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Discussion Starter · #1 ·
Almost ran the DRZ out of gas yesterday and switched it to the prime location on the petcock instead of the reserve. It feels like im not having the issues with it surging as bad with it on prime. Could this mean there is something up with the vacuum line from the tank to carb? Line is clear so im wondering if its something inside the carb? Will running it on prime mess anything up as long as I cut it back to on once im done riding? It has a stock carb with jet kit.
 

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What is your definition of Surging? A properly jetted bike should not surge.

I could not imagine how the Pri vs On or Res would impact that if the bike has fuel in it.

Are you sure you are riding under the same conditions; wind, air temp and elevation when the change is felt? It could be that you're jetting is borderline and just takes it heating up or something to push it over the edge into a lean condition.
 

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I ran my bike on prime once I converted to the FCR for about 2 years. It's fine. I finally got around to sticking an E petcock on it so I could use reserve again.

I do remember reading people having fuel delivery issues with the vacuum petcock. I'd just stick an E petcock on it and plug the line.
 

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I've actually had some of the same issues, but have not tried the prime setting. I'd take a guess that there's some kind of issue in either the vacuum line or in the vacuum diaphragm in the petcock. The prime setting doesn't require the vacuum to work, it's just ON. That said, don't park your bike with it on PRIME as it will continue to allow fuel to flow and could potentially cause issues.
 

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I have an '89 Virago that has the same vacume petcock. It ticked so I disabled it 10 years ago and never had a problem. Now Prime is ON and ON position is OFF. Just don't run out of gas because when you do on PRIME the tank is bone dry. Reserve dosn't work without the vacume line attached.
 

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Drz 400s fuel problem?

2001 drz 400s Went into the local moto shop after going full throttle on the beast
My bike sputtered and bogged out on me while on the freeway. Tried starting her and she eventually turned on and got me home. The local moto shop cleaned the carb and i took her for a test run. Agian opened her up full throttle and she shut off. After a few attempts at starting her i threw in the towel. Got her home thanks to my neighbor richa. Ok i decided to do a bit of trouble shooting once at home and disconnected the petcock fuel line that feeds the carb. No fuel flow in the ON position, Prime or Reserve positions. Checked the fuel tank which barely had any fuel. After a mission to get 1 gal of 89 octane i poured it into the tank. Rechecked the petcock. No fuel flow in ON, or Reserve. Prime showed fuel flow this time. Turned her over until she started. Did the shop leave me stranded without gas or what? I think im going to have another shop check her out. What do you all think?
 

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Did you shake the bike to see if you could hear any fuel in the tank? It may simply have been out of gas.

Fuel will not flow in the ON or RES position without the vacume line hooked up, bike running.

If no fuel came out, and you had fuel in the tank and it was in the PRI position, then you have a clogged petcock screen.

Sounds like the shop had drained the tank to take it off to work on the carb and simply didn't put any back in when you picked it up.

If it runs fine now with one gallon in it on RES, then no worries. Go top off the tank, switch to ON and ride! No need to take it to a shop.
 

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Well its too late to run it after the empty gas tank issue as i took it to another shop to be safe. I dont want to be stranded again. Im hoping its just a petcock issue and nothing more. $85 bucks for trouble shooting adds up fast. I have to wait then test her out again. Keep you all posted on the out come
 

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Some report fuel issues with the fcr. I haven't noticed any. I tried a yfz450 valve but its orientation wasn't right. Biggest issue with prime is if you drop the bike your fcr will dump all the fuel.

Em, it sounds like you just ran out of gas. When you have that issue you want to go to pri to fill the bowl then over to res. The only other thing I could think is maybe your float level is low so when you go wot and are on the main jet there isn't enough fuel.
 

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Some report fuel issues with the fcr. I haven't noticed any. I tried a yfz450 valve but its orientation wasn't right. Biggest issue with prime is if you drop the bike your fcr will dump all the fuel.

Em, it sounds like you just ran out of gas. When you have that issue you want to go to pri to fill the bowl then over to res. The only other thing I could think is maybe your float level is low so when you go wot and are on the main jet there isn't enough fuel.
I think thats what happened, being new to the drz and all. Now when i run outta gas i put her in reserve and look for a gas station. On a diff note i just bought a dynojet kit, stage 1 for my drz s. 14/39 sprocket set up. Am i going to have any problems with idleing or take offs or wide open throttleing if i install the kit to the stock carb?
 

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I think thats what happened, being new to the drz and all. Now when i run outta gas i put her in reserve and look for a gas station. On a diff note i just bought a dynojet kit, stage 1 for my drz s. 14/39 sprocket set up. Am i going to have any problems with idleing or take offs or wide open throttleing if i install the kit to the stock carb?
Nope and honestly the stage1 kit isnt really much. With stock exhaust and airbox snorkel all you really need to do is remove the brass plug and adjust your pilot screw a little bit.

On my drz i rarely hit reserve. i get to about 70-80miles and get gas. The last time i actually hit reserve was on the track on it.


Thumpertalk is a great resource for DRZ information and with the number of drz users you will usually get an answer in minutes. There is also a jetting/carb forum where you might be able to find specific answers.
 

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Nope and honestly the stage1 kit isnt really much. With stock exhaust and airbox snorkel all you really need to do is remove the brass plug and adjust your pilot screw a little bit.

On my drz i rarely hit reserve. i get to about 70-80miles and get gas. The last time i actually hit reserve was on the track on it.


Thumpertalk is a great resource for DRZ information and with the number of drz users you will usually get an answer in minutes. There is also a jetting/carb forum where you might be able to find specific answers.
Shift, thanks for the info. Ill be installing it today
 

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surging

I had the same problem I did the jd jet kit and 3x3 MOD, just got back today from test run and I've got to say I'm impressed no more surge and better throttle response. I'm running stock exhaust with 3x3 and jd jet kit (which has been the easiest MOD I've ever done)
 
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