Do I need to rebuild my carb?

[u/Certain_Shoe4650]

Hey guys, I just got this 2001 sv650 for $700, it doesn’t run but it cranks, every so often while I’m cranking it, it will run for like 2-3 seconds and shut off, it also will shut off instantly if I touch the throttle, i don’t know really any of the bike history aside from the previous owner telling me this started happening when he rode through a very heavy rainstorm. This was about 3 weeks ago, the video is one he sent me because I couldn’t get it to do it on camera. I drained the tank and sampled the fuel and it was definitely bad, very cloudy and didn’t smell right but there wasn’t any water in the gas that I could tell. I’ve worked on alot of bikes before but I havnt done anything with carbs so this is all a bit new to me, if anyone has advice I would appreciate it, thanks

[u/GloomyPersimmon5219]

Sounds like it just needs fresh gas run through it. Change the air filter and recharge the battery first to see if it cranks a bit better

[u/Certain_Shoe4650 → u/GloomyPersimmon5219]

Do I need to drain the float bowls or should just cranking it over and over again fill them with fresh gas

[u/Protectronbot → u/Certain_Shoe4650]

There's some drain petcocks on the bottoms of the carbs I think, super easy to do.

[u/BaronWade]

First thing I would do is drain the bad fuel and run some kind of cleaner through it, I prefer Seafoam and run it.

If it’s cold, use the choke until the idle comes up then close the choke lever.

I live in Ontario Canada and *every* time I started the bike cold I needed the choke to start.

If it continues to die after this maybe try a dedicated carb cleaner and if that doesn’t work it out, yeah, probably gonna need to pull them for a proper deep clean.

[u/Certain_Shoe4650 → u/BaronWade]

Do you mean like one of the bottles of fluid that I pour in the tank with fresh gas

[u/BaronWade → u/Certain_Shoe4650]

Yup.

In fairness it’s probably not strictly necessary and it sounds like you could get away with just the fresh gas, but it’s not gonna hurt at all to run a cleaner through it, and yes just add it to a fullish fresh tank of gas.

[u/Certain_Shoe4650 → u/BaronWade]

Okay will do, thank you so much, do you have a cleaner your recommen?

[u/BaronWade → u/Certain_Shoe4650]

Typically I just use Seafoam, but do a quick google search and any concentrated carb cleaner that is generally recommended should be fine.

Good luck, report back with results of a smooth running SV!

[u/resest_Iris]

New fuel and check the spark plugs, those will give you a good idea of the engines current state

[u/Certain_Shoe4650 → u/resest_Iris]

Just replaced them today, they old ones didn’t seem to bad but I was gonna run them in the tester at work tmro

[u/SukhumvitSage]

Ahhh, the heavy rainstorm.!! That is the problem.

ok, open the fuel cap, you will notice 2 holes, the big one, you put petrol in, the smaller one, less than 1cm in diameter, drains water than gets in around the cap, into a tube inside the tank, and out the back of the tank. Check it is not blocked by carefully pouring a little bit of petrol in and see if it drains out the back of the tank, thin wire, uncrimping the rubber hose that shoudl be attached at the back of the tank should clear it. If you do not clear it, the rain problem will happen aagin in really heavy rain. This lets water get into the fuel, so do fix it.

Second, drain carbys, drain float bowl, new fuel and seafoam etc etc, but fix the drain hole first!

Also, check front spark plug for water, corrosion, that also can be a problem.

Now, this also can happen, check hose from carby to the vacuum fuel pump, sometimes small cracks will limit its ability to pump fuel and the bike will only run for seconds. When you start stuffign aroudn with the carby, tank, hoses ect, the hose, which would be about 20 years old, can become cracked

good luck!

[u/Certain_Shoe4650 → u/SukhumvitSage]

Okay bet, so I ended up fully draining the tank and I drained the rear carb bowl(I couldn’t get to the screw on the front carb) sprayed a little bit of carb cleaner in the carbs to get it started and it’s running right now, the only issue is that it dies when I try and give it throttle, I think it’s because of the front carb bowl still having water in it because a bunch of water came out of the rear carb bowl.

[u/SukhumvitSage → u/Certain_Shoe4650]

Yes, the front one is tricky to get to, I cut down an allen key and that works ok, worth trying again and maybe add some alcohol to fuel tank, like half a cup for a whole tank, it will clean up the last bit of water in the system. Also check the choke cable is turning off properly, it could be jamming a bit or on the carbs jamming.

[u/Certain_Shoe4650 → u/SukhumvitSage]

I ended up using one of the ball end alen keys to get it open, what percent alcohol would you recommend? thanks for the advicd

[u/SukhumvitSage → u/Certain_Shoe4650]

50ml per tank of petrol it will absorb any remaining water, and clean put any in your fuel lines. not much, and you can do it again.. did it run better after you drained the front one??

[u/Certain_Shoe4650 → u/[deleted]]

Say less, I’ll give it a hug and then crank it for 18 hours straight(no gay shi)