Carb Float Adjustment Clarification

e3steve · Post by **e3steve** » Fri Jun 10, 2011 12:19 am

I'll get back to you, T; thanks for the info. I'll dig out the carb kits that I have and, also, investigate the currently-installed jets' threads a bit more thoroughly.

Because the ol' gal runs so well I'd not given the carbs another thought. Time for some plug chops when the motor's back in and bedded! At least, if the jets are the wrong threads, they've been erring on the rich side at ¾-to-WOT!!

e3steve · Post by **e3steve** » Fri Jun 10, 2011 3:01 am

Looks like the l/h carb, that I opened for initial inspection, has the M5 ISOmetric threaded 145 mainjet. the r/h has the correct JIS-threaded 145. The jet holders are both JIS, as are the rest of the carbs' threaded orifices. So Brewsky was right on the money! I only pulled the jet holder, in my previous look-see to inspect the thread, so I didn't give the jet another thought.

Both carbs have #39 slow/pilot jets.

I pulled both needles and re-inspected them under a strong light and two pairs of specs(!); 24231 -- the '1' looks like a scratch, on the l/h needle, but is more visible on the other -- so, T, thanks for the nudge on that one.

My unused Keyster kits comprise D3 needles, #135 mains and #42 slows.

CL77NOW · Post by **CL77NOW** » Fri Jun 10, 2011 7:00 am

data, keyster needles D9 and D13
5 data points, 1/4" apart starting just below top notch. D13 is richer.
inches: with caliper.
T1 T2, M1 B1 B2 (top to bottom) bottom2 is 1/8" from tip end.
D9 .1 .1 .89 .74 .61
D13 .1 .1 .86 .68 .52

there is a machine mark rim on the needle, at the top i start just below there. T1

D13 is richer. CL77
D9 is CB77

New in box

e3steve · Post by **e3steve** » Fri Jun 10, 2011 9:15 am

Jerry, now that is uber-useful info for this topic! Many thanks! At least, now, Brew & I can compare our Shyster and Keihin needles' tapers.

e3steve · Post by **e3steve** » Fri Jun 10, 2011 9:18 am

I have to say, BTW, that the machining quality of the Shy.... err, Keyster parts looks superb. Everything in the kits is of the highest quality; perhaps it's just a shame that the needles have been denounced by many here. I know Ed uses the kits with no problems other than sometimes needing to trim the bowl gasket.

CL77NOW · Post by **CL77NOW** » Fri Jun 10, 2011 9:31 am

too bad shyster don't sell a box of needles and jets as a kit.
really.
Best of luck.

teazer · Post by **teazer** » Fri Jun 10, 2011 9:38 am

I like to think that I'm meticulous but measuring needle tapers rarely yields accurate answers unless I have access to an optical comparator.

The way I compare needles is way more basic. I take the original needle and place it between the caliper tynes at a random point starting at say 5mm up from the tip. I then take the needle to be compared and slide it in beside the first one. If it slide down further, it's obviously thinner (richer) and if it sits higher it's thicker.

Then I repeat at the midpoint and then at the top of the taper (root diameter).

That way I can tell in seconds if the needles are identical or significantly different.

When I need top work out alternative needles, obviously I need accurate measurements, but for a quick way to see if two needles are the same, it's spot on.