Intake Boots

[mack]

Was having a stalling at intersection issues with the LH. Runs good off idle and 2 plugs look good. Nice white porcellin with just a ting of light brown at the tips, the other two though, the porcelin was grey throughout the visible length. Gas cap vent is clear. Had me puzzled so I descided to check the sync. After warming her up I tried to pull the rubber caps off to hook up the morgan and the friggin brass nipples pulled right out of the boots on the two that the plugs were grey on. I pushed them back in and hooked up the morgan and the sync was dead on.
Let it run for about five minutes and watched the idle. Sat right at 1K, over that time then slowly the rpm started to drop as the motor got hotter. To it's credit it was still trying hard to idle at 500 rpm but stalled at 400. I checked the brass nipples again and I could pull them right out again with my fingers.
I'm thinking that as the rubber heats up it allows a vacumn leak around the brass and throws off the sync and makes those to cylinders start to run lean dropping the idle.
Am I correct? I bought these things last winter from Parts n more. An other case of quality control going off the rails.

[BA80]

Super glue

[natemoen]

Superglue or permatex makes a green locktight that is for slip fit cylindrical joints.

[WSL91]

I keep lots of JB weld on hand : )

[BA80]

If you used those cheap paper gaskets that come with the new boots that is probably where they are leaking. Just use a little silicone or Threebond to seal them. Throw the gaskets away.

[TopCatGr58]

Hey Mack,

I can't speak for the PNM intake boots quality, but sounds like you're on to something. Folks have reported vacuum leaks from hardened rubber synch port caps as well, they seem like they fit, but are actually loose around the brass nipple and allow air to leak around/past them.

Greg....with above description of vac. leaks with just the rubber synch port caps, I can fully believe a similar problem can occur from the brass synch port nipples getting loose within the rubber boots. Some silicone RTV or threebond should seal around them just fine. I do agree that the mating surface of the boots can also be a source for vac. leaks...especially with a dry paper gasket, and agree that sealant should be used when mounting the boots, with or without the gaskets. Mine had gotten all crumbly when I had taken them off for my rebuild, I removed the dried crumbling rubber from the face of the boot and applied sealant when I reinstalled them and they have been working well for 10+ yrs.

T.C.

[WMarshy]

You already know their leaking but if you wanted to, you could spray them with some carb cleaner or starting fluid when its running and see if the rpm changes and how much from cold to warm.... I check my intake boots and butterfly seals one a year with starting fluid. No since in trying to tune with those leaking...

[mack]

Boots

Just pissed me off. Another case of crappie workmanship slipping by. It's becoming the norm not the exception. Unless you knew to look for it, or stumbled across it by accident like I did, something like this could plague a new owner for months. I'll give them the quick fix for the remainder of this year but over the winter I'll be ordering an oem replacement set.I just can't tolerate having a known issue and not fixing it properly.Especially when I restored this bike for my brother to ride.

[BA80]

You already know their leaking but if you wanted to, you could spray them with some carb cleaner or starting fluid when its running and see if the rpm changes and how much from cold to warm.... I check my intake boots and butterfly seals one a year with starting fluid. No since in trying to tune with those leaking...

The only problem with using carb cleaner or starting fluid is it's highly flamable and you could have a fire on your hands pretty easily. Brakleen isn't quite so flammable and will do the same thing.

Just sayin'

[Rasputin]

Was having a stalling at intersection issues with the LH. Runs good off idle and 2 plugs look good. Nice white porcellin with just a ting of light brown at the tips, the other two though, the porcelin was grey throughout the visible length. Gas cap vent is clear. Had me puzzled so I descided to check the sync. After warming her up I tried to pull the rubber caps off to hook up the morgan and the friggin brass nipples pulled right out of the boots on the two that the plugs were grey on. I pushed them back in and hooked up the morgan and the sync was dead on.
Let it run for about five minutes and watched the idle. Sat right at 1K, over that time then slowly the rpm started to drop as the motor got hotter. To it's credit it was still trying hard to idle at 500 rpm but stalled at 400. I checked the brass nipples again and I could pull them right out again with my fingers.
I'm thinking that as the rubber heats up it allows a vacumn leak around the brass and throws off the sync and makes those to cylinders start to run lean dropping the idle.
Am I correct? I bought these things last winter from Parts n more. An other case of quality control going off the rails.

I had exactly the same issue with a set I got from Georgefix. Only one of the four boots did it. Most certainly I do not blame the resellers like Georgefix nor PNM. Somewhere during the manufacture of these boots they did not bond correctly.
Myself, I pulled the brass nipple out and coated it with "The Right Stuff" inserted it and problem was solved. I would imagine that any sealant that can withstand some heat and work for both metal and rubber/nitrile type compounds would work well.