Carburetor and Fuel System
Title: Hard
starts
Hi everybody, I am new to the site and already need some help.
First problem is my 55 pan has a Super E carb, and sometimes i can start it on 2 kicks, but most of the time it takes at least 10 kicks. I need some pointers on how to start it, maybe less gas, maybe more choke , i can't figure out what it takes every time i need to start it.
Second problem, when I finally get the bike started and cruise down the road, it will run great, and then whether it is hot or cold the engine will spit and sputter for a second and then smooth out for a while and then it will do it all over again. any help is appreciated . thanks
Post by Cotten on Mar 5, 2005, 3:35am
Evil Manifold Leak strikes again.
Post by 55suicidepan on Mar 5, 2005, 3:42am
Ok so how do i check for the leak ? And how do i fix it?
will it cause any damage to the motor if it is driven ?
thanks
Post by Cotten on Mar 5, 2005, 3:56am
Second question first: Yes, extra air makes heat. Heat eats motors.
First question:
http://virtualindian.org/11techleaktest.html
You need a big cork with a hole in it to put a constant 15psi on the assembled manifold. Then dilute dishsoap on the outside will show you exactly where and how much of a problem you might have.
I pressuretest while assembling, so that I can find the sweet spot where everything seals best. And before I forget, it's my turn to ask,... you do have a support to the carb, right?
Post by Rainjester on Mar 5, 2005, 11:16pm
When it's cold, key off, choke prime it with one or two kicks, no choke, key on, then kick it over.
When it's warm and you just ran it a little while ago, you shouldn't have to prime it, just turn the key on and kick it over. If you prime it after you just rode it, you flood it and it'd take a while to start.
If these don't work, you've got something else going on. Pull out your spark plugs to see if they have black soot on them. If so, you either have a manifold leak or you're running the carb too rich. (or both) If you get into a hard starting situation again, swap out your plugs and see if it starts right up.
I had the same hard starting symptoms until I fixed the manifold leak and the fact that I was running it too rich. Putting new harley 3-4 plugs in, it'd start right up until the plugs got fouled from the leak and the richness.
jester-
Post by 55suicidepan on Mar 5, 2005, 11:32pm
cotten: I do have a support bracket going to the carb, if that is what you were asking. thanks
Post by 57pan on Mar 7, 2005, 6:00pm
55,
You should really do a search on this topic - there have been many discussions on starting techniques for these old bikes.
One thing about these old bikes: every one has its own personality. You just have to spend enough time with it to get to know its moods and how it's feeling on any particular day. That's what makes them so endearing.
Seems like everyone has their own "bag of tricks" that they use with varying degrees of success. There are just so many variables that it is hard to predict what will/won't work and something that works one time may not work the next. That's what makes them so exasperating.
Post by madcatter on Mar 9, 2005, 6:45am
manifold leak test
start bike anyway ya can get a can of wd40 and spay lightly around the manifold.motor will do goofy things if there is a leak.
Post by billy on Mar 9, 2005, 6:53am
WD-40 is NO longer flamable, besides that test is like 'pissing in the wind'....... Not the best idea...
Read Cotten's post & link to Real accurate testing.
Post by Rainjester on Mar 10, 2005, 2:49am
I'll have to agree with the WD-40 test before pulling the carb off to do the manifold leak test.
I figure, why go through all the work pulling it off just to find out that it may not be leaking?
I actually fabricated my own manifold tester based off of Cotten's leak test site for this but I still spray it first to see if it stumbles. If it does, then I'll pull things apart to further test the manifold with the leak tester and fix it.
jester-
Post by Cotten on Mar 10, 2005, 3:08am
Spraying a flammable around a large leak will affect the motor,... if the motor will even start! But how does it pinpoint the exact spot, or tell you anything about how big it is. While you are burning up the top end.
And the vacuum within the manifold changes with RPM and temperature. Are you standing there whipping and punishing the motor to test it WFO as well as at idle?
Bubbletesting allows you time to observe and inspect.
Not only does it display the tiniest of leaks, it often points out problems unsuspected, like casting porosities, or even leaks through the pancover screw over the port.
Doing it while installing saves a lot of grief and tail-chasing. And consider the benefit when firing up a fragile fresh motor! Think of all the damage done while trying to diagnose something that should have been gnat's ass in the first place.
It's time vintage Harleydom got out of the barnyard. It is too expensive not to.
Post by Rainjester on Mar 10, 2005, 6:17pm
WD-40 is NOT flammable. Get yourself a lighter and spray to find out for yourself. It is simply a lubricant and will not hurt the motor any more than motor oil will.
There are quite a few causes that will lead to symptoms of hard starts (bad plugs, timing, fuel/air mixture, carb float; just to name a few) and it'd have to be a good sized leak for it to be a main cause.
Definitely if you're putting it together once it's been disassembled use the leak test kit, but once it's together, I'm not going to take it all apart to do a leak test just because it's running funny, I'll use the spray method which does not hurt it in any way.
Agreed, it's not the best method, but it IS a method that can be quickly used short of having to take it apart. If you do find it reacting negatively to the spray method, THEN take it apart but don't take it apart until you've gone over other potential causes if it's not reacting to it.
jester-
Post by thsmith on Mar 10, 2005, 6:19pm
As several said, do a search on Linkert, hard starting and carb. You will find a wealth of information.
The pressure test is gospil, do it. One thing I found on my 49 was it had been converted to o ring intake. When you do this the space between the heads are now to narrow to fit the o ring intake. Normally people just have the outer intake flange turned down say 50 thousants but they forget to turn the innier flange the same amount making the oring not able to fit securely where it should resulting in a major leak and if you turn the idle screw out enough you will get it to start and WD40 will not affect the idle.
Preasure test it.
Good luck
Tracy
Post by hplhd on Mar 11, 2005, 9:35pm
hello, just signed in at roll call and ride. i took off my linkert and have a s&s e like you do. i don't use my enricher, a few ssquirts and a prime kick but i know besides the other things mentioned a good charged bat , points and plugs gapped right and in good shape makes a big diff to. like mentioned they all have dif quirks my 64 is nothing like my 59. you'll get to know yours and i'm sure everyone has mentioned to you, get a manual if you don't aldeady have one. nothing like a kick start bike most everyone i know can't figure out why i love them so much or would even want one. thank god for sites like this one and others. soooo just wanted to put my 2cnts in and say hello to everyone
Post by panfreak on Mar 11, 2005, 10:54pm
I built/used a pressure tester as described, and believe it is the most telling method. But I built it for my manifold as described, so I am going to ask the question I'm sure others are thinking too; why can't I build a new adaptor to fit my carb flange, then I only have to drop the filter to test? seems to make sense, after all, this way you could test carb to manifold seal as well as o-rings etc. This has never been mentioned, but I have wondered why no one does it?
Better than WD40, easier than pulling the carb......
Post by hplhd on Mar 12, 2005, 12:34am
Not sure but if you ran the comp air thru the carb could it possibly dislodge the float or move something else
Post by panfreak on Mar 12, 2005, 12:40am
You're already running air through the carb when you start it. Wouldn't 12 psi simulate this, or am I missing something?
Post by Cotten on Mar 12, 2005, 1:26am
You do not want to pressurize the carb, as it has bleed passages. Test the manifold, not the carb!!
This ain't rocket science, nor brain surgery. Take some time and think about it!
Post by 51Hog on Mar 12, 2005, 3:51am
Wouldn't pressurizing the venturi also pressurize the fuel bowl? If you plugged up the bowl vent.
You may blow a bowl gasket, or damage a brass float , or force fuel into an otherwise fuel proof float. I don't think that the air would blow by the needle and seat. Apart from those concerns, I don't think there would be a problem---At least with my linkert.
IMHO
Post by Cotten on Mar 12, 2005, 1:41pm
Carburetors are not transparent: The carb should be removed for thorough inspection of all aspects of the manifold itself.
Motors draw vacuum on carbs bores only, the bowl stays atmospheric in service. Although I occasionally benchtest castings for porosities, pressurizing an installed carb is much more mess than its worth to save five minutes of disassembly.
I would especially caution against using a shop vac, as particulates could easily plug the delicate idle bleed holes and passages. (Remember that the idle circuit actually reverses flow at intermediate speeds!)
Don't wait for tuning problems to go back and pressuretest.
Do it upon installation of the manifold, (or every time o-rings are replaced). This will help find the 'sweetspot' where it seals best, and then the carb support can be tweaked to mate the flanges ideally.
Post by fourthgear on Mar 12, 2005, 1:42pm
hi
Does anyone with o-ring manifolds line up there manifold when putting there heads on ? Just a thought.
Post by kell on Mar 12, 2005, 5:31pm
When put the heads on I line them up with the manifold.
Post by fourthgear on Mar 12, 2005, 9:17pm
kell
I was just curious , cause I have always alined mine and I think you go a long way to keep those nasty manifold leaks at bay to start with . I have always had good luck not having leaks ,all the scoots I've had and worked on have had o- ring type manifolds but I'm not worried about taking things apart to find and fix a problem. Ya gotta do what ya gotta do . I just wanted to see if I was the only one that was taught this , I figured I wasn't. So many good machanics on this sight .If you can't learn something here , somethings not right some where .
Post by Cotten on Mar 13, 2005, 1:46am
Aligning the heads (and cylinders) is a prudent practice, of course. But you only have that option if you are assembling a fresh top end.
Obviously there is a reasonable chance that if your are carefull and observant, a manifold/carb assembly can go together without a disastrous leak. At least for the short term. But some of us have learned not to trust to luck, particularly if our livelihood and reputation depends upon beating the barnyard odds.
And considering the investment that a rebuild requires, the ante is upped to a gamble that goes beyond a recreational thrill. For those of us with a budget, anyway.
Although there may only be the most minor of leaks, consider the investment in time and stomach lining to try to tune around them, chasing one's tail suspecting timeing or valve adjustment, until the 'freshly broken-in' motor overheats at highway speeds.
Sound like a familar tune?
Ever wonder if the reason why every vintage cylinder you find is shot out was actually from [i]miles?/i]
Post by leakypete on Mar 13, 2005, 4:30am
Cotten is right on. this site has a great resource in him. I down loaded the design for his leak tester and it works great. be sure to keep the gasket stack on to test also. did a slight modification to use what i had on hand. cut a piece of plexi to fit manifold and set a common valve stem into the hole, then used my HD air shock pump to bring it up to pressure. I had MINOR leaks so i was able to keep the pressure up with only a bit of pumping. major leaks will of course be obvious..... Thanks Cotten and of course Panhead yet again.
Post by billy on Mar 13, 2005, 6:57am
I agree 1000% w/Cotten, consider the expense of all the new parts at risk........Even more so, if you use 'Custom made forged stroker pistons' ( I Do )
Small price to pay for piece of mind & Knowing you have NO LEAKS.....
Post by fourthgear on Mar 13, 2005, 6:51pm
hi
I also agree with the pressure test as Cotton discribs , but you can avoid some ills by carefull and proper assembling of components. An unsurported and or incorectly installed carb will give you problems in short order. And luck has a lot to do with it more than you realize,most of us don't make the parts that hold and seal these components . At best we depend on them to with stand what we put them through. Like I said , I have no problem wrenching on HD's ,like some people open chewing gum wrapers. I'm just a wrench head.
