Carb maintenance necessary?

[later_aligator]

I have a new (to me) 81 GS450T. It's been idling and running fine except that the petcock can only be set to prime. I am going to replace the fuel valve to take care of that (the part is coming tomorrow). But I figure, as long as the bike will be taken apart anyway and out of service for the winter, it would be a good time to play. I would like to take the carburetor apart and give it a good cleaning, especially since it's been running on prime.

A friend said that wasn't necessary because it's running just fine and that carb maintenance is complicated, especially for a newbie like me (though I have extensive experience on cars, but only fuel-injected ones).

Is there a need for regular carb maintenance? Is this cleaning a good idea? Or does "don't fix it if it ain't broke" apply here?

Maybe you could suggest a cleaner to put into the fuel tank and run through the system instead of taking apart and soaking in cleaner.

Thanks in advance for your wisdom.

 

[Big T]

Cleaning your carbs sure couldn't hurt anything - I'm sure they're due for some fresh O rings

It's pretty easy

1. Take them apart
2. Dip and clean
3, Set float height
4. reassemble
5. Sync

 

[Nessism]

I recommend ordering an O-ring kit from cycleorings.com and having at it. The O-rings turn hard and brittle with age so the way to assure your bike stays running right is to do some maintenance and freshen up the seals. Think about it like performing an oil change for our carbs.

 

[ikantbreave]

Just as an FYI, I am a super newbie to mechanical stuff, motorcycles included and I just broke down my carbs (still need o-rings) but it was a piece of cake. I just kept it organized and should be in good shape. Besides electrical, the carbs seem to be the root of all evil around here. The exploded fiche for the carbs kept me from doing it before with what looked like 6000 parts. Just hope it works when I put it back together. Good luck.

 

[bwringer]

Once you get the new o-rings in, there is no regular maintenance other than making sure the bike never sits long enough for the fuel in the bowls to turn to goo (ride a lot). And most of us try to sync the carbs every so often, usually after checking the valve clearances.

I haven't touched my carbs for eight or ten years.

 

[Larry D]

The trick is to follow the tutorial to the letter. It's actually a fantastic, easily read, well thought out tutorial. Many, many folks have used it with great success. Take your time. Stay organized. Be careful with the float pins.......that about it.

I'm getting ready to do a set for the GK. I'm kinda looking forward to it.

Oops, forgot the link.......hopefully you've reviewed it already.
http://www.thegsresources.com/gs_carbrebuild.htm

 

[later_aligator]

I've got my carburetor out and ready to go (to be cleaned, that is). The screws holding it together are a bit stripped and according to the information I have from the dealer, they aren't available anymore (an 81 GS450).

I've heard that these screws aren't standard; that you should be using screwdrivers on a JIS standard to work with this. Maybe the previous user didn't know that and that's why they're like this. If I have to drill them out and replace them, what would I be replacing them with? Is something I find at a hardware store that's pretty similar close enough? Or are there specs on this? And do the screws need to be torqued back on?

Thanks.

 

[old_chopper]

Replace the bowl and slide cover screws with socket head cap screws (allen wrench style). Your bolt supply store can measure them and get the correct size (stainless steel is best) if you don't have calipers. Drilling the old ones out should be a last resort. I broke mine loose with a small pair of vise grips.

 

[Larry D]

I've got my carburetor out and ready to go (to be cleaned, that is). The screws holding it together are a bit stripped and according to the information I have from the dealer, they aren't available anymore (an 81 GS450).

I've heard that these screws aren't standard; that you should be using screwdrivers on a JIS standard to work with this. Maybe the previous user didn't know that and that's why they're like this. If I have to drill them out and replace them, what would I be replacing them with? Is something I find at a hardware store that's pretty similar close enough? Or are there specs on this? And do the screws need to be torqued back on?

Thanks.

You are correct they are JIS standard. I don't have JIS screwdrivers. But, I do have one of these.
http://www.sears.com/shc/s/p_10153_... Tools&psid=PRODUCTPLUS&sid=ISx20090511x00001

It works great for removing stubborn screws.

IMHO, all these crazy phillips head screws sould be replaced with allen head screws. You just need to take one of the screws you remove to the hardware store, size it and buy the replacement. You won't find these replacement screws at Lowes or Home Depot...you need to find an Ace Hardware or perhaps a nice "Mom and Pop" hardware store. There's a Thrifty hardware store near me...maybe the only one, but, they have a nice selection of metric fasteners.

 

[spyug]

Once the carbs are clean and gunk free you can keep them that way if you add an inline filter to your fuel line and drop in a couple of capsfull of Seafoam in every full tank. Seafoam will help stop the fuel from going bad if the bike sits for awhile and aids in cleaning the carbs and valves.

To do the job more completely, once you clean and rebuild the carbs you should also clean the petcock and maybe rebuild it as it sounds like its frozen up. The tank too should be cleaned & sealed if there's rust flaoating around. Annoying to clean the carbs then find the tank is flowing little rust particles in the fuel.

These are not complicated jobs just time consuming.......but that's why we have winter:-\\\

Cheers,
Spyug

 

[blakebird]

I glanced through the replies, and didn't see anyone mention why his vacuum (or lack thereof) petcock has to remain on prime.

Yes - the carb thing is good, and like most cases - mine was necessary.
I wish I had a dollar for every o-ring I replaced.

But.... if you have to leave it on prime so gas will gravity flow to fill the carb bowls....check your vacuum line. If it's not flowing on "ON" or "RES", you probably have no vacuum at the petcock.
Could be that a new petcock will set it right, but check the line anyway, for splits and a good connection.

 

[later_aligator]

Once the carbs are clean and gunk free you can keep them that way if you add an inline filter to your fuel line and drop in a couple of capsfull of Seafoam in every full tank. Seafoam will help stop the fuel from going bad if the bike sits for awhile and aids in cleaning the carbs and valves.

To do the job more completely, once you clean and rebuild the carbs you should also clean the petcock and maybe rebuild it as it sounds like its frozen up. The tank too should be cleaned & sealed if there's rust flaoating around. Annoying to clean the carbs then find the tank is flowing little rust particles in the fuel.

These are not complicated jobs just time consuming.......but that's why we have winter:-\\\

Cheers,
Spyug

Yes, winter is a gift for motorcycle maintenance and for other reasons as well.

I've already replaced the fuel valve and it comes with a new filter. Are you suggesting a separate filter? I can use the Seafoam, even if I don't have an inline filter, right? And how long does it take for the gasoline to get gooey? Does the bike need to sit for a few months? Is it more like years? I haven't ever done this kind of maintenance on my other gasoline powered things that sit for a while (snowblower, lawn mower) so I'm just curious.

As far as the petcock, it seems the reason it didn't turn is that the previous owner installed it *backwards*. Once I got it moving again, it seemed silly to put the old one back in - the new one turns more easily anyway.

I'll get the carbs apart and see what I can find for allen screws. Those make so much more sense and there are a few local hardware shops around where I can look.

Thank you.

LA