1982 gs850l gas mileage

[rrhuehn]

I have a question about my fuel mileage. I am getting about 37-38mpg for my 1982 GS 850L and I think it's a bit low. I know the bike seems geared low and I have a vetter SS fairing with a tall winsheild on, is this mileage normal for that setup?

Carbs have been cleaned by me top and bottom, slides and everything spotless. New airfilter, oiled it with 10 w 30 and about 16k for miles on the bike. New spark plugs as well.

I don't think there is anything else I can do short of taking it in to get the carbs sync'd since I wouldn't have a clue how to do this myself.

[Steve]

First question to ask is ... how fast are you riding?

My wife's '82 850L (click the link) has a windshield, saddlebags and trunk mounted. Granted, it's not a Windjammer, but I do have one here to go on my son's '81 850.

Last year we got the lowest mileage we have ever seen (30.6 mpg) while we were trying to stay up with a group on the freeway. Took two tanks to go 200 miles, average was about 31.5 mpg, but the speed was 70-75 mph. Later on that same trip, going through the mountains of West Virginia, then on the way home, mileage hovered in the mid- to upper-50s with a peak of 58.78, but speeds were back in to the 55-60 mph range. Overall mileage for the 1200-mile trip was 48.5 mpg.

Also important to know would be the state of tune of the engine. Poor valve adjustment, ignition timing or spark plugs will also cut your mileage, but speed is your greatest factor.8-[

By the way, welcome to the forum. Let us know a little more about you by filling out your profile with what you ride and what little corner of the world you call "home". Chances are there might be one of us that is close enough to lend a hand or a tool.

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[rrhuehn]

Thanks for your reply. I am riding about 55-60mph driving it about 25 miles one way to work on back roads so I have been easy on the throttle. To me that would seem low.

I am thinking I should take it in to a dealer to have the carbs tuned and you say valves adjusted and engine timed? I doubt the engine has been touched since it was new, I got it back in 1995 with 6200 miles, it had been wrecked and I fixed it up. It now has about 16,000 miles on it.

I just wanted to get an idea what is normal mileage for the bike to determine wether it should go into the shop or not.

[Steve]

Instead of taking it to "a shop", get a manual and some tools and do it yourself. You can visit BassCliffl's website to download a manual for your bike. A full selection of tools to keep your bike running will cost you a couple hundred dollars, or about the same as a single visit to "a shop". The advantage is that your second service will be FREE if you do it, but will cost just as much again if you go back to "a shop".

As long as you know which end of a screwdriver to pound on, there are plenty of us here that can help you through it. 8-[

Oh, and with 16,000 miles on it, the manual says it should have had the valves checked FOUR TIMES already. :shock:
Carb sync would not hurt anything, but is more of a "how it feels" thing rather than "every so many months/miles".

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[rustybronco]

I am thinking I should take it in to a dealer to have the carbs tuned and you say valves adjusted and engine timed?... to determine wether it should go into the shop or not.

Take it to the dealer, what is that?

BASSCLIFF!!!!! your turn.

[rrhuehn]

I am all for doing it myself it it's something I can do. I will check out his website, I do also have a Haynes manual for the bike, just came yesterday. Should I start with checking the valves?

Also I read on here a while back about carb syncing and there was some device you can buy that came from the UK that everyone seemed to recommend so is that also the way to go?

Thanks again for your help!

[tkent02]

Take it to the shop and it will never be the same again, do it yourself or throw the bike away.

[Steve]

I also got a Haynes manual a couple of months ago with my son's bike, I have had the Clymer manual and the factory manual that I downloaded from BassCliff. Trust me, there is nothing like the completeness and accuracy of the factory manual, but it's also nice to have other points of view or different pictures.

Probably the most poplular carb sync tools are the better unit from Motion Pro and the Morgan Carbtune (the one from the UK that you mentioned).
The Motion Pro SyncPRO retails for about $100, but can be found at Z1 Enterprises for just under $85.
The Morgan Carbtune retails for 55GBP, which converts to about $107. They have a special offer which includes a nice carrying/storage case which takes the price to about $120. Add about $7 for shipping, the total is about $127.
The Carbtune is also available (occasionally) from California Sport Touring for just under $100. The case is another $23, shipping is $12-14, for a total of $137. Some forum members have reported delays when ordering from CST. Morgan claims to have no distributors, so I think CST merely buys a few when they can, so they can re-sell them.

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[rrhuehn]

I am going to give this a shot on my own. I will order a carb tune and see how it goes. I am sure I will be back with questions.

Thanks again for all your help!

P.S. I just ordered the Morgan from the UK. When I was reading those threads a while back everyone had nothing but good things to say about it so I will give it a shot!

[Dogma]

Should I start with checking the valves?

Yes, that long overdue, you may not even be able to hear them clatter. The engine should sound a bit like a sewing machine. All balancing and tuning will be wrong until those are right. Just doing that may also help your mileage.

[Steve]

Yes, that long overdue, you may not even be able to hear them clatter.

Actually, you should never hear the valves clatter. That would indicate that they are too loose. The specs call for .001-.003" clearance, which is nowhere near enough for them to clatter, and, as the miles roll on, they clearance will tighten up, not loosen. Tight valves will lead to poor performance, then when you add throttle to compensate, the additional load will soon lead to burnt valves. Yeah, check 'em SOON. 8-[

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[Dogma]

Actually, you should never hear the valves clatter. That would indicate that they are too loose. The specs call for .001-.003" clearance, which is nowhere near enough for them to clatter, and, as the miles roll on, they clearance will tighten up, not loosen. Tight valves will lead to poor performance, then when you add throttle to compensate, the additional load will soon lead to burnt valves. Yeah, check 'em SOON. 8-[

.

Hmm... If not "clatter" how would you describe the sound everyone seems to be talking about? Perhaps I misspoke. Clatter is a specific mechanical condition, right?

[lurch12_2000]

36-38 mpg does seem a little low for "easy" driving.
I get 43-45mpg which includes bursts well over 80mph, riding in stop and go, 80% solo riding and I have a windshield and bags.
Even last year before valve adjustments, new air filter, cleaning carbs, and new intake o-rings I got around 40-42 mpg. Don't get me wrong, it starts much easier, much shorter warm up, flat spots and hesitation eliminated, and smoother running but it wasn't much in mpg increase.
I use 10w-40 oil, have stock exhaust and tire sizes(front 28 lbs, rear 30 lbs air)

[rrhuehn]

36-38 mpg does seem a little low for "easy" driving.
I get 43-45mpg which includes bursts well over 80mph, riding in stop and go, 80% solo riding and I have a windshield and bags.
Even last year before valve adjustments, new air filter, cleaning carbs, and new intake o-rings I got around 40-42 mpg. Don't get me wrong, it starts much easier, much shorter warm up, flat spots and hesitation eliminated, and smoother running but it wasn't much in mpg increase.
I use 10w-40 oil, have stock exhaust and tire sizes(front 28 lbs, rear 30 lbs air)

This is on your 1100 I take it? I think the mileage is low too as the last tank I ran I took it real easy. No interstate driving and not over 60 mph.

[lurch12_2000]

This is on your 1100 I take it? I think the mileage is low too as the last tank I ran I took it real easy. No interstate driving and not over 60 mph.

yes, on my 1100G