carb issues

[old_skool]

I got to say, this has to be the most posted complaint topic since I've joined, especially when it comes to these thing leaking or the related fuel components failing. I don't think out of all the other bikes, and I've had quite a few, including an XJ, that I've ever had even 1 tenth of the issues these XS's seem to be having. I don't mind working on a bike to upgrade old ideas to new to make them more reliable, or restoring bad components to serviceable condition, but if after all is said and done, if this monster has even close to the issues with needles/petcocks/octy's etc as with what I've read, this bike will get a quick kick to the curb. These carbs may be easy to remove or work well when set properly, but the last thing I want to do is tear them apart ever other week or so. How many of you get a couple plus years without fooling with them once cleaned and set properly??!

[GLoweVA]

I've got about 1.5 years on my 80G right now since my last cleaning/rebuild.
Maybe a can or 2 of seafoam in that time, but I haven't gone into them since.
Maybe part of that is that he's my daily driver and the gas never gets a chance to sit for very long. I'm usually filling the tank every 2 days!

[BA80]

The difficulty isn't in the carbs themselves, these same carbs are run on several different bikes. The difficulty lies in learning HOW to work on them. And the fact that there are 4 of them that need to work correctly multiplies the difficulty because they all need to be EXACTLY the same to work properly. With the exception of those that ran different size jets in the two center cylinders.

And, I'm not convinced that was even a good idea.

[DAVINCI]

+1 Greg.

Anyone who's worked on the old Rochesters or Holley's or even lawnmower carbs for that matter shouldn't have any issues getting these carbs right, they're not that complicated. I think most troubles stem from people who grew up in a fuel injected world working on obsolete technology. Carbs are pretty damned archaic, after all. More plumbing than technology. Think toilet tanks, suction, gravity and ballcocks.

[old_skool]

I've already cleaned mine and doing any necessary replacements and repairs, I've worked on countless carbs, I think everyone's misunderstanding the question...once that is all done, the frequency they and the other fuel components like to fail on these XS's, is it only operator error, not doing it right the first time, or just over finicky needing a lot of follow up maintenance fuel pieces?? I've bought old beat and abused bikes and continued the abuse with several Honda's for example, and never needed to touch the carbs once, they may have needed some minor attention, but wasn't really noticeable, even the XJ I owned use to foul plugs all the time, but none of the others, Honda's, Suzuki's, and HD's. They ran well no matter the mileage, or how long they sat, now I know eventually anything that sits with old fuel will need attention, but never had a bike leak fuel into the cylinders, or had to be diligent in worrying about them doing that.

[crazy steve]

I don't think the XS carbs are any better/worse that what you'll find on other bikes (as Greg said, these are used on a lot of other bikes), it has far more to do with how well the bike was maintained and/or if used enough. I bought my '78 new, and had zero carb issues right up until I crashed it in '85. But at this point (30+ years later), most of these have suffered mistreatment/neglect of one sort or another. Gummed/corroded up from extended sitting, contaminates in the fuel from rusty/dirty tanks, incorrect replacement parts, inexperienced repairs, all are issues with these.

I will say these carbs won't accept half-measures IMO; they have to be fixed right, or you'll have problems. You can't get the fuel system too clean either; the slightest bit of crap will cause problems. If you don't clean out your tank and petcocks when rebuilding the carbs, you're asking for trouble.

My XS2 650 had Mikunis on it; after the second year I owned it (bought used when it was only 4 months old), one or the other of the carbs would act up every spring and the bike would run crappy. I had to pull the carbs, disassemble them, blow them out and reassemble/install them. Never found anything inside them (and I looked hard), once I did this I was good to go for the season. So compared to that bike, the XS11 was the model of reliabilty...

[mack]

Carbs

I doubt anyone would question your competance in mechanic's. I've done eight sets of carbs now, four 78/79's and three 80/81's. They are completely different animals and if I had my choice I'd pick the old ones everytime. I think they are better made. I tried most of the so called upgrades to each model and basically found that the original configurations and parts work best. Maybe the designer knew a thing or two. With one exception. Dump the octy and get used to shutting off the gas. To answer your question though, when I finally got my SF carbs tuned to the head and exhausts, they are a fire and forget entity. Now will I play with them a bit to better understand how one thing affects another, sure, thats what owning a muscle bike is all about. But I've had no fuel leaks since I went back to the original floats, float needles and seats. When I turn the key and push the button, it starts before turning a full revolution, no cranking required.

[old_skool]

Maybe I'm getting gun-shy hearing all the woes of others, or maybe remembering when I was younger but so were the bikes.... still, I hear more problems from these than other makes excluding Yamaha. Has anyone ever used the old carb additives to their fuel regiment to aid in keeping from buildup of infrequent use, not meaning dry gas either.

[old_skool]

I doubt anyone would question your competance in mechanic's. I've done eight sets of carbs now, four 78/79's and three 80/81's. They are completely different animals and if I had my choice I'd pick the old ones everytime. I think they are better made. I tried most of the so called upgrades to each model and basically found that the original configurations and parts work best. Maybe the designer knew a thing or two. With one exception. Dump the octy and get used to shutting off the gas. To answer your question though, when I finally got my SF carbs tuned to the head and exhausts, they are a fire and forget entity. Now will I play with them a bit to better understand how one thing affects another, sure, thats what owning a muscle bike is all about. But I've had no fuel leaks since I went back to the original floats, float needles and seats. When I turn the key and push the button, it starts before turning a full revolution, no cranking required.

Glad to hear, eases my mind a little.

[tonyg-5386]

My carbs were rebuilt 10 years ago. I have not touched them since...except to synchronize them. I never let the bike sit in the cold months for too long and use stabil marine formula in the gas from Dec-March. I guess I'm lucky. My 79 Special runs perfectly and does not leak anything. It is without a doubt the best bike I've ever owned.

[old_skool]

My carbs were rebuilt 10 years ago. I have not touched them since...except to synchronize them. I never let the bike sit in the cold months for too long and use stabil marine formula in the gas from Dec-March. I guess I'm lucky. My 79 Special runs perfectly and does not leak anything. It is without a doubt the best bike I've ever owned.

Now thats what I want to hear!!!!!!!!!!!!!!!!!!!! Same bike here, 79SF

[BA80]

Gummed/corroded up from extended sitting, contaminates in the fuel from rusty/dirty tanks, incorrect replacement parts, inexperienced repairs, all are issues with these.

I will say these carbs won't accept half-measures IMO; they have to be fixed right, or you'll have problems.

Exactly. I learned that the hard way.

But I've had no fuel leaks since I went back to the original floats, float needles and seats. When I turn the key and push the button, it starts before turning a full revolution, no cranking required.

+1 on that. I hardly EVER have to use the enricher. Even the other morning when it was 30º when I left for work. It started on the first revolution. Then just set the throttle lock for a high idle.

It took 3 sets of carbs to get one that wasn't too POed to work properly. And I agree about the earlier carbs being better. Everything was better until Ralph Nader got involved. I have 79 carbs on my SG. Heh heh.......but then I have a 2H7 engine too. Both superior to the G and H in my opinion.

[DGXSER]

Steppenwolf has owned his bike since it rolled off the show room. it is an SG. I believe two years ago or less he had another fellow XSive locally clean and reset his carbs at the same time he replaced the cam chain, and a few other odds and ends. IIRC, it was the first time they been out of the bike in well over 20 years.

On both of the SH models I have owned, once the carbs were set up correctly, cleaned and tuned, I had/have not had to go back into them.

Yes, you do hear alot of woes about carb issues on here. For most shade tree mechanics, carbs are black voodoo magic. So they do not go into them much. And the XS carbs are so simple they lend themselves to us rookies playing with them. So you get more troubles getting them right.

[old_skool]

I have to admit, I was a little be-fuddled as to why they were being such a nuisance, they are extreeeeeemly simple compared to most other carbs I've been into the last 30+ years. I may end up creating my own headache attempting to repair the vacuum slides pinholes, but thats an easy remedy afterwards.

[mack]

Mechanic

I had no mechanic training at all but when I dug old Hermes out of the rasberries a few years ago I figured it was a good opportunity to learn. If I killed it, so what. As it sat it wasn't ever going to run again until I performed CPR on it. So with all the advice and guidence from this site, and a lot of learning through experimentation I've fully restored my SF and am largely through restoring an LH. When I say restore, I don't mean fix till it runs, what I mean is take it back to the way it looked and ran coming off the line. Time consuming yes, but you can't believe the grin on my face everytime I look at them or fire it up for a ride. Like stepping into a time machine and taking off 34 years.