Curt, as usual is giving you some great advice.

Its been a while since I was porting manifolds, but I can tell you that I never had a leak I didn't create myself by leaving the vacuum port cap off. Not one. Thats in hundreds of installs I did for other people and including the (literally) monthly take offs and reinstalls on mine. I was always messing around with mine to try out new ideas or new porting methods.

I always used the stock orings, or new ones if they were bad. Never had to use anything else, but Curt's Hylomar suggestion sounds like a really good one.

This is an old article here on the clinic, but it has some good advice for installing manifolds generally:
Ported Manifold FAQ

Might want to give it a quick read if you have time.

Gram

Oh yeah, one more thing. You probably already do this but look at your manifold flanges when you are finger tightening and constantly while you are tightening past that to be sure they remain parallel to the heads. If one side of a flange gets farther from the head than the other, tighten that one until its parallel again.

Gram

might want to try and loosen the head bolts then fit and bolt the intake. then retorque the head bolts.

might want to try and loosen the head bolts then fit and bolt the intake. then retorque the head bolts.
Dunno if I wanna go that far for a fitment.

GP

I installed a new OEM ported manifold last winter. I bought the over-sized rings then threw them away and bought stock oem rings and installed the stock sized o-rings. Greased the rings up with dielectric grease like the yamaha service manual states and bolted everything on. No leaks so far and I'm a happy camper

greyphart wrote:
might want to try and loosen the head bolts then fit and bolt the intake. then retorque the head bolts.
Dunno if I wanna go that far for a fitment.

GP

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AGREEE'D,Doing that could lead to a bad headgasket.

Scott

Had the same problem with mine and it just about drove me crazy, I even tried a brand new stock manifold and NFG on the rear head facing the carb. Tried everything, Hylomar, Scmylomar, Goose grease and bear fat NOTHING worked. Got real pissed and was able to get a Nemesis aluminum manifold and put a HSR 42 on at the same time and Bingo no more problems. Started her right up and purred like a kitten right away. Fooled with the jetting a little and thats the way it is now. I haven't touched the idle adj or pms all summer Got 47 mpg on the maine trip

Did you do the "lap dance" before mounting? I ported my stock unit. Did the "lap" thing installed new rubber rings and no problems for the last 3 seasons

I'll just say I'm one lucky fellow. I recently installed the Speedstar high-flow manifold on both of my R*s with the standard o-ring and a little silicone sealer... and viola, no leaks. But then, neither stock manifold leaked before I did the conversions either!

Just the kind of info I was hoping to hear.
Looks like I need to find some Halomar? And some stock o rings. Thats what I'll start with. Good tips guys.

Curt, That manifold looked so good I could hardly put it on a bike, Im only doing so because I am desperate! LOL

I got stuck on the Ben Herr thing and took it as a challenge to get it to work, what 3 years ago? Still leaks. And Your right! Ill have to re jet, I have to re jet according to leaks now, so its like a weekly thing. Did I tell you my dealer sells Half thickness metal washers for the needle? Sooooo sweet!

I just remember way back one day when all the leaks were absent, I had neck snapping throttle! I want that back. And I want my 40 MPG back. I currently get anywhere from 22 to 35. When its leaking, you can see the fuel drop and it needs about 50% more throttle to get the same speed.

I can't wait to get this done!

Im not putting Schatzie through 7 tank removal and repairs in inclimate weather on a trip again. She was a champ, but that was too much BS for even me.

The killer is, when the intake leaks, she can smell gas. Wonder why that is? Probably not getting enough air to suck the gas in the intake??