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Air leak from hot start port?

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Recently got an 2006 rmz450 project bike- fired it up after rebuilding the top end and it has a high idle and all the symptoms of being lean. The hot start nut is broken so I'm suspecting this is the leak. I know it's not a perfect seal but with the boot on, it's pretty snug. 

 

I'm thinking of purchasing a new hot start nut and maybe even the plunger so everything is nice and tight. 

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23 minutes ago, Jon Broadbent said:

Recently got an 2006 rmz450 project bike- fired it up after rebuilding the top end and it has a high idle and all the symptoms of being lean. The hot start nut is broken so I'm suspecting this is the leak. I know it's not a perfect seal but with the boot on, it's pretty snug. 

 

I'm thinking of purchasing a new hot start nut and maybe even the plunger so everything is nice and tight. 

Yes, it is probably leaking, but no, not becuase of a leaking nut.

The nut does not seal anything, it just provides tension for the hot start plunger along with the spring, so it will seal the plunger to the bottom of the cavity.

 

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8 hours ago, Krannie McKranface said:

Yes, it is probably leaking, but no, not becuase of a leaking nut.

The nut does not seal anything, it just provides tension for the hot start plunger along with the spring, so it will seal the plunger to the bottom of the cavity.

 

 

Thanks- It looks like the sag created by the broken nut then pulls on the plunger... and it seems like the previous owner removed the o-rings and washers from the fuel mixture screw. Don't ya love buying bikes from kids *sarcasm*

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You can develop an a lean condition if that hot start plunger is not fully seated. The cheesy plastic nuts can strip out pretty easy. I had the same issue on my 05 RMZ450. So while it's not an "air leak" it can definitely be an issue. A new one will run you 26 bucks at Tokyo mods or the dealer. It would be a good idea to check and possibly replace the choke lever at the same time as it not being fully seated can cause a rich condition. Either issue will make jetting it just right a pain in the ***

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5 hours ago, xMUDKINGx said:

You can develop an a lean condition if that hot start plunger is not fully seated. The cheesy plastic nuts can strip out pretty easy. I had the same issue on my 05 RMZ450. So while it's not an "air leak" it can definitely be an issue. A new one will run you 26 bucks at Tokyo mods or the dealer. It would be a good idea to check and possibly replace the choke lever at the same time as it not being fully seated can cause a rich condition. Either issue will make jetting it just right a pain in the ***

I went ahead and purchased an OEM one for now. It also includes the plunger which has a specific o-ring on it. There was also a bit of gunk built up so another good cleaning will be required.

 

 

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