Triumphrat

Gibbsey · 09-18-2009, 12:48 PM

What effect does heat have on the Idle Air Control Valve?

The Idle Air Control Valve on the speed four is mounted on a flimsy bracket off the cylinder head. If the engine were to get hot, say 120 degrees hot why would this cause the IACV to fail/get stuck? Obviously a lot of heat would dissipate from the head to the IACV. I'm guessing a small stepper motor such as this would not be able to cope with such a thermal shock. I'm 'guessing' it is now stuck.

The engine has become difficult to start, but eventually does after many cranks. Once warm the engine dies and refuses to start again. In this circumstance, how easy is it for Spark Plugs to become ruined? The throttles look somewhat carbonized which they were not before

I ask this because I stupidly and unknowingly failed to tighten the small hose on the heat exchanger. After a rebuild and four weeks of running fine the hose eventually came away and spilled the entire coolant contents all over the floor whilst travelling on the motorway. Obviously, the bike began to get hot so I immediately turned the engine off and coasted onto the hard shoulder.

I tightened the clip back on, refilled the coolant and bled the water pump. The bike now does not want to play ball.

How sensitive is the IACV? The bike is now at a friends several miles from home. I intend to replace the spark plugs and give the IACV a clean and reseal.

Any advice, suggestions (other than make sure you tighten your hose clips next time) would be greatly received.

Gibbsey · 09-19-2009, 09:32 AM

Just put brand new sparks in. The old ones looked fine and had only done 500 miles. I dismantled the IACV, gave it a clean although it wasn't dirty. It appeared to be working as it moved in out and freely when I tested it. No cracks or leaks anywhere.

Put everything back as it should, hit the starter and it started first time. The revs were hanging somewhat. Got to about 60 degrees and it cut out. Now it's not starting again.

What the hell is this???

It does seems to be related to the idle air control somehow?

Any suggestions anyone? I've had enough of this!

Gibbsey · 09-19-2009, 12:04 PM

Come On Guys! Please Help Me Here! Anyone Have A Clue?

KitNYC · 09-19-2009, 02:24 PM

Moving this to SuperSports, as the questions are model-specific. Hopefully someone here can diagnose.

Cheers,
-Kit

kubbie · 09-20-2009, 07:26 AM

I haven't had what you describe happen to me yet. All I can do is offer you a way to start the bike that always works for me. Learned it from the shop manager at the dealership years ago. The most it should take is three trys.

First is the standard stuff (nuetral, kill switch on run, key on). Wait for the computer to do its little start-up check. The trick is to press and hold the starter button THEN pull-in the clutch lever. Best case it'll start right up, worst case it just spins. Usually for me it'll sputter twice then just spin free.

If it did start then Yeah! If it didn't, turn off the key and count to 10. Now turn key back on and wait on the computer then repeat with the starter button then clutch. If it just spun on the first attempt it will sputter then die this time, if it sputtered the first time it will start now.

Hope this helps at least a little. Just remember constantly cranking the motor isn't good for anything other than killing the battery. Try no more than 5 seconds then turn off the key to start over.

Good luck.

Will · 09-20-2009, 01:57 PM

Make sure you put the IAC vacuum tubes back where they came from and make sure the IAC valve body is completely sealed. Leaks wreak havoc. I have never heard of the bracket failing, so I guess it's strong enough for what it has to do.

Gibbsey · 09-21-2009, 02:00 PM

Still no joy...

The battery is strong and holds a good charge

New plugs

Nice fast cranking and starter motor sounds healthy

IACV appears to be working. When I turn the ignition on and off I can see the shaft move out and then in

All tubes are crack/split free and correctly located

The bike will start when cold. And will run up to full temperature enough for the fan to come on (106ish)

If throttle blipped the revs chase and eventually die till it cuts out

Strong smell of fuel and occasionally backfiring

This has to be something to do with the IACV. It's like mixture isn't being leaned off as the bike gets warm.

The plugs are in a never ending cycle of fouling from excess fuel

Do you recommend replacing the IACV even though it appears to be working?

HELP !

Gibbsey · 09-21-2009, 02:01 PM

When I say the bike starts cold I mean eventually. It's not easy

skiTTles · 09-23-2009, 07:18 AM

I think you are chasing the wrong rabbit here, if the IACV is working there really isn’t much more to it (though swapping it for a new one could be rid of all doubt… providing they aren’t pricey). So, it does sund like you are running rich, I’d check other items in the mix such as the coolant temp sensor etc.

Gibbsey · 09-23-2009, 11:29 AM

Thanks for your help. That will be my next step then. Not sure how I know if the coolant temp sensor has failed or not as got no codes stored?

The IACV does appear to be physically working but like you say, it does seem like I'm running rich. I can see the IACV move when I test it but it's only a few mm.