Triumphrat

CharlestonRider · 07-26-2006, 08:07 PM

Hello All,
I am in the process of trying to track down an issue with my recently purchased 1999 Sprint ST. Immediately after starting the bike, the motor sounds great. No noise and it pulls cleanly. But, after about 45 seconds of warmup, I start to get what sounds like valve tappet noise. As the bike continues to warm up, it gets louder and louder and then the idle becomes a little unstable. I just synchronized the throttle bodies and while I have it apart I noticed that the idle control valve is "open" while the motor is off. My question is this: Has anyone examined the idle control valve as the bike is running? My assumption is that it opens at idle to allow air to pass the throttle bodies (which are functionally closed at idle). But, my guess is that the valve should close as the rpms rise above idle. My idle valve looks like it might be sticking and I think it might be missing a part (I think a ball might be missing from the end of the shaft). If I am correct, this would have the effect of not allowing the valve to close and would functionally result in an air leak. But, the bike would still idle because the valve is open.

Any information that anyone can provide to me regarding the air control valve would be appreciated. I am currently waiting for a crankcase gasket and when I get the motor back together I will test the valve myself. I am just hoping someone on this list has a few answers for me. Any information that I learn I will pass along to the members of this list.

Thanks in advance.

John

unummyu · 07-27-2006, 08:31 AM

I have using TuneBoy, it will step through the positions. Here is a shot of the TBs and idle stepper from my photo album with the engine off on my 2003 Sprint. BTW there are a couple of Triumph owners in CHS that I ride with sometimes on weekends. If interested send me an email usually short rides of 200 miles or under.

unummyu · 07-27-2006, 08:46 AM

Here is a shot of the TBs and idle air control valve from my photo album with the engine off, on my 2003 Sprint.

BTW there are a couple of other Triumph owners in CHS that I ride with sometimes on weekends. If interested send me an email, usually short rides of 200 miles or under.

rodneybrown · 07-27-2006, 11:25 AM

When I was doing research on exactly how to sync the TB's one of the things I was told to watch was that I didn't take the IACV apart because you could lose the spring and ball inside of it. I'm not sure how you would adjust it or even if it adjusts. You just may have to replace it. Sounds like it is just a vacuum sensitive valve which could be a bear to adjust withoug some kind of special tool. When my 04 starts it idle a bit under 2K RPM and when it warms up it is at a nice smooth 1100-1200 rpm. Those are from the tach, I could get better reading from Tuneboy. There isn't anything like the clicking you discribe.