Triumphrat

longwinter · 01-16-2010, 10:07 PM

Ok I need help form the gurus:

So my 02 Speed Four has been acting up right after I took it to the shop for the 12k service. I have an irrational fear of other people work on my bike and I usually perform all service myself... But I was short on time so I paid a shop to do a valve check, new plugs, and a throttle body sync. I then changed the air/oil/fuel filters myself.

2 weeks After I get the bike back, I start getting the problem where occasionally the bike will stall out when slowing down for a traffic light or stop sign when holding in the clutch the idle dips too low. From reading the forums it sounds like a common problem with the IACV stepper motor or a vacuum leak somewhere. So today i pulled the tank, checked all the hoses for blockage and tight seals. I pulled apart the IACV cover and motor to clean it and make sure the valve goes back and forth. I turn on the key with it apart... and the stepper motor spits the white plunger right out of the base? So I thread it back in and test it again it seems to move back and forth although it seems a little slow or strained? So i put it all back together and fire it up... Check engine light goes off and it idles a pretty rough until its warm? I am in the process of doing the "three heat cycles" to see if the light goes off.... but I am assuming my IACV motor is junk right?

It annoying, but I guesss i will shell out the $120 for a new IACV motor and see if it cures it? I don't have a OBDII scanner or tuneboy so there really isn't any way for me to see what is wrong? Anyone have any inputs before I order a new IACV?

Thanks

Will · 01-16-2010, 11:36 PM

Sounds like your IACV is toast!

BombFactory · 01-17-2010, 12:09 AM

It does sound like the IACV motor if you are getting erratic/unusual idling while the engine is coming up to running temperature. Rather than buying a new motor, you may be able to get a good one used. It took me a month of hard looking to find one, but I ended up getting one off ebay for $50 or so. No one sells them separate from complete engines, so I messaged the sellers of low-mileage engines and asked if they would sell the IACV separate. I eventually found an engine with 4,000 miles on it, whose seller sold me the IACV.

longwinter · 01-17-2010, 05:25 PM

Ok so here is the update...

I clean it up the white plunger on the end of the IACV motor. I blobbed some RTV between the valve cover and motor and screwed it back together. I made sure all the air fittings on the air box were snug. I put it back together, did the three heat cycles and the Check engine light went off. And now it seems to warm up ok and run well. The warm up routine from dead cold is:

1) idles at 3K for about 15 seconds

2) idle drops to about 2k untill the temp sensor reads about 130F

3)from 130F to about 160F the idle seems to hunt around or surge a little between 1400 - 1800 rpm.

4) at around 170F the bike seems to idle fine at 1100 RPM

I went for a test ride and the bike does not exhibit the idle dip below and occasional stall when slowing down for a stop sign. Does the warm up routine sound fairly normal to you guys? I think I may have cured it or at least temporarily prolonged the life of the IACV stepper.

Will · 01-17-2010, 05:32 PM

The only thing which doesn't sound perfectly normal is the brief period of surging.