Funny noise in exhaust note

K

Kenora

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Nov 13, 2012
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55
Location
Kenora, NW Ontario
Funny noise in exhaust sound

I have a 97 VMAX 600 XTC (twin) it was just completely rebuilt after a rough start to the season.
I noted before the rebuild (and now after) that the exhaust has an "after boom/pop" sound or tone.
Instead of a clean brap or giant chainsaw note it sounds as though there is what I would characterize as a pop a couple of times a second overlaid in the exhaust noise.
It can be heard throughout the operating range but is most noticeable around 5 - 30 mph when going slow enough that there inst a lot of noise from the track/lake surface etc.
The sled is absolutely stock, I run ethanol free 91, the carbs are clean.
Ideas?
Oh btw; I got 50 miles out of the first tank of gas since the rebuild :( the snow was deep but really that's crazy...can this be related.
 
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Sounds like it's running too rich. They get blubbery sounding when they are rich.What were the temps when you were riding it? What do your plugs look like? Piston wash? Fuel screw settings? Everything in the carbs set to spec.? I don't know those sleds, Do they have reeds? if so, are they in good shape? sealing properly?
 
no reeds, I have only had the sled for a few months, it is all stock having come out of the rebuild with new pistons/cylinders/bearings etc etc to the tune of $1900. I rode it for a few weeks before the bottom end needed $900 work :( and that was in -20C to -10C temps, I got riding again yesterday and that was -10C to 0C... the guy that rebuilt it said it was set to run "fat" so the break-in would work properly. I assume he set it rich then?!.... if so How long would I let it run rich before setting back it to normal?
Oh and the plugs were wet, I never did a chop or anything but when removed after running they were both wet, no color just fuel.
 
no reeds? Are you sure?

50 miles per tank seems awfully low mileage, even for a 600 twin in deep snow.

Talk to the guy who did the rebuild and tuning. Verify the specs with him, and what did he do to make it rich? If he said it is set up rich for the break-in, he should tell you when to un-richen it, and the specs to do so... Ask him.

In any event, as the owner I would want to know how the carbs are set up, and compare that to the factory settings. I'd return to the factory settings if anything is different, unless there are other mods done that require deviation from factory.
 
The above is correct- the rebuilder should have instructed you to bring it back after break in to set it to standard specs - and how many miles that would be. It is not uncommon for that to be done without charge, as part of the job, which you should let him know if he wants to charge you more. You have paid what seems like some high prices and it sounds like an independant shop which should be cheaper than a dealer.

After it is reset check the actual miles per gallon/liter.
 
I called the guy but no call back and the sled is 3 hours away in Kenora ON.... I would like to know how to do the work myself as well so I posted a question (new thread)
 
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