Idles around 1000 at first -- after riding 3500

[Anonymous]

I have a 1979 GS850. When I first start the bike up, it idles nice and low, a little over 1000 RPMs. After I drive it for a while, when I come up to a stop light or park it doesn't drop down. It usually ends up idling around 3500 RPMs. Then I'll let out the clutch a little and give it some throttle and the RPMs will actually drop as the bike starts to move. Any ideas?

[earlfor]

Re: Idles around 1000 at first -- after riding 3500

The most likely cause if the "O" rings on the mating surface of the induction boots between the boot and the cylinder head are dried out, broken and drawing air causing a lean mixture. A new set of four will cost about $5.

Earl

I have a 1979 GS850. When I first start the bike up, it idles nice and low, a little over 1000 RPMs. After I drive it for a while, when I come up to a stop light or park it doesn't drop down. It usually ends up idling around 3500 RPMs. Then I'll let out the clutch a little and give it some throttle and the RPMs will actually drop as the bike starts to move. Any ideas?

[Anonymous]

That's good. I actually just bought some of those figuring that might be the problem. Would that also affect my gas mileage? I'm only getting about 15 mpg.

[Anonymous]

Re: Idles around 1000 at first -- after riding 3500

I have the same problem on my GS (with the idling), and I wonder what O-rings you are mentioning?? I have brand new intake-pipes (rubber-hose between the carbs and the syl.head), so I don't think it's drawing any air. Maybe my problem can be fixed with a carb adjustment/syncronising
Any suggestions...anyone 8O

The most likely cause if the "O" rings on the mating surface of the induction boots between the boot and the cylinder head are dried out, broken and drawing air causing a lean mixture. A new set of four will cost about $5.

[earlfor]

I would have an effect on milage, but I doubt to that extent. An 850 should get something over 40 mpg in normal condition.

Earl

That's good. I actually just bought some of those figuring that might be the problem. Would that also affect my gas mileage? I'm only getting about 15 mpg.

[earlfor]

Re: Idles around 1000 at first -- after riding 3500

An 81 GSX1100 uses a straight intake boot. The GS850 uses a flanged bolt on boot and the rubber flange bolts directly to the cylinder head intake port.
Your 1100 does not use intake "O" rings. I think you are correct. A vacuum carb synchronization will probably solve your problem.

Earl

[quote="holen"]I have the same problem on my GS (with the idling), and I wonder what O-rings you are mentioning?? I have brand new intake-pipes (rubber-hose between the carbs and the syl.head), so I don't think it's drawing any air. Maybe my problem can be fixed with a carb adjustment/syncronising
Any suggestions...anyone 8O

[Anonymous]

Thanks...I think my carbs is ready for some adjustments. The exhaust-downpipes are turning blue on three of the cylinders. :?

I think I have to start saving. Here in Norway it's very expensive to leave the bike at the shop. I guess I have to pay about $200 to have my carbs synced... ](*,).

[Anonymous]

I would have an effect on milage, but I doubt to that extent. An 850 should get something over 40 mpg in normal condition.

Earl

Any suggestions regarding gas mileage? I just got the bike and put new carbs on. I should spray some carb cleaner into them. How much would synching them and adjusting the valves do? And how much should I expect to pay for it. I'm pretty new at the whole bike thing, and I don't think that's a job I can tackle myself.

Any other suggestions to get better gas mileage?

[earlfor]

A slight bluish cast is within normal range. A deeper blue cast is not. My opinion is pipes turning a golden color are just about perfect. They turn gold running slightly cooler than they do to start turning blue.

I dont know about prices in Norway, but a Morgan Cartune, which is probably the thes synching tool made anywhere only costs about 1/2 of what you would be charged for someone to do the synch for you. Synching your own carbs is not particularly difficult and something you might want to consider. With a Morgan carbtune, I can synch my carbs in about 5 minutes on my 85 GSX1100EF. Just doing it once will pay for the tool.

Earl

Thanks...I think my carbs is ready for some adjustments. The exhaust-downpipes are turning blue on three of the cylinders. :?

I think I have to start saving. Here in Norway it's very expensive to leave the bike at the shop. I guess I have to pay about $200 to have my carbs synced... ](*,).

[earlfor]

Were the carbs in like new condition and clean? I would not bother with spray carb cleaner. Its pretty much useless for cleaning a clogged carb and very good at destroying any decent seals/"O" rings you have in the carbs.

A carb synch can do wonders for how the bike runs. You dont want to do the carb synch before replacing the intake "O" rings. It is pointless to try to synch carbs when you have induction leaks.

Depending on milage, valve adjustment may or may not be needed.

I cant say how much a valve adjustment and carb synch would cost. It varies greatly by area and shop. Usually, a small indepenent shop will be cheaper.

Earl

Any suggestions regarding gas mileage? I just got the bike and put new carbs on. I should spray some carb cleaner into them. How much would synching them and adjusting the valves do? And how much should I expect to pay for it. I'm pretty new at the whole bike thing, and I don't think that's a job I can tackle myself.

Any other suggestions to get better gas mileage?

[dgeorge]

I would also check on the jet sizes. If you bought the carbs then someone may have rejetted the carbs or they could be from a different model that uses a different size jet. When I rebuilt the carbs on mine last year, the rebuild kits came with two sizes of main, pilot and air jets. I used the wrong ones to start with and the bike ran pretty bad and got terrible gas mileage.

[Anonymous]

a Morgan Cartune, which is probably the thes synching tool made anywhere only costs about 1/2 of what you would be charged for someone to do the synch for you. Synching your own carbs is not particularly difficult and something you might want to consider. With a Morgan carbtune, I can synch my carbs in about 5 minutes on my 85 GSX1100EF. Just doing it once will pay for the tool.

Would you be willing to walk me through the procedure for this? If so, I think I'd like to give it a try.

[earlfor]

Sure, not a problem. :-) Do you have one yet, or do you mean youre going to get one? The Carbtune comes with setup and pretty decent instructions and explanations. I cant say enough good about John Morgan.
Great guy, with a great product.

I'll be happy to help whenever you're ready. :-)

Earl

a Morgan Cartune, which is probably the best synching tool made anywhere only costs about 1/2 of what you would be charged for someone to do the synch for you. Synching your own carbs is not particularly difficult and something you might want to consider. With a Morgan carbtune, I can synch my carbs in about 5 minutes on my 85 GSX1100EF. Just doing it once will pay for the tool.

Would you be willing to walk me through the procedure for this? If so, I think I'd like to give it a try.

[Anonymous]

Sure, not a problem. :-) Do you have one yet, or do you mean youre going to get one?

I'll have to get one. Any particular place? We've got a CarQuest right next door, but their battery prices were kinda high...

I'm a novice to motorcycles, so stuff that seems self-evident to an experienced guy like you will take me a while to figure out. But I'd certainly appreciate the help. Thanks, Earl.