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Hi all. First time posting and I’m hoping someone, anyone, has had the same problem I’m having or have some idea about what’s going on

I bought a 2000 sv 650 as a daily rider. Nothing fancy, just something to get around that has a little zip.

Bike rode great for a few months but then started having a very strange issue. Once the motor gets hot (about 20 to 30 mins of riding) the power completely leaves the bike. She will still drive but it’s as if all the get up and go disappears. Just to keep at highway speed I’ll have to downshift and open the throttle up completely! In fact, I ran out of gas trying desperately to get home.

The weird part is that she had zero problems starting and idling and if I just shut her down and let her cool off everything would return to normal until the motor got hot again. It does also seem that it’s is happening sooner and sooner every time.

So, my suspicion was the the carbs were gunked up. I have taken them out and inspected them. They look great.

Has anyone else ever heard of this kind of issue? Had this issue? Have any educated guesses? I’m thinking of replacing the fuel pump and rebuilding the carb just to be safe for now but would really appreciate any help.

Thanks in advance
 

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My first thought. How hot, as in is it too hot and the engine is on the verge of seizing. Next thoughts, check the spark and the fuel pump. Is the spark failing when the coils are hot? I forget how the fuel pump works.
There is a dedicated SV650 SV1000 site.

UK
 

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This is just generic advice but maybe a bad ignition coil that's sensitive to heat (not uncommon) has it running only on 1 cylinder when hot? When it gets into that power loss situation ride for a minute or two then stop quickly and check exhaust pipe temps. If one is much cooler than the other that would point to one cylinder not firing at that time..which could be a few things but the coils would be where I started in that case.
 

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Ace Tuner
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My first thought. How hot, as in is it too hot and the engine is on the verge of seizing. Next thoughts, check the spark and the fuel pump. Is the spark failing when the coils are hot? I forget how the fuel pump works.
There is a dedicated SV650 SV1000 site.

UK
" on the verge of seizing " Reminds me of some ATV customers...

Is the engine on the verge of seizing due to lack of lubrication after warm up?

How old is the oil in the engine? Could the oil be sooo old that it has lost its ability to lubricate? Could the oil be contaminated with fuel?
If there is gasoline in the oil you can (or should) be able to smell it at the oil fill opening.
I've fixed ATV's by changing the very old oil or oil that is contaminated with fuel. (Usually with the rancher yelling "but its got oil in it").
Never seen it happen with a bike but fuel in the oil could make it do what you describe.
 

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Being a 18 yr old bike, in addition to everything mentioned i would start with a compression test before you start replacing things. Make sure you have the right plugs/ gap and check/clean ignition connections. Does it lose power at slow speeds around town also or just the highway? See the results, you might need a leak down test if none of the stuff mentioned is working. Hopefully its nothing serious
 
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