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carbs

5K views 36 replies 11 participants last post by  Eye_m_no_angel 
#1 ·
I see a lot of print on riders fixing carbs, why are they a repair concearn? do they clog up fast and why? is todays modern gas not clean?

Or is it due to winter storage..would not gas saver cure this? do we have to fog? bikes in the winter.. thanks
 
#2 ·
All of the above. Use Stabil every tank, at they very least every couple tanks.

The additives in gas these days will clog jets, and the older bikes did not in-line fuel filters, you can buy those for a buck or two these days.
 
#3 ·
You know, not to sound rude... but a lot of your questions could be answered by a simple Google search.

At the very least, you could start a thread called "Sanford's Master Questions Thread" or something to keep all your questions contained in a single thread. ;)
 
#6 ·
I use it all of the time because there is ethanol in the gas where I live. there are different types of it, i use the marine grade ethanol treatment every 3 or 4 tanks to help keep the jets clear and I put in an in line filter as well.
 
#10 ·
Depending on how often you ride, you don't need to use a stabilizer all the time.

If you use up more than a tank of gas in a month or so it's unnecessary. If the same fuel will be sitting in the tank for over a month it is good insurance to stabilize it.

I only use stabilizer during winter storage, but I put on about 12,000 miles a year, so my fuel is usually only a few days old at most during most of the year.
 
#11 ·
Once carbs are clean they generally will stay clean--if you ride constantly. The ethanol in modern gas will burn right up with the gas before it has a chance to separate and cause problems. Because many bikes don't get ridden much the alcohol has time to evaporate leaving behind water and the gas itself will evaporate leaving behind residue (varnish). This is why carbs need to be cleaned occasionally if not ridden often. On long trips where I am constantly burning tanks of gas I have yet to have to clean the carbs on the road. The fuel doesn't have a chance to do any damage as it gets burned and replaced quickly.

Ethanol can cause other problems, especially on older bikes with OEM carb gaskets and o-rings, which can swell and stretch. To mitigate these you can add Startron (or other brand) of additives that counter the bad effects of the alcohol and which may also give you better mileage. Often these additives act as a fuel stabilizer for long storage as well. I am sold on Startron for a regular additive when I can't get alcohol-free gas for my old Honda, and have found much improved mileage (up on average from mid 50s to upper 60s). For occasional light cleaning of carbs I like Seafoam.

Cheers,

Mike
 
#18 ·
Animedevildog said:
Well, if gas milage does go up, then I would imagine that would mean it IS extracting more energy from the gas burned. Which should (in theory) mean that you'll have more power available. I shall have to try this stuff out. Especially where as I am buying an older (1980) motorcycle. (just to save the carbs from that evil shyte they're puttin in the gas now)
Question: I got some Startron to try. LWRider, did you notice an increase in MPG right off the bat with the double-dose starter dose? Because I just filled up after using it for the first time with the double-dose and my MPG is unchanged, MAYBE a little lower (34.something this fill up). I'll report back after this next tank using the normal dosage.
 
#14 ·
Well, if gas milage does go up, then I would imagine that would mean it IS extracting more energy from the gas burned. Which should (in theory) mean that you'll have more power available. I shall have to try this stuff out. Especially where as I am buying an older (1980) motorcycle. (just to save the carbs from that evil shyte they're puttin in the gas now)
 
#15 ·
Here's a relevant comparison, a mechanical watch (carbs) vs. a quartz watch (fuel injection).




When carbs are mechanically in order, clean, and tuned correctly, it is a great system. When that's not the case it can be extremely difficult for a shade tree mechanic, and even professionals to sort out the problems. There are many small passages in carbs for fuel and air to move though that can get blocked by varnish and residue, many mechanical mechanisms and moving parts, many gaskets and o-rings.

I think a lot of people, including myself, are a bit naive when they buy an older bike that is not running, or not running well, thinking that carb problems will be an easy fix. Then the forum questions start rolling in! Sometimes fixes are as easy as cleaning and replacing obviously bad parts. Sometimes it is much more complex when systems are not functioning properly in a way that's not obvious. Then there's the whole system of tuning, which is like a science in of itself. Dialing in the jetting can drive a novice bonkers.
 
#16 ·
I think there is something to be said for both systems.

Yes, carbs can be complicated, although with a little experience they are really not too intimidating. And you can do something about it when you have problems. There may be quite a few parts, but they are mechanical and the beauty of it is they come apart.

Fuel injection in theory is more simple, but requires electronic controls, not to mention a fuel pump. If something goes wrong with the electrics, there's not a lot you can do about it, except to plug in a new controller or pump (and shell out a pile of cash). On the other hand, EFI is usually pretty trouble-free, so the chances of something going wrong is reduced.

I think for long distance riding in far off places carbs might have the upper hand, but for most riding in the US you usually won't be stuck that far away where you can't get help. Either way, for riding across Mongolia or some other such place spares need to be carried anyway, no matter how you're getting the fuel to the cylinders.

Cheers,

Mike
 
#17 ·
Another advantage to carbs is that they are much cheaper to modify than EFI in a general sense. (But not necessarily easier)

The EFI on Harley machines have the owners pretty much locked out of doing any major modifications to the intake or exhaust without having a dealership involved (and paid) or a fairly pricey add-on unit installed.

It would be a boon to the more tech-savvy owners to allow a standard Windows laptop to be attached to the EFI for tuning. But then again, the dealership would lose out on some easy money.

I just leave mine stock. :D
 
#20 ·
One advantage of EFI is aftermarket tunability with a lot of bikes. If you have a laptop, you can do a LOT with a Powercommander V. Also, if you happen to have any sort of ram air, EFI can be a lot easier to tune for that than a carbed bike.

One of my eventual goals with my Shadow would be to do a conversion to a dual throttlebody EFI setup. The same with the Yammie. It will be quite costly, of that I am sure, but, for what I want to do, it would be well worth the cost in my opinion.

Thats the one killer. COST!
 
#21 · (Edited)
I dunno... it runs about $1/oz, so for my bike it would just need to reduce the fill up cost by $1 to break even. That works out to less than a 3 MPG increase. So, going from 35 MPG to 38 MPG would be the break even point.

One thing I can say is that after putting Startron in my tank my bike starts a heck of a lot better! (Though admittedly I could have likely gotten the same results with Berryman's B12 Chemtool.)

Brain fart. Too much studying for vet school finals. I'll recalculate after I've had dinner, haha.
 
#24 ·
My bike is a 1968 and the o-ring around the float chamber gets much longer when using ethanol laced gas. It is really hard to get it back in the groove; I usually have to put a bead of grease all around in the groove and work the o-ring in accompanied by a lot of frustration. Without the ethanol I don't have that problem. Here at home I have a fuel account where I can put in 90 octane non-ethanol gas, but on the road I have to use ethanol premium (bike likes higher octane, reccomended to use 95 (old method, 93 or so new) or higher in the shop manual). So, on the road I use Startron or if the bike will sit for a while here, now that I have another bike to ride.

I don't recall the initial dose being particularly higher mileage-wise. But on all my road trips I keep track of mileage at every stop. Last October running from central Florida to Maggie Valley NC, then to Birmingham, and back I used Startron every time. My fuel consumption went from 55 or so mpg without Startron to 65 mpg with Startron with a high over 70 mpg. The results were pretty consistent.

I have not figured in the cost of the Startron and how that affects cost per mile, but for my 2.6 gallon tank, I use about a capful. It takes very little. I still have that same (small) bottle of Startron I bought back before the trip and it is half full still. Seams like it was about $9 and does 80 gallons, but I would have to check that to swear by it. What's that? about 11 cents a gallon for another 10 miles range per gallon? But even if it does not make the fuel cheaper, the benefits to those old carbs is worth it.

Cheers,

Mike
 
#26 ·
Mike, is that increased milage on your trip as measured against a similar trip in similar conditions, or compared against daily around town driving?

I use Startron as a tool, and it's great stuff! It is absolutely amazing in it's ability to clean out fuel injectors that have been blocked by someone allowing an EFI bike to sit for too long. I don't use it on carbureted bikes as it is quicker and more effective for me to physicaly clean the carburetor. I can do a better job then the chemical.

Does it give you more power? Hard to say. There's only a finite amount of energy available in a certain amount of gas, and adding an enzyme cannot increase that, but it certainly could restore the efficiency at which that energy is released. I doubt you'd feel that difference though.

But if the stuff cleans out your injectors or helps clean out some crud from your carburetor, and the bike runs better because of that, then you'll definately feel THAT difference.
 
#29 ·
Mike, is that increased milage on your trip as measured against a similar trip in similar conditions, or compared against daily around town driving?
That's comparing it to highway miles I've recorded on my other long trips (been to MI and back, Birmingham and back, and Smokies and back before). I was super surprised at my 70 mpg I got between Franklin and Maggie Valley, NC. My 350 never had given me the mpg that I hear a lot of other CB350 owners talk about. Could be the hot cam they used the first year. On long trips I was always averaging about 55 mpg (I usually run 60 mph on secondary roads) so to get ten more mpg, especially with that tiny tank was sure welcome.

On the long trips I have usually given the carbs a thorough cleaning beforehand so I added the Startron basically to counteract the ethanol in those old carbs. When I set out on my last trip to Maggie Valley and Birmingham I decided before leaving to make it a Startron test.

Cheers,

Mike
 
#31 ·
OK, just thought I would clarify the Startron economics now that I had been in the garage and actually taken a look at the bottle to refresh my memory. My $10 8 oz. bottle says you add 1 oz to 16 gallons of fuel and that the entire bottle will treat 128 gallons of gas. That makes the cost about 8 cents per gallon.

So if you used to get 55 mpg and fuel cost $3.70 a gallon, the cost per mile would be 6.7 cents. If you used Startron the gas would cost $3.78 per gallon and if you got 65 mpg, the cost per mile would be 5.8 cents per mile.

I think I got that math right.

Cheers,

Mike
 
#32 ·
Well, I suspect part of the reason it takes a tankful or two to see improvement is because the stuff probably does clean the carbs as advertised. Now, what if your carbs are nice and clean already?

I saw a noticable difference pretty quickly with this stuff. I actually got an increase in power. I guess that it works pretty quick in countering the effects of ethonal in your gas. I doubt I will see much improvement in milage, but that is due to how I ride, and not in actual improvement in economy.
 
#33 ·
Seems to be a lot of math in here lately.....

That's interesting about the milage Mike. So by using it you're saving about 1 cent a mile, right? Maybe that might not seem like a lot, but if I have my math right, that means that about the time every oil change rolls around, it will have been paid for by using the Startron.
 
#36 ·
I do not know how either, but I will attest to the fact that the bike did have more power. I do not know just how much of an increase it was, but on a bike that is not all that powerful to begin with, it is enough to notice a difference.

That makes it worthwhile for me in my opinion. I wont question how it works. I just know that it does.
 
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