SuzukiSavage.com - petcock problems

jonnychop

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petcock problems
11/03/08 at 15:45:05

Guys i have a question, now i know this petcock problem with the vacum diaphram has been beat to death, but i want to ask, untill i get a new petcock will turning the lever from PRI back to fuel really turn off the flow of gas to the carb? it seems contradictory if my diaphram is leaky, iv'e forgotten to turn it back to fuel a couple of times, ivé heard that your crankcase can get full of fuel and thin out your oil and really make a bad problem (thrown rod etc.), will capping of the vacuum line help, it only runs well in PRI anyway!

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Trippah

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Re: petcock problems
Reply #1 - 11/03/08 at 16:01:17

JC (and i could be wrong here), the petcock is , in the running (on) position, a vacum so when the bike is not running, no vacum in the carb exists so the gas should not pass through the petcock....which is why your bike is only running well on prime which does not require the vacum. If you are unsure, disconnect the gas line to the carb, set pc on "on" and watch for flowing gas. should take about ten minutes tops to scientifically get the real answer. Wink

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seviersavage Senior Member Offline SuzukiSavage.com Rocks! Posts: 364 Smoky Mountains Tennessee Gender:	Re: petcock problems Reply #2 - 11/03/08 at 16:02:42 Turning it from prime (gravity flow) to fuel (vacume flow) will turn off the fuel flow when the engine is off. Of course if its leaking because of a comprimised vacume line it could still trickle out. Raptor 660 petcock fits perfectly and no vacume to worry about but you still have to remember to shut it off after riding. Seviersavage
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verslagen1

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Re: petcock problems
Reply #3 - 11/03/08 at 16:50:02

The petcock is vacuum activated, the only time you have vacuum is when the engine is running. When the engine isn't running, no vacuum, petcock is off when set to 'on' or 'res'.

When the petcock is set to 'pri', gas will flow regardless whether the engine is running or not.

If you think your petcock is leaking thru the diaphram, remove the vac line and cap both ports. Gas might leak thru the diaphram down the vac line pouring gas into your engine.

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88pagan

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Re: petcock problems
Reply #4 - 11/03/08 at 18:18:23

Can someone specify which year raptor petcock they've been using?..or will any of them work? I did the mod but still get a slight trickle of fuel when it's turned to prime. It doesn't seem to be causing any problems but since everyone keeps saying how important it is to shut the gas off on the raptor one, I'm just wondering if I'll notice anything going wrong. For anyone that cares, it seems my rebuild was successful and I finally got it lean enough at idle to run great. Now about that petcock...

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odvelasc Ex Member	Re: petcock problems Reply #5 - 11/03/08 at 19:15:20 or tighten the bolts on your petcock. Have you taken it off lately? When reasembled the tank after painting I used the wrench to tighten, but did not tighten enough. Thus I used the socket to tighten it and it stopped leaking. Good luck
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88pagan

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Re: petcock problems
Reply #6 - 11/04/08 at 08:59:31

Sorry, I wasn't referring to the petcock leaking where it's mounted. I meant, I did the mod so it has res/on/off, and in off (old prime) there is a slight leak. That's why I was thinking of putting a raptor petcock on if I can find the right one. Otherwise it doesn't seem to negatively affect anything. Anyone tell me why leaving it as is would be bad? The fuel filter stays full but since I feel the floats are adjusted correctly now, the fuel is shutoff when the float bowl is full correct?

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96 Bobber - Screamin Eagle, header wrap, K+N cone filter, jetted, straight bar w/1.5" risers, solo seat, Ed. L fwd ctrls, custom rear fender, TKat, Metallic charcoal and polished all over.

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jonnychop

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Re: petcock problems
Reply #7 - 11/04/08 at 11:46:24

Taking into account what youve told me i pulled of the vac line last night and replaced it, (it was kind of cracked and old) i put a new line and sucked on it with my mouth petcock in fuel postition, and no gas came out at all is that what should be happening? now bike runs fine in fuel postion except when very cold then i put it in pri for the warm up and back to fuel for running. Roll Eyes

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Yonuh Adisi FSO Serious Thumper Offline Savage Jedi (Knight) Posts: 3622 Pilot Valley NV, aka Tatooine Gender:	Re: petcock problems Reply #8 - 11/04/08 at 12:01:24 There should be no fuel at all flowing through the vac line.
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