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Main Area => General GS500 Discussion => Topic started by: LOUiE on March 16, 2008, 12:18:55 PM

Title: Prime Backfire?
Post by: LOUiE on March 16, 2008, 12:18:55 PM
Hi all,

I'm new to the forum, from Calgary Alberta, riding a 90 gs500E and I've already got a question  8)

Anyways, I just got my bike from a dealer the other day with a month warranty so I want to make sure if any problems are there I find them... BEFORE the month is up.  So this morning we got some snow (not a big surprise) and I wanted to start her up to see if she starts in the cold weather (something that will be important when riding on the frozen tundra).  I tried to start it a few times, with the petcock on  reg but after 3 tries and no success I decided to prime it.  Set the petcock to prime and tried to start it.  Instead a LOUD bang happened out the back of the bike (similar to a firecracker... about 2 inches from your ear!!).  After I regained my hearing, I put it back to reg and it started no prob and ran for 5 mins before I shut it off.

So I've got 2 questions...

1) are you supposed to start the bike with it in the prime position?

2) what the heck was that noise?  scared the begeezus out of me.
Title: Re: Prime Backfire?
Post by: Jay_wolf on March 16, 2008, 01:26:36 PM
Did u try using the choke? . and that noise was a backfire , unburnt fuel in the system , its not uncommon  :thumb:
Title: Re: Prime Backfire?
Post by: LOUiE on March 16, 2008, 01:59:53 PM
yeah, tried the choke... had it wide open but it didn't start right away thats why I went for the primer.

What is the 'proper' method to prime the bike?



Title: Re: Prime Backfire?
Post by: lamoun on March 18, 2008, 03:18:48 PM
About the prime thingy..


Probably there was no fuel in the carburetor bowls. When you turned to prime, the bowl filled with fuel.

When the fuel valve is ON or RES, then fuel runs to the carburetors only when the engine works, or you use the starter.
When on PRI, fuel runs freely.
Title: Re: Prime Backfire?
Post by: LOUiE on March 18, 2008, 04:48:04 PM
gotcha!  thanks for the info
Title: Re: Prime Backfire?
Post by: yamahonkawazuki on March 18, 2008, 07:31:11 PM
or fuel tank was close to being empty