Please Help!!

[crainmain]

I am at my wits end with my bike, ready to cash in and buy a new one. I love my xs, but it won't run and stay running to save my life. Here's my problem: The only way I can start the bike, is to remove my aftermarket K&N air filters from the backside of the carbs, and spray some starting fluid into each one. It will start right up and run great. That is the problem. I can shut it down and go back outside a few hours later, and all it will do is, the starter turns it over and over and over, and won't start! It's been like that for a long time now. It's so bad that I have to bring the bottle of starting fluid with me to make sure I can restart it when I come back home. I have tried everything. I took it to a motorcycle shop to have brand new plugs, wires, and distributer put into it about a year ago. I was told the carbs were dirty, which they were because I had never cleaned them in about 5 yrs. So, I removed the carbs, totally tore them down, soaked each one in carb cleaner for a day or two a piece, rebuilt them, installed them, and it's still the same. I know what your thinking, that I messed up in the rebuild, but I followed every thread tip on this website about carb rebuilding, and am totally confident that they are no longer a problem of mine. I ensure that they all have even float heights, all synchronized, etc. I have had it running since, and it sounded better than it ever had, but it still has it's starting problems. I don't know what to do. If anyone knows another culprit that it could be, please let me know. Thanks again.

[TopCatGr58]

Hey there Crainman,

I'll take a stab! Okay, first you've got an 80G(for folks playing at home!), vacuum controlled petcocks, no Octy. You stated you set the floats even, but what height? They are actually about 2.7mm lower than the 78-79's, should be at 23mm, not 25.7! Set higher, will make it leaner!!!

You also didn't mention ever using the CHOKE?? Just thought I'd ask!

Starts with starting fluid sounds like Extra LEAN condition to me!
Have you tried putting the petcocks to PRIME for a few moments during the starting process, and pulling the choke out ALL the way? After riding it a while, gets warm, and if floats are fairly lean, possibly evaporating what little fuel left in bowls, so not much available for restart after a few hours sitting?

Once it's running, have you sprayed your starting fluid around the intakes to see/hear if you hear an RPM change, which could mean a vacuum leak, not able to suck enough thru carbs during starting slow revs!?

Somehow, it's not getting enough fuel for the starting mode, but is able to get it when running! Have you checked the vacuum hose to the petcocks for cracks, leaks, and attached to proper nipple on Intake Manifold!?

Anybody else want to play!?

[thumperjsa]

It has been a long time since I turned wrenches and I am just getting back into it. I will take a few stabs at it too.

Wouldn't a stuck advance possibly cause the same symptoms? although you should get some detination if that is the issues. Also, starting jets could be clogged. Possible that the carbs are flooded out as well. Starting fluid being a much hotter fuel can bypass a flooding condition. Pull the plugs and see if they are wet when you try to start it cold before you try starting fluid.

Also, I had a wierd condition on my 80g. PO had changed carbs to 79 carbs. Much larger jets used in that one. Did you replace any jets and it could be for the wrong carb?

[tab1324]

More stabs at it

Ok - I can sympathyze... I've come near tossing my bike any number of times but hang in and you'll get it. I'm sure I'll have a few more of those times myself.

I recently made a plea for help with a hard starting condition and the answer was found. There is what I'll call a "choke hole" in the float bowl (no rime intended) which is very easily plugged even if you've soaked the carbs in cleaner. I was super confident that I had cleaned the carbs up too but noticed that the #1 and #3 weren't firing at start-up. But if I could nurse it along until it was warm, it ran just fine.

Do a search for "Hard starting, fine when warm" and you should find the thread I'm referring to. Basically, it requires taking out the carbs, and cleaning out the choke holes. I don't think soaking would do the trick. I had to use a drill bit and drill the plug out ( a bit drastic but I couldn't remove otherwise.)

No gaurantees that this will work but it's worth a look. Be patient - The bike is so worth the time and effort. Best part about this fix is - it's free!

Tom B.

[jetmechmarty]

My guess is that you think you cleaned the carbs, but you didn't get them clean enough. Take them off and do it again. If your pockets are deep, you can send them to Rob Reil at http://www.motorcyclecarbs.com I think for about $100 each they will come back better than new.

[skids]

Re: More stabs at it

I gotta agree with Tom. Even if the pilot jets were plugged, and even if the float levels were set to the wrong model carbs to give low levels, the "choke" straw draws from the bottom of the bowl. When you start the thing, pull the choke all the way out and use no throttle. Opening the throttle kills the vacuum needed to draw fuel up the choke circuit.

Originally posted by tab1324


Do a search for "Hard starting, fine when warm" and you should find the thread I'm referring to. Basically, it requires taking out the carbs, and cleaning out the choke holes. I don't think soaking would do the trick. I had to use a drill bit and drill the plug out ( a bit drastic but I couldn't remove otherwise.)

Tom B.

[nashville_bill]

One more thought. You mentioned that you had soaked the carbs in carb cleaner for days. The throttle shafts have rubber seals that could have been damaged and could be causing eight vacuum leaks that could make starting very hard.

[jetmechmarty]

Good point Nashville Bill! Days in automotive carb cleaner might well damage them. Did you use automotive carb cleaner? Rob Reil has replacement throttle shaft seals and showed a bunch of us how to replace them at the first rally he hosted.

[crainmain]

Thanks for all the info / help guys. I'll try out your suggestions and see what I come up with. It's been a problem for so long that I am definitely considering selling and giving up. I'll give it one last effort and see what I come up with. To answer some of your questions, I adjusted to floats to the height specified in my Clymer book, can't remember what it stated now; I always use the choke to full open when starting it cold, doesn't make a difference though; I also checked all of my fuel / vacuum hoses for cracks / deteriation, and nothing is wrong with them, they look like new; I have checked my plugs and they are never wet during starting attempts; I'm not sure where the "choke hole" is that you are talking about, is it part of the float bowl, or the upper carb body?; Also, I didn't soak anything in the carb cleaner that wasn't metal. I did use motorcycle carb cleaner / soaking solution from my local cycle shop. I'll try to readjust my float heights, and see if that helps. I'll reply back with my findings. Not much spare time on my hands, so it takes me a while. Thanks again.

[xExcessive 1120]

Hard Start

To Crainmain: I might as well chime in with one item not yet mentioned. Have you run a compression check on this beast? I have found hard starting in some cases to be simple lack of high enough compression to readily support combustion, and when an engine is right on the borderline (around 90 psi) they can be the devil to start but once they get spinning like with a push start they would run. My F has 9.2 to 1 compression ratio so if in perfect condition should show just under 150psi on the compression tester. Also, while you are at it, the most important thing is not how high the numbers are ( as long as they are high enough to support combustion) but the difference between the highest and lowest cylinder. I like ten lbs or less but on my original F, I checked it that black day it was stolen and totaled and it was 150, 155, 155, 150. A lot of our bikes will actually read high as the engine is so strong that we cannot run them hard enough to prevent carbon build up in the head which will raise the test figures. Best of luck and don't give up! Christopher. "The Gimp"

[scalded dog]

Well, another thing, the petcocks wern't mentioned here, if the petcock screens are dirty inside your tank, the starting fluid, would start the bike, the draw on fuel is much stonger when the engine is running, maybe pulling the fuel thru the crud that could be on your screens, or thru the crud that could be inside your petcocks, that should be checked asap. Later 'Dog

[skids]

The choke hole is part of the bowl that the brass straw goes into when you put the bowl back on. It is a low spot in the bowl that tends to collect crap, especially if you generally don't use the choke. Watch out when you spray into the hole, because it will come right out of the other hole into your face! (like a u-trap) You can also clean the tube and enrichening circuit by pulling the "choke" lever out when spraying into the brass tube. There is a hole in the side of that tube and you will see carb spray coming out of it. Don't be alarmed, this hole is to entrain air.

Originally posted by crainmain
I have checked my plugs and they are never wet during starting attempts; I'm not sure where the "choke hole" is that you are talking about, is it part of the float bowl, or the upper carb body?; Also, I didn't soak anything in the carb cleaner that wasn't metal.

[Ken Talbot]

Here's what you're looking for:

[crainmain]

Once again, great information from all of you experts out there. My problem is, I really don't have much time to mess with it right now, but as soon as I get a chance, I'll go through the list of advise that you all have gratiously given me. I never did pull out my petcocks that one of you mentioned, that could be one of my problems. I am almost positive, everything in my carbs should be going great now, but honestly I wouldn't begin to know how to check my compression ratio. I am living in Germany right now, wouldn't begin to know how to tell the guy at the motorcycle shop what to do for me, and I don't have any tools like that, but if it comes down to it, I'll give it a go. I'll check my petcocks and my carb bowl choke holes for now and see what I come up with. Do I need to pull the carbs all the way back off again for that, or can I just take the bowl covers off while they are installed? That was actually a big pain in the ass for me last time I did that. Anyway, thanks again guys, you all have been alot of help for me dealing with "my beast"!

[Ken Talbot]

Sadly, you will really have to take the carbs off again to remove the float bowls. But, on the bright side, it will be easier this time than last. By the time you've done it a dozen times or so, it really won't seem that bad at all..