Am I running lean?

[Guest]

Bike starts fine but takes a long while to warm up. Flat spot between 2500rpm and 4000rpm. After 4000rpm pulls clean to redline but feels low on power. No top end rush. See attachment for a plug check. As far as I know bike is stock. Stock pipes, airbox intact. Air filter good. No air leaks, THAT I CAN FIND. All four plugs look the same as the one in the attached pic.

Thanks.

John 1982 GS650G

[tom203]

Somebody has to ask..... what maintenance has been done? Have carbs been properly cleaned in last decade?
This flat spot is still there when bike is warmed up? So even when you take off in first, you notice this ? Plug looks too new to tell me much. At next cold start up , determine if any cylinders aren't firing within 30 seconds or so.

Edit; make sure "choke" is fully disengaging at carbs when off; my bike will stumble in this rpm range unless choke is fully off.

[Larry D]

....along with that...have you adjusted the valves ?

[BassCliff]

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[Caferacernoc]

Somebody has to ask..... what maintenance has been done? Have carbs been properly cleaned in last decade?
This flat spot is still there when bike is warmed up? So even when you take off in first, you notice this ? Plug looks too new to tell me much. At next cold start up , determine if any cylinders aren't firing within 30 seconds or so.

Edit; make sure "choke" is fully disengaging at carbs when off; my bike will stumble in this rpm range unless choke is fully off.

Thanks for the information from everyone. Not my first bike, just my first Suzuki. This forum is fantastic!
The plugs have 500 miles on them. The valves have not been adjusted since I have owned the bike. Not looking forward to the "shim" business! But the bike is clean with 18K so it's worth it! It looks like the choke disengages properly. I'll double check. The carbs were supposedly clean when I got the bike. I know I have to pull them, just asking about being lean before I go to it. And yes, the flat spot never goes away completely although when the bike is really really warmed up, and it's really really hot out, it gets a lot better. My last bike had pods, this looks like a huge pain! Thanks again!

[tom203]

Nice find! get some covers for swing arm pivot or your pivot bearings will suffer. Basscliff has the stuff you need to know, so take advantage. Checking valve clearances is intimidating the first time, but plenty of us have muddled thru it. On these engines, the clearance wears smaller, and since it starts out at like .003 inch, it doesn't have far to go.
As an experiment, next time it's warmed up, peel back the air filter element a bit and go for spin to see if additional air changes this flat spot.

[BigD_83]

Nice find! get some covers for swing arm pivot or your pivot bearings will suffer. Basscliff has the stuff you need to know, so take advantage. Checking valve clearances is intimidating the first time, but plenty of us have muddled thru it. On these engines, the clearance wears smaller, and since it starts out at like .003 inch, it doesn't have far to go.
As an experiment, next time it's warmed up, peel back the air filter element a bit and go for spin to see if additional air changes this flat spot.

The covers Tom mentioned are available through Boulevard Suzuki if you do not have a local source. I tried to get some through CL/parting out ads, but wasn't successful.

[Caferacernoc]

The covers Tom mentioned are available through Boulevard Suzuki if you do not have a local source. I tried to get some through CL/parting out ads, but wasn't successful.

Will do. Thanks.

[7981GS]

For your carb problems, you should contact TheCafeKid on this forum.
Perhaps he missed THIS thread?

Eric

[rapidray]

I didn't see where anyone answered your question so I will tell you that, from what I can see from your picture, it IS lean. Ray.

[tom203]

I didn't see where anyone answered your question so I will tell you that, from what I can see from your picture, it IS lean. Ray.

Yeah, it sounds that way, but if he peeled filter element back for test spin, he could convince himself- filter might be overly oiled and he said "it felt low on power"

[chef1366]

Change the o-rings behind the engine carb boots and do a valve adjustment.
If the airbox boots are hard replace them too.

[Caferacernoc]

I didn't see where anyone answered your question so I will tell you that, from what I can see from your picture, it IS lean. Ray.

Thank you.

[Caferacernoc]

Yeah, it sounds that way, but if he peeled filter element back for test spin, he could convince himself- filter might be overly oiled and he said "it felt low on power"

It was overly oiled when I got it but I cleaned and re-oiled it lightly. No change.
And today I tried it with the filter cover cracked open. Flat spot was worse.

[Caferacernoc]

Change the o-rings behind the engine carb boots and do a valve adjustment.
If the airbox boots are hard replace them too.

Going to order the o-rings today and the swing arm bearing covers. Read the basscliff tutorial on the valve adjustment, and prepare for a big weekend!