Hunting and High idle permanent fix! - TRIAL

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I am AMAZED at the difference 2 turns of one screw on the IAM flange can make. Let's face it, that's a wicked bend in a fairly heavy hose from the airbox to the IAM causing a downward pressure in the outer flange and cocking it ever so slightly. Just enough to suck a little air. Went for a 66 mile ride, PERFECTION. Well almost. Made a stop at a light after 1 mile from my house, rpm dropped to 800 twice and stalled. (ECU eLearning?) After that, it was perfection. Also....no more multiple cold starts. Back to first shot. 2k....15 seconds.....1200. 1200 all the way.
TONY A.....NOW I'M HAPPY.

tach odo.jpg
 
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Sounds like an excellent example of why we all need to make sure we check the basics when a fault occurs.

Well spotted.
Yea...well...its a learning curve for me. I'm going from a twin carb non ecu to this. Thing is....I've tightened them once before, but this time was not so obvious.
I guess the word "idle" should have meant something.
 
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Made a discovery. Checked this out on three bikes today all with the same issue. Two 2014’s and a 2013. The bolts on the throttle body are the same length as the threaded hole and the throttle body flange combined. Meaning they barely clamp the throttle body and we bet with heat, the faces can seperate enough to leak air. Like a couple thousands if an inch .001-.002” This is the exact same problem as the crank bolts where the bolt bottoms out before the faces clamp which is why there have been so many engines needing a rebuild.

So we will put stainless washers under the heads and remove the ball bearing blockage putting the IAM back into play and see if that fixes this issue.

If it works, then it was down to either poor designing or someone not tapping the hole depths to the drawing.

Its cold and bike season is pretty much over so testing may have to continue in the spring. Anyone else I encorage to pull the bolts and see what they find.

Normally we would report this to the factory first to confirm and let them put out a letter to dealers to correct but the factory have officially told us to get lost and never contact them so I will now have to rely on the public to discover and confirm these issues. Looking forward to your help.

More to come.
 

BritTwit

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Richard,
That would really be something if you're correct.
Keep us up to date with your progress.
 
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Richard,
That would really be something if you're correct.
Keep us up to date with your progress.
Well its for sure an issue on three bikes. No way the factory knew this or Rob would have said something. Or Simon when we brought this up years ago. Some bikes we noticed have a thin spacer between faces. That would definitely prevent this issue. Wondering if Dreers design had the spacer and the bolts were the proper length with that spacer, then someone (??) decided to eliminate the spacer but forgot to shorten the bolts or deepen the holes. Anyhow, its easy to check the outer most bolts. If you apply torque to the bolt and its at max torque but the head moves back upon release then for sure the bolt thread is bottoming before the flange is biting.
 
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Well its for sure an issue on three bikes. No way the factory knew this or Rob would have said something. Or Simon when we brought this up years ago. Some bikes we noticed have a thin spacer between faces. That would definitely prevent this issue. Wondering if Dreers design had the spacer and the bolts were the proper length with that spacer, then someone (??) decided to eliminate the spacer but forgot to shorten the bolts or deepen the holes. Anyhow, its easy to check the outer most bolts. If you apply torque to the bolt and its at max torque but the head moves back upon release then for sure the bolt thread is bottoming before the flange is biting.
Like I've stated before, I've found both bolts backed out over 1/4 inch a few years ago, tightened them and cured my problem. This time, however, visually, you could hardly tell. I just put an allen wrench on more for experimental purposes and sure as shyte, one was two turns loose. There is no spacer on the faces, but the bolts certainly are fairly short. Plastic to plastic. A little Loctite is all I'm doing so far. Having done this before, I should have checked it first instead of posting what I did a few years ago here and doing nothing. LOL. Hoping it stays. Starts first shot and idled at 1200 at all my stops. Engine brake was superb.
 

comet

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Like I've stated before, I've found both bolts backed out over 1/4 inch.....
The way I read this was that you are talking about the idle air control valve connection and Richard is referring to the throttle body connection to the cylinder head. I'll be checking both.
 

BritTwit

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Richard,

You're referring to the 4 bolts that bolt the throttle body to the cylinder head as shown, correct?
I highlighted the top 2 bolt holes with yellow arrows.
You want to put a washer on the allen bolt before threading into the throttle body/head.
This way the bolt will not penetrate into the threaded hole as deeply.
That will prevent the bolt from bottoming out before the proper level of torque can be attained.

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Richard,

You're referring to the 4 bolts that bolt the throttle body to the cylinder head as shown, correct?
I highlighted the top 2 bolt holes with yellow arrows.
You want to put a washer on the allen bolt before threading into the throttle body/head.
This way the bolt will not penetrate into the threaded hole as deeply.
That will prevent the bolt from bottoming out before the proper level of torque can be attained.

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You got it. Thanks for doing this. Cheers
 
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The way I read this was that you are talking about the idle air control valve connection and Richard is referring to the throttle body connection to the cylinder head. I'll be checking both.
Wow. I totally misread that. Thanks, Comet. And thanks, Richard for another discovery. I'll check that myself. Meanwhile, another successful 58 mile run. Took the bike a little longer to warm up being 33 degrees F today.
 
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So...If those bolts are short and I'm supposed to have a thermal gasket between the throttle body faces ( I don't, but I now have the gasket to install) guess I'm going to have to get longer bolts and lock washers.
 
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So...If those bolts are short and I'm supposed to have a thermal gasket between the throttle body faces ( I don't, but I now have the gasket to install) guess I'm going to have to get longer bolts and lock washers.
The gasket is not that thick. Rule is 1.5times deep to the thread diameter. So if a bolt is 1/2” diameter then the threads should engage at least 3/4” for easy numbers.
 
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The gasket is 1/16 inch hard poly with embedded rubber O rings. Quite nice, actually. I thought that was rather thick and not is not crushable. Curious, Richard, having earlier imports of '13 and '14, did you or your dad's bike come with that?
 

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Fast Eddie

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How do bikes without these gasket seal? Do they have O ring grooves machined directly into the face?
 
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