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06 DRZSM High RPM pitch change

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Hey Guys, Just put my SM specific DJ jet kit (3110) in (stage2) and it works wonders, Bike is actually a pleasue to cruise around on and it has more beans. :thumbsup:

My question is it changes pitch at a certain (high) rpm in all gears but most noticeable in 5th around 65 mph. It sounds llike something in the carb opens up or something? It is most noticable at steady throttle and when you hit that rpm and above it really sounds different. :applause:

Did the 3x3, de smogged for safety! :ride: All else stock.

Thanks!! :applause:

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I just noticed the same thing on my '05 DRZS, but hadn't gotten around to posting about it. I've done the 3x3 and DJ, but I don't know if it was doing it before then.

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My bone stock 06 S does the same thing at 68 to 70 mph in 5th gear. Same RPM in lower gears. Feels like the ignition timing may be advancing at that point. Almost sounds like a secondary on the carb is opening up. Any word from the experts?

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I have the same on my stock '06 SM. Only thing I can figure is it's a weird resonant frequency thing. It got quieter when I stiffened up the padding for the CDI against the airbox (it rattlesd) and took the snorkel out. I had a similar noise in my BMW 325 (I know, I know, I drive a car too) that wasn't there until I took out the baffle and snorkel, and it then popped up.

Just my $0.02,

Gabe

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I have heard people talk about the airbox resonating and 2R41's comment seems to support it.

Try reinforcing the top of the airbox by pop riveting a piece of metal to it.

You can wrap the edge with heavy duct tape an make sure your cutout has rounded corners.

Now that the top is gone the airflow patern has significantly changed.

Wonder if anyone makes an airbox with a vented lid. It would create a different flow pattern and would either make it better or much worse.

I have seen fabricated metal airboxes on KeinTech but seemed pricey.

Even my stock S has a "whine" at higher RPM.

EXPERIMENT.

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Thanks, I'll check this out -but it really sounds like perhaps the diaphram in the carb is lifting at high vacuum or something -it sounds kind of like the secondaries opening up! I do not really understand how the diaphram works on the Mikuni...thanks again guys. -Jeff

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