Random Misfire sounds almost like air leak

[jamman]

OK I see that each tube connects to the IACV on the back ... but there are 4 ports ... does one of them get capped ?

Thanks !

[John Stenhouse]

It's correct that it will show no error codes and the tubes as you say connect to the IACV, one of the connections on that is blamked off. look in the ends and you'll see which one.

[Timbox2]

OK I see that each tube connects to the IACV on the back ... but there are 4 ports ... does one of them get capped ?

Thanks !

The 4th port on the IACV is a dummy, I had the same issue with the cracked tubes, I bought genuine pipes from Triumph,(see below) not cheap, about £40 for the 3. Some have used silicone breather tube but I didnt want to take the chance, the pipes take really sharp bends, hence the corrugated look. You wont get error codes either, the sagem system wasnt that clever.



PS: John above beat me to it :icon_wink:

[jamman]

Thanks for the info !

When looking at the IACV from the riding position .. which one is capped ? the one farthest to the left ?

[jamman]

I took a guess and hooked them up with left most port disconnected ..

[jamman]

Just took it for a spin ... Wow she runs great no more misfires !!!  Between shifts it was not returning to idle but it is now !!!

Thanks for all the help guys !!!

[Timbox2]

Thanks for the info !

When looking at the IACV from the riding position .. which one is capped ? the one farthest to the left ?

ummm, the one that doesnt have a tube going to it?

[Timbox2]

Just took it for a spin ... Wow she runs great no more misfires !!!  Between shifts it was not returning to idle but it is now !!!

Thanks for all the help guys !!!

How did you get replacement pipes that quick, or have you repaired with tape?

[jamman]

I bought vacuum hose and cut to length and hooked them up made sure no links ... seems to work fine

[Timbox2]

I bought vacuum hose and cut to length and hooked them up made sure no links ... seems to work fine

Fair enough, I know a few have done that, I wasnt sure if the tight bends would collapse the hose, obviously not, oh well whats £40

[jamman]

I founds this picture and connected the same .. but my hoses are not fuel lines they are vacuum

[Bixxer Bob]

Glad it sorted the problem.  Pity you pulled the trigger on the coils  before I'd put up my check list as it was second on my list of stuff to do:



Tank off.
IACV check using TuneECU.
IACV tube check.
Remove old coils and plugs.
Remove cam cover and check valve clearances (number one suspect).
Fit cam cover (this is all covered in the Girly Wisdom thread).  Gasket is re-usable so don't damage it but the four half circle bungs need a dab of gasket goo.  (don't overdo this, you don't want it breaking off and blocking an oilway; just a very light smear is enough).
Fit new plugs and coils (keep the old ones but mark the suspect one).
Re- assemble everything else.

[jamman]

Yeah I jumped on that a bit quick to by the coil sticks ... got a good deal on them so kind of glad to have some backups just in case ..

Now I seem to be having an issue when coming up a to traffic light when pulling in the clutch to downshift she wants to die  ... she starts right up no problem ..

Wonder if one of the new vac tubes is connected to the stubbed off one ... or maybe I need to run diagnostics again ..

She runs great except for this now ...

Any suggestions are appreciated ..

[Timbox2]

Yeah I jumped on that a bit quick to by the coil sticks ... got a good deal on them so kind of glad to have some backups just in case ..

Now I seem to be having an issue when coming up a to traffic light when pulling in the clutch to downshift she wants to die  ... she starts right up no problem ..

Wonder if one of the new vac tubes is connected to the stubbed off one ... or maybe I need to run diagnostics again ..

She runs great except for this now ...

Any suggestions are appreciated ..

Well, almost certainly something to do with the IACV assy itself or tubing. There isnt a lot of room around there when the airbox goes back on, did you make sure the little foam gasket on top of the valve was still there? Though thats unlikely to cause running issues as such but it does allow unfiltered air straight into the motor.

[JoeDirt]

I bought vacuum hose and cut to length and hooked them up made sure no links ... seems to work fine

Any suggestions are appreciated ..

I know that in an earlier quote you stated you are using "vac hose". Regular automotive vacuum hose will easily pinch, cutting off some air flow. That's why the photo above is using braided fuel line. Braided fuel line has less tendency of pinching, because of the extra structure of the hose. Even with braided fuel line you run a chance pinching on the left side (facing front) with those tight turns. I personally use braided fuel line and I also use a 90° elbow on the left hose (facing front) to relieve the chance of pinching.