HarleyTechTalk

If ur shure u have a leak but can't pin point it, back of intake push rods, plull the trottle body, attach a vacuum pump ( shop vac will work) to the intake, spray it down with water mixed with dye, then use a black light, I'll see it in the intake.

Borrow a smoke machine, that is the best way.

  Toby

I took .010 off thickness of flanges for one thing. well now I am at .020 off thickness.
I will get some new flanges next week, going riding this weekend. puttin it back together for the weekend. Leak or no leak, screw it.  Heads are stock 06, flanges were on bike when I bought it, but who knows.
Kinda wondering if I need more clearance in between ends of intake and heads. must be .010 to.020 now? seems like it is always closer to the front head for some reason.

What is a smoke machine anyway? and how would that work?

Smoke machines are usually but not always used to find evap leaks, oil leaks & vacuum leaks in any kind of internal combustion engines ( shure its uses in other industry's) they can be expensive, hence the vacuum idea., it a low pressure ( not shure what makes the smoke) but u hook it up to the intake & pressurize what ur trying to find and the smoke comes out @ point of the leak, like I said, works great, most do it yourselfers don't have 1. I would loan u mine but that would be tough.

Quote from: harleytq on August 29, 2014, 01:00:49 AM
I took .010 off thickness of flanges for one thing. well now I am at .020 off thickness.
I will get some new flanges next week, going riding this weekend. puttin it back together for the weekend. Leak or no leak, screw it.  Heads are stock 06, flanges were on bike when I bought it, but who knows.
Kinda wondering if I need more clearance in between ends of intake and heads. must be .010 to.020 now? seems like it is always closer to the front head for some reason.

What is a smoke machine anyway? and how would that work?

What air cleaner are you using?
How do the bolt holes line up, Do you have to push the TB around to get any of the intake flange or air cleaner bolts to thread in?
How is the spacing between the backing plate and the heads?

smoke machine works awesome and you can adjust the pressure accordingly. connect past the blade on the vacuum cap seal off the front of the throttle body with duct tape and have at it .

Well, got back last night and checked for leaks, looks like it is still leaking, even with .020 off the flange. Funny thing is it seems to almost leak worse after taking .020 off. I would think that it would squish the seal better like this. I don't get it.

Bolt holes all line up good. the air cleaner backer needed shims behind where it mounts to the heads. still don't think that is perfect but man how close does this need to be? should I look into getting a new air cleaner setup? What are the best ones to get?

Well I finally got the new flanges, and seals. put it together and it still leaks. It seemed way tighter with the new seals and flanges but no go with sealing it up.
Starting to wonder if all harleys leak and we are just running them anyway.

Have you tried leaving the intake manifold bolts loose then mount the AC backing plate with the breather bolts and the screws that secure the backing plate to the throttle body ? Tighten the breather bolts and backing plate screws then tighten the intake manifold bolts . And no they dont all leak .

I have been shimming the breather bolts after tightening the intake bolts, I even left the breather bolts loose one time, even tried it without the backing plate on there, still leaks.

I would try leaving the intake seals off, bolting the throttle body to the backing plate and then the backing plate to the heads. Use a feeler gauge to check between the TB spigot and head on each side to see if the gap is equal and not too big or small. With no seals you can also see if the flange bolts are centered in the bolt holes at the same time the spigots are centered in the flange bores.  This will insure everything is to size and not binding when a bolt is tightened.

You have to leave the manifold bolts loose and tighten up the breather bolts and backing plate to throttle body bolts  . Also make sure the breather bolts are centered in the backing plate . Then start snugging up the manifold bolts working criss cross pattern . Follow what 1Fstrk said to find your alignment problem

Which method are you now using to confirm it is still leaking?

How much clearance should I have between the heads and intake? I did check this once already, but it seems like when I tighten it down, it always pulls closer to the front head. I thought it looked good when it was just bolted to the backing plate. But
I am not really sure what the best clearance to have is.

The seals seem to be sticking to the intake pretty good, when I pull it off they are stuck good, but on the front one the seal is almost flush with the end of the intake. So I am wondering if I need to remove more from the end of the intake, on the front.
But if I bolt the backing plate up first maybe that will hold it centered.

I am still using the carb cleaner. keep trying wd40 but it doesn't make as much of a difference in the idle of the engine. sprayed from air cleaner side and still almost kills engine.

But if I bolt the backing plate up first maybe that will hold it centered.   

If I remember correctly I think Vic told me as long as I could get a feeler gauge between the spigot and the head, and the gaps were equal then I was good to go. It seems he was more worried about too much gap rather than too little was long as nothing was tight or binding. I had about .010 front and rear.
I cleaned the head surface, spigots, and flanges with thinner. I used dish soap to lightly coat the bevel on the flange and left the seal face and head surface dry. I left the seals slightly off the spigots so the heads would push them on as I slid the TB into place.
Worked like a charm, no leaks the first try, maybe I just got lucky.

I don't know if it matters but the new flanges seem to be all warped up. thought my originals were flatter. Should I get a new set on order?

sounds to me like the backing plate and breather bolts are pulling the throttle body away from correct alignment
I would do a loose fit with the backing plate and breather bolts and then snug intake flange bolts equally on each side a bit at a time
then have a look to see which way to adjust the backing plate and breather bolts to improve the fit at the heads

If you wan to check manifold clearances, you can do it by assembling the intakes manifold / throttle body without the rubber seals.. Leave the backing plate off.   Hold the TB at the correct angle same was when assembled.  I like to push the throotle body towared the left side of the bike.. With the TB held in that position, you should be able to move the throttle body front to rear slightly in the intake flange rings. It doesn't have to be more than a few thousands..

Quote from: 2006FXDCI on September 09, 2014, 03:43:20 PM
You have to leave the manifold bolts loose and tighten up the breather bolts and backing plate to throttle body bolts  . Also make sure the breather bolts are centered in the backing plate . Then start snugging up the manifold bolts working criss cross pattern . Follow what 1Fstrk said to find your alignment problem

That is the worse thing you can do.. You really need to mount the manifold / throttle body in a manner where it allowed to center on the ports and so that there isn't any load on the TB that might push the on the seals..  Assemble the baking plate to the TB and head but leave the screws a couple tuns loose.  Tighten down the manifold rings.. The backing plate should still be loose. If not you should be able to adjust the seals slightly so that the backing plate is loose on the screws.. Tighten the baking plate to the throttle body. There should be some clearance between the backing plate mounts and the heads.  It can be all the way down to 0 but cannot be negative clearance of more than say a couple thou.. If no clearance add gasket between the backing plate and the throttle body.. If the backing plate has move forward and bound up, trim the rear manifold  spigot.. Move to the rear, trim the front.

Maybe you have too much clearance on the manifold spigots.. Maybe a messed up injector O ring..
Max

Quote from: 1FSTRK on September 09, 2014, 04:04:40 PM
Which method are you now using to confirm it is still leaking?

X2


Just A little mist/vapor directed towards the AC will make her stumble. Hope you're spaying from AC side towards horn with no breeze pushing it back at you.

Quote from: Max Headflow on September 09, 2014, 10:52:39 PM
If you wan to check manifold clearances, you can do it by assembling the intakes manifold / throttle body without the rubber seals.. Leave the backing plate off.   Hold the TB at the correct angle same was when assembled.  I like to push the throotle body towared the left side of the bike.. With the TB held in that position, you should be able to move the throttle body front to rear slightly in the intake flange rings. It doesn't have to be more than a few thousands..

Quote from: 2006FXDCI on September 09, 2014, 03:43:20 PM
You have to leave the manifold bolts loose and tighten up the breather bolts and backing plate to throttle body bolts  . Also make sure the breather bolts are centered in the backing plate . Then start snugging up the manifold bolts working criss cross pattern . Follow what 1Fstrk said to find your alignment problem

That is the worse thing you can do.. You really need to mount the manifold / throttle body in a manner where it allowed to center on the ports and so that there isn't any load on the TB that might push the on the seals..  Assemble the baking plate to the TB and head but leave the screws a couple tuns loose.  Tighten down the manifold rings.. The backing plate should still be loose. If not you should be able to adjust the seals slightly so that the backing plate is loose on the screws.. Tighten the baking plate to the throttle body. There should be some clearance between the backing plate mounts and the heads.  It can be all the way down to 0 but cannot be negative clearance of more than say a couple thou.. If no clearance add gasket between the backing plate and the throttle body.. If the backing plate has move forward and bound up, trim the rear manifold  spigot.. Move to the rear, trim the front.

Maybe you have too much clearance on the manifold spigots.. Maybe a messed up injector O ring..
Max

This way of mounting the Tbody has worked for me on the 5 or 6 I have put together , must just be lucky .
Max , it sounds like the OP has been doing it the way you posted but hasnt had any luck .

Quote from: 2006FXDCI on September 10, 2014, 05:23:56 AM

This way of mounting the Tbody has worked for me on the 5 or 6 I have put together , must just be lucky .
Max , it sounds like the OP has been doing it the way you posted but hasnt had any luck .

You have been.. Probably because most of then TB spacing hasn't been far off or you were doing backing plates with  Mik / CV carbs where there is a flex joint between the manifold and the carb.. I've fit a number home made / semi custom backing plates / air-filters and if there is a load on the manifold from the backing plate bracket, the intake spigot can leak..

I'm not sure if this is the issue tho..  I suspect that either the leak is falsely detected or the is something wrong with the TB like a leaky O ring..

The stock setup with SE backing plate works pretty well as far as spacing goes as long as the directions are followed.

Max
 

Max I have been doing it the way you said, I will recheck alignment without seals again though just to make sure.

So Max, you are saying that, with the flanges bolted up with no seals, the intake should have some clearance even when pushed as far towards the horn side as possible? There is quite a bit of clearance on them flange diameters, I will have to check that.

Well I went out there today,was going to pull it apart. Pulled the breather bolts out and made a shield around the aircleaner and checked for leaks again. was really hard to tell, might have a really small leak. Used about a half can of carb cleaner.
Went to put breather bolts back in and it looks like the throttle body moved down a little, had to pull up on it to get the bolts back in.  So then I thought I better recheck for leaks, bought another can and went to spraying, used the whole can, still really hard to tell, but possibly still a really small leak.
So I am wondering if I should just leave it? Will it possibly seal up better after riding and getting good and hot?
I did ride it around a little yesterday, but it almost seems to have sealed up better after sitting overnight.

If you greased the seals good the TB can move around for a while before all the grease sort of evaporates..  I wouldn't be surprised if you are getting some carb cleaner in the intake causing the RPM to change before.. Having the cover off the AC helps.. Since the carb can move up and down a little, it pretty much says you have enough clearance between the spigots and the heads.. If there isn't enough, the manifold / TB will stick when moved up or down..

When doing the assy test I discussed.. The id of the spigot is about 1.9 to 1.92  The OD of a stock manifold is about 1.8.. so off of center when you push the manifold towards the horn should be about (1.92 -1. / 2 or about 0.060.. The head / manifold is angled about 18 degrees so if you can push the manifold all the way to the edge, you'll have about sine(18) * 0.060 or about 0.018 thou clearance.. It's still less than what I've seen some stock ones do.. You could easily set it up at 1/2 that with care..

Max