on both.

If you can find someone with an ultrasonic cleaner - that's the best way to ensure clean internals.  I used one the last go around for my carbs and the debris that came up was pretty amazing.

Here's a couple links to one of my flat top rebuilds, pretty much the same for all Bings...
http://tinyurl.com/82ubqpg
http://tinyurl.com/ahyouvs

I think you're going to be pleasantly surprised regarding the performance and response increase after your carb rebuild.

-Mike V.

[Bob_Roller]

I got the complete rebuild kit from Bing, so all the o-rings, gaskets, diaphragms, floats, float needle, needle and needle jets, will be replaced .

Everything needed to be replaced, a while ago !!!!!!

I found that a spring loaded automatic center punch does a quick job of peening, or mushrooming the end of the screw, got access to a rivet squeezer at work, but it won't fit in the small area of the carb throat .

I've got an ultrasonic cleaner and I wasn't too impressed with the results, when I rebuilt the carbs on my '81 R65 about 5 years ago .

I even got a cleaner specifically for aluminum and all it did was darken the metal of the carb .

[Barry]

I even got a cleaner specifically for aluminum and all it did was darken the metal of the carb  

I've been reading somewhere recently that boiling carbs in distilled water does a good job without any risk of discoloration.

http://www.thisoldtractor.com/gtbender/moto_guzzi_loopframe_carburetor.htm#gtb_carburetor_cleaning_with_boiling_distilled_water

[Mike V]

Bob,

What cleaning solution did you use in the ultrasonic cleaner when you had discloration issues?  I use a 50/50 solution of Simple Green and water, then two 15 minute finish sessions with clean water only.

Never tried Pine Sol but have been hearing of positive results with this product.

-Mike V.

[Bob_Roller]

I used Branson IS concentrate .

I used a 9:1 solution .

I'll have to try Simple Green, only reason I didn't experiment with this, the manual that came with the ultrasonic cleaner cautioned about using 'foaming' type cleaners .

[Bob_Roller]

I picked up some Simple Green disassembled the right carb today and put it in the ultrasonic cleaner, give it 4 hours of operation and see how it looks .

The brass pick up tube, does have a hole in it, the right one has the same hole in the same place .

Here's the before photo .



Here's after about 4 hours in the cleaner .



Here's the ultrasonic cleaner that I got through work .



About 6 quart/liter capacity .



Here's what the automatic center punch did to the throttle plate screw .



I found out why the carbs are in different condition looks/tarnish wise, I have a mismatch of carb bodies .



Number on this one, should have been 64/32/336, not/326 , or the other carb should be a /325 .

[Mike V]

Looks pretty nice Bob.  Did you get the butterfly perfectly lined-up so there was no daylight showing through the venturi before securing the butterfly shaft screws?

Simple Green work out ok?

-Mike V.

[Bob_Roller]

Got them aligned with no problem .

One thing that almost caught me, was that I pushed the throttle shaft in too far, got the throttle plate lined up alright, but I couldn't get the bracket that holds the throttle shaft in to go into the groove on the shaft, the shaft was just a bit too far in, loosened up the screws pulled the shaft back out realigned the plate and all was good then .

Pulled the body of the carb out and it's cleaning up good, but this carb is tarnished as compared the other .

[georgesgiralt]

Hello !
Do not be too much concerned about the reference discrepancy between your 2 carbs. These numbers just specify a set of jets and needle position.
You are going to change jets, needle and needle jet so you can make both carbs the same as per functionality.
The body is the same and, as far as I know, the venturi is also the same.
The only drawback is the corrosion.... But in a month you won't look at it.

[Barry]

Looks like the 335 carb is currently correct for an a USA 82 R65.  The 326 isn't even listed. That's probably because it was replaced by the 336

http://www.bingpower.net/english/service/einstellblaetter.html

[georgesgiralt]

The information on the Bing web site is not accurate nor complete. My R65 1982 (European) is not listed. But the bike exists, I own one copy which is sitting in my garage right now  
I, for one prefer to ask the BMW maintenance manual or the user manual. In my case (I bought the bike new, in 1984) both give the correct information for jetting. And these jets where fitted into the carbs when I rebuild them.

[Barry]

Yes the list is incomplete. My carbs are not in there either but the version for a later model year is.  It's still a useful resource to compare the fine detail between different carbs.