Linkert M741-1 rebuild

[kitabel]

With sufficient air leakage from the throttle disc's periphery, the disc must be closed tighter than spec to keep idle speed under control.
This means that the disc position may place both the idle and transition holes on its atmospheric side (rather than split them as intended).
Is the light showing in the photo enough to do that? I don't know.

[T. Cotten]

With sufficient air leakage from the throttle disc's periphery, the disc must be closed tighter than spec to keep idle speed under control.
This means that the disc position may place both the idle and transition holes on its atmospheric side (rather than split them as intended).
Is the light showing in the photo enough to do that? I don't know.

Me neither, Kitabel!

But we do know they are very forgiving, otherwise they would never have gotten so badly worn.

This 'daylight' is the combination of both of a worn disc (first attachment) or under-sized (common for NOS "seconds" and repop) discs, plus the groove worn into the body of the carb (second attachment).
Even a disc perfectly fitted to the overall bore will show daylight at the 'eyebrow' of wear, and not direct air in and out of the bleeds ('transition holes') as designed, especially when the wear extends all the way to the bleeds themselves (third attachment).

So its a matter of how well you want the machine to tune, and perform.
My personal philosophy is that only a ""blue-printed"" carb will be 'all that it can be', and perhaps even better than the average production carb at that.
(This allowed me to offer the service successfully for many, many years, without any practical means of testing. A worn carb would be a liability.)

Does the rider want the machine to be all it can be, or just 'run'?

....Cotten
PS: Even properly torquing the carb to the manifold changes the bore slightly where a DLX/L&L throttledisc should "close". Graciously, it does not operate "closed", although I machined them torqued as if it did.

[pisten-bully]

...just a follow up, I rebuilt the 741-1 six years ago for my 101 Scout and finally got to use it last week. The 101 started and ran, several times in fact, but it was particularly finicky to dial in...and so I pulled the bowl to check the float level. I immediately discovered a piece of brass in the bottom of the bowl. looked like one of the fingers from the float lever:

IMG_2476.jpeg

...and sure enough, the middle finger (seems appropriate, right?) was missing:

IMG_2478.jpeg

It was new when installed and I don't recall having to do a lot of bending to adjust the float level, and I can't think of anything else that might have caused that finger to break! At any rate, I'll find a new one (Greer's is out of stock) and hope that makes the tuning fall in line!

[T. Cotten]

If that one was 'new', Harry,

What are the chances of a 'good' new one?

Beware of some that are almost unuseable,

Like this mess that wouldn't even accept the needle:

CRAPLEVR.JPG

Or this cast one,

castLVR.jpg

Or this machined one.

cnclvr.JPG

....Cotten
PS:
Its been over a decade, but the last decent levers I bought came from Gary Stark, but even those needed re-working of both ends, and the pivot bore, before they came up to my standards.
Since everything needed a re-work, I usually just re-used the customer's OEM, and saved him money.