93 gsx 750f help

[Nick_08]

I have a 93 katana 750 and it runs perfect but once i go for a ride and then shut it off it wont start will start when its cold

[Black_peter]

Hmm way more info needed.
Unless someone here remembers a Kat specific hot start issue?

[steves]

Blocked vent tube? Bad petcock?

[Nick_08]

When my suzuki gsx 750f gets hot from riding it and i shut it off it wont start back up even if I put the choke on I have had problems in the past with my gas tank not letting air for the gas to flow but then it would cut out like it wasnt on all cylinders or running out of gas. My valves are right on and so is my timing. Could it be my coils or plug wires? It does have 25000 miles on it. Could it be jetting.

Blocked vent tube? Bad petcock?

Which is the vent tube on the bottom of the tank

[VifferJim]

I have a 92 Kat 750 motor... don't think it's a kat-specific issue. More likely, it's a fuel or electrical problem.

Questions:

When you say it doesn't start, you're turning it over and over, but it doesn't run?

How long after letting it sit does it finally start back up? Does it ever??

You might want to do new plug wires just for good practice, but if you have had this problem in the past with fuel flow, chances are really good you still have it.

Try this: with the bike still hot, turn the petcock to prime for a bit (30 seconds, say). Turn it to On, and THEN try to start it.

If it starts - check vent tubes and petcock, like Steve said... it's a fueling issue.

[whitecl0ver]

Try this: with the bike still hot, turn the petcock to prime for a bit (30 seconds, say). Turn it to On, and THEN try to start it.

If it starts - check vent tubes and petcock, like Steve said... it's a fueling issue.

Thats what i did to run down my fuel issues, turned out it was the petcock was all crudded up and wasnt flowing gas on the 'ON' or 'RES' positions.

[VifferJim]

Thats what i did to run down my fuel issues, turned out it was the petcock was all crudded up and wasnt flowing gas on the 'ON' or 'RES' positions.

Could you tell by shining a flashlight into the tank?? (I don't recommend using matches - )

[Black_peter]

One thing to remember with hot starting;
The engine actually gets hotter before it starts to cool. Oil and air flow stops..

[The CyberPoet]

He didn't say it won't turn over -- he said it wouldn't start (catch).

That causes me to believe it's a jetting issue with the idle circuit or valves way out of adjustment or incorrect start procedure...
(A) Too Rich. When the bike is "cold", the fuel doesn't evaporate/vaporize as well, and the mix is right; as it heats up, the mix gets too rich to support starting.
(B) Valve growth due to heat and really bad valve adjustment...
(C) User trying to use the choke even for a hot start.

QUESTION: How long does it need to cool down to start again?

Cheers,
=-= The CyberPoet

[Black_peter]

Bueller? Bueller?

[Nick_08]

it could be my jets I pulled the aftermarket pipes off and put the stock ones on. It turns over fine but wont fire up. I havent waited for it to cool down to start it back up or see if it will. I know when I bought it it had aftermarket cams, filter and supposed jetting too. Ill mess around with it. Which is the vent tube?I put new Plugs.MY timing and valves are right on. Its weird itll start right up when its cold.

[whitecl0ver]

Could you tell by shining a flashlight into the tank?? (I don't recommend using matches - )

No after replacing the fuel filter and that not fixing the problem i took the petcock out of the tank and looked at it as i moved the handle around and i noticed the lil valve only opened on PRI and it was staying shut on the RES and ON pos. So i spayed carb cleaner in it and took an air compressor and blew it out and cleaned it up and after that tryed it again and the valve was moving like normal, so i stuck it back on and rode out and all was well

[Nick_08]

Did your bike run at all while your petcock was plugged or did it do the same thing as mine is now.

[whitecl0ver]

Did your bike run at all while your petcock was plugged or did it do the same thing as mine is now.

While my petcock was f'ed it would start and run fine while on prime, then when switched back to ON or RES it would die after burning the gas out of the carbs

[Nick_08]

Ok well it runs fine on ON and RES I Will try it on PRI and see what happens.