Equivalece between needle clip position and needle

[georgesgiralt]

Thanks Barry,
So I either have to trim a lot the washer I've got or find new smaller washer.....

[tvrla]

All this talk about shimming the needle got me thinking about the one's I've measured. You know, when you insert the needles it's best to measure them to make sure they're in the correct groove? I've found that the needle securing bosses aren't set the same height in corresponding slides. I never got the same measurement from one slide to the other.

Looking closely, it appeared to me the differences were in manufacturing. I could see an easy way to adjust the distance - and could even possibly damage the slide, so I left them as is.

But maybe I should re-visit this problem and make a shim for one of them so they're the same.

[Barry]

I recorded the needle lengths some time back and even the gaps between the positions vary a little:
 
Position.............Needle Length mm          
1 ......................42.37                      
2 ......................40.57
3 ......................38.79
4 ......................37.10


1.8 mm gap between slots 1 & 2

1.78mm gap between slots 2 & 3

1.69mm gap between slots 3 & 4


I suppose it's possible the reducing gap is deliberate but they don't reduce in a consistent manner.  I should check both carbs next time.

[Bob_Roller]

georgesgiralt, what method is used to secure the the needle in the slide ?

My '81 has a 6 point star type washer that holds the wire clip that the needle mates with .

My '82 and '84, have a straight slot screw driver threaded plug that holds the needle in .

If you have the latter type, you can add thin washers under the needle to raise or lower the needle as required .

[georgesgiralt]

My bike is like your '81. I just checked that the washer was square in the piston and press the spring firmly on the bottom.
By the way; would you be so kind to measure the trumpets of the air cleaner cover on your 84 bike ?
I would like to know what are the differences from the 81 cover... (see my other topic about the air cleaner cover)
Thanks a lot in advance !

[Bob_Roller]

I'll check it when I get home, but I won't be able to post until tomorrow morning when I get back to work, my home computer is in for repairs (virus issues) .

[georgesgiralt]

Good enough for me. I searched for months someone able to measure them...
This week end I'll return the carbs to their stock position. The bike runs rough and no tinkering can help her.
Today I rode her a lot, with jets and tools in the pocket. It is really bad. And mileage is very poor.
So I'll put back the "plain" standard jetting as per BMW spec, and live with the excessive richness between 3000 and 3500 rpm if I open the throttle fully...
Now, I know...

[Bob_Roller]

Here's the dimensions of the horns, trumpets, etc......

The large one is 39 mm wide and 25 mm high .

This part had the following numbers molded into it , Purolator LP818-609, a number under a BMW logo, 1337  227 .

The smaller horn has the dimensions of, 26 mm wide and 16 mm high .

Has Purolator LP818/3-609 and the BMW number 1 337 501 .

Both horns are the same length, 136 mm .

Hope it helps out some !!!!!

[georgesgiralt]

Thank you very much Bob,
I'll try to figure the differences from mine... Yesterday, I saw a mechanic I know at a stop light which is good on old airhead. I explained to him that I had some issues with my jetting. He told me to make a hole as big as I can on the underside of one trumpet to increase air intake at mid range...
Told me this has worked fine for many bikes...  So now I've something new to try .... Looks like the mode BMW made on the air cover....

[Bob_Roller]

Found this for R80 bikes with issues with carbs .

https://www.bmwmc.net/catalog/2120.pdf

[georgesgiralt]

Yes, Bob, I know this one.
It seems that the filter cover you have on your latest R65 already has the modification.
I've tried the same jetting as should have an hypothetical R65 for Europe with the "new" cover with no luck at all. The only difference being the cover. So I tried the bike without air filter. Boy, what a mess !
So I put it back and, yesterday, decided to restore the factory setting for my bike (which I did this morning) and I will live with the "hole" at 3000 RPM.
One day, if I find a spare air filter cap I'll try, either the mod with non symmetrical trumpets or make a hole under one of them. This tinkering took me too much time energy and gasoline for a terrible result.  In the meantime, I've decided to ride the bike and enjoy my birthday present : a Vinyl apron protection to keep my feet and legs hot and dry !
It is made to measure by a French maker and it's inside is covered with synthetic fur.... Can't wait for bad weather  

[Bob_Roller]

What are the Bing numbers for your carbs ?

They are stamped in the vertical flange at the cylinder head side of the carb, look like : 64/32/325 .

I've got a manual from Bing, that gives the parts that were installed at the factory .

[georgesgiralt]

They are 64/32/307 and 308.
As far as I know, they are NOT in the bing manual (nor on their Website).
As I bought the bike new, in 1984, I have the user manual where the settings are written. (And in 1985 I was able to get the maintenance manual from BMW. A co-worker had a cousin which was a dealer, so he was able to buy it for me !)
So I have the settings perfect for 97 leaded fuel.... Now I only get 95 with 10 % ethanol in it....

[Bob_Roller]

They show up in the Bing manual I have .

Main jet : 145

Needle jet : 2.64

Jet needle : 241

Atomizer : 591

Idle jet : 45

Needle clip position : 4

[georgesgiralt]

Exactly what I have !
Thanks a lot.