Carburetor and Fuel System
Title: Linkert
M74-B woes
Post by Cotten on Aug 1, 2003, 3:47am
Mike!
Don't blame the Linkert,... yet.
Your symptoms are classic for a manifold leak. The surest test (spraying crap ain't accurate) is to pressure test your manifold with soap suds: http://virtualindian.org/11techleaktest.html
You need a big rubber stopper or cork with a hole in it, and a regulator on your compressor, or a lady with lungs. The you can spot exactly where and how much of a problem there might be.
Then you can sleep at night knowing that you won't be chasing your tail, wondering why your cylinders don't burn the same, or where did that hole in the piston come from.
Linkerts themselves have few problems, other than modern brass boatanchor replacement floats.
Post by 57stroker on Aug 1, 2003, 2:10pm
From your description, your Pan is running like mine does when the points gap is too wide. I chased my tail for a long time on this one. The manual says .018" to .022". The Shovel guys running points tell me .014" to .016" is more like it. The bike would run good, start ok, but at mid-throttle it would buck and surge. I would swear at my Andrews A-grind and check the timing. Finally, I spoke to a retired Harley mechanic that had been wrenching for 50 years. He told me the only way to set my points is with a new business card. He said that in broad daylight, you should NOT see any arcing from your points. At night, you should see a faint blue arc occasinally. If you see them arcing more than this, your gap is too wide or your condenser is shot. I miked a few business cards and most of them are only .010" to .012" thick. I followed his advise and all my bucking and surging problems went away. Of course, your milage may vary.....
Post by Cotten on Aug 2, 2003, 3:05am
I agree heartily with
>>I'd trade a Bendix for a Linkert any day.<<and>> don't care for the 2 pc clamps, they make the o'rings bulge and leak.<<But>> Almost every Linkert I get has had the jet drilled out to 1/16" or the smallest drill in a handyman set.<<
Only a couple of models had jets. The author doesn't see much of a selection. And M88 jets that are undersized for a Pan are a lot cheaper to drill out than a messy solder job. Even V-TWIN sells correct #18 and #19 jets for Pans.
>>I use fresh o'rings, good stainless aircraft clamps, and if I can find it, some silicone tape called F4 tape used in aircraft<<
Okay, so we ignore Pans before '55. Even still, beware of overkill "aircraft" clamps with 1/4" screws.
The bandaid of tape is a lit fuse. The expansion and contraction cycles of the motor getting hot and cooling, plus running vibration itself will cut through any clamped goo or gummy worm. The stock o-ring works only because it is compressed sideways.
Please pressure test all manifold assemblies with soap suds, and you will enjoy a tuneable machine without any lit fuses or time bombs.
Post by haggis on Aug 2, 2003, 3:23am
Hi Guys,
Do your selves a favour and listen to Cotten,when it comes to Linkert he's got it sussed.
and while your at it get one of his custom pan floats...
'tis tha bomb!~!!!
Haggis
Post by BigMike on Aug 4, 2003, 6:54pm
Checked manifold, no leaks. checked points, .018" a little tight on the gauge. reset float level, removed low speed needle and checked brass washer below spring, no problem, re installed needle and started adjusting at 5 open as in manual. had to go much leaner than I expected, about 3 1/2 to 3 3/4 turns from closed. then adjusted the high speed enrichment by rumping on throttle and watching for black smoke. adjusted in from 2 until black smoke stopped, and I got a minor backfire once in a while after backing off, (about 1- 1 1/8 out- no load) no smoke or backfire under load. problem cured! no missing or gagging at constant speed, accelerating or backing off. It now runs better than it ever has. I guess I was just not persistent and careful enough,
Thanks guys!
Now if I can get the constant oozing of oil stopped, things will be wonderful. I did get the kicker cover leak stopped, new bushings and "O" ring, put the buddy seat back on too. Even with the minor troubles, that baby is a gem. A couple of local sweet things have been bugging me for a ride, now I can accommodate! ;D
Post by haggis on Aug 5, 2003, 6:17am
Ah Yes!!!
Hard tails and tight bellys............go get em Bigmike ;D
Haggis.
Post by BigMike on Sept 30, 2003, 4:40pm
went ahead and changed to modern carb (see "forgive Me" thread) problem solved. now about those hard bellies..... life is good! ;D
