running on prime

[riverajay23]

I know I've seen a post similar to this one, but not sure if it was the exact same issue. Anyways, my 1997 katana runs great on prime, but when its turned to "on" it shuts off almost immediately. Help please!! Could it be a bad fuel cock??? It was leaking at first, but replaced the oring and now it stop leaking. Any suggestions will be appreciated about the running on prime part. Thanks in advance.

[LHOPPER]

I`m been checking on the fule cock and they need vacuum to open on run.

[HemiKat]

Make sure you have good vacuum at the center nipple in the back of the petcock. Should go to the outside port on the #4 carb. Other two lines are fuel lines that go the the "T's" on the underside of the cabs between #1 ,#2 and #3, #4. If the line is there with vacuum and you are still not getting gas, sounds like time to rebuild the petcock.

[georgedaman]

Make sure you have good vacuum at the center nipple in the back of the petcock.

I have the same problem as the poster of this tread .Just got the bike and rode it home on PRI.
Is there any way to check for vacum without the gauge?

[DumbLuck]

i use a 5cc syringe and short piece of tubing to simulate the vacuum from #4 carb. you shouldnt have to pull very hard at all to open the petcock. given your syringe and hose are good it will be quite evident if the petcock diaphram is good and holding vacuum.

[Kreylyn]

put gas lines from the petcock down to a catch (glass, cup, something to catch gas if it comes out)
Put a clean line on the petcock... apply suction.

If gas goes into the catch with suction, and stops without... your petcock is working correctly.

Krey

[riverajay23]

thanks, I'll have to check the vacuum this week, and maybe buy a fuel cock

[Kreylyn]

Don't buy one, rebuild it...

cp sells the kits for cheap.

There is a full pictorial of how to do it posted in the how too section.

Krey

[riverajay23]

nice job on the fuel cock rebuild, I'm thinking about doing that instead...its way cheaper...thanks

[georgedaman]

Got my problem sorted...vacume line was off the nipple.

[Kreylyn]

Got my problem sorted...vacume line was off the nipple.

Easy fixes are nice once in a while...

Krey