Dead spots around 4-5K

[Justin B.]

I have gotten my last couple of rebuild kits from Eurotech, about $45 for the kit with diaphragms, or $19.95 without.

http://www.eurotechmotorsports.com/forms/MyBike.cfm?q_brand=BMW

[VaSteve]

Thanks for the links, guys.  I will check them out.  I had so much fun riding the bike this weekend.  It's like I took the training wheels off!!  

[ScottColumbus]

Hi VaSteve,

do you have the old bing-carbs with the flat roof?

Is it looking like that?



The problem you describe is typically for that carbs. There is no piston-spring under the cover. The newer carbs do have this spring. I know somebody in the german Kleine-Boxer forum, who has developed and built this special spring for the old carbs. He is an engineer, his nickname is bang and you find him here:

http://kleine-boxer.redeker.net/profile.php?mode=viewprofile&u=289

I think 2 springs cost less than 5 $.

greetings from North Germany

Dirk

[VaSteve]

Sounds interesting, but where does the spring go and what exactly does it do?  Does it provide some sort of resistance for the diaphragm to push against?  If so...why?

[ScottColumbus]

Hi Steve,

I suppose you know this website:

http://www.maxbmwmotorcycles.com/fiche/MainDiagrams.asp?mospid=47851

There I took this picture from, were you can recognize the position of the piston-spring (No 7) of the newer carburetors. The spring stabilizes the up and down movements of the piston. But unfortunately this spring does not fit into your carburetors.



cu

Dirk