Big Starting problem

[Con]

My son bought a 2000 Suzuki GSX750 Katana around early August. It only has about 1400 miles on it. It was parked for 6 years by previous owner. When he bought it, we were told that they had their mechanics make sure it was in tip top shape (new plugs, new air filter, are sync, tune up, oil change, etc.

When we brought it home, we have been able to ride it for about 2 weeks with no problems and even put on 60 miles on it (wasn't registered yet, was waiting for import papers). Then all of a sudden, it decided not to start one day. It sounds as though it wasn't firing.

We tried:
1. New gas
2.Priming it for 20-25 secs.
3.pulled the plugs out, on the tip it was a dark oily wet color,
4.tested for sparks, they are just fine
5.We replaced the petcock valve (old one was giving slight leakage outside the body)

Q's
1. How to test ohm resistance from pars upstream of plug wires.
2. How verify gas going into carb etc (smells gassy when trying to start).
3. Anything else to look for?

Please remember that this bike ran perfectly fine and smooth a 6 days before there was no firing.

Please Help.

Con

[87vert]

carbs probably need to be cleaned, how is the tank, was it rusty or still clean?

[arsenic]

yeah I would certainly think you had some rust in the tank and it gunked up the carbs.

[md86]

Test for spark by pulling a plug and grounding it against the engine .

[ctandc]

Well you need fuel and spark to run...so start with the basics.

First off unplug EVERY connection that runs over the valve cover. Clean it out w/ contact cleaner, then put some dielectric grease in them and connect them back. Do this BEFORE replacing / testing / tearing apart anything else...ask me how I know to do this.

RH side rear. Check every fuse in the fuse box.

Make sure every spark plug boot is securely connected to the wire.

Make sure all caps are securely on top of each plug.

Now get another set of NEW plugs. Pull one boot, install the NEW plug, and check for spark by grounding the plug while you try to crank it.

Try these first. I bet ya you'll get fire when you get to the end.

Next is fuel.

Pull the tank. Use a flashlight and look for any rust / sediment or trash. If it rusty, pull tank, drain, and coat the tank. There are tons of webpages with instructions on this.

If not rust....with tank removed, connect two sections of fuel line to each side of petcock. Run them into a bucket. Switch petcock to PRIME and see if gas flows freely.

Then pull petcock and check for rust / trash in the filter.

If you find trash / rust anything but gas in the tank, go ahead and pull the carbs and get to cleaning.


HTH

Chris

[steves]

3.pulled the plugs out, on the tip it was a dark oily wet color,

Did you replace the plugs yet? Put new ones in.

So the starter spins, but the bike doesn't catch?

[Con]

starter grabs & spins fine - just not firing.

Gas tank did look good but I confess we did not look hard at all, will try with mirror etc.

Will try new plugs next.

fuses certainly seem like a longical choice, cannot remember if we looked at this yet or not.

Petcock is brand new - old has no rust showing, nor trashed up

I do not assume there is an easy way to check for gunk in carbs? what to look for? I do not wish to take apart carbs If I can avoid it.

Con

[Yeshua]

I am the son, just so you guys know.

When we first had the problems, I did check for broken fuses. All looked brand new and none were broken.

Hope that gets rid of some possibilities which would narrow the problem down.

Thanks to all.

[The CyberPoet]

The gas tank is still the primary suspect. Easy way to tell if it's rusted -- pull the carb float bowls and check for the presence of an orange paste. If you find any, you've got tank rust.

Sample Pic:


How to deal with it: CP's How to get Rid of Gas Tank Rust.

If you do have a rust issue, you'll need to clean the carbs extremely thoroughly to get rid of all the debris.

Cheers,
=-= The CyberPoet

[Con]

yippeeee

new plugs & fired up immediately.

Have no idea why though as the old ones were providing spark on each one as well...

Whatever... just glad it runs again - & a very sweet but short ride today

thanks for helps!!!

Con

[Yeshua]

So the bike works now....We replaced the spark plugs....and we also found out that there was actually supposed to be 3 hoses connected to the gas tank area, 2 on the petcock valve and one undernieth the gas tank....We have never actually seen the vaccum hose on...we have only ever seen 2 hoses connected total....so between those two things....the bike works now (I have been so happy all day today and just wanting to ride...too bad its still not registered and I didn't finish work until about 1:30 AM. Oh well...there is always Sat.!)

Quick question though. I have read that the Kat can be hard on spark plugs....about how often do they need to be replaced?

Thanks a lot to everyone!

[The CyberPoet]

If it's running well, every 7.5k miles according to the maint schedule, but they'll last up to 15.
If it's not running well, as short as a few start-ups, esp. if you're using lots of choke.

Cheers,
=-= The CyberPoet

[md86]

But I'd check them again shortly "just because" , as it seems you guys don't know much about this bike . The plugs can tell you a LOT about a bike .