Carburetor Rebuild - Is it worth sending out?

[bereahorn]

[elmontanero]

2. Not hard to rebuild, just make sure you do one at a time, do it carefully and systematically. Use Tom's r80g/s rebuild thread as a reference, EUBMW sells a good kit cheap

3. The independent floats from what I heard are not good. I have not used them (my bold added)

I'm digging into mine today. I bought the EUBMW kit, and needle jets and jet needles from the dealer ,

1)Can anyone spot me the location of "Toms g/s rebuild thread" or his handle on here?
2) I've got the independant floats on mine, as I've not noticed any trouble, what is typical?

[Renner]

Originally Posted by elmontanero

2) I've got the independant floats on mine, as I've not noticed any trouble, what is typical?

per the 'bum http://bmwmotorcycletech.info/bingindependent.htm
ln a nutshell: lack of overflow exit may result in excess fuel making its way into the cylinder when parked on the sidestand with leaking petcocks... or something like that.
Mostly they're not worthwhile in terms of value-added, from what I understand.

I looked at Slope'r's link which looked pretty useful .
Similarly I use a half-round file to cut off the peened throttle screw threads (which can be tricky ) only because I don't own a dremel.

My last rebuild I didn't cut them down far enough and stripped shaft threads while backing out the screw ... I really need to go buy a dremel set.

[Wirespokes]

I wouldn't pull the head if the engine is running fine. Perhaps take a peek throught the spark plug hole, or the intake with the carb off.

That doesn't look like any carb part that I'm aware of, and how it stayed on the intake port without entering the combustion chamber is a real mystery. Is that really true that it was between the carb and cylinder head?

My only guess is that it was in the airbox and when the bike tipped over, it entered the airtube and made it that far before you discovered it.

Man, that could've been messy!

As has been stated many times, these carbs aren't rocket science, but you'd think so with the prices charged for parts and rebuilds. They're actually very simple, and even with time spent asking us questions, it would be quicker than mailing them off somewhere. Besides, it's good to know your machine so you don't freak out if something happens in the middle of nowhere some day.

Don't worry about the alcohol issue - the foam floats seem to hold up just fine. It's more some of the local additives that attack fuel systems - some of us don't have any problems, others a lot.

[elmontanero]

Originally Posted by Renner

per the 'bum http://bmwmotorcycletech.info/bingindependent.htm ln a nutshell: lack of overflow exit may result in excess fuel making its way into the cylinder when parked on the sidestand with leaking petcocks... or something like that. Mostly they're not worthwhile in terms of value-added, from what I understand..

Thanks for that. They were there when I bought the bike so no value to add... I always park on the center stand, so no bother there either. Good read and I'll double check the float settings as I do the rebuild.

[BrokenR80RT]

Originally Posted by Wirespokes

I wouldn't pull the head if the engine is running fine. Perhaps take a peek throught the spark plug hole, or the intake with the carb off.

That doesn't look like any carb part that I'm aware of, and how it stayed on the intake port without entering the combustion chamber is a real mystery. Is that really true that it was between the carb and cylinder head?

My only guess is that it was in the airbox and when the bike tipped over, it entered the airtube and made it that far before you discovered it.

Man, that could've been messy!

As has been stated many times, these carbs aren't rocket science, but you'd think so with the prices charged for parts and rebuilds. They're actually very simple, and even with time spent asking us questions, it would be quicker than mailing them off somewhere. Besides, it's good to know your machine so you don't freak out if something happens in the middle of nowhere some day.

Don't worry about the alcohol issue - the foam floats seem to hold up just fine. It's more some of the local additives that attack fuel systems - some of us don't have any problems, others a lot.

Yes sir, just home from the swim meet. Son did great. I'll take your advice and not pull the head unless I can't see inside or if I see something alarming. But it seems to run fine. I know my compression is about 125-126 on both cylinders which makes me confident no real damage has been done, unless I am wrong here. Maybe I'll borrow a boroscope from work for a better look for scratches, dings, or scraped areas inside the head.

The piece was laying in the step area where the plastic tube meets the carburetor. When I saw it, I felt it asking me to take the bike out and introduce alot of airflow so it could wreek havoc on my engine. Glad I found it first.

In hindsight, I wish I would have spent more time yanking the bike apart when I first got it. The PO admitted that he wasn't very mechanically inclined, but had receipts from service done by BMW Detroit.....Hmmm.

Since I have no idea of the part's origin, I'll go ahead and do the rebuild and inspect the heck out of it. This will get me back again to the point where I will also seal better where my metal boots attach to the airbox w/RTV (previous post, which you replied). Probably should have taken it all apart back then too, but that was a half off thing I did on the intake to clean the exterior a bit. I really tried not to disturb the carbs.

Thanks for your replies, everyone! I love good advice.

[Bill Harris]

Originally Posted by Wire

Don't worry about the alcohol issue - the foam floats seem to hold up just fine. It's more some of the local additives that attack fuel systems - some of us don't have any problems, others a lot.

I got my /5 in '73 and the local gas stations started introducing gasohol (ethanol-laced gasoline) in the late '70's. My original floats "sank", weighed in a +5 grams, and were replaced with new in 1980 and I've always assumed that the gasohol got them. I generally replace floats every 5-10 years "just in case", but honestly I've not had problems running gasolhol periodically for the past 30 years.

Bing does have floats made with a black, alcohol-resistant plastic foam. But at $30 apiece, I'll wait til I have problems with the "standard" floats.

The Bing independent floats, OTOH, have never beeen on my bike, but they have caused untold misery on customer's bikes and have been the subject of many critical threads in the 'Net. They get a thumbs down.

[supershaft]

That pin looks like it could be the center pin to the older style crank breather? That or a front main bearing locating pin?

Bing has a number of "solutions" to problems that don't exist. The "solution" then has its own problems!

Keep your stock floats and adjust the float level correctly.

[The Raven]

Originally Posted by supershaft

That pin looks like it could be the center pin to the older style crank breather?

That would make sense as it has access to the carbs I believe, and the getoff.

[BrokenR80RT]

Originally Posted by supershaft

That pin looks like it could be the center pin to the older style crank breather? That or a front main bearing locating pin?

Bing has a number of "solutions" to problems that don't exist. The "solution" then has its own problems!

Keep your stock floats and adjust the float level correctly.

Supershaft,

Can you explain this a little further. I looked at the vent sysem + block micro-fish. I don't see any such pin. How old do you mean when you say older style? I have an 83 R80RT.

Thanks!

[matteo]

I found that very dowel in my oil pan. It was a mystery at the time. the theory was it was the main bearing locating pin. It's been three years and no problem. It may have been in the oil pan since day one of the bike. Now that you found one in the carb, maybe BMW just placed a few of these as an easter eggs for us to find.

[BrokenR80RT]

I saw nothing at all wrong inside the head due to this wtf dowel pin . I re-torqued my heads, which surprisingly were loose by .5-.75 turn at the bridge bolts, then reset my lash.

Dang, if I had thought in advance I'd trash the center stud on the rocker cover, I would have it back together with my shiny, refurbished black covers. The studs are on order with a bunch of other stuff I also needed from MaxBMW. Dreaming about M&M's already.

My carb re-build kit is on the way from Bing in Kansas. I opted to stay away from the independent floats from everyone's advice. An electonic balancing manometer is also on it's way from Max.

But having all that, my tank is still at the body shop with my other faring parts. I won't rush the body shop as I originally promised this to be a "winter" project for them. I cannot wait to play.

Thanks!