Not a happy rider (carb leaks)

 

After letting my Dnepr sit unused at the blueberry farm
for 2 months while we moved, I went to fire it up
the other day... to find the left-hand carb leaking gas.
It seems to be the float valve, which works when I
lift the float manually, but can't get it to work
on its own.

Uh oh... (hindsight)... I shouldda sent for a few float
valve kits back in the winter instead of right at
the start of the good riding season. So now where am I
gonna find parts for a Soviet-era K-68 Dnepr carb
in a big hurry? I found a UK supplier (Cossack M/C's)
but getting something shipped in from across the Pond
could take weeks.

Or is there something I can do to fix the float valves,
such as chucking the needle part in a lathe or hand drill
and polishing the tip with some kind of mild abrasive...
such as toothpaste?

SQ

 


Depends. Is the float not lifting because it's punctured? Or not
lifting because it's just sticking on its pivot? If the float itself
isn't punctured, then some judicious cleaning up of the pivot ought to
sort it.

It's very, very unlikely to be the needle itself that is at fault.
Could be a duff needle valve sealing O-ring, though, if Dnepr's ever
had such hi-tech kit :-/

 

TOG@Toil wrote:


Buddy of mine with an '05 FZ1 had exactly that problem.  For whatever
reason all four of the O-rings that seal the float valve seats to the
carb bodies deteriorated.  I bought him a bag of 100 O-rings for $4.26*
and now he is being inundated (FSVO inundated) with requests (& the odd
demand!) from other similarly afflicted folks on the FZ1OA forum.  I
suspect Yamaha/Mikuni just got a bad batch of O-rings.

Of course, the O-ring is not sold by Yamaha as a separate part, you have
to buy the entire needle, seat, O-ring and filter cap as an assembly,
costing about $22 per carb, IIRC.

*McMaster-Carr P/N 9262K629, 7.5mm ID x 10.5mm OD x 1.5mm width

 



A couple of my Honda 400 Four ones weep a bit, but that's sheer old age.
Like the owner, really. You can effect a cure by removing them and
applying a thin smear of gasket goo to them, then replacing.


You *sad* bastard.


--
BMW K1100LT  Ducati 750SS  Honda CB400F  Triumph Street Triple
Suzuki TS250ER GN250  Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

 

TOG@Toil wrote:

What is the float made of?  Some BMWs used a "foam" float that would
saturate and sink if exposed to 'gasahol' (10% alkahol).  Produce the same
symptom.