Carby Idle

[cus]

G'day All,
Bike is running well, but can't seem to slow the idle down.
Idle is fine when cold but increases when warmed up. I can
back off the throttle stop screw right off (even take out )
& idles not majorly fast, but still more than I would like.
Have some slack in the throttle cable, so no preasure on
the slide spring, have air screw about 1 1/4 out, plugs are
good colour. Carby is Monobloc 376, all other carbies I've
worked on, I can slow down to a stop with the throttle stop
screw. Have choke hole bunged off in the cap.

regards, Cus

[trevinoz]

Cus,
       Maybe your slide is worn. I had the same problem and resleeving the carbys fixed it.
Anyway, you should have a 389!
Trev.

[cus]

Thanks trevor,
The 376 came on the bike, & when I first checked in the Haynes manual it lists a 376 for the S/R,
but in my parts manual 389. The slide is a bit worn, but I think the body is worse, the slides a
good fit near the top, slack at the base. I'm thinking of buying a new 389 from Amal, are they
any good? or Chinese repo's. In the parts manual it lists 2 diff. 389's, would appreciate it if
you could quote me the slide & jet sizes etc. & if its 389/46 or 389/47.

regards, marcus

[Richard]

Hi
go to tech topics look at which carb on page three
Sorry I cannot work out how to put a link in this reply
Hope it helps
Richard

[MikeN]

Thanks trevor,
I'm thinking of buying a new 389 from Amal, are they
any good? or Chinese repo's. regards, marcus

Marcus
Ive had 2 new monoblocs and 2   276's from Surrey Cycles and they have all been very good.You tell him what its for and it comes ready to fit .
Mike

[trevinoz]

Marcus,
              It appears that the only difference between the 389/46 and 389/47 is the main jet size.
You need a 1 5/32 carby, 3 slide, 25 pilot jet and either 420 or 290 main jet. The top cap should have plain holes, not threaded, and a top hat ferrule is used to locate the cable ends. This is because there is limited clearance between the carby and the frame and adjusters tend to make the cables enter the top at an odd angle.
I cannot comment on the new carbys available now as I have never used one, preferring to have the old ones resleeved.
The bloke in Brisbane would probably have one, but probably expensive and worn.
Trev.