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Main Area => General GS500 Discussion => Topic started by: theonewolf on October 31, 2008, 12:29:49 PM

Title: Left PRI On ?
Post by: theonewolf on October 31, 2008, 12:29:49 PM
Hey, I accidentally left PRI on on my GS500F (2004) overnight last night. 


Is there anything I need to do to make sure the engine/bike will be ok?
Title: Re: Left PRI On ?
Post by: beRto on October 31, 2008, 01:05:52 PM
Quote from: theonewolf on October 31, 2008, 12:29:49 PM
Hey, I accidentally left PRI on on my GS500F (2004) overnight last night. 


Is there anything I need to do to make sure the engine/bike will be ok?

No. There is nothing immediately wrong with leaving your bike on PRI. The only potential problem is that you will get a fuel leak if the carb float valves do not seal properly. If this had happened, you would likely see/smell gasoline.

If you are interested, the wiki provides some reference info on how the petcock works:
http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/Petcock
Title: Re: Left PRI On ?
Post by: theonewolf on October 31, 2008, 01:16:13 PM
Thanks beRto!  I was reading all kinds of stuff online, trying to figure out what to do.  It really makes me feel better having someone else answer my question :)

There was no gasoline under the bike, nor did anything smell excessively of gasoline.  I was checking the oil multiple times and trying to see if I detected any gasoline smell at all, but I couldn't smell anything out of the ordinary (I think).

Also, thanks for the reference.  I'm still trying to figure out how motorcycles work mechanically (so I can answer my own questions right?)  and I'm a CS guy so I don't have a huge mechanical background.
Title: Re: Left PRI On ?
Post by: galahs on November 01, 2008, 12:28:07 AM
No real problem with leaving it on prime, however... if your fuel float sticks your entire tank could drain.

If you do a simple modification to your petcock you can run a prime system that uses the main pickup (not the reserve) so if this happenes, you will still have some fuel left in your tank.

http://gstwins.com/gsboard/index.php?topic=37366.0
Title: Re: Left PRI On ?
Post by: Pigeonroost on November 01, 2008, 07:42:13 AM
On this model of bike, if a float sticks and the valves are in that just right position, will the leaking fuel fill the cylinder jug -locking up teh whole shebang, or does it always run to the outside.  I've had the former happen on some small engines and an old Duke 350 single banger I had as a kid back in the 70's.

prs
Title: Re: Left PRI On ?
Post by: gsJack on November 01, 2008, 08:12:12 AM
I parked my old totalled and repaired 97 GS once in Pri after I was riding my 02 replacement GS most of the time.  The fuel selector positions for the Res and Pri were reversed between the 97 and 02 GSs.  When I went to use it again I first checked the oil and it was overfull and smelled like gas.  I switched the selector to Res, changed the oil, and off I went.  No problem, if the needle valve in a carb is being held open by a speck of dirt it more often than not purges itself.

I had 4 Hondas before the 2 GSs and all but one didn't have a vacuum shutoff.  Your supposed to switch it to off when you park the bike but I never did and never had a problem with a leaky carb needle valve.  I put 230k miles on those 4 Hondas over 15 years.  Leaving the old Hondas w/o vacuum shutoff in the on position is the same as leaving the GS in the Pri position.  Only the float needle valve in the carbs is stopping the gas tank from emptying into the engine.
Title: Re: Left PRI On ?
Post by: theonewolf on November 02, 2008, 06:48:33 PM
Cool, thanks for the advice/wisdom.
Title: Re: Left PRI On ?
Post by: yamahonkawazuki on November 03, 2008, 02:48:59 AM
Quote from: gsJack on November 01, 2008, 08:12:12 AM
I parked my old totalled and repaired 97 GS once in Pri after I was riding my 02 replacement GS most of the time.  The fuel selector positions for the Res and Pri were reversed between the 97 and 02 GSs.  When I went to use it again I first checked the oil and it was overfull and smelled like gas.  I switched the selector to Res, changed the oil, and off I went.  No problem, if the needle valve in a carb is being held open by a speck of dirt it more often than not purges itself.

I had 4 Hondas before the 2 GSs and all but one didn't have a vacuum shutoff.  Your supposed to switch it to off when you park the bike but I never did and never had a problem with a leaky carb needle valve.  I put 230k miles on those 4 Hondas over 15 years.  Leaving the old Hondas w/o vacuum shutoff in the on position is the same as leaving the GS in the Pri position.  Only the float needle valve in the carbs is stopping the gas tank from emptying into the engine.
yup jack here knows it all. if you EVER have a question about tires, hes the guy to go to  :bowdown: :bowdown: :bowdown: