Carburetor and Fuel System
Title: Linkert
insulator block question
Post by Cotten on Mar 13, 2007, 2:44am
Yep.
Grind all four surfaces flat;
Line up your complete assembly before you pressuretest the manifold separately...
Use sealers sparingly, if at all....
And above all,
Avoid the urge to overtorque.
....Cotten
Post by Skip on Mar 13, 2007, 3:13am
Thanks....thought so but here lately second guessing everything...Don't think I will use sealer at all...do not see the need for such things...is screw length an issue, or just as long as tight...have oem set but they seem a tad short when using all three gaskets...they tighten up well enough, but not much screw in the hole...the long ones I have are too long...Skip
Post by 62trvler on Mar 13, 2007, 11:47am
I read on Roadrat Roberts web site that he uses plain chapstick on his gaskets and has never had a leak. Has anyone ever tried this?
Post by Cotten on Mar 13, 2007, 2:29pm
Skip!
OEM lockwashers were quite thin, and the gaskets may have been also, adding up to an extra thread or two.
What is the condition of the threads in the casting?
If they have been chamfered or boogered, then you may want to helicoil for strength.
Your long screws must be WLA or something?
and 62trvler!
That's a new use for Chapstick that I wasn't aware of.
Although James gaskets and others may have adhesives already applied, the only reason I use a little Gasgacinch is for an assembly aid. (And to make it clean up easier upon the next service.)
....Cotten
Post by Skip on Mar 13, 2007, 3:14pm
Mr. Cotten...The threads are excellent...the problem, I think is the screw being too short...maybe...they do tighten well, but not very long into the carb holes...and yes I have 2 1/2 sets of the long (WLA) screws and tried to use them...just a tad too long...Thanks Skip
Post by Skip on Apr 11, 2007, 11:18pm
I have another linkert question...mine seems to be leaking around the bowl nut...think if I replace the copper/brass crush washer it will fix that?...any other suggestions...Thanks Skip
Post by Cotten on Apr 12, 2007, 1:06am
Skip asked: "mine seems to be leaking around the bowl nut...think if I replace the copper/brass crush washer it will fix that?"
Maybe.
If you grind the bowl deck flat before lathe-cutting the bowlnut gasket surface flat parallel to it,.. it certainly assures the best odds.
....Cotten
Post by Skip on Apr 30, 2007, 2:38pm
I have another question......seems eveything is going great so far...but...the semi-problem I have is that the carb seems to be wet all the time...the bowl seems damp and the brass carb body itself appears to be wet as well...I believe I did as Mr. Cotten suggested above but still here we are...is this a problem? Thanks Skip
Post by Cotten on Apr 30, 2007, 2:45pm
If it is 'wet' with fuel, it certainly is not safe.
....Cotten
Post by 56panman on Apr 30, 2007, 3:27pm
Skip I rebuilt my linkert this year also. I also was getting a drip hanging from the bowl nut everyday. I had not tightened the bowl drain plug completely. I thought it was the bowl nut also but it was the bowl drain plug.
Quote:"carb seems to be wet all the time...the bowl seems damp and the brass carb body itself appears to be wet as well..." What kind of humidity are you working in..? Could it be condensation..? :-/
Post by fourthgear on Apr 30, 2007, 5:29pm
Don't Linkerts have a vent in the carb body ? Interesting use of chap stick.
Post by Skip on Apr 30, 2007, 9:14pm
fourthgear: You know I thought about the vent hole....seems to do it mostly after I run it for a while...starting and running so good I hate to take it off for a look...may wait...I guess I used the term "all the time" too freely....56Panman...my bowl does not have the drain hole...wish it did...I live in WV...it is like the rain forest without the rain, and the forest...but all the humidity...good thought.....thanks....Skip
Post by panacea on May 1, 2007, 4:40am
Skip, have you seen the Blue ridge parkway? I'm ridin' down there in July with some freinds, sounds like a nice ride, Mike
Post by Skip on May 1, 2007, 2:56pm
Panacea...Yes I have seen the parkway and it has seen me...beautiful ride...if you are in the area anyway, take 250/219 through Elkins and Marlington WV areas south to the Parkway...some of the best WV has to offer....then you can hit the Parkway a little further south at 250/I-64 junction...if you come by WV give us a holler....Skip
Post by King on May 1, 2007, 9:10pm
Mike
The Blue Ridge Parkway is a beautiful ride. I was up there on Sunday (I live about 5 miles from the start @ I 64). It is quite a mecca for bikes in the summer.
Riding the whole length would be a gas but it takes a while. In early the 60's I drove it in a 55 Ford. It took about three days but was a great trip.
If you are coming through give me a buzz.
King
Post by panacea on May 2, 2007, 1:56am
Skip, Thanks for the tip, I've never been east so I'm lookin' forward to it!... King, hopefully we won't be in a big rush, I like playin' it by ear!....Mike
Post by Skip on May 14, 2007, 1:53am
Ok guys, 310 miles and only one minor problem today...seems that when I "twist the wick" it acts like it wants to cut out if too fast...high speed adjustment??? too rich???I can sloooowly twist and get there, but when I want it now...cuts out then catches...Thanks Skip.
Post by wreck74 on May 21, 2007, 4:45am
too lean. back your A/F mixture screw out just a little.Re: Linkert question
Post by Fixman on May 21, 2007, 12:34pm
Skip, Cotten taught me that the idle must be fairly high (pretty even and smooth pulses) for the Linkert to work properly. Since it has no accelerator pump it relies on a fairly fast idle to get enough vacuum to keep the fuel high enough in the emulsion tube so that you don't have the hesitation when twisting the throttle. Sure worked on my 57.
Kent
Post by Cotten on May 21, 2007, 1:50pm
Let me add that the two needles (or circuits) overlap.
A change in adjustment on one affects the other.
This is most apparent with changes of the lowspeed needle. As it is enrichened, it actually leans the high end. This occurs because the entire lowspeed circuit reverses itself when speeds are reached where the venturi kicks in and draws from the nozzle. Air is pulled from both the idle bleeds and the orifice in the spring collar around the LS needle to mix with fuel at the bottom of the nozzle.
Thus the LS needle meters air at high speed!
Adjusting the idle extremely low is tuning for a condition that the motor can't use on the road.
The accellerator effect occurs when a sudden demand (throwing the throttle open) purges the fuel stored in the cutaway on the outside of the nozzle. Air from the vent hole on the side (or at the bottom of the venturi on M88s and Indian carbs) rushes down into the cutaway void to mix with fuel, through the holes, and spray up out of the nozzle spigot.
Like a mechanical pump, it must refill. How quickly it refills depends alot upon the sensitivity of the float mechanism, and the volume of available reserve in the bowl. (Which is why brass floats suck.)
Be aware also that a common problem with Linkerts occurs when the venturi has shrank to where not only can air pass around it, it can shake and wear upon the nozzle spigot. If the spigot is not a tight fit within the venturi hole, it defeats the 'accellerator" action.
(The cure is to swage the venturi back to size, and put a seal around the spigot.)
....Cotten
Post by Skip on May 21, 2007, 1:57pm
Thanks for the info guys...will play around with iot some more this evening...getting real close...Skip
Re: Linkert question
Post by Bikerdonho on Jul 11, 2007, 3:00pm
''Apr 30, 2007, 5:29pm, fourthgear wrote:
Don't Linkerts have a vent in the carb body ?''
Don't Linkerts have a vent in the carb body ?''
I've been having a severe leak also, sometimes as much as one gallon per day. After relapping the tank shutoff valve, not much improved.
The next stage was putzing around with the bowl lockwasher and locknut. Here, I discovered an tricky illusion. Drippage from the bowl vent ends up on the nut, creating the appearance of a bowlnut leak.
Monday (July 9, 2007), I pulled the Linkert from the bike. Sure enough, there's a 1/16 dia "bowl vent" hole on the body of the gasket surface below the throttle pivot shaft. It was really EASY to drain the gas from the wet carb--I just poured it out of the vent hole into a container.
Everything in the float and float valve assembly is worn sloppy, but the float (brass) definitely isn't "logged." Here's hoping that a better seating of the float valve needle will keep the gas in the gas tank.
Post by fourthgear on Jul 11, 2007, 6:41pm
bikerdonho
The best thing you can do for your Linkert is to get and put in one of Cotten's floats in there and as long as your float valve is sealing , you will be able to leave your tank shut off valve open , its that good of a float . It will probably help in performance out of the old girl too. Cotten fess up with your contact info for him.
Post by Cotten on Jul 12, 2007, 2:08am
I'm way behind in production right now...
liberty@npoint.net
Thanks.
...Cotten
