Fouled plugs are just a plain foul! Help!

[frank]

Here's the deal family. I have a 78 xs 650 with which i believe are the stock 38mm carbs. The problem i'm having is not only do i get that annoying pop and fire coming out of my exhaust but my plugs keep fouling out and leaving me stranded. The plugs foul out in two different ways, one is by really fuel soaked plugs. The second is they get really charcoaled just after a spin or around the block. Now the things i have done to it already was i set the timming per the spec manual and also the new points and guaged per spec manual. So i know its not any of those. I'm pretty sure its in the carb adjustment but the spec book doesn't really go into detail about that. I've heard i need to take them in to get synchronized but doesn't that cost big $$$$$$$? Any help here would be very appreciated! Thanks and ride free!

 

[CDNTX650]

syncing carbs is like 15 minutes worth of work....but that shouldn't cause fouling. What is the jetting? what is the condition of your coils and condensers?

 

[frank]

Condesors are new coils are fairly old more than likely the originals. jetting is stock. the guy i bought the bike from said he never messed with anything in the carbs or engine for that matter. I am running pod filters and straight pipe. I just forgot to mention that in my last thread.

 

[CDNTX650]

i dunno, i would definetly pull the carbs and check the jetting first. Main and needle jet especially. plugs are BP7es i assume?

 

[frank]

Yes i believe so. ok i'll do that.

 

[CDNTX650]

not sure on stock needle settings. have to axe someone on here.

 

[5twins]

Check the setting and condition of your floats. They may have sprung a leak and be taking on fuel. That would make them heavy and they would run lower in the bowl, allowing a higher fuel level. That would make the bike run rich. The setting for your model is 24 +/- 1mm from the gasket surface, not the gasket itself. If you measure off the gasket, subtract 1mm from the spec and set them at 23.

Once you fix the rich running problem, with your mods you're going to be running too lean. Considering how hot it is where you live, I strongly suggest you rejet. I just jetted some '78 carbs for mods like yours - one up on the pilots, 2 up on the mains, needles dropped 1 step, and mix screws @ 2 1/4 turns out.

 

[CDNTX650]

depends on altitude. I know on all my old bikes i have never had to rejet here, my SOHC 4 and my last XS.

 

[gggGary]

What kind of pods? Some of the pods are noted to block ports on the front of the carbs and cause carburation issues. A quick check might be to loosen them and pull them back from the carb a bit? And yes check for fuel in the floats. home built synch tools are easy and cheap.

 

[frank]

Ok I'll tear down the carbs and do what you mentioned. But one question? Excuse if i sound like an idiot but what exactly will i be measuring?

 

[frank]

gggGary- they are regular run of the mill slip over pod foilters the clean and re-use typ with the wire mesh around them?

 

[5twins]

Try a test run without the filters. If they are those cheapo $12 imitations, there's a good chance they're at least partly responsible for your problems.

What you'll be measuring is float height. This is for the later carbs but the method is the same, just use the measurement from above .....

 

[frank]

Thanks a ton my friend! I will do exactly this and get back to you hopefully by Monday!

 

[frank]

Ok! I tore down the carbs and it turned out the floats were all out of whack so i followed the info you sent and did everything it said! wierd thing though. As i was tearing down the carbs i found two ball bearings one each ventury slide. I posted what i found and gggGary informed me they shouldn't be in there so i through them out. Reassembly begins tomorrow but i still need to tackle the wirring which i know nothng about. I have a wirring diagram that i got from here so lets hope it helps! Thanks everyone for all your help so far, and i'm sure i'll be back on here again with questions on the wiring LOL!!!!

 

[jay760]

How big were the ballbearings? could they have been put there to try and make the slides return down? maybe there is a diaphragm problem and the bearings were put in to weigh the slides down,