mazdaspeedrex

I was driving last night and I heard a new noise coming from the intake. It sounds like a fluttering when I lightly tap the gas. Almost sounds like a stuck lifter does on a boinger. I've got a Mikuni and I just changed some vacuum lines but I've rechecked them and they are all hooked up right. I haven't noticed any loss of power but it's also wet on the groung so I'm not pushing it too hard. Any suggestions would be appreciated.

rxguru

still got the air pump on that thing?

mazdaspeedrex

no air pump, RB header and exhaust. After driving it more today, I noticed the noise more when I mash the throttle instead of slowly accelerating. I also checked and found no exhaust leaks. I hear the noise coming from the carb.

82transam

iTrader: (18)

shutter valve going bad maybe? Just a shot in the dark

someone82

notice he said he has a mikuni.. no shudder valve on that puppy. check your ignition timing. does the motor studder or is it smooth?

matt

mazdaspeedrex

The timing isn't any different than it was 2 days ago. As for smooth it seems to have no power below 3000 rpm, but i've been noticing that since it got cold. I attribute that to running rich and bogging out in the cold.

Project84

Rotor seal chatter? Its so hard to diagnose sounds without hearing the sound and hearing where it is coming from. Does it sound like ball bearings in a blender, or a dry fart?

82transam

iTrader: (18)

hmmm, guess i should slow down when i read these things. haha

mazdaspeedrex

I would consider it more of a dry fart sound. I'm hearing the sound coming from the carb. I've heard an FD with a blown apex seal and it sound very different and the loss of power was very noticable. I haven't noticed it too much because I'm not out there racing it on the wet streets. When it idles or I press the accelerator slowly I don't notice a thing. If I press the pedal hard I can hear it fluttering. I'm going to do a compression check to see if there is any variance.

MIKE-P-28

iTrader: (1)

Justa shot in the dark here, but are the air filters tight? Did you suck some of the foam loose in there?

mazdaspeedrex

I took the filter off yesterday and didn't see anything in the venturis but it's not at the best angle to see all the way in. When I checked the compression I didn't see any big difference between chambers and rotors.