1999 MM 700 carb question

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akhunter83

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Jan 28, 2010

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• Nov 21, 2010

• #1

I just noticed that there is a small amount of coolant in my airbox and i am assuming it came from the carbs. Has anyone had this happen before and what was the fix?

 

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MRFUSION

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Aug 8, 2008

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Peace River AB

• Nov 21, 2010

• #2

Never seen it end up in the airbox but the coolant carb valve of that year had issues with the fitting leaking when hot and either coming out or just leaking. It was mounted on the airbox, just an idea. Shad

 

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akhunter83

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Jan 28, 2010

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• Nov 21, 2010

• #3

thanks for the input, i looked at the that valve and was wondering if it was leaking from there too. Maybe i'll change that valve out and see what happens. If anyone else has any input i liked to hear what you think. If its not the valve that means its from the carbs, does this mean the carbs need to be rebuilt.

 

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akhunter83

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Jan 28, 2010

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• Nov 21, 2010

• #4

ok how about oil in the air box, any thoughts on that. Could it have come from the carbs?

 

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SRXSRULE

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• Nov 21, 2010

• #5

One other place those carbs would leak is between them. They have small aluminum coolant transfer tubes between the carbs and those tubes have O-rings sealing them. Sometimes they will seep, if they are just try twisting the tubes back and forth. Sometimes thats all it takes to get the o-ring to seal agian.

As for the oil in the air box, thats pretty normal for a 2-stroke. Small amount is normal, thin coating on the inside of air box and maybe a small amont of liquid oil in there. More then that and you shoudl take a look at the Reed valves. Eric

 

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akhunter83

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Jan 28, 2010

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• Nov 21, 2010

• #6

how does the reed valves make oil get into the airbox? Will this make the engine run rich becasue it is seem to be and the plugs look fouled.

 

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SRXSRULE

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• Nov 21, 2010

• #7

If the reed valve petals are cracked or chipped it can no longer seal correctly and it can allow oil from the crank case to be forced back through the carbs and into the crankcase. You have to remove the reed blocks and look at the tips to check for damage. on a yamaha tripple I rarley seen any problems with sleds under 3-4000 miles.

This will have little to no effect to making the sled run rich. Have you ridden the sled yet this year? You cant really tell much by what the plugs look like if the sled has been idling a bunch. Eric

 

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akhunter83

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Jan 28, 2010

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• Nov 21, 2010

• #8

Thanks for the info on the reed valves, i didn't know exactly what there function was. It seems like the reed valves could be the problem, i'll take a look at them. Do you think the carbs should be cleaned also after the reed valves weren't sealing properly. My sled has about 2400 miles.

 

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TRUEBLUEMAX

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Aug 4, 2010

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• Nov 22, 2010

• #9

If you have the carbs off to take a look at the reeds then I would clean them for sure unless you know they were cleaned very recently. Just don't go overboard. You can get to all the places that need to be cleaned from the float bowl on the bottom of the carb. Be careful the screws can be very tight on the carbs. Just pull the two jets out in the bottom of the carbs and blow carb cleaner through them and all of the air bleeds in the throat of the carbs.

 

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akhunter83

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• Nov 26, 2010

• #10

Today I finally had time to get the carbs off and reed valves off. I'll most likely clean the carbs this weekend when i get some carb cleaner. I am replacing the reed valves with new and was wondering if there is that much difference between stock reed valves and after market ones? Also, after i had the reed valves off i was looking at the crank and noticed that it had some discoloration to it on two cylinders. It amost looks like if you heat up some metal with a torch, I'll tey post some pics later today. Any thoughts on why it might look like this.