Post-carb cleanout & float adjustment, no start

[Aweebaweeba]

First off, let me apologize for the length of this post... I am trying not to leave out any detail of what I now call my "XS650 Odyssey".

I bought a 1983 XS650 Heritage special. It ran badly when I first got it, was hard to start, and showed obvious signs of carb trouble. So my father and I got to it, ordering a few parts from mikesxs.

The first thing we did was clean the carbs out, replace the needle and seat aswell as change the gasket. The seats on one side was so gunked up, it was crazy. We replaced the rubber o-rings too. Once we were finished with that, we tried to fix the starter with mike's repair kit... This required taking the clutch off, which we did. Once the new gear was in place, we put everything back together, tested the starter and... nothing. It still spun right off, giving maybe half of a full crank before letting go. Nevertheless we pushed on, put the gas tank back on and tried to get her to start. We also fixed the air/fuel screw, which was adjusted way fucked up (one of them was at 1 1/2 turns, the other at 2 3/4 turns, set them both to 3 turns out from the bottom as per information found online). We cranked for 20 minutes, no go. We then tried to bump start it, and after spraying some fuel directly into the cylinder, she started, and started strong.


After she ran for a while we started asking ourselves why it wasn't starting easy. I looked around and found out that when installing the gasket, I left one of the holes unopened which did not allow fuel to enter when starting. A-ha! So we took the carbs off, corrected the gasket, put the carbs back on, and as soon as we connected the gas line and turned the petcock on, fuel started leaking out of the airbox. Shit.

After a brief search online we found out that the float height may have been all out of whack. When testing with the two tubes connected to the bottom of the carbs, we found that one of the carbs (the side that the fuel was leaking out of) was adjusted way off. So we took the carbs off and adjusted that float (One float ended up being set differently than the other, which I thought was strange. I can provide pictures if anyone is interested). We also tested to see if the floats were puncutered/leaking, no bubbles. So now when testing with the tubes, both float levels were just where they needed to be (can provide pictures for this aswell, in case I am mistaken). So then we put the gas tank on, started cranking, and nothing. Since the starter was still shot, we tried bump starting, and she wouldn't even try. She would backfire every once in a while, too. At this point I am very frustrated. Still too much fuel getting to the carbs?

The only other thing I can think of now is a bad spark, but we verified by kicking with the plugs out and sure enough, after gapping them to the correct height, the sparks were visible, and the spark leads were clean.

What's next? I'm thinking the ignition coils may be weak. What sort of test can I run to see if they're done? Can you guys suggest anything else for me to try? We're already halfway through may and the bike still won't start easy, and the most frustrating thing is that once she is running, she runs so smooth! Idles perfectly, doesn't burp or backfire once warm, and the throttle is very responsive.

You guys have been very helpful already, I feel blessed to have this forum as a resource because it's helped us so much with all the kinks we've run into so far. I really hope I can find an answer here because I'm starting to lose my fucking mind with this bike not starting.

Thanks in advance.

 

[xjwmx]

I used Mike's starter repair kit and it worked and works great.

The floats should be at the same height to give the same level. Something is wrong there and it's probably your problem. Or at least contributing to it. If the carbs are original the black plastic floats don't leak.

Since it runs fine once it's started it's a pretty good sign the coil and ignition are good.

 

[Aweebaweeba]

I used Mike's starter repair kit and it worked and works great.

I bought the same thing, and when installing it we made sure it was where it needed to be... replaced the spring and the gear, but for some reason it still just jumps out.

 

[xjwmx]

^Did you copy what was already there when you put it in? Maybe it was wrong to start with?

 

[Aweebaweeba]

^Very possible, also just read up on the clip #3 tightening trick and/or removing the spring, wondering if that might do anything. The main issue is at least getting it to kick start, though. Not sure what to look for at this point.

The weird thing about the floats was that one of them was at the correct height and let in the correct amount of fuel, but the other was at the right height but didn't, so one of the floats ended up being adjusted higher than the one next to it to let the same amount of fuel in.

 

[xjwmx]

^With a new kit the wishbone spring should be plenty tight already.

What to look for at this point to get it to start easily is find out why the carb floats need to be different heights. Make sure the float needles and seats aren't leaking and the seats are well seated and then set the floats to 22mm using a ruler. You'll fine the exact technique for setting them on the site somewhere.

I had one of Mike's needle tips balloon up from something in the gas. Make sure that hasn't happened.

 

[5twins]

The drag clip in Mike's kit isn't as strong as the original. Bend the original tight and re-use it. When you cleaned the carbs, you may not have cleared the choke jets. If they're plugged (and it's very common), the choke won't work .....

 

[Aweebaweeba]

Thanks for the input. I'll try to get these checked out tonight, I'll post an update when it's done.

 

[weekendrider]

Aweebaweeba,
A note of caution on the choke jet. You can't replace it once "hogged out".
Keep your cleaning to carb cleaner and compressed air, NO PROBES in this hole.
When cleaning your carbs, the metering holes by the throttle plate, you SAW carb cleaner coming through them? Again NO PROBES, compressed air and aerosol carb cleaner. If spraying through the pilot jet hole doesn't clear them try the mixture screw hole. Remove the mixture screw, spring, washer and o-ring(make note of the sequence)
This will allow you good access to the mixture hole(straight shot) and closer proximenty to the pilot metering holes. Carb cleaner to soften and compressed air to blow them clear.

 

[Aweebaweeba]

After checking choke jets, found that one side was blocked... Thanks for the tip!

Gonna let it soak overnight and try compressed air to dislodge it, if that fails, going to order a new one...

 

[xjwmx]

^Let me ask you something. If you get it running and warm it up, then turn it off, is it easy to start back up (with the choke all the way off). A plugged choke problem would only make it hard to start the first time. And are you using the choke properly at various temperatures of the engine? Mine can be finicky for the right choke position vs temperature to give instant starting.


If you couldn't get the jet in the bowl cleaned out, and were going to get a replacement bowl, at that point you might as well stick something in the hole to try and clean it. Start with something like a bristle cut from a plastic broom that won't scratch brass.

 

[Aweebaweeba]

^Yes, it starts first kick with no choke once warm.

Also, we tried with some stranded copper wire in the hole, aswell as a small plastic bristle from a broom and still, it remains blocked.

 

[5twins]

The choke jet is actually a little above that bottom inlet hole. The whole area below it can get clogged with crap. You can safely dig that stuff out with a pick of some sort without damaging the jet .....

I have a long pin extension for my blow gun. It fits right down the passageway and onto the top of the jet. It does a good job of blowing them clear .....

 

[xjwmx]

If you don't have a lot of tools, before you resort to ramming guitar strings down the hole try boiling it water for an hour or so. That should do something. Then follow with carb cleaner.

 

[XSLeo]

For probing the holes in the carbs I like to use the quick tie from a loaf of bread. Strip off a bout 1/2 to 3/4 inch of the cover. This leaves a very thin soft piece of wire.
Not large enough or strong enough to hurt the carb. With care this can get a hole through the blockage. Then the carb cleaner can get at more of the plug. Speeds up cleaning.
Also have you read www.amckayltd.com/carbguide.pdf ?
Leo

 

[Aweebaweeba]

For probing the holes in the carbs I like to use the quick tie from a loaf of bread. Strip off a bout 1/2 to 3/4 inch of the cover. This leaves a very thin soft piece of wire.

That's what we used last night, just burned off some of the plastic at the end and poked down... We weren't able to dislodge the blockage, but it's been sitting in carb cleaner overnight and this evening we're gonna take the compressed air to it, see it that works.

 

[Aweebaweeba]

Hello again, gents!

Put everything back together, and it started! Still running very rich though, because it floods often... After it was warm I went for a rip on it and everything was fine, but after about an hour or so, I started noticing this little tube kept jumping off its nipple, especially during low revs/take-off from first gear.

Also it turned dark black and was flexing/pinching when the bike was really hot. After about 2 hours total of ride time, when accelerating, something was off. When I'd give it a good shot of gas, it would stutter, and then when I'd slow down fast it would idle really low. Any ideas?

Also THANK YOU GUYS SO MUCH... been months at this and finally it starts reliably. You guys are the FUCKING BEST

 

[5twins]

That's the vacuum supply line for your petcock. Without it, the petcock won't flow fuel. You should probably change the hose to something more reliable. What you have on there now is just some sort of plastic hose and obviously not up to the task (or the heat). Also, there's usually a little clip on the hose to help retain it on the nipple .....

 

[gggGary]

What 5 twins says, and that leads us to look at the petcock. As a test; block the vacuum port, short hose and golf tee is handy, run the petcock in the prime position, how does it run? A torn diaphragm in the petcock will allow gas to be pulled directly into the vacuum port.

 

[weekendrider]

Starting fluid will dissolve varnish quicker than carb cleaner.
It is also more dangerous to have around. Wreaks havoc on thin rubber (all rubber it maybe). But it will clean that brown hard varnish out.